import { Injectable, Logger } from '@nestjs/common';
import { Cron } from '@nestjs/schedule';
import { PrismaService } from '../prisma/prisma.service';
import { jalaliMonthKeyOf, previousPeriod } from './gamification-engine';
import { GamificationService } from './gamification.service';

@Injectable()
export class GamificationCronService {
  private readonly logger = new Logger(GamificationCronService.name);

  constructor(
    private readonly prisma: PrismaService,
    private readonly game: GamificationService,
  ) {}

  /** پاداش «نفر اول ماه» برای ماه شمسی گذشته؛ روزانه اجرا می‌شود و تکراری ثبت نمی‌کند */
  @Cron('20 0 * * *', { timeZone: 'Asia/Tehran' })
  async awardTopOfMonth() {
    const range = previousPeriod('month');
    if (!range) return;
    const monthKey = jalaliMonthKeyOf(range.from);
    const bonuses = await this.prisma.gamificationBonus.findMany({
      where: { kind: 'top_of_month', isActive: true },
    });
    for (const bonus of bonuses) {
      try {
        const settings = await this.game.settingsFor(bonus.organizationId);
        if (!settings?.enabled) continue;
        const memberIds = new Set((await this.game.members(bonus.organizationId)).map((m) => m.userId));
        const rows = await this.prisma.gamificationTransaction.groupBy({
          by: ['userId'],
          where: {
            organizationId: bonus.organizationId,
            status: 'approved',
            createdAt: { gte: range.from, lt: range.to },
          },
          _sum: { score: true },
        });
        const winner = rows
          .filter((r) => memberIds.has(r.userId) && (r._sum.score ?? 0) > 0)
          .sort((a, b) => (b._sum.score ?? 0) - (a._sum.score ?? 0))[0];
        if (!winner) continue;
        await this.game.record({
          organizationId: bonus.organizationId,
          userId: winner.userId,
          kind: 'bonus',
          bonusId: bonus.id,
          score: bonus.score,
          coins: bonus.coins,
          title: `پاداش ویژه: ${bonus.name}`,
          idempotencyKey: `b:${bonus.id}:m:${monthKey}`,
        });
      } catch (err) {
        this.logger.warn(`top-of-month ${bonus.id}: ${err instanceof Error ? err.message : String(err)}`);
      }
    }
  }
}