package tool

import (
	"context"
	"encoding/json"
	"fmt"
	"runtime"
	"time"

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

var StartTime = time.Now()

// HealthChecker 用于 system 工具检查其他工具的连通性。
type HealthChecker interface {
	HealthCheckAll(ctx context.Context) map[string]error
}

type SystemTool struct {
	version  string
	registry HealthChecker
}

func NewSystemTool(version string, reg HealthChecker) *SystemTool {
	return &SystemTool{version: version, registry: reg}
}

func (s *SystemTool) Name() string        { return "system" }
func (s *SystemTool) Description() string { return "服务健康检查和信息查询" }
func (s *SystemTool) Initialize(_ context.Context) error { return nil }
func (s *SystemTool) Shutdown(_ context.Context) error   { return nil }
func (s *SystemTool) HealthCheck(_ context.Context) error { return nil }

func (s *SystemTool) Register(mcpServer *server.MCPServer) error {
	mcpServer.AddTool(mcp.NewTool("health",
		mcp.WithDescription("服务健康检查：运行时间、内存、连接状态"),
	), s.handleHealth)

	mcpServer.AddTool(mcp.NewTool("info",
		mcp.WithDescription("服务信息：版本号、Go 版本、已加载工具"),
	), s.handleInfo)

	return nil
}

func (s *SystemTool) handleHealth(ctx context.Context, _ mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)

	result := map[string]any{
		"status":     "ok",
		"uptime":     time.Since(StartTime).String(),
		"goroutines": runtime.NumGoroutine(),
		"heap_mb":    float64(m.HeapAlloc) / 1024 / 1024,
	}

	if s.registry != nil {
		result["connections"] = s.registry.HealthCheckAll(ctx)
	}

	data, _ := json.MarshalIndent(result, "", "  ")
	return mcp.NewToolResultText(string(data)), nil
}

func (s *SystemTool) handleInfo(ctx context.Context, _ mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	result := map[string]any{
		"version":    s.version,
		"go_version": runtime.Version(),
		"os":         runtime.GOOS,
		"arch":       runtime.GOARCH,
		"cpus":       runtime.NumCPU(),
		"start_time": StartTime.Format(time.RFC3339),
	}
	data, _ := json.MarshalIndent(result, "", "  ")
	return mcp.NewToolResultText(fmt.Sprintf("```json\n%s\n```", string(data))), nil
}