from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy import delete, func, select
from sqlalchemy.ext.asyncio import AsyncSession

from haunt_fm.db import get_session
from haunt_fm.models.track import (
    ListenEvent,
    Profile,
    SpeakerProfileMapping,
    TasteProfile,
)

router = APIRouter(prefix="/api/profiles")


class CreateProfileRequest(BaseModel):
    name: str
    display_name: str | None = None


class SetSpeakersRequest(BaseModel):
    speakers: list[str]


async def _get_profile_or_404(session: AsyncSession, name: str) -> Profile:
    result = await session.execute(select(Profile).where(Profile.name == name))
    profile = result.scalar_one_or_none()
    if profile is None:
        raise HTTPException(status_code=404, detail=f"Profile '{name}' not found")
    return profile


@router.get("/")
async def list_profiles(session: AsyncSession = Depends(get_session)):
    """List all profiles with stats."""
    result = await session.execute(
        select(
            Profile.name,
            Profile.display_name,
            Profile.created_at,
            func.count(ListenEvent.id).label("event_count"),
            func.count(func.distinct(ListenEvent.track_id)).label("track_count"),
            func.max(ListenEvent.listened_at).label("last_listen"),
        )
        .outerjoin(ListenEvent, ListenEvent.profile_id == Profile.id)
        .group_by(Profile.id)
        .order_by(Profile.created_at)
    )
    profiles = []
    for row in result:
        profiles.append({
            "name": row.name,
            "display_name": row.display_name,
            "created_at": row.created_at.isoformat() if row.created_at else None,
            "event_count": row.event_count,
            "track_count": row.track_count,
            "last_listen": row.last_listen.isoformat() if row.last_listen else None,
        })

    # Also count events with no profile_id (belong to "default")
    unassigned = await session.execute(
        select(func.count(ListenEvent.id)).where(ListenEvent.profile_id.is_(None))
    )
    unassigned_count = unassigned.scalar() or 0

    # Add unassigned counts to default profile
    for p in profiles:
        if p["name"] == "default":
            p["event_count"] += unassigned_count
            break

    return {"profiles": profiles}


@router.post("/", status_code=201)
async def create_profile(req: CreateProfileRequest, session: AsyncSession = Depends(get_session)):
    """Create a new profile."""
    existing = await session.execute(select(Profile).where(Profile.name == req.name))
    if existing.scalar_one_or_none() is not None:
        raise HTTPException(status_code=409, detail=f"Profile '{req.name}' already exists")

    profile = Profile(name=req.name, display_name=req.display_name)
    session.add(profile)
    await session.commit()
    await session.refresh(profile)
    return {
        "name": profile.name,
        "display_name": profile.display_name,
        "created_at": profile.created_at.isoformat(),
    }


@router.get("/{name}")
async def get_profile(name: str, session: AsyncSession = Depends(get_session)):
    """Get a single profile with stats."""
    profile = await _get_profile_or_404(session, name)

    # Event stats — include NULL profile_id events for "default"
    if name == "default":
        event_filter = (ListenEvent.profile_id == profile.id) | (ListenEvent.profile_id.is_(None))
    else:
        event_filter = ListenEvent.profile_id == profile.id

    stats = await session.execute(
        select(
            func.count(ListenEvent.id).label("event_count"),
            func.count(func.distinct(ListenEvent.track_id)).label("track_count"),
            func.max(ListenEvent.listened_at).label("last_listen"),
        ).where(event_filter)
    )
    row = stats.one()

    # Speaker mappings
    speakers = await session.execute(
        select(SpeakerProfileMapping.speaker_name)
        .where(SpeakerProfileMapping.profile_id == profile.id)
    )

    # Taste profile status
    taste = await session.execute(
        select(TasteProfile).where(TasteProfile.profile_id == profile.id)
    )
    taste_profile = taste.scalar_one_or_none()

    return {
        "name": profile.name,
        "display_name": profile.display_name,
        "created_at": profile.created_at.isoformat(),
        "event_count": row.event_count,
        "track_count": row.track_count,
        "last_listen": row.last_listen.isoformat() if row.last_listen else None,
        "speakers": [r.speaker_name for r in speakers],
        "taste_profile": {
            "track_count": taste_profile.track_count,
            "updated_at": taste_profile.updated_at.isoformat(),
        } if taste_profile else None,
    }


@router.delete("/{name}")
async def delete_profile(name: str, session: AsyncSession = Depends(get_session)):
    """Delete a profile, reassigning its events to default."""
    if name == "default":
        raise HTTPException(status_code=400, detail="Cannot delete the default profile")

    profile = await _get_profile_or_404(session, name)

    # Reassign listen events to NULL (i.e. default)
    await session.execute(
        ListenEvent.__table__.update()
        .where(ListenEvent.profile_id == profile.id)
        .values(profile_id=None)
    )

    # Delete speaker mappings
    await session.execute(
        delete(SpeakerProfileMapping).where(SpeakerProfileMapping.profile_id == profile.id)
    )

    # Delete taste profile for this profile
    await session.execute(
        delete(TasteProfile).where(TasteProfile.profile_id == profile.id)
    )

    await session.delete(profile)
    await session.commit()
    return {"ok": True, "deleted": name}


@router.put("/{name}/speakers")
async def set_speakers(name: str, req: SetSpeakersRequest, session: AsyncSession = Depends(get_session)):
    """Set speaker→profile mappings (replaces existing)."""
    profile = await _get_profile_or_404(session, name)

    # Remove existing mappings for this profile
    await session.execute(
        delete(SpeakerProfileMapping).where(SpeakerProfileMapping.profile_id == profile.id)
    )

    # Create new mappings
    for speaker in req.speakers:
        # Check if this speaker is already mapped to another profile
        existing = await session.execute(
            select(SpeakerProfileMapping).where(SpeakerProfileMapping.speaker_name == speaker)
        )
        if existing.scalar_one_or_none() is not None:
            raise HTTPException(
                status_code=409,
                detail=f"Speaker '{speaker}' is already mapped to another profile",
            )
        session.add(SpeakerProfileMapping(speaker_name=speaker, profile_id=profile.id))

    await session.commit()
    return {"ok": True, "profile": name, "speakers": req.speakers}


@router.get("/{name}/speakers")
async def get_speakers(name: str, session: AsyncSession = Depends(get_session)):
    """List speaker mappings for a profile."""
    profile = await _get_profile_or_404(session, name)
    result = await session.execute(
        select(SpeakerProfileMapping.speaker_name)
        .where(SpeakerProfileMapping.profile_id == profile.id)
    )
    return {"profile": name, "speakers": [r.speaker_name for r in result]}