import { Injectable, OnModuleInit } from '@nestjs/common';
import { generateShortId } from '../../common/utils/id.util';

export interface Notification {
  id: string;
  userId: string;
  type: string;
  title: string;
  body: string;
  read: boolean;
  createdAt: Date;
}

@Injectable()
export class NotificationsRepository implements OnModuleInit {
  private notifications: Notification[] = [];

  onModuleInit() {
    const demos: Partial<Notification>[] = [
      { title: '欢迎使用', body: '欢迎来到知习，开始你的学习之旅！', type: 'system' },
      { title: '复习提醒', body: '你有 5 张卡片需要复习', type: 'review_due' },
    ];
    for (const demo of demos) {
      this.notifications.push({
        id: generateShortId(),
        userId: '1',
        type: demo.type || 'system',
        title: demo.title || '',
        body: demo.body || '',
        read: false,
        createdAt: new Date(),
      });
    }
  }

  async findAll(): Promise<Notification[]> {
    return [...this.notifications].sort(
      (a, b) => b.createdAt.getTime() - a.createdAt.getTime(),
    );
  }

  async create(data: Partial<Notification>): Promise<Notification> {
    const notification: Notification = {
      id: data.id || generateShortId(),
      userId: data.userId || 'anonymous',
      type: data.type || 'system',
      title: data.title || '',
      body: data.body || '',
      read: false,
      createdAt: new Date(),
    };
    this.notifications.push(notification);
    return notification;
  }

  async findById(id: string): Promise<Notification | undefined> {
    return this.notifications.find((n) => n.id === id);
  }

  async markRead(id: string): Promise<Notification | undefined> {
    const n = this.notifications.find((x) => x.id === id);
    if (!n) return undefined;
    n.read = true;
    return n;
  }
}