"""匿名接口，统一放在 /api/public 下，一眼能看出哪些不鉴权"""

from typing import Annotated, Any

from fastapi import APIRouter, Query, Response
from fastapi.responses import FileResponse

from app.api.screens import Service, thumbnail_url
from app.common.response import ApiResponse, success_response
from app.config import settings
from app.core.exceptions import BizException
from app.schemas.saved_screen import (
    DemoScreen,
    DemoScreenList,
    PublicScreen,
    PublishBrief,
)
from app.services.screens import LIVE_VARS_MAX_CHARS, public_page

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

# 演示数据的条数上限和浏览器缓存时长（秒）
DEMO_LIMIT = 20
DEMO_CACHE_SECONDS = 60


@router.get("/demo/screens")
async def list_demo_screens(
    service: Service, response: Response
) -> ApiResponse[DemoScreenList]:
    """未登录演示：演示账号（DEMO_OWNER_ID）下的大屏，页面去掉数据源 headers；没配账号时为空"""
    owner_id = settings.demo_owner_id
    if owner_id is None:
        return success_response(DemoScreenList(items=[]))
    records = await service.list_demo(owner_id, DEMO_LIMIT)
    response.headers["Cache-Control"] = f"public, max-age={DEMO_CACHE_SECONDS}"
    return success_response(
        DemoScreenList(
            items=[
                DemoScreen(
                    screen_id=record.screen_id,
                    name=record.name,
                    page=public_page(record.page),
                    thumbnail_url=thumbnail_url(record.thumbnail),
                    revision=record.revision,
                    updated_at=record.updated_at,
                    publish=None
                    if record.publish is None
                    else PublishBrief.model_validate(
                        record.publish.model_dump(exclude={"revision"})
                    ),
                )
                for record in records
            ]
        )
    )


@router.get("/screens/{share_id}")
async def get_public_screen(
    share_id: str, service: Service
) -> ApiResponse[PublicScreen]:
    """线上版本：返回发布快照，不是草稿；已下线、已删除、不存在都是 404"""
    summary, snapshot = await service.get_live(share_id)
    return success_response(
        PublicScreen(
            name=summary.name,
            page=public_page(snapshot.page),
            version=snapshot.version,
            published_at=snapshot.published_at,
        )
    )


@router.get("/screens/{share_id}/datasources/{datasource_id}")
async def fetch_public_datasource(
    share_id: str,
    datasource_id: str,
    service: Service,
    variables: Annotated[
        str | None, Query(alias="vars", max_length=LIVE_VARS_MAX_CHARS)
    ] = None,
) -> ApiResponse[dict[str, Any] | list[Any]]:
    """线上取数：地址取自已发布快照里的数据源配置，前端只传 ID

    vars 是 JSON 对象 {变量ID: 值}，只传该数据源 params 里引用到的变量；服务端只代入 params
    """
    return success_response(
        await service.fetch_live_datasource(share_id, datasource_id, variables)
    )


@router.get("/thumbnails/{thumbnail_id}")
async def get_thumbnail(thumbnail_id: str, service: Service) -> FileResponse:
    opened = service.open_thumbnail(thumbnail_id)
    if opened is None:
        raise BizException(404, "封面不存在")
    path, media_type = opened
    # 每次上传都换新 ID，内容永远不变，可以放心长期缓存
    return FileResponse(
        path,
        media_type=media_type,
        headers={"Cache-Control": "public, max-age=31536000, immutable"},
    )