"""Writer Agent：调用推理引擎生成单章内容（Phase 5）。

接入真实 InferenceEngine.chat_structured（session_id/prompt/variables/schema/retry_count），
并对章节级失败做有限重试；token 估算分块（真实拼回留待后续并发实现）。
"""
from __future__ import annotations

import asyncio

from genesis.inference.engine import InferenceEngine
from genesis.inference.prompt_registry import PromptRegistry
from genesis.inference.types import Prompt, StructuredResult
from genesis.writer.models import ChapterContent, GenerationContext
from genesis.writer.writer_state import WriterState
from genesis.writer.exceptions import WriterGenerationError


WRITER_PROMPT_TEMPLATE = (
    "你是概要设计书撰写专家。\n"
    "章节: {{chapter_id}} {{title}}\n"
    "写入规则:\n{{write_rules}}\n"
    "设计规则:\n{{design_rules}}\n"
    "模板样式:\n{{template_styles}}\n"
    "影响调查上下文:\n{{impact}}\n"
    "参考资料:\n{{source}}\n"
    "请输出符合 schema 的章节内容 JSON。\n"
    "【语言约束】章节正文（所有 block 的 text 字段）所使用的自然语言，"
    "必须与章节标题「{{title}}」所用语言保持一致：标题为日文则用日文撰写，"
    "为中文则用中文撰写，依此类推。"
)

CHAPTER_OUTPUT_SCHEMA = {
    "type": "object",
    "properties": {
        "title": {"type": "string"},
        "blocks": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "type": {"type": "string"},
                    "text": {"type": "string"},
                    "level": {"type": "integer"},
                    "headers": {"type": "array", "items": {"type": "string"}},
                    "rows": {"type": "array", "items": {"type": "array", "items": {"type": "string"}}},
                    "items": {"type": "array", "items": {"type": "string"}},
                    "source_uris": {"type": "array", "items": {"type": "string"}},
                },
                "required": ["type"],
            },
        },
    },
    "required": ["title", "blocks"],
}


class WriterAgent:
    def __init__(
        self,
        session_id,
        engine: InferenceEngine,
        prompt_registry: PromptRegistry,
        state: WriterState,
        max_retries: int = 1,
    ) -> None:
        self.session_id = session_id
        self.engine = engine
        self.prompt_registry = prompt_registry
        self.state = state
        self.max_retries = max_retries

    def _chunk_source(self, source) -> list[dict]:
        if source is None:
            return [{"index": 0, "text": ""}]
        src = source if isinstance(source, str) else str(source)
        n = max(1, len(src) // 1800 + 1)
        return [{"index": i, "text": src[i * 1800:(i + 1) * 1800]} for i in range(n)]

    def _resolve_prompt(self) -> Prompt:
        """取用/注册 writer.chapter 模板。

        优先使用 get_or_create（与测试 Fake 兼容）；真实 PromptRegistry 无该方法时，
        回退为 register + get。
        """
        get_or_create = getattr(self.prompt_registry, "get_or_create", None)
        if get_or_create is not None:
            return get_or_create("writer.chapter", WRITER_PROMPT_TEMPLATE)
        self.prompt_registry.register("writer.chapter", "1", WRITER_PROMPT_TEMPLATE)
        return self.prompt_registry.get("writer.chapter", "1")

    def _call_llm(self, context: GenerationContext) -> dict:
        prompt = self._resolve_prompt()
        result = self.engine.chat_structured(
            session_id=self.session_id,
            prompt=prompt,
            variables=context.to_vars(),
            schema=CHAPTER_OUTPUT_SCHEMA,
            retry_count=2,
        )
        # 真实 InferenceEngine.chat_structured 为 async；测试用同步 FakeEngine 返回普通对象。
        # 兼容两者：若返回协程则通过 asyncio.run 驱动（调用方 orchestrator/qa_loop/脚本均为同步上下文）。
        if asyncio.iscoroutine(result):
            result = asyncio.run(result)
        if result.status not in ("ok", "fallback"):
            # 透传底层错误详情（如 401 鉴权失败原因），便于人工门禁定位
            err = getattr(result, "error", None)
            code = getattr(result, "error_code", None)
            suffix = ""
            if err:
                suffix += f"; {err}"
            if code:
                suffix += f" (code={code})"
            raise WriterGenerationError(f"引擎返回异常状态: {result.status}{suffix}")
        return result.data

    def generate_chapter(self, context: GenerationContext) -> ChapterContent:
        self._chunk_source(context.structured_source)  # 分块可用性验证（真实拼回留待后续）
        last_err: Exception | None = None
        for _ in range(max(1, self.max_retries)):
            try:
                data = self._call_llm(context)
            except Exception as e:  # 引擎可能抛出任意异常，统一按章节级失败重试
                last_err = e
                continue
            try:
                content = ChapterContent.from_llm(context.chapter_id, context.title, data)
            except (KeyError, TypeError, ValueError) as e:
                last_err = e
                continue
            self.state.record_success(content)
            return content
        raise WriterGenerationError(f"章节 {context.chapter_id} 重试耗尽: {last_err}")