"""待办清单接口。"""
from __future__ import annotations

from datetime import datetime
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy import and_, func, or_, select
from sqlalchemy.orm import Session

from app.api.deps import db_session
from app.models.todo import Todo, TodoStatus
from app.schemas.common import TodoUpdate
from app.schemas.screenshot import TodoBrief, TodoListResp


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


def _todo_filters(
    status: Optional[str],
    kind: Optional[str],
    q: Optional[str],
) -> list:
    """构建待办筛选条件。"""
    filters = []
    if status:
        filters.append(Todo.status == status)
    if kind:
        filters.append(Todo.kind == kind)
    if q:
        like = f"%{q.strip()}%"
        filters.append(or_(Todo.title.ilike(like), Todo.note.ilike(like)))
    return filters


@router.get("", response_model=TodoListResp)
def list_todos(
    session: Session = Depends(db_session),
    status: Optional[str] = Query(None),
    kind: Optional[str] = Query(None),
    q: Optional[str] = Query(None, description="标题/备注关键词"),
    page: int = Query(1, ge=1),
    size: int = Query(50, ge=1, le=200),
) -> TodoListResp:
    """按状态/类型/关键词分页查询。"""
    filters = _todo_filters(status, kind, q)
    base = select(Todo)
    if filters:
        base = base.where(and_(*filters))

    total = session.scalar(select(func.count()).select_from(base.subquery())) or 0
    rows = session.scalars(
        base.order_by(Todo.created_at.desc()).offset((page - 1) * size).limit(size)
    ).all()
    return TodoListResp(
        items=[TodoBrief.model_validate(r) for r in rows],
        total=int(total),
        page=page,
        size=size,
    )


@router.get("/summary")
def summary(session: Session = Depends(db_session)) -> dict:
    """各状态待办数量。"""
    return {
        st.value: session.scalar(select(func.count(Todo.id)).where(Todo.status == st.value)) or 0
        for st in TodoStatus
    }


@router.patch("/{todo_id}", response_model=TodoBrief)
def update_todo(
    todo_id: int,
    payload: TodoUpdate,
    session: Session = Depends(db_session),
) -> TodoBrief:
    """更新状态/标题/备注。"""
    todo = session.get(Todo, todo_id)
    if todo is None:
        raise HTTPException(404, "Todo not found")
    if payload.status is not None:
        todo.status = payload.status
        if payload.status == TodoStatus.DONE.value:
            todo.completed_at = datetime.utcnow()
    if payload.title is not None:
        todo.title = payload.title
    if payload.note is not None:
        todo.note = payload.note
    session.commit()
    session.refresh(todo)
    return TodoBrief.model_validate(todo)


@router.delete("/{todo_id}")
def delete_todo(
    todo_id: int,
    session: Session = Depends(db_session),
) -> dict:
    todo = session.get(Todo, todo_id)
    if todo is None:
        raise HTTPException(404, "Todo not found")
    session.delete(todo)
    session.commit()
    return {"ok": True}