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

from app.core.deps import get_current_user, require_role
from app.db.database import get_db
from app.db.models import User
from app.schemas.class_ import ClassCreate, ClassUpdate, ClassOut
from app.schemas.user import UserListItem
from app.schemas.common import PageResponse
from app.services.class_service import (
    create_class,
    update_class,
    delete_class,
    get_class_by_id,
    list_classes,
    get_member_count,
    get_class_members,
)

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


@router.get("/", response_model=PageResponse[ClassOut])
async def get_classes(
    page: int = 1,
    page_size: int = 50,
    db: AsyncSession = Depends(get_db),
):
    classes, total = await list_classes(db, page, page_size)
    total_pages = (total + page_size - 1) // page_size
    result = []
    for c in classes:
        count = await get_member_count(db, c.id)
        out = ClassOut.model_validate(c)
        out.member_count = count
        result.append(out)
    return PageResponse(
        items=result, total=total, page=page, page_size=page_size, total_pages=total_pages
    )


@router.post("/", response_model=ClassOut)
async def create_new_class(
    data: ClassCreate,
    admin: User = Depends(require_role("super_admin")),
    db: AsyncSession = Depends(get_db),
):
    class_ = await create_class(db, data)
    out = ClassOut.model_validate(class_)
    out.member_count = 0
    return out


@router.put("/{class_id}", response_model=ClassOut)
async def update_existing_class(
    class_id: int,
    data: ClassUpdate,
    admin: User = Depends(require_role("super_admin")),
    db: AsyncSession = Depends(get_db),
):
    class_ = await get_class_by_id(db, class_id)
    if class_ is None:
        raise HTTPException(status_code=404, detail="Class not found")
    updated = await update_class(db, class_, data)
    out = ClassOut.model_validate(updated)
    out.member_count = await get_member_count(db, class_id)
    return out


@router.delete("/{class_id}")
async def delete_existing_class(
    class_id: int,
    admin: User = Depends(require_role("super_admin")),
    db: AsyncSession = Depends(get_db),
):
    class_ = await get_class_by_id(db, class_id)
    if class_ is None:
        raise HTTPException(status_code=404, detail="Class not found")
    await delete_class(db, class_)
    return {"message": "Class deleted"}


@router.get("/{class_id}/members", response_model=PageResponse[UserListItem])
async def get_members(
    class_id: int,
    status: str | None = None,
    page: int = 1,
    page_size: int = 50,
    admin: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    if admin.role == "class_admin" and admin.class_id != class_id:
        raise HTTPException(status_code=403, detail="Access denied for this class")

    members, total = await get_class_members(db, class_id, status, page, page_size)
    total_pages = (total + page_size - 1) // page_size
    return PageResponse(
        items=[UserListItem.model_validate(m) for m in members],
        total=total,
        page=page,
        page_size=page_size,
        total_pages=total_pages,
    )


@router.get("/{class_id}/pending", response_model=PageResponse[UserListItem])
async def get_pending_members(
    class_id: int,
    page: int = 1,
    page_size: int = 50,
    admin: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    if admin.role == "class_admin" and admin.class_id != class_id:
        raise HTTPException(status_code=403, detail="Access denied for this class")

    members, total = await get_class_members(db, class_id, status="pending", page=page, page_size=page_size)
    total_pages = (total + page_size - 1) // page_size
    return PageResponse(
        items=[UserListItem.model_validate(m) for m in members],
        total=total,
        page=page,
        page_size=page_size,
        total_pages=total_pages,
    )