"""Import admin API: trigger scan, list tasks, retry, clear."""

from datetime import UTC, datetime, timedelta

from quart import Blueprint, jsonify, request
from sqlalchemy import delete, select, update

from ..extensions import make_engine, make_session_factory
from ..models import ImportBatch, ImportTask

import_admin_bp = Blueprint("import_admin", __name__, url_prefix="/api/import")

_engine = None
_Session = None


def _session_factory():
    global _engine, _Session
    if _engine is None:
        _engine = make_engine()
        _Session = make_session_factory(_engine)
    return _Session


@import_admin_bp.route("/trigger", methods=["POST"])
async def trigger_scan():
    body = await request.get_json(silent=True) or {}
    mode = body.get("mode", "quick")
    if mode != "quick":
        # FC-2d will accept 'deep'. For now, reject anything else.
        return jsonify({"error": f"mode {mode!r} not supported in FC-2a; use 'quick'"}), 400

    # Enqueue the scan task in Celery. The task creates the batch itself.
    from ..tasks.scan import scan_directory

    async_result = scan_directory.delay(triggered_by="manual")
    return jsonify({"celery_task_id": async_result.id, "mode": mode}), 202


@import_admin_bp.route("/status", methods=["GET"])
async def status():
    Session = _session_factory()
    async with Session() as session:
        active = (
            await session.execute(
                select(ImportBatch)
                .where(ImportBatch.status == "running")
                .order_by(ImportBatch.started_at.desc())
                .limit(1)
            )
        ).scalar_one_or_none()
        payload = {"active_batch": None}
        if active:
            payload["active_batch"] = {
                "id": active.id,
                "total_files": active.total_files,
                "imported": active.imported,
                "skipped": active.skipped,
                "failed": active.failed,
                "started_at": active.started_at.isoformat(),
            }
        return jsonify(payload)


@import_admin_bp.route("/tasks", methods=["GET"])
async def list_tasks():
    status_filter = request.args.get("status")
    try:
        limit = min(int(request.args.get("limit", "50")), 200)
    except ValueError:
        return jsonify({"error": "limit must be an integer"}), 400
    cursor_raw = request.args.get("cursor")
    cursor_id = int(cursor_raw) if cursor_raw else None

    Session = _session_factory()
    async with Session() as session:
        stmt = select(ImportTask).order_by(ImportTask.created_at.desc(), ImportTask.id.desc())
        if status_filter:
            stmt = stmt.where(ImportTask.status == status_filter)
        if cursor_id is not None:
            stmt = stmt.where(ImportTask.id < cursor_id)
        stmt = stmt.limit(limit + 1)
        rows = (await session.execute(stmt)).scalars().all()

    has_more = len(rows) > limit
    rows = rows[:limit]
    return jsonify({
        "tasks": [
            {
                "id": t.id,
                "batch_id": t.batch_id,
                "source_path": t.source_path,
                "task_type": t.task_type,
                "status": t.status,
                "result_image_id": t.result_image_id,
                "error": t.error,
                "size_bytes": t.size_bytes,
                "created_at": t.created_at.isoformat(),
                "started_at": t.started_at.isoformat() if t.started_at else None,
                "finished_at": t.finished_at.isoformat() if t.finished_at else None,
            }
            for t in rows
        ],
        "next_cursor": rows[-1].id if has_more and rows else None,
    })


@import_admin_bp.route("/retry-failed", methods=["POST"])
async def retry_failed():
    Session = _session_factory()
    async with Session() as session:
        failed_ids = (
            await session.execute(select(ImportTask.id).where(ImportTask.status == "failed"))
        ).scalars().all()
        if not failed_ids:
            return jsonify({"retried": 0})
        await session.execute(
            update(ImportTask)
            .where(ImportTask.id.in_(failed_ids))
            .values(status="queued", error=None, started_at=None, finished_at=None)
        )
        await session.commit()

    from ..tasks.import_file import import_media_file
    for tid in failed_ids:
        import_media_file.delay(tid)

    return jsonify({"retried": len(failed_ids)})


@import_admin_bp.route("/clear-completed", methods=["POST"])
async def clear_completed():
    body = await request.get_json(silent=True) or {}
    age_days = body.get("age_days", 0)
    status_filter = body.get("status", ["complete", "skipped"])
    if not isinstance(status_filter, list):
        return jsonify({"error": "status must be a list"}), 400

    cutoff = (
        datetime.now(UTC) - timedelta(days=int(age_days)) if age_days else None
    )

    Session = _session_factory()
    async with Session() as session:
        stmt = delete(ImportTask).where(ImportTask.status.in_(status_filter))
        if cutoff is not None:
            stmt = stmt.where(ImportTask.finished_at < cutoff)
        result = await session.execute(stmt)
        await session.commit()

    return jsonify({"deleted": result.rowcount or 0})