"""规则端点（C3 扩 / PRODUCT_SPEC §7 `POST /projects/:id/rules`；不变量 #3）。

POST /projects/:id/rules：作者显式加规则——审稿发现的问题/亮点随手沉淀为项目规则。
写一行 `rules`（level + content），喂给 assemble 的四级合并（`merge_rules`）。

加规则是**作者显式动作**（不变量 #3：规则入库不经 AI 静默写库）。`level` 合法性由
`RuleCreateRequest` 的 Literal 校验（非法 → FastAPI 422）。

提交边界：`RuleWriteRepo.create` 只 `flush()`，端点写后 `await session.commit()`
（仿 foreshadow/outline 写侧，见 memory/gotchas）。
"""

from __future__ import annotations

import uuid
from typing import Annotated

from fastapi import APIRouter, Depends, Request
from sqlalchemy.ext.asyncio import AsyncSession
from ww_core.domain import RuleWriteRepo
from ww_db import get_session

from ww_api.logging_config import get_logger
from ww_api.schemas.rules import RuleCreateRequest, RuleView
from ww_api.services.project_deps import get_rule_write_repo

log = get_logger("ww.api.rules")

router = APIRouter(prefix="/projects", tags=["rules"])

RuleWriteRepoDep = Annotated[RuleWriteRepo, Depends(get_rule_write_repo)]
SessionDep = Annotated[AsyncSession, Depends(get_session)]


@router.post("/{project_id}/rules", status_code=201)
async def create_rule(
    project_id: uuid.UUID,
    body: RuleCreateRequest,
    request: Request,
    repo: RuleWriteRepoDep,
    session: SessionDep,
) -> RuleView:
    """新增一条规则（201）。非法 level / 空 content → FastAPI 422。"""
    request_id = getattr(request.state, "request_id", None)
    view = await repo.create(project_id, level=body.level, content=body.content)
    await session.commit()
    log.info(
        "rule_created",
        project_id=str(project_id),
        request_id=request_id,
        level=body.level,
    )
    return RuleView(level=view.level, content=view.content)