"""site_import API（spec §4）——2 端点，两角色可用，_tenant_guard 守租户。

- POST /{slug}/site-import：新建（body.url）或复活（body.retry="generate"
  + body.task_id）。校验次序：鉴权（_tenant_guard 依赖链，401/403/409 门
  连锁）→ 租户存在且未停用（404/403）→ 形态预检（retry 只认 generate 且
  task_id 非空；新建 URL 过 safe_fetch 的 URL 层预检——scheme/host 字面量
  禁段/端口白名单，spec §5「内网/非法地址 POST 即拒」，连接层二次兜底）
  → task.start。异常映射（Task 7 备忘）：ImportRateLimited→429 /
  ConcurrentLimit→409 / LookupError→404（retry 目标不存在）/ ValueError→
  409（非 generate-failed 态），str(exc) 作 detail——任务层的白话文案
  原样透出，API 层不二次翻译（FetchError 已在任务层白话化，同理由）。
- GET /{slug}/site-import/{task_id}：轮询。task.get 的 (slug, task_id)
  联合索引即越权防线（跨租户持他人 id → None → 404）；30 分钟过期同理
  404「任务不存在或已过期」（前端按终态「任务已过期，请重新导入」处理）。
  响应五键（spec §4）：status（=任务 state）/ phase / pages（=任务
  pages_fetched）/ draft（仅 done，spec §4 草稿包整包）/ error。

启动只做校验+建任务——pipeline 由任务模块的后台 aio task 跑，本层不
感知 crawler/generator（测试也因此能整体打桩 task.start/task.get）。
"""
from fastapi import APIRouter, Depends, HTTPException, Request
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.platform.db import TenantConfigVersion
from app.platform.routes.tenant_routes import _get_tenant_or_404, _tenant_guard
from app.platform.site_import import safe_fetch, task

router = APIRouter(prefix="/api/platform/tenants", tags=["platform-site-import"])


class StartRequest(BaseModel):
    url: str = ""
    retry: str = ""          # "generate" 复活模式（spec §3.3）
    task_id: str = ""        # retry 时指定任务


@router.post("/{slug}/site-import")
async def start_import(slug: str, body: StartRequest, request: Request,
                       user=Depends(_tenant_guard)):
    """启动/复活导入任务 → {task_id}。校验次序与异常映射见模块 docstring。"""
    engine = request.app.state.platform_engine
    async with AsyncSession(engine, expire_on_commit=False) as session:
        tenant = await _get_tenant_or_404(session, slug)
        # 租户配置快照（终审 Important #2：AI 三级链的租户槽位——传给
        # task.start → make_provider；自有 ai.* 配置的租户烧自己配额）
        latest = (await session.execute(
            select(TenantConfigVersion.config_json)
            .where(TenantConfigVersion.tenant_id == tenant.id)
            .order_by(TenantConfigVersion.version.desc())
            .limit(1))).scalar_one_or_none()
    if tenant.status != "active":
        raise HTTPException(
            status_code=403, detail=f"租户 {slug!r} 已停用，无法发起导入")

    url: str | None = None
    retry_task_id: str | None = None
    if body.retry:
        if body.retry != "generate":
            raise HTTPException(
                status_code=400,
                detail=f"retry 只支持 generate（实际 {body.retry!r}）")
        if not body.task_id:
            raise HTTPException(
                status_code=400, detail="retry 形态必须带 task_id")
        retry_task_id = body.task_id
    else:
        # URL 层预检单一事实源在 safe_fetch（scheme/禁段字面量/端口）——
        # 私有口内部复用，不另抄一份漂移；不公网形态统一白话 400
        try:
            safe_fetch._validate_url(body.url)
        except safe_fetch.FetchError as exc:
            raise HTTPException(
                status_code=400, detail="仅支持公网网站地址") from exc
        url = body.url

    try:
        task_id = await task.start(slug, url, retry_task_id=retry_task_id,
                                    config_data=latest)
    except task.ImportRateLimited as exc:
        raise HTTPException(status_code=429, detail=str(exc)) from exc
    except task.ConcurrentLimit as exc:
        raise HTTPException(status_code=409, detail=str(exc)) from exc
    except LookupError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc)) from exc
    return {"task_id": task_id}


@router.get("/{slug}/site-import/{task_id}")
async def get_import_task(slug: str, task_id: str,
                          user=Depends(_tenant_guard)):
    """轮询任务状态（spec §4 五键；404=不存在/已过期/跨租户）。"""
    t = task.get(slug, task_id)
    if t is None:
        raise HTTPException(status_code=404, detail="任务不存在或已过期")
    return {
        "status": t.state,
        "phase": t.phase,
        "pages": t.pages_fetched,
        "draft": t.draft if t.state == task.TaskState.DONE else None,
        "error": t.error,
    }