package llm

import (
	"context"
	"fmt"
	"strings"

	"ai-agent-scaffold-go/internal/model"
)

// ChatModelAdapter 适配器，将 OpenAIClient 包装为 model.ChatModel
type ChatModelAdapter struct {
	client *OpenAIClient
	tools  []model.Tool
}

// NewChatModelAdapter 创建 ChatModel 适配器
func NewChatModelAdapter(client *OpenAIClient, tools []model.Tool) *ChatModelAdapter {
	return &ChatModelAdapter{client: client, tools: tools}
}

// Generate 实现 model.ChatModel 接口
func (m *ChatModelAdapter) Generate(ctx context.Context, messages []model.ChatMessage) (model.ChatReply, error) {
	return m.client.Generate(ctx, messages, m.toolDefs())
}

// Stream 实现 model.ChatModel 接口
func (m *ChatModelAdapter) Stream(ctx context.Context, messages []model.ChatMessage) (<-chan model.ChatStreamEvent, <-chan error) {
	return m.client.Stream(ctx, messages, m.toolDefs())
}

// Tools 返回注册的工具列表
func (m *ChatModelAdapter) Tools() []model.Tool {
	return m.tools
}

// CallTool 根据名称和参数调用对应的工具
func (m *ChatModelAdapter) CallTool(ctx context.Context, name, arguments string) (string, error) {
	query := extractQuery(arguments)
	for _, t := range m.tools {
		if t.Name() == name {
			return t.Call(ctx, query)
		}
	}
	return "", fmt.Errorf("tool %q not found", name)
}

// toolDefs 将 model.Tool 转换为 ToolDef 列表
func (m *ChatModelAdapter) toolDefs() []ToolDef {
	defs := make([]ToolDef, 0, len(m.tools))
	for _, t := range m.tools {
		defs = append(defs, ToolDef{Name: t.Name(), Description: t.Description()})
	}
	return defs
}

// extractQuery 从工具调用参数 JSON 中提取 query 字段
func extractQuery(arguments string) string {
	arguments = strings.TrimSpace(arguments)
	if arguments == "" {
		return ""
	}
	if idx := strings.Index(arguments, `"query"`); idx >= 0 {
		rest := arguments[idx+7:]
		if colon := strings.Index(rest, `:`); colon >= 0 {
			rest = strings.TrimSpace(rest[colon+1:])
			if strings.HasPrefix(rest, `"`) {
				rest = rest[1:]
				if end := strings.Index(rest, `"`); end >= 0 {
					return rest[:end]
				}
			}
		}
	}
	return arguments
}