"""LLM-powered analysis of rule diagnostics and low-score samples."""
from __future__ import annotations

import logging
from typing import Any

from .rules import Diagnosis

logger = logging.getLogger("rag_eval.advisor")

_PROMPT_TEMPLATE = """\
你是一个 RAG 系统优化专家，正在分析西门子医疗 CT 文档问答系统的评测结果。
请用中文撰写一份优化建议报告，格式为 Markdown。

## 评测诊断摘要

{diagnosis_summary}

## 低分样本示例

{low_sample_text}

## 报告要求

1. 按指标分节（## 指标名  [severity]），先解释"为什么低"（结合低分样本具体分析），再给出"具体怎么改"
2. "具体怎么改"要结合低分样本的实际内容，而不只是泛泛建议
3. 最后写一节 **## 优先优化次序**，按性价比排序（不增加 LLM 调用次数的优化优先）
4. 语言简洁，面向工程师，不要废话，不要重复列表内容

只输出 Markdown 报告正文，不要任何前置说明。
"""


def _build_diagnosis_summary(diagnoses: list[Diagnosis]) -> str:
    lines = []
    for d in diagnoses:
        direction = "（越低越好）" if d.metric == "noise_sensitivity" else ""
        lines.append(
            f"- **{d.metric}** {direction} 均值={d.mean_score:.4f}，"
            f"阈值={d.threshold}，严重程度={d.severity}"
        )
        lines.append(f"  - 可能原因：{'; '.join(d.root_causes)}")
        lines.append(f"  - 建议动作：{'; '.join(d.suggested_actions)}")
    return "\n".join(lines)


def _build_low_sample_text(diagnoses: list[Diagnosis]) -> str:
    lines = []
    for d in diagnoses:
        if not d.low_samples:
            continue
        lines.append(f"### {d.metric} 低分样本（最多 3 条）")
        for i, s in enumerate(d.low_samples, 1):
            score = s.get(d.metric, "N/A")
            lines.append(f"\n**样本 {i}**（分数={score}）")
            lines.append(f"- 问题：{s.get('question', '')}")
            lines.append(f"- 回答：{s.get('answer', '')[:300]}")
            lines.append(f"- 标准答案：{s.get('ground_truth', '')[:200]}")
    return "\n".join(lines)


async def analyze(
    diagnoses: list[Diagnosis],
    llm: Any,
    scenario_name: str,
) -> str:
    """Call the judge LLM to generate a Chinese optimization report.

    Args:
        diagnoses: Non-empty list of Diagnosis from rules.diagnose().
        llm: RAGAS LLM wrapper (has .agenerate() method).
        scenario_name: Used only for logging.

    Returns:
        LLM-generated Markdown string, or "" on failure (triggers writer fallback).
    """
    if not diagnoses:
        return ""

    diagnosis_summary = _build_diagnosis_summary(diagnoses)
    low_sample_text = _build_low_sample_text(diagnoses)
    prompt = _PROMPT_TEMPLATE.format(
        diagnosis_summary=diagnosis_summary,
        low_sample_text=low_sample_text,
    )

    try:
        logger.info("[advisor] calling LLM for optimization analysis  scenario=%s", scenario_name)
        from langchain_core.messages import HumanMessage
        # Use the underlying langchain chat model directly (RAGAS LangchainLLMWrapper wraps BaseChatModel)
        response = await llm.langchain_llm.ainvoke([HumanMessage(content=prompt)])
        text = response.content.strip()
        logger.info("[advisor] LLM analysis complete  chars=%d", len(text))
        return text
    except Exception as exc:
        logger.warning(
            "[advisor] LLM analysis failed (%s: %s) — falling back to rule report",
            type(exc).__name__, exc,
        )
        return ""