"""
sharing.py — Forenklet deling af playlister.
Kun ejeren kan redigere. Delte brugere får read-only via sync.
"""
from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from sqlalchemy.orm import Session
from pydantic import BaseModel, EmailStr

from app.core.database import get_db
from app.core.security import get_current_user
from app.models import User, Project, PlaylistShare

router = APIRouter(prefix="/sharing", tags=["sharing"])


class ShareRequest(BaseModel):
    email: EmailStr


# ── Del med bruger ────────────────────────────────────────────────────────────

@router.post("/playlists/{project_id}/share", status_code=201)
async def share_playlist(
    project_id: str,
    data: ShareRequest,
    background_tasks: BackgroundTasks,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    """Del en playliste med en bruger — de får listen ved næste sync."""
    project = db.query(Project).filter_by(id=project_id, owner_id=me.id).first()
    if not project:
        raise HTTPException(404, "Playliste ikke fundet eller du er ikke ejer")

    target = db.query(User).filter_by(email=data.email).first()

    existing = db.query(PlaylistShare).filter_by(
        project_id=project_id, invited_email=data.email
    ).first()
    if existing:
        return {"detail": "Allerede delt med denne bruger"}

    share = PlaylistShare(
        project_id=project_id,
        shared_with_id=target.id if target else None,
        invited_email=data.email,
        permission="view",
    )
    db.add(share)
    db.commit()

    # Send invitation-mail
    try:
        from app.core.mail import send_share_invitation
        from app.core.config import settings
        background_tasks.add_task(
            send_share_invitation,
            email=data.email,
            owner_name=me.username,
            playlist_name=project.name,
            permission="view",
            accept_url=f"{settings.BASE_URL}/sharing/playlists/{project_id}",
        )
    except Exception:
        pass

    return {"detail": f"Delt med {data.email}"}


@router.delete("/playlists/{project_id}/share/{share_id}", status_code=204)
def remove_share(
    project_id: str,
    share_id: str,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    project = db.query(Project).filter_by(id=project_id, owner_id=me.id).first()
    if not project:
        raise HTTPException(404, "Playliste ikke fundet")
    share = db.query(PlaylistShare).filter_by(id=share_id, project_id=project_id).first()
    if not share:
        raise HTTPException(404, "Deling ikke fundet")
    db.delete(share)
    db.commit()


@router.get("/playlists/{project_id}/shares")
def list_shares(
    project_id: str,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    project = db.query(Project).filter_by(id=project_id, owner_id=me.id).first()
    if not project:
        raise HTTPException(404, "Playliste ikke fundet")
    shares = db.query(PlaylistShare).filter_by(project_id=project_id).all()
    return [{"id": s.id, "email": s.invited_email} for s in shares]


# ── Visibility ────────────────────────────────────────────────────────────────

@router.patch("/playlists/{project_id}/visibility")
def set_visibility(
    project_id: str,
    visibility: str,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    if visibility not in ("private", "shared", "public"):
        raise HTTPException(400, "Brug private, shared eller public")
    project = db.query(Project).filter_by(id=project_id, owner_id=me.id).first()
    if not project:
        raise HTTPException(404, "Playliste ikke fundet")
    project.visibility = visibility
    db.commit()
    return {"detail": f"Synlighed: {visibility}"}


# ── Hent playliste-indhold ────────────────────────────────────────────────────

@router.get("/public")
def list_public_playlists(db: Session = Depends(get_db)):
    """Hent alle public playlister — ingen login krævet."""
    projects = db.query(Project).filter_by(visibility="public").all()
    result = []
    for p in projects:
        owner = db.query(User).filter_by(id=p.owner_id).first()
        result.append({
            "id":         p.id,
            "name":       p.name,
            "owner":      owner.username if owner else "?",
            "song_count": len(p.project_songs),
        })
    return result


@router.post("/playlists/{project_id}/copy", status_code=201)
def copy_playlist(
    project_id: str,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    """Kopiér en public playliste til brugerens egen konto."""
    p = db.query(Project).filter_by(id=project_id).first()
    if not p:
        raise HTTPException(404, "Playliste ikke fundet")
    if p.visibility != "public":
        raise HTTPException(403, "Kun public playlister kan kopieres")
    if p.owner_id == me.id:
        raise HTTPException(400, "Du ejer allerede denne playliste")

    from app.models import Song
    owner = db.query(User).filter_by(id=p.owner_id).first()
    new_name = f"{p.name} (kopi fra {owner.username if owner else '?'})"

    new_p = Project(
        owner_id=me.id,
        name=new_name,
        description=p.description or "",
        visibility="private",
    )
    db.add(new_p)
    db.flush()

    for ps in p.project_songs:
        from app.models import ProjectSong
        db.add(ProjectSong(
            project_id=new_p.id,
            song_id=ps.song_id,
            position=ps.position,
            status="pending",
            is_workshop=ps.is_workshop,
            dance_override=ps.dance_override or "",
        ))

    db.commit()
    return {"detail": "Kopieret", "id": new_p.id}


@router.get("/playlists/{project_id}")
def get_shared_playlist(
    project_id: str,
    db: Session = Depends(get_db),
    me: User = Depends(get_current_user),
):
    p = db.query(Project).filter_by(id=project_id).first()
    if not p:
        raise HTTPException(404, "Playliste ikke fundet")
    if p.owner_id != me.id:
        if p.visibility != "public":
            share = db.query(PlaylistShare).filter(
                PlaylistShare.project_id == project_id,
                (PlaylistShare.shared_with_id == me.id) |
                (PlaylistShare.invited_email == me.email)
            ).first()
            if not share:
                raise HTTPException(403, "Ingen adgang")

    from app.models import Song
    songs = []
    for ps in p.project_songs:
        song = db.query(Song).filter_by(id=ps.song_id).first()
        if not song:
            continue
        songs.append({
            "title":          song.title,
            "artist":         song.artist,
            "position":       ps.position,
            "status":         ps.status,
            "is_workshop":    ps.is_workshop,
            "dance_override": ps.dance_override or "",
        })

    return {
        "id":          p.id,
        "name":        p.name,
        "description": p.description or "",
        "visibility":  p.visibility,
        "songs":       sorted(songs, key=lambda x: x["position"]),
    }