import type { VideoItem, LiveRoom } from '../services/types';

export interface NormalRow {
  type: 'pair';
  left: VideoItem;
  right: VideoItem | null;
}

export interface BigRow {
  type: 'big';
  item: VideoItem;
}

export interface LiveRow {
  type: 'live';
  left: LiveRoom;
  right?: LiveRoom;
}

export type ListRow = NormalRow | BigRow | LiveRow;

export function toListRows(pages: VideoItem[][], liveRooms?: LiveRoom[]): ListRow[] {
  const rows: ListRow[] = [];
  let roomIdx = 0;

  for (const chunk of pages) {
    if (chunk.length === 0) continue;

    // Highest view count becomes BigRow
    let bigIdx = 0;
    let maxView = chunk[0].stat?.view ?? 0;
    for (let i = 1; i < chunk.length; i++) {
      const v = chunk[i].stat?.view ?? 0;
      if (v > maxView) { maxView = v; bigIdx = i; }
    }

    const bigItem = chunk[bigIdx];
    const rest = chunk.filter((_, i) => i !== bigIdx);

    const pairs: (NormalRow | LiveRow)[] = [];
    for (let i = 0; i < rest.length; i += 2) {
      pairs.push({ type: 'pair', left: rest[i], right: rest[i + 1] ?? null });
    }

    // Inject 1 LiveRow per chunk at a deterministic position (seed = first video aid)
    if (liveRooms && roomIdx < liveRooms.length && pairs.length > 0) {
      const seed = chunk[0]?.aid ?? 0;
      const insertAt = seed % (pairs.length + 1);
      pairs.splice(insertAt, 0, {
        type: 'live',
        left: liveRooms[roomIdx],
      });
      roomIdx++;
    }

    rows.push(...pairs);
    rows.push({ type: 'big', item: bigItem });
  }
  return rows;
}