package mcp

import (
	"context"
	"fmt"
	"net/http"
	"runtime/debug"
	"time"
	"yunyan/lego/sys/log"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

const (
	ToolGroup_GLOBAL   = "GLOBAL"   // 全局工具组
	ToolGroup_OVERSEAS = "OVERSEAS" // 海外工具组
	ToolGroup_CHINA    = "CHINA"    // 国内工具组
)

type (
	ITool interface {
		Tool() (tool mcp.Tool)
		Handl(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error)
	}
)

func stringInArray(target string, array []string) bool {
	for _, item := range array {
		if item == target {
			return true
		}
	}
	return false
}

// safeLogErrorf 记录错误日志，日志系统未初始化等异常不向外扩散
func safeLogErrorf(format string, args ...interface{}) {
	defer func() { _ = recover() }()
	log.Errorf(format, args...)
}

// safeToolHandler 包装工具处理函数，保证任何情况下都给大模型返回一个可读的结果:
//  1. 捕获 handler 内部 panic(参数异常导致的空指针、数组越界等)，不让单个工具打崩整条请求;
//  2. 兜底 handler 返回 (nil, nil) 的情况——mcp-go 的 request_handler 会直接解引用结果(*result)，
//     result 为 nil 时必然 panic;
//  3. 把 error 转成工具错误结果(IsError)，让模型能看到失败原因并自行重试/换参数，
//     而不是整条 JSON-RPC 请求失败。
func safeToolHandler(name string, handler server.ToolHandlerFunc) server.ToolHandlerFunc {
	return func(ctx context.Context, request mcp.CallToolRequest) (result *mcp.CallToolResult, err error) {
		defer func() {
			if r := recover(); r != nil {
				//先给出结果，再记录日志，保证日志系统本身出问题也不影响返回
				result = mcp.NewToolResultError(fmt.Sprintf("工具 %s 执行异常，请确认调用参数是否正确后重试", name))
				err = nil
				safeLogErrorf("tool %s panic recovered: %v\nstack: %s", name, r, string(debug.Stack()))
			}
		}()
		if result, err = handler(ctx, request); err != nil {
			safeLogErrorf("tool %s exec err: %v", name, err)
			result = mcp.NewToolResultError(fmt.Sprintf("工具 %s 执行失败: %s", name, err.Error()))
			err = nil
			return
		}
		if result == nil {
			safeLogErrorf("tool %s return nil result", name)
			result = mcp.NewToolResultError(fmt.Sprintf("工具 %s 未返回结果，请确认调用参数是否正确后重试", name))
		}
		return
	}
}

func isValidDate(dateStr string) bool {
	_, err := time.Parse("2006-01-02", dateStr)
	return err == nil
}

// withRecover 添加panic恢复中间件，防止单个请求的panic导致整个服务崩溃
func withRecover(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer func() {
			if err := recover(); err != nil {
				// 记录panic信息
				log.Errorf("Panic recovered in %s %s: %v", r.Method, r.URL.Path, err)

				// 打印堆栈信息用于调试
				if stack := debug.Stack(); len(stack) > 0 {
					log.Errorf("Stack trace: %s", string(stack))
				}

				// 返回500错误给客户端
				w.Header().Set("Content-Type", "application/json")
				w.WriteHeader(http.StatusInternalServerError)
				w.Write([]byte(`{"error":"Internal server error","message":"服务器内部错误，请稍后重试"}`))
			}
		}()

		next.ServeHTTP(w, r)
	})
}

func withCORS(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		origin := r.Header.Get("Origin")
		if origin != "" {
			w.Header().Set("Access-Control-Allow-Origin", origin)
		} else {
			w.Header().Set("Access-Control-Allow-Origin", "*")
		}
		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Session-Id, Mcp-Session-Id")
		w.Header().Set("Access-Control-Expose-Headers", "Mcp-Session-Id")
		w.Header().Set("Access-Control-Allow-Credentials", "true")

		// 处理预检请求
		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusOK)
			return
		}

		next.ServeHTTP(w, r)
	})
}