# app/main.py

from flask import Blueprint, render_template, flash, redirect, url_for, abort, send_from_directory, request, jsonify, current_app

from sqlalchemy import desc, func, text, extract, and_
from sqlalchemy.orm import joinedload, aliased
from collections import OrderedDict
from datetime import datetime

from app.models import ImageRecord, Tag, ArchiveRecord, image_tags, ImportTask, ImportBatch, AppSettings
from app import db
from app.utils.tag_names import normalize_display_name
import os
import re
import shutil

main = Blueprint('main', __name__)


def _parse_character_fandom(name_after_prefix):
    """Parse 'Name (Fandom)' -> ('Name', 'Fandom') or ('Name', None)."""
    m = re.match(r'^(.+?)\s*\((.+)\)$', name_after_prefix)
    if m:
        return m.group(1).strip(), m.group(2).strip()
    return name_after_prefix, None


def _ensure_fandom_tag(fandom_name):
    """Find or create a fandom tag by name. Returns the Tag object.

    Normalizes the display name so callers don't have to remember.
    """
    normalized = normalize_display_name(fandom_name.strip())
    full_name = f"fandom:{normalized}"
    fandom_tag = Tag.query.filter_by(name=full_name).first()
    if not fandom_tag:
        fandom_tag = Tag(name=full_name, kind="fandom")
        db.session.add(fandom_tag)
        db.session.flush()
    return fandom_tag


@main.route('/')
def index():
    """
    Showcase view: full-bleed masonry collage of random images/videos.
    """
    images = (
        ImageRecord.query
        .options(joinedload(ImageRecord.tags))
        .order_by(func.random())
        .limit(20)
        .all()
    )
    return render_template('showcase.html', images=images)


@main.route('/api/random-images')
def random_images_api():
    """
    JSON endpoint returning random images for shuffle/infinite scroll.

    Query params:
      - count: number of images to return (default 12)
      - exclude: comma-separated list of image IDs to exclude (for infinite scroll)
    """
    count = request.args.get('count', 12, type=int)
    exclude_str = request.args.get('exclude', '')

    # Parse exclusion list
    exclude_ids = []
    if exclude_str:
        try:
            exclude_ids = [int(x) for x in exclude_str.split(',') if x.strip()]
        except ValueError:
            pass

    # Build query
    q = ImageRecord.query.options(joinedload(ImageRecord.tags))

    if exclude_ids:
        q = q.filter(~ImageRecord.id.in_(exclude_ids))

    images = q.order_by(func.random()).limit(count).all()

    result = []
    for img in images:
        is_video = img.filename.lower().endswith(('.mp4', '.mov'))
        thumb_path = (img.thumb_path or img.filepath).replace('/images/', '')
        full_path = img.filepath.replace('/images/', '')

        result.append({
            'id': img.id,
            'filename': img.filename,
            'thumb_url': url_for('main.serve_image', filename=thumb_path),
            'full_url': url_for('main.serve_image', filename=full_path),
            'is_video': is_video,
            'date': (img.taken_at or img.imported_at).strftime('%Y-%m-%d') if (img.taken_at or img.imported_at) else '',
            'tags': [{'name': t.name, 'kind': t.kind} for t in img.tags]
        })

    return jsonify(images=result)


@main.route('/gallery')
def gallery():
    """
    Gallery with infinite scroll and year-month date dividers.
    Server renders initial batch, then JS takes over for infinite scroll.
    Optional tag filter via ?tag=artist:NAME or any tag name.
    """
    from app.models import PostMetadata

    initial_limit = 30
    tag_name = request.args.get('tag')

    # Base query + eager-load tags
    q = ImageRecord.query.options(joinedload(ImageRecord.tags))

    # Optional tag filter
    active_tag_obj = None
    if tag_name:
        active_tag_obj = Tag.query.filter_by(name=tag_name).first()
        if active_tag_obj:
            q = q.join(ImageRecord.tags).filter(Tag.name == tag_name)

    # Fetch initial batch ordered by date descending
    images = q.order_by(
        desc(func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at))
    ).limit(initial_limit + 1).all()

    # Check if there are more images
    has_more = len(images) > initial_limit
    if has_more:
        images = images[:initial_limit]

    # Group by year-month for initial render
    grouped_images = _group_images_by_month(images)

    # Compute initial cursor for JS to continue from
    initial_cursor = None
    if images and has_more:
        last_img = images[-1]
        last_dt = _get_image_date(last_img)
        if last_dt:
            initial_cursor = last_dt.isoformat()

    # Fetch post metadata if filtering by a post tag
    post_metadata = None
    if active_tag_obj and active_tag_obj.kind == 'post':
        pm = PostMetadata.query.filter_by(tag_id=active_tag_obj.id).first()
        if pm:
            post_metadata = {
                'title': pm.title,
                'description': pm.description,
                'source_url': pm.source_url,
                'platform': pm.platform,
                'artist': pm.artist,
                'post_id': pm.post_id,
                'attachment_count': pm.attachment_count,
                'published_at': pm.published_at,
            }

    # Fetch series info if filtering by a series tag
    from app.models import SeriesPage
    series_info = None
    if active_tag_obj and active_tag_obj.kind == 'series':
        page_count = SeriesPage.query.filter_by(series_tag_id=active_tag_obj.id).count()
        series_info = {
            'tag_id': active_tag_obj.id,
            'name': active_tag_obj.name.split(':', 1)[1] if ':' in active_tag_obj.name else active_tag_obj.name,
            'page_count': page_count,
        }

    return render_template(
        'gallery.html',
        grouped_images=grouped_images,
        active_tag=tag_name,
        active_tag_obj=active_tag_obj,
        initial_cursor=initial_cursor,
        has_more=has_more,
        post_metadata=post_metadata,
        series_info=series_info
    )


@main.route('/images/<path:filename>')
def serve_image(filename):
    return send_from_directory('/images', filename)


# ----------------------------
# Gallery Infinite Scroll API
# ----------------------------

def _get_image_date(img):
    """Get the effective date for an image (taken_at or imported_at)."""
    return img.taken_at or img.imported_at


def _format_year_month(dt):
    """Format a datetime as year-month key and label."""
    if not dt:
        return 'unknown', 'Unknown Date'
    return dt.strftime('%Y-%m'), dt.strftime('%B %Y')


def _group_images_by_month(images):
    """
    Group images by year-month, preserving order.
    Returns list of (group_info, images) tuples.
    """
    groups = OrderedDict()

    for img in images:
        dt = _get_image_date(img)
        key, label = _format_year_month(dt)

        if key not in groups:
            groups[key] = {'key': key, 'label': label, 'images': []}

        groups[key]['images'].append(img)

    return [(info['key'], info['label'], info['images']) for info in groups.values()]


def _serialize_image(img):
    """Serialize an ImageRecord for JSON response."""
    is_video = img.filename.lower().endswith(('.mp4', '.mov'))
    thumb_path = (img.thumb_path or img.filepath).replace('/images/', '')
    full_path = img.filepath.replace('/images/', '')
    dt = _get_image_date(img)
    key, label = _format_year_month(dt)

    return {
        'id': img.id,
        'filename': img.filename,
        'thumb_url': url_for('main.serve_image', filename=thumb_path),
        'full_url': url_for('main.serve_image', filename=full_path),
        'is_video': is_video,
        'date': dt.strftime('%Y-%m-%d') if dt else '',
        'year_month': key,
        'year_month_label': label,
        'tags': [{'name': t.name, 'kind': t.kind} for t in img.tags if t.kind != 'archive']
    }


@main.route('/api/gallery/scroll')
def gallery_scroll():
    """
    Cursor-based infinite scroll endpoint with date grouping.

    Query params:
      - cursor: ISO datetime string for pagination (fetch images older than this)
      - limit: number of images per batch (default 30)
      - tag: optional tag filter

    Returns:
      - images: list of image objects with year_month grouping info
      - next_cursor: datetime string for next batch (null if no more)
      - date_groups: summary of year-month groups in this batch
      - has_more: boolean indicating if more images exist
    """
    cursor_str = request.args.get('cursor')
    limit = request.args.get('limit', 30, type=int)
    tag_name = request.args.get('tag')

    # Build base query
    q = ImageRecord.query.options(joinedload(ImageRecord.tags))

    # Optional tag filter
    if tag_name:
        q = q.join(ImageRecord.tags).filter(Tag.name == tag_name)

    # Apply cursor filter (fetch images older than cursor)
    if cursor_str:
        try:
            cursor_dt = datetime.fromisoformat(cursor_str.replace('Z', '+00:00'))
            q = q.filter(
                func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at) < cursor_dt
            )
        except ValueError:
            pass  # Invalid cursor, ignore

    # Order by date descending and fetch with limit + 1 to check has_more
    images = q.order_by(
        desc(func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at))
    ).limit(limit + 1).all()

    # Check if there are more images
    has_more = len(images) > limit
    if has_more:
        images = images[:limit]

    # Serialize images
    serialized = [_serialize_image(img) for img in images]

    # Build date_groups summary
    groups_seen = OrderedDict()
    for s in serialized:
        key = s['year_month']
        if key not in groups_seen:
            groups_seen[key] = {'key': key, 'label': s['year_month_label'], 'count': 0}
        groups_seen[key]['count'] += 1

    # Compute next cursor
    next_cursor = None
    if images and has_more:
        last_img = images[-1]
        last_dt = _get_image_date(last_img)
        if last_dt:
            next_cursor = last_dt.isoformat()

    return jsonify(
        images=serialized,
        next_cursor=next_cursor,
        has_more=has_more,
        date_groups=list(groups_seen.values())
    )


@main.route('/api/gallery/timeline')
def gallery_timeline():
    """
    Returns all year-month groups with counts for timeline navigation.

    Query params:
      - tag: optional tag filter (same as gallery)

    Returns list of {key, label, count, year} ordered newest to oldest.
    """
    tag_name = request.args.get('tag')

    # Use SQL to aggregate by year-month
    date_expr = func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at)

    q = db.session.query(
        extract('year', date_expr).label('year'),
        extract('month', date_expr).label('month'),
        func.count(ImageRecord.id).label('count')
    )

    if tag_name:
        q = q.join(ImageRecord.tags).filter(Tag.name == tag_name)

    q = q.group_by(
        extract('year', date_expr),
        extract('month', date_expr)
    ).order_by(
        extract('year', date_expr).desc(),
        extract('month', date_expr).desc()
    )

    results = q.all()

    # Format results
    groups = []
    for row in results:
        if row.year and row.month:
            year = int(row.year)
            month = int(row.month)
            key = f"{year:04d}-{month:02d}"
            # Create a date object to format the month name
            dt = datetime(year, month, 1)
            label = dt.strftime('%B %Y')
            short_label = dt.strftime('%b')  # Short month name for sidebar
            groups.append({
                'key': key,
                'label': label,
                'short_label': short_label,
                'year': year,
                'month': month,
                'count': row.count
            })

    return jsonify(groups=groups)


@main.route('/api/gallery/jump')
def gallery_jump():
    """
    Fetch images starting from a specific year-month for timeline jump navigation.

    Query params:
      - year_month: target year-month (e.g., '2024-03')
      - limit: number of images (default 30)
      - tag: optional tag filter

    Returns same format as /api/gallery/scroll but starting from the target month.
    """
    year_month = request.args.get('year_month', '')
    limit = request.args.get('limit', 30, type=int)
    tag_name = request.args.get('tag')

    if not year_month:
        return jsonify(error='year_month is required'), 400

    try:
        # Parse year-month to get start of that month
        target_dt = datetime.strptime(year_month + '-01', '%Y-%m-%d')
        # Get end of month (start of next month)
        if target_dt.month == 12:
            next_month = datetime(target_dt.year + 1, 1, 1)
        else:
            next_month = datetime(target_dt.year, target_dt.month + 1, 1)
    except ValueError:
        return jsonify(error='Invalid year_month format'), 400

    # Build query for images in that month and earlier
    q = ImageRecord.query.options(joinedload(ImageRecord.tags))

    if tag_name:
        q = q.join(ImageRecord.tags).filter(Tag.name == tag_name)

    # Get images from start of target month onwards (but ordered descending)
    date_expr = func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at)
    q = q.filter(date_expr < next_month)

    images = q.order_by(desc(date_expr)).limit(limit + 1).all()

    has_more = len(images) > limit
    if has_more:
        images = images[:limit]

    serialized = [_serialize_image(img) for img in images]

    # Build date_groups summary
    groups_seen = OrderedDict()
    for s in serialized:
        key = s['year_month']
        if key not in groups_seen:
            groups_seen[key] = {'key': key, 'label': s['year_month_label'], 'count': 0}
        groups_seen[key]['count'] += 1

    next_cursor = None
    if images and has_more:
        last_img = images[-1]
        last_dt = _get_image_date(last_img)
        if last_dt:
            next_cursor = last_dt.isoformat()

    return jsonify(
        images=serialized,
        next_cursor=next_cursor,
        has_more=has_more,
        date_groups=list(groups_seen.values()),
        target_year_month=year_month
    )


def _get_tags_with_previews(kind=None, limit=35, offset=0, images_per_tag=3, search=None):
    """
    Helper function to get tags with counts and preview images.
    Returns (tag_data list, total_count, has_more).

    Optimized to use 2 queries instead of N+1:
    1. Get tags with counts (paginated)
    2. Get preview images for those tags using window function
    """
    # Query for total count
    count_q = db.session.query(func.count(Tag.id))
    if kind:
        count_q = count_q.filter(Tag.kind == kind)
    if search:
        count_q = count_q.filter(Tag.name.ilike(f'%{search}%'))
    total_count = count_q.scalar()

    # Query 1: Get tags with image counts (paginated)
    q = db.session.query(
        Tag,
        func.count(image_tags.c.image_id).label('img_count')
    ).outerjoin(image_tags).group_by(Tag.id)

    if kind:
        q = q.filter(Tag.kind == kind)
    if search:
        q = q.filter(Tag.name.ilike(f'%{search}%'))

    tags_with_counts = q.order_by(Tag.name.asc()).offset(offset).limit(limit).all()

    # Build tag_id list and initialize tag_data dict
    tag_ids = [t.id for t, _ in tags_with_counts]
    tag_map = {}
    for t, count in tags_with_counts:
        label = t.name.split(":", 1)[1] if (":" in t.name) else t.name
        tag_map[t.id] = {
            "id": t.id,
            "name": label,
            "tag": t.name,
            "images": [],
            "kind": t.kind,
            "count": count
        }

    # Query 2: Get preview images for all tags at once using a subquery with row_number
    if tag_ids:
        row_num = func.row_number().over(
            partition_by=image_tags.c.tag_id,
            order_by=desc(func.coalesce(ImageRecord.taken_at, ImageRecord.imported_at))
        ).label('rn')

        subq = (
            db.session.query(
                image_tags.c.tag_id,
                ImageRecord.id.label('image_id'),
                row_num
            )
            .join(ImageRecord, ImageRecord.id == image_tags.c.image_id)
            .filter(image_tags.c.tag_id.in_(tag_ids))
            .subquery()
        )

        preview_rows = (
            db.session.query(subq.c.tag_id, ImageRecord)
            .join(ImageRecord, ImageRecord.id == subq.c.image_id)
            .filter(subq.c.rn <= images_per_tag)
            .all()
        )

        for tag_id, img in preview_rows:
            if tag_id in tag_map:
                tag_map[tag_id]["images"].append(img)

    # Convert to list maintaining original order
    tag_data = [tag_map[t.id] for t, _ in tags_with_counts]
    has_more = (offset + len(tag_data)) < total_count

    return tag_data, total_count, has_more


@main.route('/tags')
def tag_list():
    """
    Generic tag explorer with infinite scroll:
      /tags            -> all tags
      /tags?kind=user  -> only user tags
      /tags?search=xyz -> tags matching search term
      etc.
    Shows a few preview images per tag.
    Initially loads 35 tags, more loaded via API as user scrolls.
    """
    kind = request.args.get('kind')
    search = request.args.get('search', '').strip() or None
    limit = 35
    images_per_tag = 3

    tag_data, total_count, has_more = _get_tags_with_previews(
        kind=kind, limit=limit, offset=0, images_per_tag=images_per_tag, search=search
    )

    return render_template('tags_list.html',
                           tag_data=tag_data,
                           images_per_tag=images_per_tag,
                           active_kind=kind,
                           search_query=search or '',
                           total_count=total_count,
                           has_more=has_more,
                           page_size=limit)


@main.route('/api/tags/list')
def api_tags_list():
    """
    API endpoint for loading more tags (infinite scroll).
    Returns JSON with tag cards HTML and pagination info.
    """
    kind = request.args.get('kind')
    search = request.args.get('search', '').strip() or None
    offset = request.args.get('offset', 0, type=int)
    limit = request.args.get('limit', 35, type=int)
    images_per_tag = 3

    tag_data, total_count, has_more = _get_tags_with_previews(
        kind=kind, limit=limit, offset=offset, images_per_tag=images_per_tag, search=search
    )

    # Render tag cards to HTML
    cards_html = render_template('_tag_cards.html', tag_data=tag_data)

    return jsonify(
        ok=True,
        html=cards_html,
        count=len(tag_data),
        total=total_count,
        has_more=has_more,
        offset=offset + len(tag_data)
    )

@main.route('/artists')
def artist_list():
    # Backward-compatible route that now shows the Tag Explorer filtered to artist tags
    return redirect(url_for('main.tag_list', kind='artist'))

@main.route('/artist/<artist_name>')
def artist_gallery(artist_name):
    # Backward-compatible: go to gallery filtered by artist tag
    return redirect(url_for('main.gallery', tag=f"artist:{artist_name}"))


@main.route('/settings')
def settings():
    valid_tabs = {'overview', 'import', 'maintenance'}
    tab = request.args.get('tab', 'overview')
    if tab not in valid_tabs:
        tab = 'overview'
    return render_template('settings.html', active_tab=tab)


@main.post('/settings/maintenance/ml-backfill')
def trigger_ml_backfill():
    from app.tasks.ml import backfill
    backfill.apply_async(queue='ml')
    return redirect(url_for('main.settings', tab='maintenance'))


@main.post('/settings/maintenance/recompute-centroids')
def trigger_recompute_all_centroids():
    from app.tasks.ml import recompute_all_centroids
    recompute_all_centroids.apply_async(queue='ml')
    return redirect(url_for('main.settings', tab='maintenance'))


@main.post('/settings/maintenance/sync-character-fandoms')
def trigger_sync_character_fandoms():
    from app.tasks.maintenance import sync_character_fandoms
    sync_character_fandoms.apply_async(queue='maintenance')
    return redirect(url_for('main.settings', tab='maintenance'))


# ----------------------------
# Tag add/remove endpoints
# ----------------------------

@main.get("/api/tags/search")
def search_tags():
    """
    Search existing tags for autocomplete.
    Query params:
      - q: search query (matches tag name, case-insensitive)
      - limit: max results (default 10)
      - exclude_kind: comma-separated list of tag kinds to exclude (e.g., 'archive')
      - kind: filter to only include tags of this kind (e.g., 'series')
    """
    query = request.args.get('q', '').strip().lower()
    limit = request.args.get('limit', 10, type=int)
    exclude_kind = request.args.get('exclude_kind', '').strip()
    exclude_kinds = [k.strip() for k in exclude_kind.split(',') if k.strip()]
    include_kind = request.args.get('kind', '').strip()

    if not query:
        # Return most-used tags when no query
        base_query = (
            Tag.query
            .join(image_tags)
            .group_by(Tag.id)
        )
        if exclude_kinds:
            base_query = base_query.filter(~Tag.kind.in_(exclude_kinds))
        if include_kind:
            base_query = base_query.filter(Tag.kind == include_kind)
        tags = (
            base_query
            .order_by(func.count(image_tags.c.image_id).desc())
            .limit(limit)
            .all()
        )
    else:
        base_query = Tag.query.filter(Tag.name.ilike(f'%{query}%'))
        if exclude_kinds:
            base_query = base_query.filter(~Tag.kind.in_(exclude_kinds))
        if include_kind:
            base_query = base_query.filter(Tag.kind == include_kind)
        tags = (
            base_query
            .order_by(Tag.name)
            .limit(limit)
            .all()
        )

    return jsonify(tags=[
        {
            "id": t.id,
            "name": t.name,
            "kind": t.kind,
            "fandom_id": t.fandom_id if t.kind == "character" else None,
            "fandom_name": (t.fandom.name.split(":", 1)[1] if t.fandom else None) if t.kind == "character" else None
        }
        for t in tags
    ])


@main.get("/image/<int:image_id>/tags")
def list_tags(image_id):
    img = ImageRecord.query.get_or_404(image_id)
    return jsonify(ok=True, tags=[
        {
            "name": t.name,
            "kind": t.kind,
            "fandom_id": t.fandom_id if t.kind == "character" else None,
            "fandom_name": (t.fandom.name.split(":", 1)[1] if t.fandom else None) if t.kind == "character" else None
        }
        for t in img.tags
    ])


# ---------------------------------------------------------------------------
# Tag suggestions (ML-backed)
# ---------------------------------------------------------------------------

@main.get("/image/<int:image_id>/suggestions")
def get_image_suggestions(image_id):
    from app.services.tag_suggestions import get_suggestions
    suggestions = get_suggestions(image_id)
    return jsonify({'ok': True, 'suggestions': suggestions})


@main.post("/image/<int:image_id>/suggestions/accept")
def accept_image_suggestion(image_id):
    from app.models import SuggestionFeedback
    from app.services.tag_suggestions import _WD14_CATEGORY_TO_KIND, _canonicalize_wd14_name
    payload = request.get_json(force=True, silent=True) or {}
    tag_name = (payload.get('tag_name') or '').strip()
    source = payload.get('source') or ''
    category = payload.get('category') or ''
    confidence = float(payload.get('confidence') or 0.0)
    if not tag_name or not source or not category:
        return jsonify({'ok': False, 'error': 'missing_fields'}), 400

    image = ImageRecord.query.get(image_id)
    if image is None:
        return jsonify({'ok': False, 'error': 'image_not_found'}), 404

    # Canonicalize before lookup so an already-attached "big hair" matches a
    # freshly-POSTed "big_hair" (defensive — the client should already send canonical).
    tag_name = _canonicalize_wd14_name(tag_name, category)

    tag = Tag.query.filter_by(name=tag_name).first()
    if tag is None:
        kind = _WD14_CATEGORY_TO_KIND.get(category)  # None for 'general'
        tag = Tag(name=tag_name, kind=kind)
        db.session.add(tag)
        db.session.flush()

    if tag not in image.tags:
        image.tags.append(tag)

    db.session.add(SuggestionFeedback(
        image_id=image_id,
        tag_name=tag_name,
        suggestion_source=source,
        confidence=confidence,
        decision='accepted',
    ))
    db.session.commit()

    # Schedule centroid recompute if this tag's kind is eligible and delta is exceeded.
    from app.services.tag_suggestions import ELIGIBLE_CENTROID_KINDS
    if tag.kind in ELIGIBLE_CENTROID_KINDS:
        from app.models import TagReferenceEmbedding, TagSuggestionConfig
        from app.tasks.ml import recompute_centroid
        from app.ml.siglip import MODEL_VERSION as SIGLIP_VER

        delta_cfg = TagSuggestionConfig.query.filter_by(key='centroid_recompute_delta').first()
        delta_threshold = int(delta_cfg.value) if delta_cfg else 3

        current_count = (
            db.session.query(db.func.count(image_tags.c.image_id))
            .filter(image_tags.c.tag_id == tag.id)
            .scalar()
        ) or 0
        ref = (
            TagReferenceEmbedding.query
            .filter_by(tag_name=tag_name, model_version=SIGLIP_VER)
            .first()
        )
        last_count = ref.reference_count if ref else 0
        if current_count - last_count >= delta_threshold:
            try:
                recompute_centroid.apply_async(args=[tag_name], queue='ml')
            except Exception:
                # Don't fail the accept if enqueue fails
                pass

    return jsonify({
        'ok': True,
        'tag': {'id': tag.id, 'name': tag.name, 'kind': tag.kind},
    })


@main.post("/image/<int:image_id>/suggestions/reject")
def reject_image_suggestion(image_id):
    from app.models import SuggestionFeedback
    payload = request.get_json(force=True, silent=True) or {}
    tag_name = (payload.get('tag_name') or '').strip()
    source = payload.get('source') or ''
    confidence = float(payload.get('confidence') or 0.0)
    if not tag_name or not source:
        return jsonify({'ok': False, 'error': 'missing_fields'}), 400

    if ImageRecord.query.get(image_id) is None:
        return jsonify({'ok': False, 'error': 'image_not_found'}), 404

    db.session.add(SuggestionFeedback(
        image_id=image_id,
        tag_name=tag_name,
        suggestion_source=source,
        confidence=confidence,
        decision='rejected',
    ))
    db.session.commit()
    return jsonify({'ok': True})


@main.post("/image/<int:image_id>/tags/add")
def add_tag(image_id):
    """
    Minimal JSON endpoint to add a tag to an image.
    Accepts either 'artist:NAME' / 'archive:...' or a bare freeform tag ('mytag').

    For character tags with a fandom suffix (e.g. 'character:Saber (Fate)'),
    automatically creates/finds the fandom tag and adds it to the image.
    """
    name = (request.form.get("name") or "").strip()
    if not name:
        abort(400)

    # Normalize: keep explicit kind prefixes, otherwise treat as user tag
    if ":" in name:
        kind = name.split(":", 1)[0]
        tag_name = name
    else:
        # No prefix — treat as a user-typed general tag. Strip underscores so
        # WD14-style names pasted into the add box converge with our convention.
        from app.utils.tag_names import underscores_to_spaces
        kind = "user"
        tag_name = underscores_to_spaces(name)

    img = ImageRecord.query.get_or_404(image_id)
    tag = Tag.query.filter_by(name=tag_name).first()

    fandom_tag = None

    if not tag:
        # For new character tags, parse + normalize + link fandom
        if kind == "character":
            char_part = tag_name.split(":", 1)[1]
            char_name, fandom_name = _parse_character_fandom(char_part)
            norm_char = normalize_display_name(char_name)
            if fandom_name:
                fandom_tag = _ensure_fandom_tag(fandom_name)
                tag_name = f"character:{norm_char} ({fandom_tag.name.split(':', 1)[1]})"
            else:
                tag_name = f"character:{norm_char}"
        elif kind == "fandom":
            fandom_part = tag_name.split(":", 1)[1]
            tag_name = f"fandom:{normalize_display_name(fandom_part)}"
        # Look up again under the normalized name — an existing row may match.
        tag = Tag.query.filter_by(name=tag_name).first()
        if not tag:
            tag = Tag(name=tag_name, kind=kind)
            if kind == "character" and fandom_name:
                tag.fandom_id = fandom_tag.id
            db.session.add(tag)
            db.session.flush()
        elif kind == "character" and tag.fandom_id:
            fandom_tag = Tag.query.get(tag.fandom_id)
    elif tag.kind == "character" and tag.fandom_id:
        # Existing character tag with a fandom — grab the fandom tag for auto-apply
        fandom_tag = Tag.query.get(tag.fandom_id)

    if tag not in img.tags:
        img.tags.append(tag)

    # Auto-apply fandom tag to the image
    if fandom_tag and fandom_tag not in img.tags:
        img.tags.append(fandom_tag)

    db.session.commit()

    result = {"name": tag.name, "kind": tag.kind}
    if fandom_tag:
        result["fandom_tag"] = {"name": fandom_tag.name, "kind": fandom_tag.kind}
    return jsonify(ok=True, tag=result)


@main.post("/image/<int:image_id>/tags/remove")
def remove_tag(image_id):
    """
    Minimal JSON endpoint to remove a tag from an image.
    """
    name = (request.form.get("name") or "").strip()
    img = ImageRecord.query.get_or_404(image_id)
    tag = Tag.query.filter_by(name=name).first()
    if tag and tag in img.tags:
        img.tags.remove(tag)
        db.session.commit()
    return jsonify(ok=True)


# ----------------------------
# Tag management endpoints
# ----------------------------

@main.get("/api/tag/<int:tag_id>")
def get_tag(tag_id):
    """Get a single tag's details."""
    tag = Tag.query.get_or_404(tag_id)
    # Get display name (without prefix)
    display_name = tag.name.split(":", 1)[1] if ":" in tag.name else tag.name
    result = {
        "id": tag.id,
        "name": tag.name,
        "display_name": display_name,
        "kind": tag.kind,
        "fandom_id": tag.fandom_id,
        "fandom_name": tag.fandom.name.split(":", 1)[1] if tag.fandom else None
    }
    return jsonify(ok=True, tag=result)


@main.post("/api/tag/<int:tag_id>/set-fandom")
def set_tag_fandom(tag_id):
    """
    Set or clear a character tag's fandom association.
    Updates the tag name to include/remove the (Fandom) suffix.

    Form params:
        fandom_id: ID of an existing fandom tag (optional, clears if absent)
        fandom_name: Name to find/create a fandom tag (used if fandom_id not given)
    """
    tag = Tag.query.get_or_404(tag_id)

    if tag.kind != "character":
        return jsonify(ok=False, error="Only character tags can have fandoms"), 400

    fandom_id = request.form.get("fandom_id", type=int)
    fandom_name = (request.form.get("fandom_name") or "").strip()

    # Get the character's base name (strip existing fandom suffix) and normalize it.
    char_part = tag.name.split(":", 1)[1] if ":" in tag.name else tag.name
    char_base, _ = _parse_character_fandom(char_part)
    char_base = normalize_display_name(char_base)

    if fandom_id:
        fandom_tag = Tag.query.get(fandom_id)
        if not fandom_tag or fandom_tag.kind != "fandom":
            return jsonify(ok=False, error="Invalid fandom tag"), 400
        fandom_display = fandom_tag.name.split(":", 1)[1] if ":" in fandom_tag.name else fandom_tag.name
    elif fandom_name:
        # _ensure_fandom_tag normalizes internally.
        fandom_tag = _ensure_fandom_tag(fandom_name)
        fandom_display = fandom_tag.name.split(":", 1)[1]
    else:
        # Clear fandom
        tag.fandom_id = None
        tag.name = f"character:{char_base}"
        db.session.commit()
        return jsonify(ok=True, tag={
            "id": tag.id,
            "name": tag.name,
            "kind": tag.kind,
            "fandom_id": None,
            "fandom_name": None
        })

    # Check for name conflict before renaming
    new_name = f"character:{char_base} ({fandom_display})"
    conflict = Tag.query.filter(Tag.name == new_name, Tag.id != tag_id).first()
    if conflict:
        return jsonify(ok=False, error=f"A tag named '{new_name}' already exists"), 409

    tag.fandom_id = fandom_tag.id
    tag.name = new_name
    db.session.commit()

    # Retroactive backfill: every image already tagged with this character should
    # also have the fandom tag attached. Runs in a second transaction so a failed
    # backfill doesn't roll back the rename.
    try:
        db.session.execute(
            text("""
                INSERT INTO image_tags (image_id, tag_id)
                SELECT it.image_id, :fandom_id
                FROM image_tags it
                WHERE it.tag_id = :char_id
                  AND NOT EXISTS (
                      SELECT 1 FROM image_tags it2
                      WHERE it2.image_id = it.image_id
                        AND it2.tag_id = :fandom_id
                  )
            """),
            {'char_id': tag.id, 'fandom_id': fandom_tag.id},
        )
        db.session.commit()
    except Exception as e:
        db.session.rollback()
        # Rename already committed; log and continue. Sweep button recovers.
        current_app.logger.warning(
            "set_tag_fandom backfill failed for tag %s -> fandom %s: %s",
            tag.id, fandom_tag.id, e,
        )

    return jsonify(ok=True, tag={
        "id": tag.id,
        "name": tag.name,
        "kind": tag.kind,
        "fandom_id": tag.fandom_id,
        "fandom_name": fandom_display
    })


@main.get("/api/post-metadata/<int:tag_id>")
def get_post_metadata(tag_id):
    """
    Get post metadata for a post tag.
    Returns title, description, source URL, etc. for display in the gallery.
    """
    from app.models import PostMetadata

    tag = Tag.query.get_or_404(tag_id)

    # Only post tags have metadata
    if tag.kind != 'post':
        return jsonify(ok=False, error="Not a post tag"), 400

    pm = PostMetadata.query.filter_by(tag_id=tag_id).first()
    if not pm:
        return jsonify(ok=True, metadata=None)

    return jsonify(ok=True, metadata={
        "id": pm.id,
        "tag_id": pm.tag_id,
        "tag_name": tag.name,
        "platform": pm.platform,
        "post_id": pm.post_id,
        "artist": pm.artist,
        "title": pm.title,
        "description": pm.description,
        "source_url": pm.source_url,
        "attachment_count": pm.attachment_count,
        "published_at": pm.published_at.isoformat() if pm.published_at else None,
    })


@main.get("/api/post-metadata/by-tag-name/<path:tag_name>")
def get_post_metadata_by_name(tag_name):
    """
    Get post metadata by tag name (e.g., post:patreon:artist:12345).
    Useful when filtering gallery by tag name.
    """
    from app.models import PostMetadata

    tag = Tag.query.filter_by(name=tag_name).first()
    if not tag:
        return jsonify(ok=True, metadata=None)

    if tag.kind != 'post':
        return jsonify(ok=False, error="Not a post tag"), 400

    pm = PostMetadata.query.filter_by(tag_id=tag.id).first()
    if not pm:
        return jsonify(ok=True, metadata=None)

    return jsonify(ok=True, metadata={
        "id": pm.id,
        "tag_id": pm.tag_id,
        "tag_name": tag.name,
        "platform": pm.platform,
        "post_id": pm.post_id,
        "artist": pm.artist,
        "title": pm.title,
        "description": pm.description,
        "source_url": pm.source_url,
        "attachment_count": pm.attachment_count,
        "published_at": pm.published_at.isoformat() if pm.published_at else None,
    })


@main.post("/api/tag/<int:tag_id>/update")
def update_tag(tag_id):
    """
    Update a tag's name and/or kind.
    For prefixed kinds (artist, archive, character, series, rating),
    the name will be stored as 'kind:name'.

    If the new name matches an existing tag, merge them:
    - Move all images from source tag to target tag
    - Delete the source tag
    - Return the target tag info with merged=True
    """
    tag = Tag.query.get_or_404(tag_id)

    new_name = (request.form.get("name") or "").strip()
    new_kind = (request.form.get("kind") or "user").strip()
    force_merge = request.form.get("merge") == "true"

    if not new_name:
        return jsonify(ok=False, error="Name is required"), 400

    # Build the full tag name based on kind
    prefixed_kinds = ("artist", "archive", "character", "series", "fandom", "rating")
    if new_kind in prefixed_kinds:
        # Remove any existing prefix from name if present
        if ":" in new_name:
            new_name = new_name.split(":", 1)[1]
        full_name = f"{new_kind}:{new_name}"
    else:
        # User tags don't have prefixes
        full_name = new_name

    # Check for duplicates (excluding current tag)
    existing = Tag.query.filter(Tag.name == full_name, Tag.id != tag_id).first()
    if existing:
        if not force_merge:
            # Ask user to confirm merge
            return jsonify(
                ok=False,
                error="A tag with this name already exists",
                can_merge=True,
                target_tag={
                    "id": existing.id,
                    "name": existing.name,
                    "kind": existing.kind
                }
            ), 409  # Conflict status

        # Merge: move all images from source tag to target tag
        source_images = tag.images[:]  # Copy list to avoid mutation during iteration
        merged_count = 0
        for img in source_images:
            if existing not in img.tags:
                img.tags.append(existing)
                merged_count += 1
            img.tags.remove(tag)

        # Delete the source tag
        db.session.delete(tag)
        db.session.commit()

        return jsonify(ok=True, merged=True, merged_count=merged_count, tag={
            "id": existing.id,
            "name": existing.name,
            "kind": existing.kind
        })

    # Handle fandom-related updates
    old_kind = tag.kind
    old_name = tag.name

    # No conflict - just update the tag
    tag.name = full_name
    tag.kind = new_kind

    # If editing a character tag, handle fandom from the name suffix
    if new_kind == "character":
        char_part = full_name.split(":", 1)[1]
        char_name, fandom_name = _parse_character_fandom(char_part)
        if fandom_name:
            fandom_tag = _ensure_fandom_tag(fandom_name)
            tag.fandom_id = fandom_tag.id
        else:
            tag.fandom_id = None

    # If renaming a fandom tag, cascade rename to all character tags that reference it
    if new_kind == "fandom" and old_kind == "fandom" and full_name != old_name:
        new_fandom_display = full_name.split(":", 1)[1]
        old_fandom_display = old_name.split(":", 1)[1] if ":" in old_name else old_name
        # Find all character tags linked to this fandom
        linked_chars = Tag.query.filter_by(fandom_id=tag.id, kind="character").all()
        for char_tag in linked_chars:
            # Replace old fandom suffix with new one
            char_part = char_tag.name.split(":", 1)[1] if ":" in char_tag.name else char_tag.name
            char_base, _ = _parse_character_fandom(char_part)
            char_tag.name = f"character:{char_base} ({new_fandom_display})"

    db.session.commit()

    return jsonify(ok=True, tag={
        "id": tag.id,
        "name": tag.name,
        "kind": tag.kind,
        "fandom_id": tag.fandom_id
    })


@main.post("/api/tag/<int:tag_id>/delete")
def delete_tag(tag_id):
    """Delete a tag entirely."""
    tag = Tag.query.get_or_404(tag_id)

    # Remove from all images first (handled by cascade, but explicit is clearer)
    db.session.delete(tag)
    db.session.commit()

    return jsonify(ok=True)


# ----------------------------
# Filtered deletion endpoints
# ----------------------------

@main.post("/api/delete-by-tag")
def delete_images_by_tag():
    """
    Delete all images that have a specific tag.
    Also removes the image files and thumbnails from disk.
    Query params:
      - tag_id: ID of the tag whose images should be deleted
      - tag_name: Name of the tag (must match for security validation)
      - delete_tag: if "true", also delete the tag itself
    """
    tag_id = request.form.get("tag_id", type=int)
    tag_name = request.form.get("tag_name", "").strip()
    delete_tag_also = request.form.get("delete_tag") == "true"

    if not tag_id:
        return jsonify(ok=False, error="tag_id is required"), 400

    if not tag_name:
        return jsonify(ok=False, error="tag_name confirmation is required"), 400

    tag = Tag.query.get_or_404(tag_id)

    # Security: verify the provided tag name matches the actual tag
    if tag.name != tag_name:
        return jsonify(ok=False, error="Tag name confirmation does not match"), 403

    images_to_delete = list(tag.images)

    deleted_count = 0
    errors = []

    for img in images_to_delete:
        try:
            # Remove image file from disk
            if img.filepath and os.path.exists(img.filepath):
                os.remove(img.filepath)
            # Remove thumbnail if exists
            if img.thumb_path and os.path.exists(img.thumb_path):
                os.remove(img.thumb_path)
            # Delete DB record
            db.session.delete(img)
            deleted_count += 1
        except Exception as e:
            errors.append(f"Failed to delete {img.filename}: {e}")

    # Optionally delete the tag itself
    if delete_tag_also:
        db.session.delete(tag)

    db.session.commit()

    return jsonify(
        ok=True,
        deleted_count=deleted_count,
        tag_deleted=delete_tag_also,
        errors=errors if errors else None
    )


@main.get("/api/tag/<int:tag_id>/image-count")
def get_tag_image_count(tag_id):
    """Get the number of images associated with a tag."""
    tag = Tag.query.get_or_404(tag_id)
    count = len(tag.images)
    return jsonify(ok=True, count=count, tag_name=tag.name)


# ----------------------------
# Import settings endpoints
# ----------------------------

@main.get("/api/import-settings")
def get_import_settings():
    """Get current import filter settings from database."""
    from app.utils.version_migration import (
        get_setting_int, get_setting_float, get_setting_bool
    )

    settings = {
        "min_width": get_setting_int("import_min_width", int(os.environ.get("IMPORT_MIN_WIDTH", "0"))),
        "min_height": get_setting_int("import_min_height", int(os.environ.get("IMPORT_MIN_HEIGHT", "0"))),
        "skip_transparent": get_setting_bool("import_skip_transparent", os.environ.get("IMPORT_SKIP_TRANSPARENT", "false").lower() == "true"),
        "transparency_threshold": get_setting_float("import_transparency_threshold", float(os.environ.get("IMPORT_TRANSPARENCY_THRESHOLD", "0.9"))),
        "phash_threshold": get_setting_int("phash_threshold", int(os.environ.get("IMPORT_PHASH_THRESHOLD", "10"))),
    }
    return jsonify(ok=True, settings=settings)


@main.post("/api/import-settings")
def save_import_settings():
    """
    Save import filter settings to database.
    Settings are loaded by the Celery workers via load_import_settings().
    """
    from app.utils.version_migration import set_setting

    min_width = request.form.get("min_width", 0, type=int)
    min_height = request.form.get("min_height", 0, type=int)
    skip_transparent = request.form.get("skip_transparent") == "true"
    transparency_threshold = request.form.get("transparency_threshold", 0.9, type=float)
    phash_threshold = request.form.get("phash_threshold", 10, type=int)

    try:
        set_setting("import_min_width", str(min_width))
        set_setting("import_min_height", str(min_height))
        set_setting("import_skip_transparent", str(skip_transparent).lower())
        set_setting("import_transparency_threshold", str(transparency_threshold))
        set_setting("phash_threshold", str(phash_threshold))

        settings = {
            "min_width": min_width,
            "min_height": min_height,
            "skip_transparent": skip_transparent,
            "transparency_threshold": transparency_threshold,
            "phash_threshold": phash_threshold,
        }
        return jsonify(ok=True, settings=settings)
    except Exception as e:
        return jsonify(ok=False, error=str(e)), 500


# ----------------------------
# Image filter/cleanup endpoints
# ----------------------------

@main.get("/api/filter-scan")
def scan_filterable_images():
    """
    Scan existing images against current filter settings.
    Returns counts and IDs of images that would be filtered.
    Query params:
      - filter_type: 'transparency' or 'dimensions'
      - threshold: for transparency (0.0-1.0), or min_width/min_height for dimensions
      - min_width: minimum width (for dimensions filter)
      - min_height: minimum height (for dimensions filter)
      - limit: max results to return (default 100)
    """
    from app.utils.image_importer import is_mostly_transparent

    filter_type = request.args.get("filter_type", "transparency")
    limit = request.args.get("limit", 100, type=int)

    results = []

    if filter_type == "transparency":
        threshold = request.args.get("threshold", 0.9, type=float)

        # Only check images that could have transparency
        images = ImageRecord.query.filter(
            ImageRecord.filepath.ilike("%.png") |
            ImageRecord.filepath.ilike("%.gif") |
            ImageRecord.filepath.ilike("%.webp")
        ).limit(limit * 5).all()  # Check more to find enough matches

        for img in images:
            if len(results) >= limit:
                break
            if img.filepath and os.path.exists(img.filepath):
                try:
                    if is_mostly_transparent(img.filepath, threshold):
                        results.append({
                            "id": img.id,
                            "filename": img.filename,
                            "filepath": img.filepath,
                            "thumb_url": url_for('main.serve_image',
                                filename=(img.thumb_path or img.filepath).replace('/images/', ''))
                        })
                except Exception:
                    pass

    elif filter_type == "dimensions":
        min_width = request.args.get("min_width", 0, type=int)
        min_height = request.args.get("min_height", 0, type=int)

        if min_width <= 0 and min_height <= 0:
            return jsonify(ok=True, count=0, images=[], message="No dimension filter set")

        query = ImageRecord.query
        if min_width > 0:
            query = query.filter(ImageRecord.width < min_width)
        if min_height > 0:
            query = query.filter(ImageRecord.height < min_height)

        images = query.limit(limit).all()

        for img in images:
            results.append({
                "id": img.id,
                "filename": img.filename,
                "filepath": img.filepath,
                "width": img.width,
                "height": img.height,
                "thumb_url": url_for('main.serve_image',
                    filename=(img.thumb_path or img.filepath).replace('/images/', ''))
            })

    # Get total count (without limit) for progress indication
    total_count = len(results)

    return jsonify(ok=True, count=total_count, images=results, filter_type=filter_type)


@main.post("/api/filter-delete")
def delete_filtered_images():
    """
    Delete images by their IDs after filter review.
    Query params:
      - image_ids: comma-separated list of image IDs to delete
      - confirm: must be 'true' to actually delete
    """
    image_ids_str = request.form.get("image_ids", "")
    confirm = request.form.get("confirm") == "true"

    if not confirm:
        return jsonify(ok=False, error="Confirmation required"), 400

    if not image_ids_str:
        return jsonify(ok=False, error="No image IDs provided"), 400

    try:
        image_ids = [int(x) for x in image_ids_str.split(",") if x.strip()]
    except ValueError:
        return jsonify(ok=False, error="Invalid image IDs"), 400

    deleted_count = 0
    errors = []

    for img_id in image_ids:
        img = ImageRecord.query.get(img_id)
        if not img:
            continue

        try:
            # Remove image file from disk
            if img.filepath and os.path.exists(img.filepath):
                os.remove(img.filepath)
            # Remove thumbnail if exists
            if img.thumb_path and os.path.exists(img.thumb_path):
                os.remove(img.thumb_path)
            # Delete DB record
            db.session.delete(img)
            deleted_count += 1
        except Exception as e:
            errors.append(f"Failed to delete {img.filename}: {e}")

    db.session.commit()

    return jsonify(
        ok=True,
        deleted_count=deleted_count,
        errors=errors if errors else None
    )


# ----------------------------
# Import Task Queue API (Celery)
# ----------------------------

@main.route('/api/import/trigger', methods=['POST'])
def trigger_import_celery():
    """
    Trigger a directory scan and import via Celery.

    Supports two modes:
    - Quick scan (default): Fast O(1) duplicate detection using pre-loaded lookups.
      Only queues truly new files. Skips pHash comparison for speed.
    - Deep scan: Full reprocessing of all files. Re-extracts metadata,
      runs pHash comparison, optionally regenerates thumbnails and re-applies sidecars.

    POST params:
        source_dir: Source directory (default: /import)
        dest_dir: Destination directory (default: /images)
        deep: Set to 'true' for deep scan mode
        regenerate_thumbnails: For deep scan, regenerate all thumbnails (default: true)
        reapply_sidecars: For deep scan, re-apply sidecar metadata (default: true)
        verify_hashes: For deep scan, verify content hashes (default: true)
    """
    try:
        from app.tasks.scan import scan_directory, deep_scan_directory

        source_dir = request.form.get('source_dir', '/import')
        dest_dir = request.form.get('dest_dir', '/images')
        is_deep = request.form.get('deep', 'false').lower() == 'true'

        if is_deep:
            # Deep scan with full reprocessing
            regenerate_thumbnails = request.form.get('regenerate_thumbnails', 'true').lower() == 'true'
            reapply_sidecars = request.form.get('reapply_sidecars', 'true').lower() == 'true'
            verify_hashes = request.form.get('verify_hashes', 'true').lower() == 'true'

            result = deep_scan_directory.delay(
                source_dir, dest_dir,
                regenerate_thumbnails=regenerate_thumbnails,
                reapply_sidecars=reapply_sidecars,
                verify_hashes=verify_hashes
            )
            message = 'Deep import scan started'
        else:
            # Quick scan with optimized lookups
            result = scan_directory.delay(source_dir, dest_dir)
            message = 'Quick import scan started'

        return jsonify({
            'ok': True,
            'task_id': result.id,
            'message': message,
            'mode': 'deep' if is_deep else 'quick'
        })
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/status')
def import_queue_status():
    """
    Get current import queue status.
    Returns counts by task status and recent task info.
    """
    try:
        # Count tasks by status
        status_counts = dict(
            db.session.query(
                ImportTask.status,
                func.count(ImportTask.id)
            ).group_by(ImportTask.status).all()
        )

        # Get active batch info
        active_batch = ImportBatch.query.filter_by(status='running').order_by(
            ImportBatch.started_at.desc()
        ).first()

        # Recent tasks (last 20)
        recent_tasks = ImportTask.query.order_by(
            ImportTask.created_at.desc()
        ).limit(20).all()

        return jsonify({
            'ok': True,
            'status_counts': {
                'pending': status_counts.get('pending', 0),
                'queued': status_counts.get('queued', 0),
                'processing': status_counts.get('processing', 0),
                'complete': status_counts.get('complete', 0),
                'failed': status_counts.get('failed', 0),
                'skipped': status_counts.get('skipped', 0),
            },
            'active_batch': {
                'id': active_batch.id,
                'source_directory': active_batch.source_directory,
                'total_files': active_batch.total_files,
                'processed_files': active_batch.processed_files,
                'imported_count': active_batch.imported_count,
                'skipped_count': active_batch.skipped_count,
                'failed_count': active_batch.failed_count,
                'started_at': active_batch.started_at.isoformat() if active_batch.started_at else None
            } if active_batch else None,
            'recent_tasks': [
                {
                    'id': t.id,
                    'source_path': os.path.basename(t.source_path) if t.source_path else None,
                    'task_type': t.task_type,
                    'status': t.status,
                    'error_message': t.error_message[:100] if t.error_message else None,
                    'created_at': t.created_at.isoformat() if t.created_at else None
                }
                for t in recent_tasks
            ]
        })
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/tasks')
def list_import_tasks():
    """
    List import tasks with filtering and pagination.

    Query params:
        status: Filter by status (comma-separated, e.g., 'failed,skipped')
        task_type: Filter by task type ('import_image', 'import_archive')
        search: Search in source_path or error_message
        limit: Max results (default 50, max 200)
        offset: Skip first N results
        sort: Sort field ('created_at', 'completed_at', default: 'created_at')
        order: Sort order ('asc', 'desc', default: 'desc')
    """
    try:
        # Parse parameters
        status_filter = request.args.get('status', '')
        task_type = request.args.get('task_type', '')
        search = request.args.get('search', '')
        limit = min(int(request.args.get('limit', 50)), 200)
        offset = int(request.args.get('offset', 0))
        sort_field = request.args.get('sort', 'created_at')
        sort_order = request.args.get('order', 'desc')

        # Build query
        query = ImportTask.query

        # Filter by status
        if status_filter:
            statuses = [s.strip() for s in status_filter.split(',') if s.strip()]
            if statuses:
                query = query.filter(ImportTask.status.in_(statuses))

        # Filter by task type
        if task_type:
            query = query.filter_by(task_type=task_type)

        # Search in source_path or error_message
        if search:
            search_pattern = f'%{search}%'
            query = query.filter(
                db.or_(
                    ImportTask.source_path.ilike(search_pattern),
                    ImportTask.error_message.ilike(search_pattern)
                )
            )

        # Get total count before pagination
        total = query.count()

        # Sort
        sort_col = getattr(ImportTask, sort_field, ImportTask.created_at)
        if sort_order == 'asc':
            query = query.order_by(sort_col.asc())
        else:
            query = query.order_by(sort_col.desc())

        # Paginate
        tasks = query.offset(offset).limit(limit).all()

        return jsonify({
            'ok': True,
            'total': total,
            'offset': offset,
            'limit': limit,
            'tasks': [
                {
                    'id': t.id,
                    'source_path': t.source_path,
                    'filename': os.path.basename(t.source_path) if t.source_path else None,
                    'task_type': t.task_type,
                    'status': t.status,
                    'error_message': t.error_message,  # Full error message
                    'file_size': t.file_size,
                    'retry_count': t.retry_count,
                    'created_at': t.created_at.isoformat() if t.created_at else None,
                    'completed_at': t.completed_at.isoformat() if t.completed_at else None
                }
                for t in tasks
            ]
        })
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/task/<int:task_id>')
def get_import_task(task_id):
    """
    Get detailed status for a specific import task.
    """
    task = ImportTask.query.get_or_404(task_id)

    # Check Celery task status if still processing
    celery_status = None
    if task.celery_task_id:
        try:
            from app.celery_app import celery
            result = celery.AsyncResult(task.celery_task_id)
            celery_status = result.status
        except Exception:
            pass

    return jsonify({
        'ok': True,
        'task': {
            'id': task.id,
            'source_path': task.source_path,
            'file_hash': task.file_hash,
            'file_size': task.file_size,
            'task_type': task.task_type,
            'status': task.status,
            'celery_status': celery_status,
            'celery_task_id': task.celery_task_id,
            'error_message': task.error_message,
            'retry_count': task.retry_count,
            'context': task.context,
            'batch_id': task.batch_id,
            'result_image_id': task.result_image_id,
            'created_at': task.created_at.isoformat() if task.created_at else None,
            'started_at': task.started_at.isoformat() if task.started_at else None,
            'completed_at': task.completed_at.isoformat() if task.completed_at else None
        }
    })


@main.route('/api/import/retry-failed', methods=['POST'])
def retry_failed_import_tasks():
    """
    Re-queue all failed import tasks.
    """
    try:
        from app.tasks.import_file import import_media_file, import_archive

        failed_tasks = ImportTask.query.filter_by(status='failed').all()
        retried = 0

        for task in failed_tasks:
            task.status = 'pending'
            task.error_message = None
            task.retry_count = 0
            task.started_at = None
            task.completed_at = None

            if task.task_type == 'import_image':
                result = import_media_file.delay(task.id)
            elif task.task_type == 'import_archive':
                result = import_archive.delay(task.id)
            else:
                continue

            task.celery_task_id = result.id
            task.status = 'queued'
            retried += 1

        db.session.commit()

        return jsonify({
            'ok': True,
            'retried': retried
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/clear-completed', methods=['POST'])
def clear_completed_tasks():
    """
    Clear import tasks from the database with optional age filtering.

    POST params:
        statuses: Comma-separated statuses to clear (default: complete,skipped)
        older_than_days: Only clear tasks older than N days (default: 0 = all)
    """
    from datetime import timedelta

    try:
        # Parse parameters
        statuses_param = request.form.get('statuses', 'complete,skipped')
        older_than_days = int(request.form.get('older_than_days', 0))

        # Validate statuses
        allowed_statuses = {'complete', 'skipped', 'failed'}
        statuses = [s.strip() for s in statuses_param.split(',') if s.strip() in allowed_statuses]
        if not statuses:
            statuses = ['complete', 'skipped']

        # Build query
        query = ImportTask.query.filter(ImportTask.status.in_(statuses))

        # Apply age filter if specified
        if older_than_days > 0:
            cutoff = datetime.utcnow() - timedelta(days=older_than_days)
            query = query.filter(ImportTask.completed_at < cutoff)

        deleted = query.delete(synchronize_session=False)
        db.session.commit()

        return jsonify({
            'ok': True,
            'deleted': deleted,
            'statuses': statuses,
            'older_than_days': older_than_days
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/clear-queue', methods=['POST'])
def clear_import_queue():
    """
    Clear pending and queued import tasks from the queue.
    This stops tasks that haven't started processing yet.
    """
    try:
        # Find and delete pending/queued tasks
        deleted = ImportTask.query.filter(
            ImportTask.status.in_(['pending', 'queued'])
        ).delete(synchronize_session=False)

        db.session.commit()

        return jsonify({
            'ok': True,
            'deleted': deleted
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/import/task-stats')
def import_task_stats():
    """
    Get detailed task statistics with age breakdown.
    """
    from datetime import timedelta

    try:
        now = datetime.utcnow()
        today = now - timedelta(days=1)
        week_ago = now - timedelta(days=7)

        stats = {}
        for status in ['complete', 'skipped', 'failed']:
            total = ImportTask.query.filter_by(status=status).count()
            today_count = ImportTask.query.filter(
                ImportTask.status == status,
                ImportTask.completed_at >= today
            ).count()
            week_count = ImportTask.query.filter(
                ImportTask.status == status,
                ImportTask.completed_at >= week_ago,
                ImportTask.completed_at < today
            ).count()
            older = total - today_count - week_count

            stats[status] = {
                'total': total,
                'today': today_count,
                'this_week': week_count,
                'older': older
            }

        return jsonify({'ok': True, 'stats': stats})
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/system/stats')
def system_stats():
    """
    Get system-wide statistics for the dashboard.

    Returns cached stats computed by the update_system_stats Celery task.
    Stats are updated every 5 minutes by Celery Beat.

    Query params:
        refresh: If 'true', triggers an immediate stats update (async)
    """
    import json

    try:
        # Check for refresh request
        if request.args.get('refresh') == 'true':
            from app.tasks.scan import update_system_stats
            update_system_stats.delay()

        # Get cached stats from AppSettings
        setting = AppSettings.query.filter_by(key='system_stats_cache').first()

        if setting and setting.value:
            stats = json.loads(setting.value)
            return jsonify({
                'ok': True,
                'cached': True,
                **stats
            })

        # No cached stats - return empty with flag to indicate first run
        return jsonify({
            'ok': True,
            'cached': False,
            'images': {'total': 0, 'storage_bytes': 0, 'storage_human': '0 B'},
            'tags': {'total': 0, 'by_kind': {}},
            'import_folder': {'pending_files': 0, 'pending_archives': 0},
            'message': 'Stats not yet computed. Will be available shortly.'
        })

    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/thumbnails/regenerate', methods=['POST'])
def regenerate_thumbnails_celery():
    """
    Trigger thumbnail regeneration for all images via Celery.
    """
    try:
        from app.tasks.thumbnail import regenerate_all_thumbnails

        overwrite = request.form.get('overwrite', 'true').lower() == 'true'
        result = regenerate_all_thumbnails.delay(overwrite=overwrite)

        return jsonify({
            'ok': True,
            'task_id': result.id,
            'message': 'Thumbnail regeneration started'
        })
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/thumbnails/regenerate-missing', methods=['POST'])
def regenerate_missing_thumbnails_celery():
    """
    Generate thumbnails only for images that don't have them.
    """
    try:
        from app.tasks.thumbnail import regenerate_missing_thumbnails

        result = regenerate_missing_thumbnails.delay()

        return jsonify({
            'ok': True,
            'task_id': result.id,
            'message': 'Missing thumbnail generation started'
        })
    except Exception as e:
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/reapply-artist-tags', methods=['POST'])
def reapply_artist_tags_from_paths():
    """
    Re-apply artist tags to all images based on their file paths.
    Artist is extracted from the first directory component after /images/
    (e.g., /images/artist_name/file.jpg -> artist:artist_name)
    """
    try:
        images = ImageRecord.query.all()
        updated = 0
        skipped = 0
        errors = []

        for img in images:
            if not img.filepath:
                skipped += 1
                continue

            # Extract artist from path: /images/{artist}/...
            # Handle both /images/artist/file.jpg and /images/artist/subdir/file.jpg
            path_parts = img.filepath.split('/')
            try:
                # Find 'images' in path and get the next component
                images_idx = path_parts.index('images')
                if images_idx + 1 < len(path_parts):
                    artist_name = path_parts[images_idx + 1]
                else:
                    skipped += 1
                    continue
            except ValueError:
                # 'images' not in path, try alternative format
                # Maybe it's a Windows path or different structure
                skipped += 1
                continue

            if not artist_name or artist_name == '':
                skipped += 1
                continue

            # Create or get the artist tag
            tag_name = f"artist:{artist_name}"
            tag = Tag.query.filter_by(name=tag_name).first()
            if not tag:
                tag = Tag(name=tag_name, kind='artist')
                db.session.add(tag)
                db.session.flush()

            # Add tag if not already present
            if tag not in img.tags:
                img.tags.append(tag)
                updated += 1

        db.session.commit()

        return jsonify({
            'ok': True,
            'updated': updated,
            'skipped': skipped,
            'total': len(images),
            'errors': errors if errors else None
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/cleanup-orphaned-tags', methods=['POST'])
def cleanup_orphaned_tags():
    """
    Delete tags that aren't attached to any images.
    Returns the count and names of deleted tags.
    """
    from sqlalchemy import func

    try:
        # Find tags with no associated images
        # A tag is orphaned if it has no entries in the image_tags junction table
        orphaned = (
            Tag.query
            .outerjoin(image_tags)
            .group_by(Tag.id)
            .having(func.count(image_tags.c.image_id) == 0)
            .all()
        )

        deleted_tags = []
        for tag in orphaned:
            deleted_tags.append({'name': tag.name, 'kind': tag.kind})
            db.session.delete(tag)

        db.session.commit()

        return jsonify({
            'ok': True,
            'deleted_count': len(deleted_tags),
            'deleted_tags': deleted_tags
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({'ok': False, 'error': str(e)}), 500


@main.route('/api/celery/status')
def celery_cluster_status():
    """
    Get Celery cluster status (workers, queues, etc.).
    """
    try:
        from app.celery_app import celery

        inspect = celery.control.inspect()

        # Get worker stats
        active = inspect.active() or {}
        scheduled = inspect.scheduled() or {}
        reserved = inspect.reserved() or {}
        stats = inspect.stats() or {}

        # Count active tasks
        active_count = sum(len(tasks) for tasks in active.values())

        return jsonify({
            'ok': True,
            'workers': list(stats.keys()),
            'worker_count': len(stats),
            'active_tasks': active_count,
            'active': active,
            'scheduled': scheduled,
            'reserved': reserved
        })
    except Exception as e:
        return jsonify({
            'ok': False,
            'error': str(e),
            'message': 'Celery may not be running'
        }), 503


@main.route('/api/import/batches')
def list_import_batches():
    """
    List recent import batches with statistics.
    """
    limit = request.args.get('limit', 10, type=int)

    batches = ImportBatch.query.order_by(
        ImportBatch.started_at.desc()
    ).limit(limit).all()

    return jsonify({
        'ok': True,
        'batches': [
            {
                'id': b.id,
                'source_directory': b.source_directory,
                'status': b.status,
                'total_files': b.total_files,
                'processed_files': b.processed_files,
                'imported_count': b.imported_count,
                'skipped_count': b.skipped_count,
                'failed_count': b.failed_count,
                'started_at': b.started_at.isoformat() if b.started_at else None,
                'completed_at': b.completed_at.isoformat() if b.completed_at else None
            }
            for b in batches
        ]
    })


# =============================================
# Duplicate Detection API
# =============================================

@main.route('/api/duplicates/scan', methods=['POST'])
def scan_duplicates():
    """
    Scan for duplicate images using perceptual hash comparison.
    Returns groups of similar images within the specified hamming distance.
    """
    import imagehash

    threshold = request.form.get('threshold', 10, type=int)
    limit = request.form.get('limit', 100, type=int)

    # Get all images with perceptual hashes
    images = ImageRecord.query.filter(
        ImageRecord.perceptual_hash.isnot(None)
    ).all()

    if not images:
        return jsonify({'ok': True, 'groups': [], 'message': 'No images with perceptual hashes found'})

    # Build hash lookup
    hash_data = []
    for img in images:
        try:
            phash = imagehash.hex_to_hash(img.perceptual_hash)
            hash_data.append({
                'id': img.id,
                'hash': phash,
                'width': img.width,
                'height': img.height,
                'filename': img.filename,
                'filepath': img.filepath,
                'thumb_path': img.thumb_path,
                'file_size': img.file_size
            })
        except Exception:
            continue

    # Find duplicate groups
    duplicate_groups = []
    processed = set()

    for i, img1 in enumerate(hash_data):
        if img1['id'] in processed:
            continue

        group = [img1]

        for j, img2 in enumerate(hash_data[i+1:], start=i+1):
            if img2['id'] in processed:
                continue

            distance = img1['hash'] - img2['hash']
            if distance <= threshold:
                group.append(img2)
                processed.add(img2['id'])

        if len(group) > 1:
            processed.add(img1['id'])
            # Sort group by resolution (largest first)
            group.sort(key=lambda x: x['width'] * x['height'], reverse=True)
            duplicate_groups.append(group)

        if len(duplicate_groups) >= limit:
            break

    # Format response
    result_groups = []
    for group in duplicate_groups:
        result_groups.append([
            {
                'id': img['id'],
                'filename': img['filename'],
                'width': img['width'],
                'height': img['height'],
                'file_size': img['file_size'],
                'thumb_url': url_for('main.serve_image',
                    filename=(img['thumb_path'] or img['filepath']).replace('/images/', ''))
            }
            for img in group
        ])

    return jsonify({
        'ok': True,
        'groups': result_groups,
        'total_groups': len(result_groups),
        'threshold': threshold
    })


@main.route('/api/duplicates/delete', methods=['POST'])
def delete_duplicates():
    """
    Delete specified duplicate images.
    Expects JSON body with 'image_ids' array.
    """
    data = request.get_json() or {}
    image_ids = data.get('image_ids', [])

    if not image_ids:
        return jsonify({'ok': False, 'error': 'No image IDs provided'})

    deleted_count = 0
    errors = []

    for image_id in image_ids:
        try:
            image = ImageRecord.query.get(image_id)
            if not image:
                errors.append(f"Image {image_id} not found")
                continue

            # Delete physical files
            if image.filepath and os.path.exists(image.filepath):
                os.remove(image.filepath)
            if image.thumb_path and os.path.exists(image.thumb_path):
                os.remove(image.thumb_path)

            # Delete database record
            db.session.delete(image)
            deleted_count += 1

        except Exception as e:
            errors.append(f"Error deleting {image_id}: {str(e)}")

    db.session.commit()

    return jsonify({
        'ok': True,
        'deleted_count': deleted_count,
        'errors': errors if errors else None
    })


# =============================================
# Bulk Tag Operations API
# =============================================

@main.route('/api/images/common-tags', methods=['POST'])
def get_common_tags():
    """
    Get tags that are common to all specified images.
    Expects JSON body with 'image_ids' array.
    Returns tags that appear on EVERY selected image.
    """
    data = request.get_json() or {}
    image_ids = data.get('image_ids', [])

    if not image_ids:
        return jsonify({'ok': True, 'tags': []})

    # Find tags that appear on ALL selected images
    # We use a subquery approach: count occurrences of each tag and filter
    # for tags where the count equals the number of images
    num_images = len(image_ids)

    # Query: get tags where the count of associated images (from our list) equals num_images
    common_tags = db.session.query(Tag).join(image_tags).filter(
        image_tags.c.image_id.in_(image_ids)
    ).group_by(Tag.id).having(
        func.count(image_tags.c.image_id) == num_images
    ).order_by(Tag.name).all()

    return jsonify({
        'ok': True,
        'tags': [
            {'id': t.id, 'name': t.name, 'kind': t.kind}
            for t in common_tags
        ]
    })


@main.route('/api/images/bulk-add-tag', methods=['POST'])
def bulk_add_tag():
    """
    Add a tag to multiple images at once.
    Expects JSON body with 'image_ids' array and 'tag_name' string.

    For character tags with a fandom, automatically adds the fandom tag too.
    """
    data = request.get_json() or {}
    image_ids = data.get('image_ids', [])
    tag_name = (data.get('tag_name') or '').strip()

    if not image_ids:
        return jsonify({'ok': False, 'error': 'No image IDs provided'}), 400

    if not tag_name:
        return jsonify({'ok': False, 'error': 'No tag name provided'}), 400

    # Determine tag kind from name
    if ':' in tag_name:
        kind = tag_name.split(':', 1)[0]
    else:
        # No prefix — treat as a user-typed general tag. Strip underscores so
        # WD14-style names pasted into the bulk box converge with our convention.
        from app.utils.tag_names import underscores_to_spaces
        kind = 'user'
        tag_name = underscores_to_spaces(tag_name)

    # Get or create the tag
    tag = Tag.query.filter_by(name=tag_name).first()
    fandom_tag = None

    if not tag:
        if kind == 'character':
            char_part = tag_name.split(':', 1)[1]
            char_name, fandom_name = _parse_character_fandom(char_part)
            norm_char = normalize_display_name(char_name)
            if fandom_name:
                fandom_tag = _ensure_fandom_tag(fandom_name)
                tag_name = f"character:{norm_char} ({fandom_tag.name.split(':', 1)[1]})"
            else:
                tag_name = f"character:{norm_char}"
        elif kind == 'fandom':
            fandom_part = tag_name.split(':', 1)[1]
            tag_name = f"fandom:{normalize_display_name(fandom_part)}"
        tag = Tag.query.filter_by(name=tag_name).first()
        if not tag:
            tag = Tag(name=tag_name, kind=kind)
            if kind == 'character' and fandom_name:
                tag.fandom_id = fandom_tag.id
            db.session.add(tag)
            db.session.flush()
        elif tag.kind == 'character' and tag.fandom_id:
            fandom_tag = Tag.query.get(tag.fandom_id)
    elif tag.kind == 'character' and tag.fandom_id:
        fandom_tag = Tag.query.get(tag.fandom_id)

    # Get images
    images = ImageRecord.query.filter(
        ImageRecord.id.in_(image_ids)
    ).all()

    added_count = 0
    for img in images:
        if tag not in img.tags:
            img.tags.append(tag)
            added_count += 1
        # Auto-apply fandom tag
        if fandom_tag and fandom_tag not in img.tags:
            img.tags.append(fandom_tag)

    db.session.commit()

    result = {'id': tag.id, 'name': tag.name, 'kind': tag.kind}
    if fandom_tag:
        result['fandom_tag'] = {'id': fandom_tag.id, 'name': fandom_tag.name, 'kind': fandom_tag.kind}

    return jsonify({
        'ok': True,
        'added_count': added_count,
        'tag': result
    })


@main.route('/api/images/bulk-remove-tag', methods=['POST'])
def bulk_remove_tag():
    """
    Remove a tag from multiple images at once.
    Expects JSON body with 'image_ids' array and 'tag_name' string.
    """
    data = request.get_json() or {}
    image_ids = data.get('image_ids', [])
    tag_name = (data.get('tag_name') or '').strip()

    if not image_ids:
        return jsonify({'ok': False, 'error': 'No image IDs provided'}), 400

    if not tag_name:
        return jsonify({'ok': False, 'error': 'No tag name provided'}), 400

    # Find the tag
    tag = Tag.query.filter_by(name=tag_name).first()
    if not tag:
        return jsonify({'ok': True, 'removed_count': 0, 'message': 'Tag not found'})

    # Get images that have this tag
    images = ImageRecord.query.filter(
        ImageRecord.id.in_(image_ids)
    ).all()

    removed_count = 0
    for img in images:
        if tag in img.tags:
            img.tags.remove(tag)
            removed_count += 1

    db.session.commit()

    return jsonify({
        'ok': True,
        'removed_count': removed_count
    })


# =============================================
# Series / Reader API
# =============================================

@main.route('/read/<int:tag_id>')
def read_series(tag_id):
    """
    Reader view for a series - displays images in page order.
    Supports jump-to-page via ?page=N parameter.
    """
    from app.models import SeriesPage

    tag = Tag.query.get_or_404(tag_id)

    if tag.kind != 'series':
        return "Not a series tag", 400

    # Get all pages in order
    pages = SeriesPage.query.filter_by(series_tag_id=tag_id).order_by(
        SeriesPage.page_number
    ).all()

    # Get starting page from query param
    start_page = request.args.get('page', 1, type=int)

    # Get series name (strip prefix if present)
    series_name = tag.name.split(':', 1)[1] if ':' in tag.name else tag.name

    return render_template(
        'reader.html',
        tag=tag,
        series_name=series_name,
        pages=pages,
        start_page=start_page,
        total_pages=len(pages)
    )


@main.get('/api/series/<int:tag_id>/pages')
def get_series_pages(tag_id):
    """Get all pages in a series with their images."""
    from app.models import SeriesPage

    tag = Tag.query.get_or_404(tag_id)

    if tag.kind != 'series':
        return jsonify(ok=False, error="Not a series tag"), 400

    pages = SeriesPage.query.filter_by(series_tag_id=tag_id).order_by(
        SeriesPage.page_number
    ).all()

    return jsonify(ok=True, pages=[
        {
            'id': p.id,
            'page_number': p.page_number,
            'image_id': p.image_id,
            'image': {
                'id': p.image.id,
                'filename': p.image.filename,
                'filepath': p.image.filepath,
                'thumb_path': p.image.thumb_path,
                'width': p.image.width,
                'height': p.image.height,
            }
        }
        for p in pages
    ], total_pages=len(pages))


@main.post('/api/series/<int:tag_id>/pages/add')
def add_series_page(tag_id):
    """
    Add an image to a series with a specific page number.
    Expects form data: image_id, page_number
    """
    from app.models import SeriesPage

    tag = Tag.query.get_or_404(tag_id)

    if tag.kind != 'series':
        return jsonify(ok=False, error="Not a series tag"), 400

    image_id = request.form.get('image_id', type=int)
    page_number = request.form.get('page_number', type=int)

    if not image_id or page_number is None:
        return jsonify(ok=False, error="image_id and page_number required"), 400

    # Check if image exists
    image = ImageRecord.query.get(image_id)
    if not image:
        return jsonify(ok=False, error="Image not found"), 404

    # Check if image is already in a series
    existing = SeriesPage.query.filter_by(image_id=image_id).first()
    if existing:
        return jsonify(ok=False, error="Image is already in a series",
                      existing_series_id=existing.series_tag_id), 409

    # Check if page number is already taken
    page_exists = SeriesPage.query.filter_by(
        series_tag_id=tag_id, page_number=page_number
    ).first()
    if page_exists:
        return jsonify(ok=False, error=f"Page {page_number} already exists"), 409

    # Create the series page
    sp = SeriesPage(
        series_tag_id=tag_id,
        image_id=image_id,
        page_number=page_number
    )
    db.session.add(sp)

    # Also ensure the image has the series tag
    if tag not in image.tags:
        image.tags.append(tag)

    db.session.commit()

    return jsonify(ok=True, page={
        'id': sp.id,
        'page_number': sp.page_number,
        'image_id': sp.image_id
    })


@main.post('/api/series/<int:tag_id>/pages/bulk-add')
def bulk_add_series_pages(tag_id):
    """
    Add multiple images to a series with sequential page numbers.
    Expects JSON: { image_ids: [id1, id2, ...], start_page: N }
    Images are added in order starting from start_page.
    """
    from app.models import SeriesPage

    tag = Tag.query.get_or_404(tag_id)

    if tag.kind != 'series':
        return jsonify(ok=False, error="Not a series tag"), 400

    data = request.get_json() or {}
    image_ids = data.get('image_ids', [])
    start_page = data.get('start_page', 1)

    if not image_ids:
        return jsonify(ok=False, error="No image IDs provided"), 400

    added = []
    skipped = []
    current_page = start_page

    for image_id in image_ids:
        image = ImageRecord.query.get(image_id)
        if not image:
            skipped.append({'image_id': image_id, 'reason': 'not found'})
            continue

        # Check if image is already in a series
        existing = SeriesPage.query.filter_by(image_id=image_id).first()
        if existing:
            skipped.append({'image_id': image_id, 'reason': 'already in series'})
            continue

        # Find next available page number
        while SeriesPage.query.filter_by(
            series_tag_id=tag_id, page_number=current_page
        ).first():
            current_page += 1

        sp = SeriesPage(
            series_tag_id=tag_id,
            image_id=image_id,
            page_number=current_page
        )
        db.session.add(sp)

        # Ensure image has the series tag
        if tag not in image.tags:
            image.tags.append(tag)

        added.append({'image_id': image_id, 'page_number': current_page})
        current_page += 1

    db.session.commit()

    return jsonify(ok=True, added=added, skipped=skipped)


@main.post('/api/series/page/<int:page_id>/update')
def update_series_page(page_id):
    """Update a series page's page number."""
    from app.models import SeriesPage

    sp = SeriesPage.query.get_or_404(page_id)
    new_page_number = request.form.get('page_number', type=int)

    if new_page_number is None:
        return jsonify(ok=False, error="page_number required"), 400

    # Check if the new page number is taken
    existing = SeriesPage.query.filter(
        SeriesPage.series_tag_id == sp.series_tag_id,
        SeriesPage.page_number == new_page_number,
        SeriesPage.id != page_id
    ).first()

    if existing:
        return jsonify(ok=False, error=f"Page {new_page_number} already exists"), 409

    sp.page_number = new_page_number
    db.session.commit()

    return jsonify(ok=True, page={
        'id': sp.id,
        'page_number': sp.page_number,
        'image_id': sp.image_id
    })


@main.post('/api/series/page/<int:page_id>/delete')
def delete_series_page(page_id):
    """Remove an image from a series (doesn't delete the image)."""
    from app.models import SeriesPage

    sp = SeriesPage.query.get_or_404(page_id)
    db.session.delete(sp)
    db.session.commit()

    return jsonify(ok=True)


@main.get('/api/image/<int:image_id>/series-info')
def get_image_series_info(image_id):
    """Check if an image is part of a series and return its page info."""
    from app.models import SeriesPage

    sp = SeriesPage.query.filter_by(image_id=image_id).first()

    if not sp:
        # Return any series tags the image has (for auto-select in dropdown)
        image = ImageRecord.query.get(image_id)
        series_tags = []
        if image:
            series_tags = [
                {'id': t.id, 'name': t.name}
                for t in image.tags if t.kind == 'series'
            ]
        return jsonify(ok=True, in_series=False, series_tags=series_tags)

    return jsonify(ok=True, in_series=True, series_page={
        'id': sp.id,
        'page_number': sp.page_number,
        'series_tag_id': sp.series_tag_id,
        'series_name': sp.series_tag.name
    })


@main.post('/api/image/<int:image_id>/add-to-series')
def add_image_to_series(image_id):
    """Add or update an image in a series with a specific page number.

    Handles three cases:
    1. Image not in any series -> create new SeriesPage
    2. Image already in this series -> update page number
    3. Image in a different series -> move to new series
    """
    from app.models import SeriesPage, Tag

    data = request.get_json() or {}
    series_tag_id = data.get('series_tag_id')
    page_number = data.get('page_number')

    if not series_tag_id:
        return jsonify(ok=False, error="series_tag_id required"), 400
    if not page_number:
        return jsonify(ok=False, error="page_number required"), 400

    # Verify the series tag exists and is a series
    series_tag = Tag.query.get(series_tag_id)
    if not series_tag:
        return jsonify(ok=False, error="Series not found"), 404
    if series_tag.kind != 'series':
        return jsonify(ok=False, error="Tag is not a series"), 400

    # Check if image is already in this series
    existing_in_target = SeriesPage.query.filter_by(
        series_tag_id=series_tag_id,
        image_id=image_id
    ).first()

    # Check if image is in any other series
    existing_in_other = SeriesPage.query.filter(
        SeriesPage.image_id == image_id,
        SeriesPage.series_tag_id != series_tag_id
    ).first()

    if existing_in_target:
        # Case 2: Already in this series - update page number
        if existing_in_target.page_number == page_number:
            # No change needed
            return jsonify(ok=True, series_page={
                'id': existing_in_target.id,
                'page_number': existing_in_target.page_number,
                'series_tag_id': existing_in_target.series_tag_id,
                'series_name': series_tag.name
            })

        # Check if new page number is taken by another image
        page_taken = SeriesPage.query.filter(
            SeriesPage.series_tag_id == series_tag_id,
            SeriesPage.page_number == page_number,
            SeriesPage.image_id != image_id
        ).first()
        if page_taken:
            return jsonify(ok=False, error=f"Page {page_number} already exists in this series"), 409

        existing_in_target.page_number = page_number
        db.session.commit()

        return jsonify(ok=True, series_page={
            'id': existing_in_target.id,
            'page_number': existing_in_target.page_number,
            'series_tag_id': existing_in_target.series_tag_id,
            'series_name': series_tag.name
        })

    # Check if page number is taken in target series
    page_taken = SeriesPage.query.filter_by(
        series_tag_id=series_tag_id,
        page_number=page_number
    ).first()
    if page_taken:
        return jsonify(ok=False, error=f"Page {page_number} already exists in this series"), 409

    if existing_in_other:
        # Case 3: In a different series - move to new series
        db.session.delete(existing_in_other)

    # Case 1 & 3: Create new series page
    sp = SeriesPage(
        series_tag_id=series_tag_id,
        image_id=image_id,
        page_number=page_number
    )
    db.session.add(sp)
    db.session.commit()

    return jsonify(ok=True, series_page={
        'id': sp.id,
        'page_number': sp.page_number,
        'series_tag_id': sp.series_tag_id,
        'series_name': series_tag.name
    })