"""
RAG 节点模块 - 独立的 RAG 检索节点
包含：
- rag_retrieve_node: RAG 检索节点（带超时重试）
- rag_re_retrieve_node: 重新检索节点
- 相关的 RAG 工具集成
"""

import time
from typing import Dict, Any, Optional
from datetime import datetime

from .state import MainGraphState, ErrorRecord, ErrorSeverity
from .retry_utils import (
    RetryConfig,
    RAG_RETRY_CONFIG,
    create_retry_wrapper_for_node
)

# 尝试导入现有的 RAG 工具
try:
    from ..rag.tools import create_rag_tool_sync
    from ..rag.pipeline import RAGPipeline
    HAS_RAG = True
except ImportError:
    HAS_RAG = False


def get_rag_tool_from_state(state: MainGraphState) -> Optional[Any]:
    """
    从状态中获取 RAG 工具（如果有）
    
    Args:
        state: 主图状态
    
    Returns:
        RAG 工具实例或 None
    """
    if "rag_tool" in state.debug_info:
        return state.debug_info["rag_tool"]
    return None


# ========== RAG 检索核心逻辑 ==========
def _rag_retrieve_core(state: MainGraphState) -> MainGraphState:
    """
    RAG 检索核心逻辑（不带重试）
    
    Args:
        state: 主图状态
    
    Returns:
        更新后的状态
    """
    # 获取检索查询（优先使用推理结果中的优化查询）
    retrieval_query = state.user_query
    if "reasoning_result" in state.debug_info:
        reasoning_result = state.debug_info["reasoning_result"]
        if hasattr(reasoning_result, "retrieval_config"):
            cfg = reasoning_result.retrieval_config
            if cfg and cfg.retrieval_query:
                retrieval_query = cfg.retrieval_query
    
    # 尝试获取 RAG 工具
    rag_tool = get_rag_tool_from_state(state)
    
    if rag_tool and HAS_RAG:
        # 使用真实的 RAG 工具
        try:
            rag_context = rag_tool.invoke(retrieval_query)
            state.rag_context = rag_context
            state.rag_docs = [
                {"source": "rag_doc", "content": rag_context}
            ]
            state.rag_retrieved = True
            state.success = True
            return state
        except Exception as e:
            raise RuntimeError(f"RAG 调用失败: {str(e)}") from e
    else:
        # 没有 RAG 工具，使用模拟数据（演示用）
        state.rag_context = (
            f"[RAG 检索结果]\n"
            f"查询: {retrieval_query}\n"
            f"这是来自知识库的相关信息。"
        )
        state.rag_docs = [
            {"source": "doc1.txt", "content": "LangGraph 是一个用于构建 Agent 的框架"},
            {"source": "doc2.txt", "content": "React 模式是 '思考→行动→观察' 循环"}
        ]
        state.rag_retrieved = True
        state.success = True
        return state


# ========== RAG 检索节点（带超时和重试） ==========
def rag_retrieve_node(state: MainGraphState) -> MainGraphState:
    """
    RAG 检索节点：带超时和重试
    
    Args:
        state: 主图状态
    
    Returns:
        更新后的状态
    """
    state.current_phase = "rag_retrieving"
    
    start_time = time.time()
    last_error = None
    
    for attempt in range(RAG_RETRY_CONFIG.max_retries + 1):
        try:
            # 执行核心逻辑
            result = _rag_retrieve_core(state)
            
            # 成功
            state.debug_info["rag_retrieval"] = {
                "attempt": attempt + 1,
                "success": True,
                "time": time.time() - start_time
            }
            return result
            
        except Exception as e:
            last_error = e
            
            if attempt >= RAG_RETRY_CONFIG.max_retries:
                break
            
            # 指数退避等待
            delay = RAG_RETRY_CONFIG.base_delay * (2 ** attempt)
            time.sleep(min(delay, RAG_RETRY_CONFIG.max_delay))
    
    # 所有重试都失败，记录结构化错误
    error_record = ErrorRecord(
        error_type="RAGRetrievalError",
        error_message=str(last_error) if last_error else "RAG 检索超时",
        severity=ErrorSeverity.WARNING,
        source="rag_retrieve_node",
        timestamp=datetime.now().isoformat(),
        retry_count=RAG_RETRY_CONFIG.max_retries,
        max_retries=RAG_RETRY_CONFIG.max_retries,
        context={
            "query": state.user_query,
            "total_time": time.time() - start_time,
            "timeout": RAG_RETRY_CONFIG.timeout
        }
    )
    
    state.errors.append(error_record)
    state.current_error = error_record
    state.current_phase = "error_handling"
    
    return state


# ========== 重新检索节点 ==========
def rag_re_retrieve_node(state: MainGraphState) -> MainGraphState:
    """
    重新检索节点：用于第二次检索（不同的参数）
    
    Args:
        state: 主图状态
    
    Returns:
        更新后的状态
    """
    state.current_phase = "rag_re_retrieving"
    
    # 可以在这里修改检索参数（例如：扩大范围、调整查询）
    state.debug_info["rag_re_retrieve"] = {
        "original_retrieved": state.rag_retrieved,
        "original_docs_count": len(state.rag_docs)
    }
    
    # 使用相同的检索逻辑
    return rag_retrieve_node(state)


# ========== 工具：将 RAG 工具注入到状态 ==========
def inject_rag_tool_to_state(state: MainGraphState, rag_tool: Any) -> MainGraphState:
    """
    将 RAG 工具注入到状态中，供后续节点使用
    
    Args:
        state: 主图状态
        rag_tool: RAG 工具实例
    
    Returns:
        更新后的状态
    """
    state.debug_info["rag_tool"] = rag_tool
    state.debug_info["rag_tool_injected"] = datetime.now().isoformat()
    return state


# ========== 导出 ==========
__all__ = [
    "rag_retrieve_node",
    "rag_re_retrieve_node",
    "inject_rag_tool_to_state",
    "get_rag_tool_from_state"
]