import { Injectable } from '@nestjs/common';
import { LearningActivityRepository } from './learning-activity.repository';

@Injectable()
export class LearningActivityService {
  constructor(private readonly repository: LearningActivityRepository) {}

  async getHeatmap(userId: string) {
    const activities = await this.repository.findAll(userId);
    const heatmap: Record<string, number> = {};
    for (const a of activities) {
      const dateStr = a.activityDate instanceof Date
        ? a.activityDate.toISOString().split('T')[0]
        : String(a.activityDate).split('T')[0];
      heatmap[dateStr] = a.durationSeconds;
    }
    return heatmap;
  }

  async getSummary(userId: string) {
    const activities = await this.repository.findAll(userId);
    const totalMinutes = Math.round(
      activities.reduce((s, a) => s + a.durationSeconds, 0) / 60,
    );
    const totalCards = activities.reduce((s, a) => s + a.reviewCount, 0);
    const activeDays = activities.filter((a) => a.durationSeconds > 0).length;
    const dailyAverage = activeDays > 0 ? Math.round(totalMinutes / activeDays) : 0;
    return { totalMinutes, totalCardsReviewed: totalCards, activeDays, dailyAverage };
  }
}