import json
import logging
import uuid

from fastapi import APIRouter, Depends, HTTPException, Query, status
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession

from rehearsalhub.config import get_settings
from rehearsalhub.db.engine import get_session, get_session_factory
from rehearsalhub.queue.redis_queue import flush_pending_pushes
from rehearsalhub.db.models import Member
from rehearsalhub.dependencies import get_current_member
from rehearsalhub.repositories.band import BandRepository
from rehearsalhub.repositories.band_storage import BandStorageRepository
from rehearsalhub.repositories.comment import CommentRepository
from rehearsalhub.repositories.song import SongRepository
from rehearsalhub.routers.versions import _member_from_request
from rehearsalhub.schemas.comment import SongCommentCreate, SongCommentRead
from rehearsalhub.schemas.song import SongCreate, SongRead, SongUpdate
from rehearsalhub.services.band import BandService
from rehearsalhub.services.nc_scan import scan_band_folder
from rehearsalhub.services.song import SongService
from rehearsalhub.storage.factory import StorageFactory

log = logging.getLogger(__name__)

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

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


class NcScanResult(BaseModel):
    folder: str
    files_found: int
    imported: int
    skipped: int
    songs: list[SongRead]


@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.get("/bands/{band_id}/songs/search", response_model=list[SongRead])
async def search_songs(
    band_id: uuid.UUID,
    q: str | None = Query(None, description="Title substring search"),
    tags: list[str] = Query(default=[], description="Songs must have ALL these tags"),
    key: str | None = Query(None, description="Musical key, e.g. 'Am' or 'C'"),
    bpm_min: float | None = Query(None, ge=0),
    bpm_max: float | None = Query(None, ge=0),
    session_id: uuid.UUID | None = Query(None),
    unattributed: bool = Query(False, description="Only songs with no rehearsal session"),
    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_repo = SongRepository(session)
    songs = await song_repo.search(
        band_id,
        q=q,
        tags=tags or None,
        key=key,
        bpm_min=bpm_min,
        bpm_max=bpm_max,
        session_id=session_id,
        unattributed=unattributed,
    )
    return [
        SongRead.model_validate(s).model_copy(update={"version_count": len(s.versions)})
        for s in songs
    ]


@router.get("/songs/{song_id}", response_model=SongRead)
async def get_song(
    song_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    song_repo = SongRepository(session)
    song = await song_repo.get_with_versions(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, current_member.id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")
    return SongRead.model_validate(song).model_copy(update={"version_count": len(song.versions)})


@router.patch("/songs/{song_id}", response_model=SongRead)
async def update_song(
    song_id: uuid.UUID,
    data: SongUpdate,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    song_repo = SongRepository(session)
    song = await song_repo.get_with_versions(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, current_member.id)
    except PermissionError:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")

    updates = {k: v for k, v in data.model_dump().items() if v is not None}
    if updates:
        song = await song_repo.update(song, **updates)

    return SongRead.model_validate(song).model_copy(update={"version_count": len(song.versions)})


@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)
    read = SongRead.model_validate(song)
    read.version_count = 0
    return read


async def _get_band_and_assert_member(
    band_id: uuid.UUID,
    current_member: Member,
    session: AsyncSession,
):
    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")
    return band


@router.get("/bands/{band_id}/nc-scan/stream")
async def scan_nextcloud_stream(
    band_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(_member_from_request),
):
    """
    SSE endpoint: streams scan progress as newline-delimited JSON events.
    Each event is a JSON object on its own line.
    Accepts ?token= for EventSource clients that can't set headers.
    """
    band = await _get_band_and_assert_member(band_id, current_member, session)
    bs = await BandStorageRepository(session).get_active_for_band(band_id)
    band_folder = (bs.root_path if bs and bs.root_path else None) or f"bands/{band.slug}/"
    member_id = current_member.id
    settings = get_settings()

    async def event_generator():
        async with get_session_factory()() as db:
            try:
                storage = await StorageFactory.create(db, band_id, settings)
                async for event in scan_band_folder(db, storage, band_id, band_folder, member_id):
                    yield json.dumps(event) + "\n"
                    if event.get("type") in ("song", "session"):
                        await db.commit()
                        await flush_pending_pushes(db)
            except LookupError as exc:
                yield json.dumps({"type": "error", "message": str(exc)}) + "\n"
            except Exception:
                log.exception("SSE scan error for band %s", band_id)
                yield json.dumps({"type": "error", "message": "Scan failed due to an internal error."}) + "\n"
            finally:
                await db.commit()
                await flush_pending_pushes(db)

    return StreamingResponse(
        event_generator(),
        media_type="application/x-ndjson",
    )


@router.post("/bands/{band_id}/nc-scan", response_model=NcScanResult)
async def scan_nextcloud(
    band_id: uuid.UUID,
    session: AsyncSession = Depends(get_session),
    current_member: Member = Depends(get_current_member),
):
    """
    Blocking scan — collects all results then returns. Delegates to scan_band_folder.
    Prefer the SSE /nc-scan/stream endpoint for large folders.
    """
    band = await _get_band_and_assert_member(band_id, current_member, session)
    bs = await BandStorageRepository(session).get_active_for_band(band_id)
    band_folder = (bs.root_path if bs and bs.root_path else None) or f"bands/{band.slug}/"

    try:
        storage = await StorageFactory.create(session, band_id, get_settings())
    except LookupError as exc:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=str(exc))

    songs: list[SongRead] = []
    stats = {"found": 0, "imported": 0, "skipped": 0}

    async for event in scan_band_folder(session, storage, band_id, band_folder, current_member.id):
        if event["type"] == "song":
            songs.append(SongRead(**event["song"]))
        elif event["type"] == "done":
            stats = event["stats"]
        elif event["type"] == "error":
            raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY, detail=event["message"])

    return NcScanResult(
        folder=band_folder,
        files_found=stats["found"],
        imported=stats["imported"],
        skipped=stats["skipped"],
        songs=songs,
    )


# ── 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, timestamp=data.timestamp, tag=data.tag)
    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)