"""WriterAgent 防御分支覆盖（P0 补测）。

覆盖：_resolve_prompt 直返回 Prompt、引擎异常状态无详情、LLM 返回非法 data 触发重试。
"""
import pytest
from types import SimpleNamespace

from genesis.inference.types import Prompt
from genesis.writer.writer_agent import WriterAgent, WriterGenerationError
from genesis.writer.writer_state import WriterState
from genesis.writer.models import ChapterSpec, GenerationContext


class _Registry:
    def get_or_create(self, name, template):
        return Prompt(name=name, version="1", template=template)


class _FailedEngine:
    def chat_structured(self, **kw):
        return SimpleNamespace(status="failed", data=None)   # 无 error / error_code


class _BadDataEngine:
    def chat_structured(self, **kw):
        return SimpleNamespace(status="ok", data={"title": "x", "blocks": None})


def _ctx():
    return GenerationContext(
        chapter_id="db_design", title="DB 設計",
        template_marker=ChapterSpec(chapter_id="db_design", title="DB 設計",
                                    section_placeholder=None),
        structured_source="src", write_rules=["W"], design_rules=["D"],
        template_styles={"Heading 1"}, output_language="ja",
    )


def _agent(engine, max_retries=1):
    return WriterAgent(
        session_id="s", engine=engine, prompt_registry=_Registry(),
        state=WriterState(["db_design"]), max_retries=max_retries,
    )


def test_resolve_prompt_passthrough_when_registry_returns_prompt():
    assert isinstance(_agent(_FailedEngine())._resolve_prompt(), Prompt)


def test_engine_failed_status_without_details_raises():
    with pytest.raises(WriterGenerationError, match="failed"):
        _agent(_FailedEngine()).generate_chapter(_ctx())


def test_invalid_llm_data_triggers_retry_and_raises():
    with pytest.raises(WriterGenerationError, match="重试耗尽"):
        _agent(_BadDataEngine()).generate_chapter(_ctx())