// Large-course mode API — learner-facing course manifest list (L2, public read).
//
//   GET /api/learn/courses?limit=N

import { type NextRequest } from 'next/server';
import { apiError, apiSuccess, API_ERROR_CODES } from '@/lib/server/api-response';
import { createLogger } from '@/lib/logger';
import { courseManifestRepo } from '@/lib/course-manifest-repo/store';
import { isPinnedCourseManifestModule } from '@/lib/course-manifest-repo/types';

const log = createLogger('Learner Courses API');

export async function GET(request: NextRequest) {
  try {
    const limitParam = Number(new URL(request.url).searchParams.get('limit') ?? 50);
    const limit = Number.isFinite(limitParam) && limitParam > 0 ? Math.min(limitParam, 100) : 50;
    const records = (await courseManifestRepo.listRecords(limit)).filter(
      (record) => record.schemaVersion === 2 && record.modules.every(isPinnedCourseManifestModule),
    );
    return apiSuccess({
      items: records.map((record) => ({
        courseId: record.courseId,
        version: record.version,
        title: record.title,
        summary: record.summary,
        moduleCount: record.modules.length,
        publishedAt: record.publishedAt,
      })),
    });
  } catch (error) {
    log.error('Learner course listing failed:', error);
    return apiError(API_ERROR_CODES.INTERNAL_ERROR, 500, 'Failed to list courses');
  }
}