frontend/src/services/systemNotificationService.ts

/**
 * 系统通知服务
 * 使用 expo-notifications 处理原生系统通知
 * 支持本地通知，类似 QQ 在通知栏显示消息
 */

import * as Notifications from 'expo-notifications';
import { Platform, AppState, AppStateStatus } from 'react-native';
import type { WSChatMessage, WSNotificationMessage, WSAnnouncementMessage } from './websocketService';
import { extractTextFromSegments } from '../types/dto';

// 通知渠道配置
const CHANNEL_ID = 'default';
const CHANNEL_NAME = '默认通知';
const CHANNEL_DESCRIPTION = '接收系统消息、互动通知等';

// 通知类型
export type AppNotificationType =
  | 'like_post'
  | 'like_comment'
  | 'like_reply'
  | 'favorite_post'
  | 'comment'
  | 'reply'
  | 'follow'
  | 'mention'
  | 'system'
  | 'announcement'
  | 'announce'
  | 'chat';

// 获取通知标题
export function getNotificationTitle(type: AppNotificationType, operatorName?: string): string {
  const titles: Record<AppNotificationType, string> = {
    like_post: '有人赞了你的帖子',
    like_comment: '有人赞了你的评论',
    like_reply: '有人赞了你的回复',
    favorite_post: '有人收藏了你的帖子',
    comment: '新评论',
    reply: '新回复',
    follow: '新粉丝',
    mention: '@提及',
    system: '系统通知',
    announcement: '公告',
    announce: '公告',
    chat: '新消息',
  };
  return titles[type] || '新通知';
}

class SystemNotificationService {
  private isInitialized: boolean = false;
  private appStateSubscription: any = null;
  private currentAppState: AppStateStatus = 'active';

  async initialize(): Promise<boolean> {
    if (this.isInitialized) {
      return true;
    }

    try {
      const { status: existingStatus } = await Notifications.getPermissionsAsync();
      let finalStatus = existingStatus;

      if (existingStatus !== 'granted') {
        const { status } = await Notifications.requestPermissionsAsync();
        finalStatus = status;
      }

      if (finalStatus !== 'granted') {
        console.log('[SystemNotification] 通知权限未授权');
        return false;
      }

      // 设置 notification handler，确保前台也能显示通知、播放声音和震动
      Notifications.setNotificationHandler({
        handleNotification: async () => ({
          shouldShowAlert: true,
          shouldPlaySound: true,
          shouldSetBadge: true,
          shouldShowBanner: true,
          shouldShowList: true,
        }),
      });

      if (Platform.OS === 'android') {
        await Notifications.setNotificationChannelAsync(CHANNEL_ID, {
          name: CHANNEL_NAME,
          importance: Notifications.AndroidImportance.HIGH, // HIGH 优先级足以触发震动
          vibrationPattern: [0, 300, 200, 300], // 等待0ms，震动300ms，停止200ms，震动300ms
          lightColor: '#FF6B35',
          enableVibrate: true, // 启用震动
          enableLights: true, // 启用呼吸灯
        });
      }

      this.currentAppState = AppState.currentState;
      this.appStateSubscription = AppState.addEventListener('change', (nextAppState) => {
        this.currentAppState = nextAppState;
      });

      this.isInitialized = true;
      console.log('[SystemNotification] 通知服务初始化成功');
      return true;
    } catch (error) {
      console.error('[SystemNotification] 初始化失败:', error);
      return false;
    }
  }

  async showNotification(options: {
    title: string;
    body: string;
    data?: Record<string, string | number | object>;
    type: AppNotificationType;
  }): Promise<string | null> {
    if (!this.isInitialized) {
      await this.initialize();
    }

    try {
      // 使用 scheduleNotificationAsync 立即显示通知
      // 配合 setNotificationHandler 确保前台也能显示
      
      // 构建通知内容
      const content: Notifications.NotificationContentInput = {
        title: options.title,
        body: options.body,
        data: options.data as Record<string, string | number | object> | undefined,
        // 显式设置震动（仅 Android 生效）
        ...(Platform.OS === 'android' ? {
          vibrationPattern: [0, 300, 200, 300],
        } : {}),
      };

      const notificationId = await Notifications.scheduleNotificationAsync({
        content,
        trigger: null, // null 表示立即显示
      });

      console.log('[SystemNotification] 通知已显示:', notificationId);
      return notificationId;
    } catch (error) {
      console.error('[SystemNotification] 显示通知失败:', error);
      return null;
    }
  }

  async showChatNotification(message: WSChatMessage): Promise<string | null> {
    const body = extractTextFromSegments(message.segments);
    return this.showNotification({
      title: '新消息',
      body,
      data: {
        type: 'chat',
        conversationId: message.conversation_id,
        messageId: String(message.id),
        senderId: message.sender_id,
      },
      type: 'chat',
    });
  }

  async showWSNotification(message: WSNotificationMessage | WSAnnouncementMessage): Promise<string | null> {
    const type = message.system_type as AppNotificationType;
    const title = getNotificationTitle(type);
    const body = message.content;

    return this.showNotification({
      title,
      body,
      data: {
        type: message.type,
        id: String(message.id),
        senderId: message.sender_id,
        receiverId: message.receiver_id,
        systemType: message.system_type,
        extraData: JSON.stringify(message.extra_data || {}),
      },
      type,
    });
  }

  async handleWSMessage(message: WSChatMessage | WSNotificationMessage | WSAnnouncementMessage): Promise<void> {
    console.log('[SystemNotification] handleWSMessage 被调用, 当前AppState:', this.currentAppState);
    
    // 仅在后台时显示通知，前台时不显示（用户正在使用应用，可以直接看到消息）
    if (this.currentAppState !== 'active') {
      // 判断是否是聊天消息（通过 segments 字段）
      if ('segments' in message) {
        const chatMsg = message as WSChatMessage;
        const body = extractTextFromSegments(chatMsg.segments);
        console.log('[SystemNotification] 后台模式 - 显示聊天通知:', chatMsg.id, body);
        await this.showChatNotification(chatMsg);
      } else {
        const notifMsg = message as WSNotificationMessage | WSAnnouncementMessage;
        console.log('[SystemNotification] 后台模式 - 显示系统通知:', notifMsg.id, notifMsg.content);
        await this.showWSNotification(notifMsg);
      }
    } else {
      console.log('[SystemNotification] 前台模式 - 不显示通知');
    }
  }

  async clearAllNotifications(): Promise<void> {
    await Notifications.dismissAllNotificationsAsync();
  }

  async clearBadge(): Promise<void> {
    await Notifications.setBadgeCountAsync(0);
  }

  async setBadgeCount(count: number): Promise<void> {
    await Notifications.setBadgeCountAsync(count);
  }

  cleanup(): void {
    if (this.appStateSubscription) {
      this.appStateSubscription.remove();
      this.appStateSubscription = null;
    }
    this.isInitialized = false;
  }

  getAppState(): AppStateStatus {
    return this.currentAppState;
  }
}

export const systemNotificationService = new SystemNotificationService();