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.subject import Subject
from app.models.user import User
from app.schemas.subject import SubjectCreate, SubjectOut, SubjectUpdate

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


@router.get("", response_model=list[SubjectOut])
async def list_subjects(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Subject).where(Subject.user_id == current_user.id).order_by(Subject.name)
    )
    return result.scalars().all()


@router.post("", response_model=SubjectOut, status_code=status.HTTP_201_CREATED)
async def create_subject(
    body: SubjectCreate,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    subject = Subject(**body.model_dump(), user_id=current_user.id)
    db.add(subject)
    await db.commit()
    await db.refresh(subject)
    return subject


@router.get("/{subject_id}", response_model=SubjectOut)
async def get_subject(
    subject_id: int,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Subject).where(Subject.id == subject_id, Subject.user_id == current_user.id)
    )
    subject = result.scalar_one_or_none()
    if not subject:
        raise HTTPException(status_code=404, detail="Subject not found")
    return subject


@router.patch("/{subject_id}", response_model=SubjectOut)
async def update_subject(
    subject_id: int,
    body: SubjectUpdate,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Subject).where(Subject.id == subject_id, Subject.user_id == current_user.id)
    )
    subject = result.scalar_one_or_none()
    if not subject:
        raise HTTPException(status_code=404, detail="Subject not found")

    for field, value in body.model_dump(exclude_none=True).items():
        setattr(subject, field, value)
    await db.commit()
    await db.refresh(subject)
    return subject


@router.delete("/{subject_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_subject(
    subject_id: int,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Subject).where(Subject.id == subject_id, Subject.user_id == current_user.id)
    )
    subject = result.scalar_one_or_none()
    if not subject:
        raise HTTPException(status_code=404, detail="Subject not found")
    await db.delete(subject)
    await db.commit()