"""会话创建与历史查询接口"""

from typing import Annotated

from fastapi import APIRouter, Depends, Query, Request

from app.common.response import ApiResponse, success_response
from app.core.auth import get_current_user
from app.core.exceptions import BizException
from app.schemas.conversation import (
    ConversationCreate,
    ConversationCreated,
    ConversationDetail,
    ConversationList,
    ConversationRename,
)
from app.schemas.user import CurrentUser

MAX_OFFSET = 10000

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


@router.post("")
async def create_conversation(
    request: Request,
    user: CurrentUser = Depends(get_current_user),
    body: ConversationCreate | None = None,
) -> ApiResponse[ConversationCreated]:
    store = request.app.state.conversation_store
    screen_id = body.screen_id if body else None
    # 会话挂到大屏上，大屏必须是自己的；没配 MongoDB（没有大屏服务）时无从校验，直接放过
    screens = getattr(request.app.state, "screen_service", None)
    if screen_id is not None and screens is not None:
        if not await screens.exists(screen_id, user.id):
            raise BizException(404, "大屏不存在或已删除")
    return success_response(
        ConversationCreated(conversation_id=await store.create(user.id, screen_id))
    )


@router.get("")
async def list_conversations(
    request: Request,
    user: Annotated[CurrentUser, Depends(get_current_user)],
    limit: Annotated[int, Query(ge=1, le=100)] = 20,
    offset: Annotated[int, Query(ge=0, le=MAX_OFFSET)] = 0,
    screen_id: Annotated[str | None, Query(min_length=1)] = None,
) -> ApiResponse[ConversationList]:
    store = request.app.state.conversation_store
    return success_response(
        ConversationList(
            conversations=await store.list_by_user(user.id, limit, offset, screen_id),
            total=await store.count_by_user(user.id, screen_id),
        )
    )


@router.get("/{conversation_id}")
async def get_conversation(
    conversation_id: str,
    request: Request,
    user: CurrentUser = Depends(get_current_user),
) -> ApiResponse[ConversationDetail]:
    store = request.app.state.conversation_store
    # 他人的会话与不存在同样返回 404
    if not await store.exists(conversation_id, user.id):
        raise BizException(404, "会话不存在或已过期")
    turns = await store.load_turns(conversation_id, None)
    return success_response(
        ConversationDetail(conversation_id=conversation_id, turns=turns)
    )


@router.patch("/{conversation_id}")
async def rename_conversation(
    conversation_id: str,
    body: ConversationRename,
    request: Request,
    user: CurrentUser = Depends(get_current_user),
) -> ApiResponse[dict]:
    store = request.app.state.conversation_store
    if not await store.rename(conversation_id, user.id, body.title):
        raise BizException(404, "会话不存在或已过期")
    return success_response()


@router.delete("/{conversation_id}")
async def delete_conversation(
    conversation_id: str,
    request: Request,
    user: CurrentUser = Depends(get_current_user),
) -> ApiResponse[dict]:
    store = request.app.state.conversation_store
    if not await store.delete(conversation_id, user.id):
        raise BizException(404, "会话不存在或已过期")
    return success_response()