from __future__ import annotations

from typing import Annotated, Any

from fastapi import APIRouter, Header
from fastapi.responses import StreamingResponse
from sqlalchemy import func, select

from bid_doctor.core import events
from bid_doctor.core.db import tenant_tx
from bid_doctor.identity.deps import Ctx
from bid_doctor.notification.models import Notification

router = APIRouter(tags=["notifications"])


@router.get("/events")
async def stream_events(ctx: Ctx, last_event_id: Annotated[str | None, Header()] = None) -> StreamingResponse:
    """SSE（API2：前端用 fetch 读，可以带 Bearer 头）。"""
    return StreamingResponse(
        events.stream(ctx.tenant_id, last_event_id),
        media_type="text/event-stream",
        headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
    )


@router.get("/notifications")
async def list_notifications(ctx: Ctx, unread: bool | None = None) -> dict[str, Any]:
    async with tenant_tx(ctx) as s:
        q = select(Notification).where(Notification.user_id == ctx.user_id)
        if unread:
            q = q.where(Notification.read_at.is_(None))
        rows = (await s.execute(q.order_by(Notification.created_at.desc()).limit(50))).scalars().all()
        n = (
            await s.execute(
                select(func.count())
                .select_from(Notification)
                .where(Notification.user_id == ctx.user_id, Notification.read_at.is_(None))
            )
        ).scalar_one()
    titles = {
        "parse_succeeded": "招标文件解析完成",
        "parse_failed": "招标文件解析失败，额度已退回",
        "check_succeeded": "投标文件检查完成",
        "check_failed": "投标文件检查没有完成，不扣额度",
        "report_succeeded": "检查报告已生成",
        "report_failed": "检查报告生成失败",
    }
    return {
        "unread_count": n,
        "next_cursor": None,
        "items": [
            {
                "id": r.id,
                "kind": r.kind,
                "title": titles.get(r.kind, r.kind),
                "project_id": r.project_id,
                "link": f"/projects/{r.project_id}/checklist" if r.project_id else None,
                "read_at": r.read_at,
                "created_at": r.created_at,
            }
            for r in rows
        ],
    }