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

from app.dependencies import get_db, get_current_user
from app.models.user import User
from app.models.entry import Entry, EntryType
from app.schemas.entry import EntryCreate, EntryResponse, BottleStats

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


def _calc_stats(entries: list[Entry]) -> BottleStats:
    adds = [e for e in entries if e.entry_type == EntryType.add]
    removes = [e for e in entries if e.entry_type == EntryType.remove]

    total_add_shots = sum(e.amount_shots for e in adds)
    total_remove_shots = sum(e.amount_shots for e in removes)
    current_total = total_add_shots - total_remove_shots

    # Weighted average proof across all add entries
    weighted_proof_sum = sum(e.proof * e.amount_shots for e in adds if e.proof is not None)
    proof_shot_total = sum(e.amount_shots for e in adds if e.proof is not None)
    estimated_proof = (weighted_proof_sum / proof_shot_total) if proof_shot_total > 0 else None

    return BottleStats(
        total_add_entries=len(adds),
        current_total_shots=round(current_total, 2),
        estimated_proof=round(estimated_proof, 1) if estimated_proof is not None else None,
    )


@router.get("", response_model=list[EntryResponse])
async def list_entries(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(
        select(Entry)
        .where(Entry.user_id == current_user.id)
        .order_by(Entry.date.desc(), Entry.created_at.desc())
    )
    return result.scalars().all()


@router.post("", response_model=EntryResponse, status_code=status.HTTP_201_CREATED)
async def create_entry(
    body: EntryCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if body.entry_type == EntryType.add and not body.bourbon_name:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="bourbon_name is required for add entries")

    entry = Entry(
        user_id=current_user.id,
        entry_type=body.entry_type,
        date=body.date,
        bourbon_name=body.bourbon_name,
        proof=body.proof,
        amount_shots=body.amount_shots,
        notes=body.notes,
    )
    async with db.begin():
        db.add(entry)

    await db.refresh(entry)
    return entry


@router.delete("/{entry_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_entry(
    entry_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(
        select(Entry).where(Entry.id == entry_id, Entry.user_id == current_user.id)
    )
    entry = result.scalar_one_or_none()
    if not entry:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Entry not found")

    async with db.begin():
        await db.delete(entry)


@router.get("/stats", response_model=BottleStats)
async def get_stats(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(select(Entry).where(Entry.user_id == current_user.id))
    entries = result.scalars().all()
    return _calc_stats(entries)