from datetime import datetime, timezone
from typing import List

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

from app.core.database import get_db
from app.core.security import get_current_user, require_role
from app.models.user import User
from app.models.announcement import Announcement
from app.schemas.announcement import (
    AnnouncementCreate,
    AnnouncementUpdate,
    AnnouncementResponse,
)

router = APIRouter(prefix="/announcements", tags=["公告管理"])


@router.get("", response_model=List[AnnouncementResponse])
async def list_announcements(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """所有登录用户可查看公告列表"""
    stmt = select(Announcement).order_by(Announcement.id.desc())
    result = await db.execute(stmt)
    return result.scalars().all()


@router.post("", response_model=AnnouncementResponse, status_code=201)
async def create_announcement(
    data: AnnouncementCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin")),
):
    """管理员创建公告"""
    announcement = Announcement(
        title=data.title,
        content=data.content,
        is_published=False,
    )
    db.add(announcement)
    await db.commit()
    await db.refresh(announcement)
    return announcement


@router.put("/{announcement_id}", response_model=AnnouncementResponse)
async def update_announcement(
    announcement_id: int,
    data: AnnouncementUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin")),
):
    """管理员更新公告"""
    result = await db.execute(
        select(Announcement).where(Announcement.id == announcement_id)
    )
    announcement = result.scalar_one_or_none()
    if not announcement:
        raise HTTPException(status_code=404, detail="公告不存在")

    update_data = data.model_dump(exclude_unset=True)
    # If publishing for the first time, set published_at
    if update_data.get("is_published") and not announcement.published_at:
        announcement.published_at = datetime.now(timezone.utc)

    for key, value in update_data.items():
        setattr(announcement, key, value)
    await db.commit()
    await db.refresh(announcement)
    return announcement


@router.delete("/{announcement_id}")
async def delete_announcement(
    announcement_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin")),
):
    """管理员删除公告"""
    result = await db.execute(
        select(Announcement).where(Announcement.id == announcement_id)
    )
    announcement = result.scalar_one_or_none()
    if not announcement:
        raise HTTPException(status_code=404, detail="公告不存在")

    await db.delete(announcement)
    await db.commit()
    return {"message": "公告已删除"}