"""
错误处理节点 - 处理子图/工具调用错误
"""

from ...main_graph.state import MainGraphState, ErrorSeverity
from backend.app.logger import info


def error_handling_node(state: MainGraphState) -> MainGraphState:
    """
    错误处理节点：处理子图/工具调用错误

    返回结构化错误信息，格式如下：
    {
        "tool/node": "...",
        "status": "failed",
        "error": "...",
        "retries_exceeded": true/false,
        "suggestion": "..."
    }
    """
    state.current_phase = "error_handling"

    if not state.current_error:
        state.current_phase = "react_reasoning"
        return state

    error = state.current_error

    # 更新错误状态
    state.error_message = f"{error.error_type}: {error.error_message}"

    # 记录结构化错误信息
    structured_error = {
        "tool": error.source,
        "status": "failed",
        "error": error.error_message,
        "retries_exceeded": error.retry_count >= error.max_retries,
        "retry_count": error.retry_count,
        "max_retries": error.max_retries
    }

    # 根据错误类型添加建议
    if "RAG" in error.error_type:
        structured_error["suggestion"] = "尝试重新表述问题或直接询问"
    elif "subgraph" in error.source or "contact" in error.source:
        structured_error["suggestion"] = "子图执行失败，请尝试简化查询"
    elif "timeout" in error.error_message.lower():
        structured_error["suggestion"] = "请求超时，请稍后再试"
    else:
        structured_error["suggestion"] = "请尝试其他方式提问"

    state.debug_info["structured_error"] = structured_error

    # 策略1: 检查是否可以重试
    can_retry = (
        error.severity in [ErrorSeverity.WARNING, ErrorSeverity.ERROR]
        and error.retry_count < error.max_retries
    )

    if can_retry:
        error.retry_count += 1
        state.retry_action = error.source
        state.debug_info["retry_count"] = error.retry_count

        if "RAG" in error.error_type:
            state.last_action = "RE_RETRIEVE_RAG"
        elif "subgraph" in error.source:
            state.last_action = "DIRECT_RESPONSE"
        else:
            state.last_action = "REASON"

        state.current_phase = "retrying"
        return state

    # 策略2: 无法重试，尝试降级方案
    if error.severity != ErrorSeverity.FATAL:
        state.final_result = (
            f"⚠️  遇到一些问题：\n"
            f"```json\n{structured_error}\n```\n"
            f"但我会尽力用现有信息回答您。"
        )
        state.success = True
        state.current_phase = "finalizing"
        return state

    # 策略3: 致命错误
    state.final_result = (
        f"❌ 服务暂时不可用，请稍后再试。\n"
        f"```json\n{structured_error}\n```"
    )
    state.success = False
    state.current_phase = "finalizing"

    return state