import { Injectable, Logger } from '@nestjs/common';
import { Cron } from '@nestjs/schedule';
import { InjectModel } from '@nestjs/sequelize';
import { Medication } from '../models/medication.model';
import { MedicationRecord } from '../models/medication-record.model';
import { MedicationStatusEnum } from '../enums/medication-status.enum';
import { PushNotificationsService } from '../../push-notifications/push-notifications.service';
import { Op } from 'sequelize';
import * as dayjs from 'dayjs';

/**
 * 药物提醒推送服务
 * 在服药时间前15分钟发送推送提醒
 */
@Injectable()
export class MedicationReminderService {
  private readonly logger = new Logger(MedicationReminderService.name);
  private readonly REMINDER_MINUTES_BEFORE = 15; // 提前15分钟提醒

  constructor(
    @InjectModel(Medication)
    private readonly medicationModel: typeof Medication,
    @InjectModel(MedicationRecord)
    private readonly recordModel: typeof MedicationRecord,
    private readonly pushService: PushNotificationsService,
  ) {}

  /**
   * 每5分钟检查一次需要发送的提醒
   */
  @Cron('*/5 * * * *')
  async checkAndSendReminders(): Promise<void> {
    this.logger.log('开始检查服药提醒');

    try {
      // 计算时间范围：当前时间 + 15分钟
      const now = new Date();
      const reminderTime = dayjs(now)
        .add(this.REMINDER_MINUTES_BEFORE, 'minute')
        .toDate();

      // 查找在接下来15分钟内需要提醒的记录
      const startRange = now;
      const endRange = dayjs(now).add(5, 'minute').toDate(); // 5分钟窗口期

      const upcomingRecords = await this.recordModel.findAll({
        where: {
          status: MedicationStatusEnum.UPCOMING,
          deleted: false,
          scheduledTime: {
            [Op.between]: [
              dayjs(startRange).add(this.REMINDER_MINUTES_BEFORE, 'minute').toDate(),
              dayjs(endRange).add(this.REMINDER_MINUTES_BEFORE, 'minute').toDate(),
            ],
          },
        },
        include: [
          {
            model: Medication,
            as: 'medication',
            where: {
              isActive: true,
              deleted: false,
            },
          },
        ],
      });

      if (upcomingRecords.length === 0) {
        this.logger.debug('没有需要发送的服药提醒');
        return;
      }

      this.logger.log(`找到 ${upcomingRecords.length} 条需要发送提醒的记录`);

      // 按用户分组发送提醒
      const userRecordsMap = new Map<string, MedicationRecord[]>();
      for (const record of upcomingRecords) {
        const userId = record.userId;
        if (!userRecordsMap.has(userId)) {
          userRecordsMap.set(userId, []);
        }
        userRecordsMap.get(userId)!.push(record);
      }

      // 为每个用户发送提醒
      for (const [userId, records] of userRecordsMap.entries()) {
        await this.sendReminderToUser(userId, records);
      }

      this.logger.log(`成功发送 ${upcomingRecords.length} 条服药提醒`);
    } catch (error) {
      this.logger.error('检查服药提醒失败', error.stack);
    }
  }

  /**
   * 为单个用户发送提醒
   */
  private async sendReminderToUser(
    userId: string,
    records: MedicationRecord[],
  ): Promise<void> {
    try {
      const medicationNames = records
        .map((r) => r.medication?.name)
        .filter(Boolean)
        .join('、');

      const title = '服药提醒';
      const body =
        records.length === 1
          ? `该服用 ${medicationNames} 了`
          : `该服用 ${records.length} 种药物了：${medicationNames}`;

      await this.pushService.sendNotification({
        userIds: [userId],
        title,
        body,
        payload: {
          type: 'medication_reminder',
          recordIds: records.map((r) => r.id),
          medicationIds: records.map((r) => r.medicationId),
        },
        sound: 'default',
        badge: 1,
      });

      this.logger.log(`成功向用户 ${userId} 发送服药提醒`);
    } catch (error) {
      this.logger.error(
        `向用户 ${userId} 发送服药提醒失败`,
        error.stack,
      );
    }
  }

  /**
   * 手动为用户发送即时提醒（用于测试或特殊情况）
   */
  async sendImmediateReminder(userId: string, recordId: string): Promise<void> {
    const record = await this.recordModel.findOne({
      where: {
        id: recordId,
        userId,
        deleted: false,
      },
      include: [
        {
          model: Medication,
          as: 'medication',
        },
      ],
    });

    if (!record || !record.medication) {
      throw new Error('服药记录不存在');
    }

    await this.sendReminderToUser(userId, [record]);
  }

  /**
   * 为新创建的药物设置提醒（预留方法，实际提醒由定时任务触发）
   */
  async setupRemindersForMedication(medication: Medication): Promise<void> {
    this.logger.log(`为药物 ${medication.id} 设置提醒（由定时任务自动触发）`);
    // 实际的提醒由定时任务 checkAndSendReminders 自动处理
    // 这里只需要确保药物处于激活状态
  }

  /**
   * 取消药物的所有提醒（停用或删除药物时调用）
   */
  async cancelRemindersForMedication(medicationId: string): Promise<void> {
    this.logger.log(`取消药物 ${medicationId} 的所有提醒`);
    // 由于提醒是基于记录的状态和药物的激活状态动态生成的
    // 所以只需要确保药物被停用或删除，定时任务就不会再发送提醒
  }

  /**
   * 获取用户今天的待提醒数量
   */
  async getTodayReminderCount(userId: string): Promise<number> {
    const startOfDay = dayjs().startOf('day').toDate();
    const endOfDay = dayjs().endOf('day').toDate();

    const count = await this.recordModel.count({
      where: {
        userId,
        status: MedicationStatusEnum.UPCOMING,
        deleted: false,
        scheduledTime: {
          [Op.between]: [startOfDay, endOfDay],
        },
      },
      include: [
        {
          model: Medication,
          as: 'medication',
          where: {
            isActive: true,
            deleted: false,
          },
        },
      ],
    });

    return count;
  }
}