package mcp

import (
	"encoding/json"
	"fmt"
	"reflect"
	"sync"

	"git.x2erp.com/qdy/go-base/ctx"
	"git.x2erp.com/qdy/go-db/factory/database"
)

// Tool 接口，工具实现此接口以支持自动注册
type Tool interface {
	Name() string
	Description() string
	InputSchema() map[string]interface{}
	Execute(input json.RawMessage, dep *ToolDependencies) (interface{}, error)
}

// ToolDefinition 定义 MCP 工具
type ToolDefinition struct {
	Name        string                 `json:"name"`
	Description string                 `json:"description"`
	InputSchema map[string]interface{} `json:"inputSchema"`
	Execute     ToolExecuteFunc        `json:"-"`
}

// ToolExecuteFunc 工具执行函数签名
type ToolExecuteFunc func(input json.RawMessage, dep *ToolDependencies) (interface{}, error)

// ToolDependencies 工具执行依赖项
type ToolDependencies struct {
	DBFactory *database.DBFactory
	ReqCtx    *ctx.RequestContext
}

// globalRegistry 全局工具注册表
var (
	globalRegistry   = make(map[string]ToolDefinition)
	registryMu       sync.RWMutex
	dependencies     *ToolDependencies
	dependenciesOnce sync.Once
)

// Register 注册一个工具
func Register(name, description string, inputSchema map[string]interface{}, execute ToolExecuteFunc) {
	registryMu.Lock()
	defer registryMu.Unlock()

	if _, exists := globalRegistry[name]; exists {
		panic(fmt.Sprintf("tool already registered: %s", name))
	}

	globalRegistry[name] = ToolDefinition{
		Name:        name,
		Description: description,
		InputSchema: inputSchema,
		Execute:     execute,
	}
}

// GetTool 获取工具定义
func GetTool(name string) (ToolDefinition, bool) {
	registryMu.RLock()
	defer registryMu.RUnlock()
	tool, ok := globalRegistry[name]
	return tool, ok
}

// ListTools 返回所有工具定义
func ListTools() []ToolDefinition {
	registryMu.RLock()
	defer registryMu.RUnlock()
	tools := make([]ToolDefinition, 0, len(globalRegistry))
	for _, tool := range globalRegistry {
		tools = append(tools, tool)
	}
	return tools
}

// SetDependencies 设置全局依赖项
func SetDependencies(dbFactory *database.DBFactory, reqCtx *ctx.RequestContext) {
	dependenciesOnce.Do(func() {
		dependencies = &ToolDependencies{
			DBFactory: dbFactory,
			ReqCtx:    reqCtx,
		}
	})
}

// GetDependencies 获取依赖项（如果已设置）
func GetDependencies() *ToolDependencies {
	return dependencies
}

// AutoRegister 自动注册实现 Tool 接口的类型
func AutoRegister(tool interface{}) {
	val := reflect.ValueOf(tool)
	typ := val.Type()

	// 检查是否实现了 Tool 接口
	if tool, ok := tool.(Tool); ok {
		Register(tool.Name(), tool.Description(), tool.InputSchema(), tool.Execute)
		return
	}

	// 检查是否具有适当方法的其他接口
	// 这里可以根据需要扩展
	panic(fmt.Sprintf("type %v does not implement Tool interface", typ))
}