/**
 * 消息发送服务
 * 处理消息发送相关逻辑
 */

import type { MessageResponse, MessageSegment, ConversationResponse } from '../../../types/dto';
import { messageService } from '@/services/message';
import { messageRepository } from '@/database';
import type { IMessageSendService } from '../types';
import { useMessageStore } from '../store';

export class MessageSendService implements IMessageSendService {
  private getCurrentUserId: () => string | null;

  constructor(getCurrentUserId: () => string | null) {
    this.getCurrentUserId = getCurrentUserId;
  }

  /**
   * 发送消息
   */
  async sendMessage(
    conversationId: string,
    segments: MessageSegment[],
    options?: { replyToId?: string }
  ): Promise<MessageResponse | null> {
    const store = useMessageStore.getState();
    
    try {
      // 调用API发送
      const response = await messageService.sendMessage(conversationId, {
        segments,
        reply_to_id: options?.replyToId,
      });

      if (response) {
        const currentUserId = this.getCurrentUserId();
        
        // 原子性合并新消息到内存（防止并发 WS 消息丢失）
        const newMessage: MessageResponse = {
          id: response.id,
          conversation_id: conversationId,
          sender_id: currentUserId || '',
          seq: response.seq,
          segments,
          created_at: new Date().toISOString(),
          status: 'normal',
        };

        store.mergeMessages(conversationId, [newMessage]);

        // 更新会话最后消息
        this.updateConversationWithNewMessage(conversationId, newMessage);

        // 保存到本地数据库
        const textContent = segments
          ?.filter((s: any) => s.type === 'text')
          .map((s: any) => s.data?.text || '')
          .join('') || '';
        
        messageRepository.saveMessage({
          id: response.id,
          conversationId,
          senderId: currentUserId || '',
          content: textContent,
          type: segments?.find((s: any) => s.type === 'image') ? 'image' : 'text',
          isRead: true,
          createdAt: newMessage.created_at,
          seq: response.seq,
          status: 'normal',
          segments,
        }).catch(console.error);

        return newMessage;
      }

      return null;
    } catch (error) {
      console.error('[MessageSendService] 发送消息失败:', error);
      return null;
    }
  }

  /**
   * 更新会话的最后消息信息
   */
  private updateConversationWithNewMessage(
    conversationId: string,
    message: MessageResponse
  ): void {
    const store = useMessageStore.getState();
    const conversation = store.getConversation(conversationId);
    const createdAt = message.created_at || new Date().toISOString();

    if (conversation) {
      // 更新现有会话
      const updatedConv: ConversationResponse = {
        ...conversation,
        last_seq: message.seq,
        last_message: message,
        last_message_at: createdAt,
        updated_at: createdAt,
      };

      store.updateConversation(updatedConv);
    }
  }
}