package builtin

// ToolSearch 工具 -- 搜索并发现延迟加载的工具.
//
// 当工具数量较多时,非核心工具会被延迟加载.
// 模型通过 ToolSearch 搜索匹配的工具,发现后自动激活.
//
// 特性:
//   - ConcurrencySafe: true,ReadOnly: true
//   - 搜索范围包括工具名称,描述和搜索提示词
//   - 搜索到的工具自动激活,后续调用中可直接使用

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"

	"git.flytoex.net/yuanwei/flyto-agent/pkg/permission"
	"git.flytoex.net/yuanwei/flyto-agent/pkg/tools"
)

// ToolSearchTool 是工具搜索工具.
type ToolSearchTool struct {
	deferred *tools.DeferredRegistry
}

// NewToolSearchTool 创建一个 ToolSearch 工具实例.
//
// deferred 是延迟加载注册表,用于搜索和激活延迟工具.
// 如果 deferred 为 nil,搜索将返回空结果.
func NewToolSearchTool(deferred *tools.DeferredRegistry) *ToolSearchTool {
	return &ToolSearchTool{
		deferred: deferred,
	}
}

// toolSearchInput 是 ToolSearch 工具的输入参数.
type toolSearchInput struct {
	Query string `json:"query"`
}

// Name 返回工具名称.
func (t *ToolSearchTool) Name() string {
	return "ToolSearch"
}

// Description 返回工具描述.
func (t *ToolSearchTool) Description(ctx context.Context) string {
	return "Searches for available tools by keyword. " +
		"Use this when you need a tool that is not in the current active tool list. " +
		"Matched tools will be automatically activated for subsequent use. " +
		"Returns tool names and descriptions."
}

// InputSchema 返回工具的 JSON Schema 输入定义.
func (t *ToolSearchTool) InputSchema() json.RawMessage {
	return json.RawMessage(`{
		"type": "object",
		"properties": {
			"query": {
				"type": "string",
				"description": "Search query to find tools (e.g., 'fetch web page', 'search files')"
			}
		},
		"required": ["query"]
	}`)
}

// Metadata 返回工具元数据.
func (t *ToolSearchTool) Metadata() tools.Metadata {
	return tools.Metadata{
		ConcurrencySafe: true,
		ReadOnly:        true,
		Destructive:     false,
		SearchHint:      "tool search find discover deferred",
		PermissionClass: permission.PermClassReadOnly,
		AuditOperation:  "read",
	}
}

// Execute 执行工具搜索.
func (t *ToolSearchTool) Execute(ctx context.Context, input json.RawMessage, progress tools.ProgressFunc) (*tools.Result, error) {
	var params toolSearchInput
	if err := json.Unmarshal(input, &params); err != nil {
		return &tools.Result{
			Output:  fmt.Sprintf("error: invalid input: %v", err),
			IsError: true,
		}, nil
	}

	if params.Query == "" {
		return &tools.Result{
			Output:  "error: query is required",
			IsError: true,
		}, nil
	}

	// 如果未配置延迟注册表,返回空结果
	if t.deferred == nil {
		return &tools.Result{
			Output:  "No deferred tools available. All tools are already active.",
			IsError: false,
		}, nil
	}

	// 搜索匹配的工具
	matches := t.deferred.SearchTools(params.Query)

	if len(matches) == 0 {
		return &tools.Result{
			Output:  fmt.Sprintf("No tools found matching '%s'.", params.Query),
			IsError: false,
		}, nil
	}

	// 构建输出并激活匹配的工具
	var sb strings.Builder
	sb.WriteString(fmt.Sprintf("Found %d tool(s) matching '%s':\n\n", len(matches), params.Query))

	for _, tool := range matches {
		name := tool.Name()
		desc := tool.Description(ctx)

		sb.WriteString(fmt.Sprintf("- %s: %s\n", name, desc))

		// 自动激活搜索到的工具
		t.deferred.ActivateTool(name)
	}

	sb.WriteString("\nThese tools have been activated and are now available for use.")

	return &tools.Result{
		Output:  sb.String(),
		IsError: false,
		Data: map[string]any{
			"matched_count": len(matches),
			"query":         params.Query,
		},
	}, nil
}