"""在线课程：只有外链的视频/课程资源，与教材分表维护。"""
from __future__ import annotations

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session

from database import get_db
from dependencies import get_current_user, require_permission
from models import Course, User
from schemas import CourseCreate, CourseOut, CourseUpdate

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


def _load(db: Session, course_id: int) -> Course:
    course = db.get(Course, course_id)
    if course is None:
        raise HTTPException(status_code=404, detail="课程不存在")
    return course


def _clean_url(url: str | None) -> str:
    url = (url or "").strip()
    if not url:
        raise HTTPException(status_code=400, detail="请填写课程链接")
    return url


@router.get("", response_model=list[CourseOut])
def list_courses(
    db: Session = Depends(get_db),
    _: User = Depends(get_current_user),
):
    return (
        db.query(Course)
        .order_by(Course.position.asc(), Course.id.asc())
        .all()
    )


@router.post("", response_model=CourseOut)
def create_course(
    payload: CourseCreate,
    db: Session = Depends(get_db),
    _: User = Depends(require_permission("catalog:manage")),
):
    if db.query(Course).filter(Course.name == payload.name).first():
        raise HTTPException(status_code=400, detail="同名课程已存在")
    course = Course(
        name=payload.name,
        provider=payload.provider,
        url=_clean_url(payload.url),
        grade=payload.grade,
        description=payload.description,
        position=db.query(Course).count(),
    )
    db.add(course)
    db.commit()
    return course


@router.put("/{course_id}", response_model=CourseOut)
def update_course(
    course_id: int,
    payload: CourseUpdate,
    db: Session = Depends(get_db),
    _: User = Depends(require_permission("catalog:manage")),
):
    course = _load(db, course_id)
    fields = payload.model_dump(exclude_unset=True)
    if "name" in fields and fields["name"] != course.name:
        exists = (
            db.query(Course)
            .filter(Course.name == fields["name"], Course.id != course.id)
            .first()
        )
        if exists:
            raise HTTPException(status_code=400, detail="同名课程已存在")
    if "url" in fields:
        fields["url"] = _clean_url(fields["url"])
    for field, value in fields.items():
        setattr(course, field, value)
    db.commit()
    return course


@router.delete("/{course_id}")
def delete_course(
    course_id: int,
    db: Session = Depends(get_db),
    _: User = Depends(require_permission("catalog:manage")),
):
    course = _load(db, course_id)
    db.delete(course)
    db.commit()
    return {"deleted": course_id}