import { Injectable, Logger } from '@nestjs/common';
import { Interval } from '@nestjs/schedule';
import { PrismaService } from '../prisma/prisma.service';
import { NowPlayingService } from './now-playing.service';

/**
 * Now-playing для «Русская Волна» (сеть Волна / amgradio.ru, ~27 каналов). Потоки
 * mp3.amgradio.ru НЕ отдают ICY. Единый JSON со всеми каналами:
 * `https://info.volna.top/radio.json` → поля `{prefix}_title` = «АРТИСТ - ПЕСНЯ».
 * Маунт нашего потока (RusRock128, ChillaFM128…) приводим к префиксу volna
 * (rusrock, chilla — с fallback на отброс «fm»). Обложек у них нет (covers 404) →
 * подтянет обогащение (iTunes/Deezer).
 */
@Injectable()
export class VolnaNowPlayingService {
  private readonly logger = new Logger(VolnaNowPlayingService.name);
  private readonly headers = { 'User-Agent': 'Mozilla/5.0' };

  constructor(
    private readonly prisma: PrismaService,
    private readonly nowPlayingService: NowPlayingService,
  ) {}

  @Interval(30000)
  async pollVolnaNowPlaying() {
    const stations = await this.prisma.station.findMany({
      where: { streamUrl: { contains: 'amgradio.ru' } },
    });
    if (stations.length === 0) return;

    let data: Record<string, unknown> | null = null;
    try {
      const res = await fetch('https://info.volna.top/radio.json', {
        headers: this.headers,
      });
      if (res.ok) data = (await res.json()) as Record<string, unknown>;
    } catch {
      data = null;
    }
    if (!data) return;

    const prefixes = new Set(
      Object.keys(data)
        .filter((k) => k.endsWith('_title'))
        .map((k) => k.slice(0, -'_title'.length)),
    );

    let updated = 0;
    await Promise.allSettled(
      stations.map(async (station) => {
        const prefix = this.resolvePrefix(station.streamUrl, prefixes);
        if (!prefix) return;
        const raw = data[`${prefix}_title`];
        const parsed = this.parseTitle(typeof raw === 'string' ? raw : undefined);
        if (!parsed) return;

        await this.nowPlayingService.ingest({
          stationDbId: station.id,
          stationNumericId: station.stationId,
          artist: parsed.artist,
          song: parsed.song,
          coverUrl: null,
        });
        if (!station.isOnline) {
          await this.prisma.station.update({
            where: { id: station.id },
            data: { isOnline: true },
          });
        }
        updated++;
      }),
    );
    this.logger.log(`Volna poll: ${updated}/${stations.length} обновлено`);
  }

  // mp3.amgradio.ru/RusRock128 → rusrock ; ChillaFM128 → chilla (fallback -fm)
  private resolvePrefix(streamUrl: string, prefixes: Set<string>): string | null {
    const m = streamUrl.match(/amgradio\.ru\/([A-Za-z0-9_]+)/i);
    if (!m) return null;
    const norm = m[1].replace(/\d+$/, '').toLowerCase();
    if (prefixes.has(norm)) return norm;
    if (norm.endsWith('fm') && prefixes.has(norm.slice(0, -2))) {
      return norm.slice(0, -2);
    }
    return null;
  }

  private parseTitle(title?: string): { artist: string; song: string } | null {
    if (!title) return null;
    const t = title.trim();
    if (!t || /listen radio|^https?:/i.test(t)) return null;
    const idx = t.indexOf(' - ');
    if (idx < 0) return null;
    const artist = t.slice(0, idx).trim();
    const song = t.slice(idx + 3).trim();
    if (!artist || !song) return null;
    return { artist, song };
  }
}