"""MediaAsset router — /api/media."""
import io
import math
import uuid
import zipfile

from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import StreamingResponse
from sqlalchemy import select, func
from sqlalchemy.ext.asyncio import AsyncSession

from app.database import get_db
from app.domains.auth.models import User
from app.domains.media.models import MediaAsset, MediaAssetType
from app.domains.media.schemas import MediaAssetOut, MediaAssetBrowseItem, MediaAssetBrowseResponse
from app.domains.media import service
from app.utils.auth import get_current_user

router = APIRouter(prefix="/api/media", tags=["media"], redirect_slashes=False)


async def _resolve_thumbnails_bulk(db: AsyncSession, assets: list) -> None:
    """Resolve thumbnail_url for assets using the same priority as product pages.

    Priority per asset (applied only when thumbnail_url is not yet set):
      1. Latest 'still' MediaAsset for the same product (rendered preview)
      2. Product's linked CadFile thumbnail (/api/cad/{id}/thumbnail)
    """
    needs = [a for a in assets if not a.thumbnail_url and a.product_id]
    if not needs:
        return

    product_ids = list({a.product_id for a in needs})

    # 1. Latest 'still' asset per product (DISTINCT ON product_id ORDER BY created_at DESC)
    still_rows = await db.execute(
        select(MediaAsset.product_id, MediaAsset.id)
        .where(
            MediaAsset.product_id.in_(product_ids),
            MediaAsset.asset_type == MediaAssetType.still,
            MediaAsset.is_archived == False,  # noqa: E712
        )
        .order_by(MediaAsset.product_id, MediaAsset.created_at.desc())
        .distinct(MediaAsset.product_id)
    )
    best_still: dict[str, str] = {str(pid): str(sid) for pid, sid in still_rows.all()}

    # 2. Fallback: product's cad_file_id → CAD thumbnail endpoint
    from app.domains.products.models import Product
    from sqlalchemy import text
    # products has RLS — bypass for this internal read-only lookup
    await db.execute(text("SET LOCAL app.current_tenant_id = 'bypass'"))
    prod_rows = await db.execute(
        select(Product.id, Product.cad_file_id).where(Product.id.in_(product_ids))
    )
    product_cad: dict[str, str] = {
        str(pid): str(cid) for pid, cid in prod_rows.all() if cid
    }

    for a in needs:
        pid = str(a.product_id)
        if pid in best_still:
            a.thumbnail_url = f"/api/media/{best_still[pid]}/download"
        elif pid in product_cad:
            a.thumbnail_url = f"/api/cad/{product_cad[pid]}/thumbnail"


@router.get("", response_model=list[MediaAssetOut])
@router.get("/", response_model=list[MediaAssetOut], include_in_schema=False)
async def list_assets(
    product_id: uuid.UUID | None = None,
    order_line_id: uuid.UUID | None = None,
    cad_file_id: uuid.UUID | None = None,
    asset_type: MediaAssetType | None = None,
    asset_types: list[MediaAssetType] = Query(default=[]),
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=500),
    sort_by: str = Query("created_at"),
    sort_dir: str = Query("desc"),
    _user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    assets = await service.list_media_assets(
        db,
        product_id=product_id,
        order_line_id=order_line_id,
        cad_file_id=cad_file_id,
        asset_type=asset_type,
        asset_types=asset_types if asset_types else None,
        skip=skip,
        limit=limit,
        sort_by=sort_by,
        sort_dir=sort_dir,
    )
    for a in assets:
        a.download_url = service.get_download_url(a)
        a.thumbnail_url = service.get_thumbnail_url(a)
    await _resolve_thumbnails_bulk(db, assets)
    return assets


@router.get("/assets", response_model=MediaAssetBrowseResponse)
async def browse_media_assets(
    asset_type: str | None = None,
    category_key: str | None = None,
    render_status: str | None = None,
    q: str | None = None,
    page: int = Query(1, ge=1),
    page_size: int = Query(50, ge=1, le=200),
    _user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
) -> MediaAssetBrowseResponse:
    """Media browser: server-side filtered + paginated asset list with product context."""
    from app.domains.products.models import Product
    from app.domains.orders.models import OrderLine
    from sqlalchemy import desc

    # Build query with LEFT JOINs to get product and order_line context.
    # MediaAsset has direct product_id FK and order_line_id FK.
    # OrderLine has render_status which we also want to surface.
    stmt = (
        select(
            MediaAsset,
            Product.name.label("product_name"),
            Product.pim_id.label("product_pim_id"),
            Product.category_key.label("category_key"),
            OrderLine.render_status.label("render_status"),
        )
        .outerjoin(Product, MediaAsset.product_id == Product.id)
        .outerjoin(OrderLine, MediaAsset.order_line_id == OrderLine.id)
        .where(MediaAsset.is_archived == False)  # noqa: E712
        .order_by(desc(MediaAsset.created_at))
    )

    # Apply filters
    if asset_type:
        try:
            at_enum = MediaAssetType(asset_type)
            stmt = stmt.where(MediaAsset.asset_type == at_enum)
        except ValueError:
            pass  # invalid type → ignore filter

    if category_key:
        stmt = stmt.where(Product.category_key == category_key)

    if render_status:
        stmt = stmt.where(OrderLine.render_status == render_status)

    if q:
        pattern = f"%{q}%"
        from sqlalchemy import or_
        stmt = stmt.where(
            or_(
                Product.name.ilike(pattern),
                Product.pim_id.ilike(pattern),
            )
        )

    # Count total matching rows
    count_stmt = select(func.count()).select_from(stmt.subquery())
    total_result = await db.execute(count_stmt)
    total = total_result.scalar_one()

    # Paginate
    offset = (page - 1) * page_size
    stmt = stmt.offset(offset).limit(page_size)

    rows = await db.execute(stmt)
    items: list[MediaAssetBrowseItem] = []
    for row in rows.all():
        asset: MediaAsset = row[0]
        product_name: str | None = row[1]
        product_pim_id: str | None = row[2]
        cat_key: str | None = row[3]
        r_status: str | None = row[4]

        item = MediaAssetBrowseItem(
            id=asset.id,
            asset_type=asset.asset_type,
            file_path=asset.storage_key,
            file_size_bytes=asset.file_size_bytes,
            mime_type=asset.mime_type,
            created_at=asset.created_at,
            order_line_id=asset.order_line_id,
            product_id=asset.product_id,
            product_name=product_name,
            product_pim_id=product_pim_id,
            category_key=cat_key,
            render_status=r_status,
            download_url=f"/api/media/{asset.id}/download",
            thumbnail_url=service.get_thumbnail_url(asset),
        )
        items.append(item)

    pages = max(1, math.ceil(total / page_size))
    return MediaAssetBrowseResponse(
        items=items,
        total=total,
        page=page,
        page_size=page_size,
        pages=pages,
    )


@router.get("/{asset_id}", response_model=MediaAssetOut)
async def get_asset(asset_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
    asset = await service.get_media_asset(db, asset_id)
    if not asset:
        raise HTTPException(404, "Asset not found")
    asset.download_url = service.get_download_url(asset)
    asset.thumbnail_url = service.get_thumbnail_url(asset)
    await _resolve_thumbnails_bulk(db, [asset])
    return asset


@router.api_route("/{asset_id}/download", methods=["GET", "HEAD"])
async def download_asset(
    asset_id: uuid.UUID,
    _user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """Proxy file content directly — avoids internal MinIO hostname issues."""
    from fastapi.responses import FileResponse, Response
    from pathlib import Path
    asset = await service.get_media_asset(db, asset_id)
    if not asset:
        raise HTTPException(404, "Asset not found")

    key = asset.storage_key
    mime = asset.mime_type or "application/octet-stream"

    # Local file path (absolute or relative to UPLOAD_DIR)
    from app.config import settings
    candidate = Path(key)
    if not candidate.is_absolute():
        candidate = Path(settings.upload_dir) / key
    # Legacy path remapping: /shared/renders/{uuid}/{file} → UPLOAD_DIR/renders/{uuid}/{file}
    if not candidate.exists() and "/shared/renders/" in key:
        import logging
        parts = key.split("/")
        if len(parts) >= 2:
            remapped = Path(settings.upload_dir) / "renders" / parts[-2] / parts[-1]
            if remapped.exists():
                logging.getLogger(__name__).warning(
                    "Remapped legacy path %s → %s", key, remapped
                )
                candidate = remapped
    if candidate.exists():
        ext = candidate.suffix.lstrip(".")
        fname = f"{asset.asset_type.value}_{asset_id}.{ext or 'bin'}"
        return FileResponse(
            str(candidate), media_type=mime, filename=fname,
            headers={"Cache-Control": "max-age=3600, public"},
        )

    # Fall back to MinIO
    try:
        from app.core.storage import get_storage
        data = get_storage().download_bytes(key)
        ext = key.rsplit(".", 1)[-1] if "." in key else "bin"
        fname = f"{asset.asset_type.value}_{asset_id}.{ext}"
        return Response(
            content=data,
            media_type=mime,
            headers={
                "Content-Disposition": f"attachment; filename={fname}",
                "Cache-Control": "max-age=3600, public",
            },
        )
    except Exception:
        raise HTTPException(404, "File not available")


@router.post("/zip")
async def zip_download(
    asset_ids: list[uuid.UUID],
    _user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    assets = []
    for aid in asset_ids:
        a = await service.get_media_asset(db, aid)
        if a:
            assets.append(a)
    if not assets:
        raise HTTPException(404, "No assets found")

    def generate():
        import logging
        from pathlib import Path
        from app.core.storage import get_storage
        logger = logging.getLogger(__name__)
        buf = io.BytesIO()
        seen_names: dict[str, int] = {}
        with zipfile.ZipFile(buf, "w", zipfile.ZIP_DEFLATED) as zf:
            storage = get_storage()
            for a in assets:
                key = a.storage_key
                # Use filename from storage_key (always has correct extension)
                original_name = Path(key).name
                ext = Path(key).suffix.lstrip(".") or (a.mime_type or "").split("/")[-1] or "bin"
                base = original_name if original_name else f"{a.asset_type.value}_{a.id}.{ext}"
                # Deduplicate filenames within the ZIP
                if base in seen_names:
                    seen_names[base] += 1
                    stem = Path(base).stem
                    suffix = Path(base).suffix
                    fname = f"{stem}_{seen_names[base]}{suffix}"
                else:
                    seen_names[base] = 0
                    fname = base
                try:
                    # Check absolute path first (local filesystem)
                    candidate = Path(key)
                    if not candidate.is_absolute():
                        from app.config import settings
                        candidate = Path(settings.upload_dir) / key
                    if candidate.exists():
                        data = candidate.read_bytes()
                    else:
                        data = storage.download_bytes(key)
                    zf.writestr(fname, data)
                except Exception as exc:
                    logger.warning("ZIP: skipping asset %s — %s", a.id, exc)
        yield buf.getvalue()

    return StreamingResponse(
        generate(),
        media_type="application/zip",
        headers={"Content-Disposition": "attachment; filename=media-export.zip"},
    )


@router.delete("/{asset_id}")
async def archive_asset(asset_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
    asset = await service.archive_media_asset(db, asset_id)
    if not asset:
        raise HTTPException(404, "Asset not found")
    return {"ok": True}


@router.delete("/{asset_id}/permanent")
async def delete_asset_permanent(asset_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
    """Permanently remove a MediaAsset record from the database."""
    deleted = await service.delete_media_asset(db, asset_id)
    if not deleted:
        raise HTTPException(404, "Asset not found")
    return {"ok": True}