import { YahooFinanceClient, chunkArray } from '../../domains/shared';
import type { CalendarEvent } from '../../domains/shared';

export class CalendarService {
  constructor(private readonly yahoo: YahooFinanceClient) {}

  async getEvents(tickers: string[]): Promise<{ events: CalendarEvent[]; tickers: string[] }> {
    if (tickers.length === 0) return { events: [], tickers: [] };

    const raw: Record<string, any> = {};
    for (const batch of chunkArray(tickers, 5)) {
      await Promise.all(
        batch.map(async (ticker) => {
          const cal = await this.yahoo.fetchCalendarEvents(ticker);
          if (cal) raw[ticker] = cal;
        }),
      );
      await new Promise<void>((r) => setTimeout(r, 500));
    }

    const now = Date.now();
    const events = CalendarService.buildEvents(raw, now);
    CalendarService.sortEvents(events);

    return { events, tickers };
  }

  private static buildEvents(raw: Record<string, any>, now: number): CalendarEvent[] {
    const events: CalendarEvent[] = [];

    for (const [ticker, cal] of Object.entries(raw)) {
      for (const dateVal of cal.earnings?.earningsDate ?? []) {
        const d = new Date(dateVal as string);
        events.push({
          ticker,
          type: 'earnings',
          date: d.toISOString().slice(0, 10),
          label: 'Earnings',
          detail: cal.earnings.isEarningsDateEstimate ? 'Estimated' : 'Confirmed',
          epsEstimate: cal.earnings.earningsAverage ?? null,
          revEstimate: cal.earnings.revenueAverage ?? null,
          isPast: d.getTime() < now,
        });
      }

      if (cal.exDividendDate) {
        const d = new Date(cal.exDividendDate);
        events.push({
          ticker,
          type: 'exdividend',
          date: d.toISOString().slice(0, 10),
          label: 'Ex-Dividend',
          detail: null,
          isPast: d.getTime() < now,
        });
      }

      if (cal.dividendDate) {
        const d = new Date(cal.dividendDate);
        events.push({
          ticker,
          type: 'dividend',
          date: d.toISOString().slice(0, 10),
          label: 'Dividend',
          detail: null,
          isPast: d.getTime() < now,
        });
      }
    }

    return events;
  }

  private static sortEvents(events: CalendarEvent[]): void {
    events.sort((a, b) => {
      if (a.isPast !== b.isPast) return a.isPast ? 1 : -1;
      return a.isPast
        ? new Date(b.date).getTime() - new Date(a.date).getTime()
        : new Date(a.date).getTime() - new Date(b.date).getTime();
    });
  }
}