"""
SQL Generator Agent - SQL生成专家
根据Schema和问题生成高质量SQL
"""

import logging
import json
import re
from typing import Dict, Optional

from camel.agents import ChatAgent
from camel.models import ChatModel
from config.prompts import SQL_GENERATOR_SYSTEM

logger = logging.getLogger(__name__)


class SQLGeneratorAgent:
    """
    SQL Generator Agent

    职责：
    - 理解用户问题和Schema结构
    - 生成准确的SQL语句
    - 处理复杂的JOIN、聚合、子查询
    - 遵循金融/证券业务特殊规则
    """

    def __init__(
        self,
        model: ChatModel,
        system_message: Optional[str] = None,
        dialect: str = "tsql"
    ):
        """
        初始化Agent

        Args:
            model: CAMEL AI模型实例
            system_message: 系统提示词
            dialect: SQL方言
        """
        self.dialect = dialect
        self.system_message = system_message or SQL_GENERATOR_SYSTEM
        self.agent = ChatAgent(
            system_message=self.system_message,
            model=model,
        )
        logger.info(f"[OK] SQLGeneratorAgent初始化完成 (dialect={dialect})")

    def generate(
        self,
        question: str,
        schema_str: str,
        examples: Optional[List[Dict]] = None,
        dialect: Optional[str] = None
    ) -> str:
        """
        生成SQL

        Args:
            question: 用户问题
            schema_str: Schema描述字符串
            examples: Few-shot示例列表
            dialect: 覆盖默认dialect

        Returns:
            SQL语句字符串
        """
        from config.prompts import SQL_GENERATOR_USER

        dialect = dialect or self.dialect
        prompt = SQL_GENERATOR_USER.format(
            schema=schema_str,
            question=question,
            dialect=dialect
        )

        # 添加few-shot示例（如果有）
        if examples:
            prompt = self._inject_examples(prompt, examples)

        try:
            response = self.agent.step(prompt)
            sql = self._extract_sql(response.msg.content)

            logger.debug(f"生成的SQL: {sql[:200]}...")
            return sql

        except Exception as e:
            logger.error(f"SQL生成失败: {e}")
            raise

    def _extract_sql(self, content: str) -> str:
        """
        从Agent响应中提取SQL语句

        处理：
        - Markdown代码块 (```sql ... ```)
        - 纯SQL文本
        - JSON格式 {"sql": "..."}
        """
        content = content.strip()

        # 尝试提取```sql```块
        if "```sql" in content:
            start = content.find("```sql") + 6
            end = content.find("```", start)
            if end != -1:
                return content[start:end].strip()

        # 尝试提取通用代码块```
        if "```" in content:
            start = content.find("```") + 3
            end = content.find("```", start)
            if end != -1:
                return content[start:end].strip()

        # 尝试解析JSON
        try:
            data = json.loads(content)
            if "sql" in data:
                return data["sql"]
        except json.JSONDecodeError:
            pass

        # 返回原始内容（假设是纯SQL）
        return content

    def _inject_examples(
        self,
        prompt: str,
        examples: List[Dict]
    ) -> str:
        """
        注入few-shot示例到提示词

        Args:
            prompt: 原始提示词
            examples: 示例列表，每项为 {"question": "...", "schema": "...", "sql": "..."}

        Returns:
            增强后的提示词
        """
        examples_text = []
        for ex in examples[:3]:  # 最多3个示例
            examples_text.append(
                f"示例：\n问题：{ex['question']}\n"
                f"Schema: {ex['schema'][:200]}...\n"
                f"SQL: {ex['sql']}"
            )

        examples_block = "\n\n".join(examples_text)

        # 插入到提示词末尾（要求之前）
        return f"{prompt}\n\n参考示例：\n{examples_block}\n\n请生成SQL："

    def generate_with_reasoning(
        self,
        question: str,
        schema_str: str,
        dialect: Optional[str] = None
    ) -> Tuple[str, str]:
        """
        生成SQL并返回解释

        Args:
            question: 用户问题
            schema_str: Schema描述
            dialect: SQL方言

        Returns:
            (SQL语句, 解释)
        """
        from config.prompts import SQL_GENERATOR_USER

        dialect = dialect or self.dialect
        prompt = f"""
{sql_generator_user.format(schema=schema_str, question=question, dialect=dialect)}

请同时输出SQL和简要解释（JSON格式）：
{{
  "sql": "SELECT ...",
  "explanation": "SQL逻辑说明"
}}
"""

        try:
            response = self.agent.step(prompt)
            content = response.msg.content.strip()

            # 尝试解析JSON
            try:
                if "```json" in content:
                    start = content.find("```json") + 7
                    end = content.find("```", start)
                    content = content[start:end].strip()
                data = json.loads(content)
                return data.get("sql", ""), data.get("explanation", "")
            except (json.JSONDecodeError, ValueError):
                # 降级：提取SQL，解释为空
                return self._extract_sql(content), ""

        except Exception as e:
            logger.error(f"生成失败: {e}")
            raise