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

from app.core.deps import ensure_class_access, ensure_class_permission, require_role, resolve_class_id_for_user
from app.db.database import get_db
from app.db.models import User
from app.schemas.schedule import ScheduleCreate, ScheduleUpdate, ScheduleOut
from app.schemas.common import PageResponse
from app.services.schedule_service import (
    create_schedule,
    update_schedule,
    delete_schedule,
    get_schedule_by_id,
    list_schedules,
    get_upcoming_schedules,
)

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


@router.get("/upcoming", response_model=list[ScheduleOut])
async def get_upcoming(
    limit: int = 10,
    class_id: int | None = None,
    user: User = Depends(require_role("super_admin", "teacher", "student")),
    db: AsyncSession = Depends(get_db),
):
    effective_class_id = resolve_class_id_for_user(user, class_id)
    if effective_class_id is None:
        return []
    ensure_class_access(user, effective_class_id)
    items = await get_upcoming_schedules(db, effective_class_id, limit)
    return [ScheduleOut.model_validate(i) for i in items]


@router.get("/", response_model=PageResponse[ScheduleOut])
async def get_schedules(
    type: str | None = None,
    page: int = 1,
    page_size: int = 50,
    class_id: int | None = None,
    user: User = Depends(require_role("super_admin", "teacher", "student")),
    db: AsyncSession = Depends(get_db),
):
    effective_class_id = resolve_class_id_for_user(user, class_id)
    if effective_class_id is None:
        return PageResponse(items=[], total=0, page=page, page_size=page_size, total_pages=0)
    ensure_class_access(user, effective_class_id)

    items, total = await list_schedules(db, effective_class_id, type, page, page_size)
    total_pages = (total + page_size - 1) // page_size
    return PageResponse(
        items=[ScheduleOut.model_validate(i) for i in items],
        total=total,
        page=page,
        page_size=page_size,
        total_pages=total_pages,
    )


@router.post("/", response_model=ScheduleOut)
async def create_new_schedule(
    data: ScheduleCreate,
    class_id: int | None = None,
    user: User = Depends(require_role("super_admin", "teacher", "student")),
    db: AsyncSession = Depends(get_db),
):
    effective_class_id = resolve_class_id_for_user(user, class_id)
    if effective_class_id is None:
        raise HTTPException(status_code=400, detail="You are not assigned to a class")
    ensure_class_permission(user, "schedule_manage", effective_class_id)

    item = await create_schedule(db, effective_class_id, data)
    return ScheduleOut.model_validate(item)


@router.put("/{schedule_id}", response_model=ScheduleOut)
async def update_existing_schedule(
    schedule_id: int,
    data: ScheduleUpdate,
    user: User = Depends(require_role("super_admin", "teacher", "student")),
    db: AsyncSession = Depends(get_db),
):
    item = await get_schedule_by_id(db, schedule_id)
    if item is None:
        raise HTTPException(status_code=404, detail="Schedule not found")
    ensure_class_permission(user, "schedule_manage", item.class_id)

    updated = await update_schedule(db, item, data)
    return ScheduleOut.model_validate(updated)


@router.delete("/{schedule_id}")
async def delete_existing_schedule(
    schedule_id: int,
    user: User = Depends(require_role("super_admin", "teacher", "student")),
    db: AsyncSession = Depends(get_db),
):
    item = await get_schedule_by_id(db, schedule_id)
    if item is None:
        raise HTTPException(status_code=404, detail="Schedule not found")
    ensure_class_permission(user, "schedule_manage", item.class_id)

    await delete_schedule(db, item)
    return {"message": "Schedule deleted"}