import logging
import uuid
from pathlib import Path

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession

from rehearsalhub.db.engine import get_session
from rehearsalhub.db.models import Member
from rehearsalhub.dependencies import get_current_member
from rehearsalhub.repositories.audio_version import AudioVersionRepository
from rehearsalhub.repositories.band import BandRepository
from rehearsalhub.repositories.comment import CommentRepository
from rehearsalhub.repositories.song import SongRepository
from rehearsalhub.schemas.comment import SongCommentCreate, SongCommentRead
from rehearsalhub.schemas.song import SongCreate, SongRead
from rehearsalhub.services.band import BandService
from rehearsalhub.services.song import SongService
from rehearsalhub.storage.nextcloud import NextcloudClient

log = logging.getLogger(__name__)

router = APIRouter(tags=["songs"])

AUDIO_EXTENSIONS = {".mp3", ".wav", ".flac", ".ogg", ".m4a", ".aac", ".opus"}


@router.get("/bands/{band_id}/songs", response_model=list[SongRead])
async def list_songs(
    band_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    band_svc = BandService(session)
    try:
        await band_svc.assert_membership(band_id, current_member.id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")
    song_svc = SongService(session)
    return await song_svc.list_songs(band_id)


@router.post("/bands/{band_id}/songs", response_model=SongRead, status_code=status.HTTP_201_CREATED)
async def create_song(
    band_id: uuid.UUID,
    data: SongCreate,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    band_svc = BandService(session)
    try:
        await band_svc.assert_membership(band_id, current_member.id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")

    band_repo = BandRepository(session)
    band = await band_repo.get_by_id(band_id)
    if band is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Band not found")

    song_svc = SongService(session)
    song = await song_svc.create_song(band_id, data, current_member.id, band.slug, creator=current_member)
    read = SongRead.model_validate(song)
    read.version_count = 0
    return read


@router.post("/bands/{band_id}/nc-scan", response_model=list[SongRead])
async def scan_nextcloud(
    band_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    """
    Scan the band's Nextcloud folder for audio files and import any not yet
    registered as songs/versions. Idempotent — safe to call multiple times.
    """
    band_svc = BandService(session)
    try:
        await band_svc.assert_membership(band_id, current_member.id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")

    band_repo = BandRepository(session)
    band = await band_repo.get_by_id(band_id)
    if band is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Band not found")

    nc = NextcloudClient.for_member(current_member)
    version_repo = AudioVersionRepository(session)
    song_svc = SongService(session)

    # dav_prefix to strip full WebDAV hrefs → user-relative paths
    dav_prefix = f"/remote.php/dav/files/{nc._auth[0]}/"

    def relative(href: str) -> str:
        if href.startswith(dav_prefix):
            return href[len(dav_prefix):]
        return href.lstrip("/")

    imported: list[SongRead] = []
    band_folder = band.nc_folder_path or f"bands/{band.slug}/"

    log.info("Starting NC scan for band '%s' in folder '%s'", band.slug, band_folder)

    try:
        items = await nc.list_folder(band_folder)
    except Exception as exc:
        raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY, detail=f"Nextcloud unreachable: {exc}")

    log.info("Found %d top-level entries in '%s'", len(items), band_folder)

    # Collect (nc_file_path, nc_folder, song_title, rehearsal_label) tuples.
    # nc_folder is the directory that groups versions of the same song.
    # For YYMMDD / dated rehearsal subfolders each file is its own song —
    # the song title comes from the filename stem, not the folder name.
    to_import: list[tuple[str, str, str, str | None]] = []

    for item in items:
        rel = relative(item.path)
        if rel.endswith("/"):
            dir_name = Path(rel.rstrip("/")).name
            try:
                sub_items = await nc.list_folder(rel)
            except Exception as exc:
                log.warning("Could not list subfolder '%s': %s", rel, exc)
                continue

            audio_files = [s for s in sub_items if Path(relative(s.path)).suffix.lower() in AUDIO_EXTENSIONS]
            log.info("Subfolder '%s': %d audio files found", dir_name, len(audio_files))

            for sub in audio_files:
                sub_rel = relative(sub.path)
                song_title = Path(sub_rel).stem
                # Each file in a rehearsal folder is its own song,
                # grouped under its own sub-subfolder path for version tracking.
                song_folder = str(Path(sub_rel).parent) + "/"
                rehearsal_label = dir_name  # e.g. "231015" or "2023-10-15"
                to_import.append((sub_rel, song_folder, song_title, rehearsal_label))
        else:
            if Path(rel).suffix.lower() in AUDIO_EXTENSIONS:
                folder = str(Path(rel).parent) + "/"
                title = Path(rel).stem
                to_import.append((rel, folder, title, None))

    log.info("NC scan: %d audio files to evaluate for import", len(to_import))

    song_repo = SongRepository(session)
    from rehearsalhub.schemas.audio_version import AudioVersionCreate  # noqa: PLC0415

    for nc_file_path, nc_folder, song_title, rehearsal_label in to_import:
        # Skip if this exact file version is already registered
        try:
            meta = await nc.get_file_metadata(nc_file_path)
            etag = meta.etag
        except Exception as exc:
            log.warning("Could not fetch metadata for '%s': %s — skipping", nc_file_path, exc)
            continue

        if etag and await version_repo.get_by_etag(etag):
            log.debug("Skipping '%s' — etag already registered", nc_file_path)
            continue

        # Find or create song record
        song = await song_repo.get_by_nc_folder_path(nc_folder)
        if song is None:
            song = await song_repo.get_by_title_and_band(band_id, song_title)
        if song is None:
            log.info("Creating new song '%s' (folder: %s)", song_title, nc_folder)
            song = await song_repo.create(
                band_id=band_id,
                title=song_title,
                status="jam",
                notes=f"Rehearsal: {rehearsal_label}" if rehearsal_label else None,
                nc_folder_path=nc_folder,
                created_by=current_member.id,
            )
        else:
            log.info("Found existing song '%s' (id: %s)", song.title, song.id)

        await song_svc.register_version(
            song.id,
            AudioVersionCreate(
                nc_file_path=nc_file_path,
                nc_file_etag=etag,
                format=Path(nc_file_path).suffix.lstrip(".").lower(),
                file_size_bytes=meta.size if etag else None,
            ),
            current_member.id,
        )

        read = SongRead.model_validate(song)
        read.version_count = 1
        imported.append(read)
        label_info = f" [rehearsal: {rehearsal_label}]" if rehearsal_label else ""
        log.info("Imported '%s' as song '%s'%s", nc_file_path, song_title, label_info)

    log.info("NC scan complete: %d new versions imported", len(imported))
    return imported


# ── Comments ──────────────────────────────────────────────────────────────────


async def _assert_song_membership(
    song_id: uuid.UUID, member_id: uuid.UUID, session: AsyncSession
) -> None:
    song_repo = SongRepository(session)
    song = await song_repo.get_by_id(song_id)
    if song is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Song not found")
    band_svc = BandService(session)
    try:
        await band_svc.assert_membership(song.band_id, member_id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")


@router.get("/songs/{song_id}/comments", response_model=list[SongCommentRead])
async def list_comments(
    song_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    await _assert_song_membership(song_id, current_member.id, session)
    repo = CommentRepository(session)
    comments = await repo.list_for_song(song_id)
    return [SongCommentRead.from_model(c) for c in comments]


@router.post("/songs/{song_id}/comments", response_model=SongCommentRead, status_code=status.HTTP_201_CREATED)
async def create_comment(
    song_id: uuid.UUID,
    data: SongCommentCreate,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    await _assert_song_membership(song_id, current_member.id, session)
    repo = CommentRepository(session)
    comment = await repo.create(song_id=song_id, author_id=current_member.id, body=data.body)
    comment = await repo.get_with_author(comment.id)
    return SongCommentRead.from_model(comment)


@router.delete("/comments/{comment_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_comment(
    comment_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    repo = CommentRepository(session)
    comment = await repo.get_with_author(comment_id)
    if comment is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Comment not found")

    # Allow author or band admin
    if comment.author_id != current_member.id:
        song_repo = SongRepository(session)
        song = await song_repo.get_by_id(comment.song_id)
        band_svc = BandService(session)
        try:
            await band_svc.assert_admin(song.band_id, current_member.id)  # type: ignore[union-attr]
        except PermissionError:
            raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not allowed")

    await repo.delete(comment)