"""FC-3k: /api/admin — destructive admin actions.

Five action surfaces:
  POST   /api/admin/artists/<slug>/cascade-delete  (Tier C)
  POST   /api/admin/images/bulk-delete             (Tier C)
  DELETE /api/admin/tags/<int:tag_id>              (Tier B)
  POST   /api/admin/tags/<int:dest_id>/merge       (Tier B)
  POST   /api/admin/tags/prune-unused              (Tier A)
  POST   /api/admin/posts/prune-bare               (Tier A)
  POST   /api/admin/tags/purge-legacy              (Tier A)
  GET    /api/admin/tags/<int:tag_id>/usage-count  (helper)

Tier-C ops take a dry_run body flag (returns projection inline,
no dispatch) and a confirm body field (server-recomputed token).
Long-running ops dispatch a maintenance-queue Celery task; the UI
tails FC-3i's /api/system/activity/runs to surface progress.
"""
from __future__ import annotations

import hashlib

from quart import Blueprint, jsonify, request
from sqlalchemy import select, text

from ..extensions import get_session
from ..models import Artist
from ..services.cleanup_service import project_artist_cascade, project_bulk_image_delete
from ._responses import error_response as _bad

admin_bp = Blueprint("admin", __name__, url_prefix="/api/admin")


def _bulk_image_confirm_token(image_ids: list[int]) -> str:
    """Stable 8-hex token derived from the sorted id list. Mutates
    when the selection changes; stays the same across modal opens of
    the same selection so the operator can paste without confusion."""
    canon = ",".join(str(i) for i in sorted(image_ids))
    digest = hashlib.sha256(canon.encode("utf-8")).hexdigest()
    return digest[:8]


@admin_bp.route("/artists/<slug>/cascade-delete", methods=["POST"])
async def artist_cascade_delete(slug: str):
    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", False))
    supplied_confirm = body.get("confirm", "")

    async with get_session() as session:
        artist = (await session.execute(
            select(Artist).where(Artist.slug == slug)
        )).scalar_one_or_none()
        if artist is None:
            return _bad("not_found", status=404)
        artist_id = artist.id

        projected = await session.run_sync(
            lambda sync_sess: project_artist_cascade(sync_sess, slug=slug)
        )

    if dry_run:
        return jsonify(projected)

    expected = f"delete-artist-{artist_id}"
    if supplied_confirm != expected:
        return _bad(
            "confirm_mismatch",
            detail=f"confirm must equal {expected!r}",
            expected=expected,
        )

    from ..tasks.admin import delete_artist_cascade_task
    async_result = delete_artist_cascade_task.delay(artist_id=artist_id)
    return jsonify({"task_id": async_result.id}), 202


@admin_bp.route("/images/bulk-delete", methods=["POST"])
async def images_bulk_delete():
    body = await request.get_json(silent=True) or {}
    image_ids = body.get("image_ids")
    if not isinstance(image_ids, list) or not image_ids:
        return _bad("invalid_image_ids", detail="image_ids must be non-empty list of int")
    try:
        image_ids = [int(i) for i in image_ids]
    except (TypeError, ValueError):
        return _bad("invalid_image_ids", detail="image_ids must contain only ints")

    dry_run = bool(body.get("dry_run", False))
    supplied_confirm = body.get("confirm", "")

    async with get_session() as session:
        projected = await session.run_sync(
            lambda sync_sess: project_bulk_image_delete(
                sync_sess, image_ids=image_ids,
            )
        )

    sha8 = _bulk_image_confirm_token(image_ids)
    expected = f"delete-images-{sha8}"

    if dry_run:
        # Hand the canonical Tier-C confirm token back with the
        # projection so the frontend doesn't have to recompute SHA-256
        # client-side via crypto.subtle (Secure-Context-gated,
        # undefined on plain-HTTP origins per the homelab posture).
        # Operator-flagged 2026-05-27.
        projected["confirm_token"] = expected
        return jsonify(projected)


    if supplied_confirm != expected:
        return _bad(
            "confirm_mismatch",
            detail=f"confirm must equal {expected!r}",
            expected=expected,
        )

    from ..tasks.admin import bulk_delete_images_task
    async_result = bulk_delete_images_task.delay(image_ids=image_ids)
    return jsonify({"task_id": async_result.id}), 202


@admin_bp.route("/tags/<int:tag_id>", methods=["DELETE"])
async def tag_delete(tag_id: int):
    """Tier-B sync delete. UI yes/no modal is the only confirmation."""
    from ..services.cleanup_service import delete_tag

    async with get_session() as session:
        try:
            result = await session.run_sync(
                lambda sync_sess: delete_tag(sync_sess, tag_id=tag_id)
            )
        except LookupError:
            return _bad("not_found", status=404)
    return jsonify(result)


@admin_bp.route("/tags/<int:dest_id>/merge", methods=["POST"])
async def tag_merge(dest_id: int):
    """Wraps TagService.merge. Source repoints to dest, dest survives,
    source row deleted, protective alias auto-created if source was
    ML-applied or allowlisted."""
    from ..services.tag_service import TagMergeConflict, TagService, TagValidationError

    body = await request.get_json(silent=True) or {}
    source_id = body.get("source_id")
    if not isinstance(source_id, int) or source_id == dest_id:
        return _bad("invalid_source_id", detail="source_id must be int and differ from dest")

    async with get_session() as session:
        try:
            result = await TagService(session).merge(
                source_id=source_id, target_id=dest_id,
            )
        except TagMergeConflict as exc:
            return _bad("merge_conflict", status=409, detail=str(exc))
        except TagValidationError as exc:
            return _bad("tag_kind_mismatch", detail=str(exc))
        except LookupError:
            return _bad("not_found", status=404)

    # MergeResult is a frozen dataclass — flatten to dict.
    return jsonify({
        "result": {
            "target_id": result.target_id,
            "target_name": result.target_name,
            "target_kind": result.target_kind,
            "merged_count": result.merged_count,
            "alias_created": result.alias_created,
            "source_deleted": result.source_deleted,
        },
    })


@admin_bp.route("/tags/<int:tag_id>/usage-count", methods=["GET"])
async def tag_usage_count(tag_id: int):
    """Helper for the Tier-B yes/no prompt; surfaces "N associations"
    in the dialog so the operator knows what they're nuking."""
    from ..services.cleanup_service import count_tag_associations

    async with get_session() as session:
        count = await session.run_sync(
            lambda sync_sess: count_tag_associations(
                sync_sess, tag_id=tag_id,
            )
        )
    return jsonify({"count": count})


@admin_bp.route("/tags/prune-unused", methods=["POST"])
async def tags_prune_unused():
    """Tier-A: dry-run preview list IS the prompt. UI calls with
    dry_run=true first, shows the list, operator clicks button to
    re-call with dry_run=false."""
    from ..services.cleanup_service import prune_unused_tags

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", False))

    async with get_session() as session:
        result = await session.run_sync(
            lambda sync_sess: prune_unused_tags(
                sync_sess, dry_run=dry_run,
            )
        )
    return jsonify(result)


@admin_bp.route("/posts/prune-bare", methods=["POST"])
async def posts_prune_bare():
    """Tier-A: delete bare posts — Post rows with no linked images (primary OR
    provenance) and no attachments. Dry-run preview list IS the prompt: UI calls
    with dry_run=true first, shows the count + sample, operator confirms by
    re-calling with dry_run=false. Same preview/apply-parity predicate as the
    prune itself, so the preview can't diverge from the delete."""
    from ..services.cleanup_service import prune_bare_posts

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", False))

    async with get_session() as session:
        result = await session.run_sync(
            lambda sync_sess: prune_bare_posts(
                sync_sess, dry_run=dry_run,
            )
        )
    return jsonify(result)


@admin_bp.route("/tags/purge-legacy", methods=["POST"])
async def tags_purge_legacy():
    """Tier-A: delete legacy IR-migration tags — archive/post/artist
    kinds (e.g. `BlenderKnight:Hannah_BJ_Loops`) PLUS general tags with
    a legacy name prefix (`source:*`, from IR's source kind that fell
    back to general). dry-run preview returns per-kind + per-prefix
    counts + a sample so the UI shows exactly what'll go before the
    operator confirms with dry_run=false."""
    from ..services.cleanup_service import purge_legacy_tags

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", False))

    async with get_session() as session:
        result = await session.run_sync(
            lambda sync_sess: purge_legacy_tags(sync_sess, dry_run=dry_run)
        )
    return jsonify(result)


@admin_bp.route("/tags/reset-content", methods=["POST"])
async def tags_reset_content():
    """Tier-A: delete ALL general + character tags (the Camie-suggestable
    content vocabulary) so the operator can re-tag from scratch via
    auto-suggest. fandom + series tags + series_page ordering are preserved,
    and image_prediction rows are untouched so suggestions repopulate.
    dry-run preview returns per-kind counts + applications + a sample so the
    UI shows exactly what'll go before the operator confirms (dry_run=false).
    Irreversible except via DB backup restore."""
    from ..services.cleanup_service import reset_content_tagging

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", False))

    async with get_session() as session:
        result = await session.run_sync(
            lambda sync_sess: reset_content_tagging(sync_sess, dry_run=dry_run)
        )
    return jsonify(result)


@admin_bp.route("/tags/normalize", methods=["POST"])
async def tags_normalize():
    """#714: retro-normalize existing tags to the #701 canonical form (Title
    Case + collapsed whitespace) and merge case/whitespace-variant duplicates.

    dry_run=true (default) returns a projection inline — group/collision/rename
    counts + a sample of the changes — so the UI shows exactly what'll happen.
    dry_run=false dispatches the long-running maintenance task (the merge FK
    repoints can touch many tags); the UI tails the activity dashboard for the
    summary. Idempotent; back up first (the merges are irreversible)."""
    from ..services.tag_service import normalize_existing_tags

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", True))

    if dry_run:
        async with get_session() as session:
            result = await normalize_existing_tags(session, dry_run=True)
        return jsonify(result)

    from ..tasks.admin import normalize_tags_task

    async_result = normalize_tags_task.delay()
    return jsonify({"task_id": async_result.id, "status": "queued"}), 202


@admin_bp.route("/maintenance/db-stats", methods=["GET"])
async def db_stats():
    """Per-table bloat readout (pg_stat_user_tables) for the high-churn tables
    so the operator can see when a VACUUM is worth running."""
    from ..tasks.maintenance import VACUUM_TABLES

    wanted = set(VACUUM_TABLES)
    async with get_session() as session:
        rows = (await session.execute(text(
            "SELECT relname, n_live_tup, n_dead_tup, last_vacuum, "
            "last_autovacuum, last_analyze FROM pg_stat_user_tables"
        ))).all()

    def _iso(v):
        return v.isoformat() if v is not None else None

    out = []
    for r in rows:
        if r.relname not in wanted:
            continue
        live = r.n_live_tup or 0
        dead = r.n_dead_tup or 0
        total = live + dead
        out.append({
            "table": r.relname,
            "live": live,
            "dead": dead,
            "dead_pct": round(100 * dead / total, 1) if total else 0.0,
            "last_vacuum": _iso(r.last_vacuum),
            "last_autovacuum": _iso(r.last_autovacuum),
            "last_analyze": _iso(r.last_analyze),
        })
    out.sort(key=lambda t: t["dead"], reverse=True)
    return jsonify({"tables": out})


@admin_bp.route("/maintenance/vacuum", methods=["POST"])
async def trigger_vacuum():
    """Operator-triggered VACUUM (ANALYZE) over the high-churn tables — the
    same maintenance-queue task the weekly Beat schedule runs."""
    from ..tasks.maintenance import vacuum_analyze

    vacuum_analyze.delay()
    return jsonify({"status": "queued"}), 202


@admin_bp.route("/maintenance/reextract-archives", methods=["POST"])
async def trigger_reextract_archives():
    """Operator-triggered re-extract (#713): PostAttachments that are actually
    archives but were filed opaquely (pre magic-byte gate) get extracted and
    their members linked to the post. Idempotent; runs on the maintenance queue."""
    from ..tasks.admin import reextract_archive_attachments_task

    async_result = reextract_archive_attachments_task.delay()
    return jsonify({"task_id": async_result.id, "status": "queued"}), 202


@admin_bp.route("/maintenance/prune-missing-files", methods=["POST"])
async def trigger_prune_missing_files():
    """Operator-triggered orphan repair (#859): delete ImageRecords whose backing
    file is gone from disk (e.g. left by the external-attach unlink bug), so they
    stop 404-ing on playback. The task aborts WITHOUT deleting if a large fraction
    of files look missing (a filesystem/NFS stall). Maintenance queue;
    operator-triggered only — never an unattended sweep."""
    from ..tasks.admin import prune_missing_file_records_task

    async_result = prune_missing_file_records_task.delay()
    return jsonify({"task_id": async_result.id, "status": "queued"}), 202


@admin_bp.route("/maintenance/dedup-videos", methods=["POST"])
async def trigger_dedup_videos():
    """Tier-1 video dedup (#871). Body {"dry_run": bool}: dry_run=true previews
    what would be removed (groups / redundant count / reclaimable bytes) WITHOUT
    deleting; dry_run=false applies it (re-link posts to the keeper, then delete
    the redundant copies). Either way it first re-probes NULL-duration videos so
    the existing library participates. Returns the Celery task id — poll
    /maintenance/task-result/<id> for the summary."""
    from ..tasks.admin import dedup_videos_task

    body = await request.get_json(silent=True) or {}
    dry_run = bool(body.get("dry_run", True))  # default to the SAFE preview
    async_result = dedup_videos_task.delay(dry_run=dry_run)
    return jsonify({"task_id": async_result.id, "status": "queued"}), 202


@admin_bp.route("/maintenance/task-result/<task_id>", methods=["GET"])
async def maintenance_task_result(task_id: str):
    """Poll a maintenance Celery task's result (the summary dict it returns).
    Used by the video-dedup card to show the dry-run projection before apply."""
    from ..celery_app import celery

    res = celery.AsyncResult(task_id)
    ready = res.ready()
    return jsonify({
        "ready": ready,
        "successful": res.successful() if ready else None,
        "result": res.result if (ready and res.successful()) else None,
    })