// app/api/progress/all/route.ts
// Everything the signed-in user has watched, in one response, so pages do not
// have to ask about each video separately.
import { NextResponse } from 'next/server';
import { prisma } from '@/lib/prisma';
import { getViewer } from '@/lib/video-access';
import { mergeRanges } from '@/lib/watch-progress';

type Segment = { startSec: number; endSec: number; watchedAt?: Date };

/**
 * GET /api/progress/all            – all of the user's progress
 * GET /api/progress/all?playlistId – only videos in that playlist
 *
 * Returns { progress: { [videoId]: { percent, watchedSec, segments } } }.
 * Videos the user has never played are simply absent.
 */
export async function GET(req: Request) {
  try {
    const viewer = await getViewer();
    if (!viewer) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });

    const playlistId = new URL(req.url).searchParams.get('playlistId');
    const where = {
      userId: viewer.id,
      ...(playlistId ? { video: { playlistId } } : {}),
    };

    const [progressRows, segmentRows] = await Promise.all([
      prisma.videoProgress.findMany({
        where,
        select: { videoId: true, percent: true, watchedSec: true },
      }),
      prisma.videoWatchSegment.findMany({
        where,
        select: { videoId: true, startSec: true, endSec: true, watchedAt: true },
      }),
    ]);

    const segmentsByVideo = new Map<string, Segment[]>();
    for (const { videoId, ...segment } of segmentRows) {
      const list = segmentsByVideo.get(videoId);
      if (list) list.push(segment);
      else segmentsByVideo.set(videoId, [segment]);
    }

    const progress: Record<
      string,
      { percent: number; watchedSec: number; segments: Segment[] }
    > = {};
    for (const row of progressRows) {
      progress[row.videoId] = {
        percent: row.percent,
        watchedSec: row.watchedSec,
        // Older data can hold many overlapping rows per video; send the merged view.
        segments: mergeRanges(segmentsByVideo.get(row.videoId) ?? []),
      };
    }

    return NextResponse.json({ progress });
  } catch (err: any) {
    console.error('progress/all GET error', err);
    return NextResponse.json({ error: err?.message ?? 'server error' }, { status: 500 });
  }
}