// Large-course mode API — create + list courses (ops side).
//
//   POST /api/courses        create a large course from a requirement and start
//                            the two-layer generation job (framework → modules)
//   GET  /api/courses        list courses (newest first)
//
// The generation job runs on the server (after()), reusing the classroom job
// infrastructure per module; closing the page does not interrupt it. Poll the
// course detail route (`GET /api/courses/:id`) for progress.

import { after, type NextRequest } from 'next/server';
import { nanoid } from 'nanoid';
import { apiError, apiSuccess, API_ERROR_CODES } from '@/lib/server/api-response';
import { buildRequestOrigin } from '@/lib/server/classroom-storage';
import { createLogger } from '@/lib/logger';
import type { CourseCreateInput } from '@/lib/course-framework/types';
import { createCourse, runCourseFrameworkGeneration } from '@/lib/course-framework/runner';
import { listCourseRecords, readCourseRecordReconciled } from '@/lib/course-framework/store';
import {
  configuredWorksSquareApiOrigin,
  requireOpsAccess,
} from '@/lib/server/ops-access';

const log = createLogger('Courses API');

export async function POST(req: NextRequest) {
  const denied = await requireOpsAccess(req);
  if (denied) return denied;

  let requirementSnippet: string | undefined;
  try {
    const rawBody = (await req.json()) as Partial<CourseCreateInput>;
    requirementSnippet = rawBody.requirement?.substring(0, 60);

    const body: CourseCreateInput = {
      requirement: rawBody.requirement || '',
      ...(rawBody.enableWebSearch != null ? { enableWebSearch: rawBody.enableWebSearch } : {}),
      ...(rawBody.enableImageGeneration != null
        ? { enableImageGeneration: rawBody.enableImageGeneration }
        : {}),
      ...(rawBody.enableVideoGeneration != null
        ? { enableVideoGeneration: rawBody.enableVideoGeneration }
        : {}),
      ...(rawBody.enableTTS != null ? { enableTTS: rawBody.enableTTS } : {}),
      ...(rawBody.interactiveMode != null ? { interactiveMode: rawBody.interactiveMode } : {}),
      ...(rawBody.taskEngineMode != null ? { taskEngineMode: rawBody.taskEngineMode } : {}),
      ...(rawBody.pdfContent ? { pdfContent: rawBody.pdfContent } : {}),
    };
    const { requirement } = body;

    if (!requirement) {
      return apiError(
        API_ERROR_CODES.MISSING_REQUIRED_FIELD,
        400,
        'Missing required field: requirement',
      );
    }

    const worksOrigin = configuredWorksSquareApiOrigin();
    if (worksOrigin) {
      const upstream = await fetch(`${worksOrigin}/api/admin/learning/generations`, {
        method: 'POST',
        headers: {
          Authorization: req.headers.get('authorization') ?? '',
          'Content-Type': 'application/json',
          Accept: 'application/json',
        },
        body: JSON.stringify({
          requirement: body.requirement,
          enableWebSearch: body.enableWebSearch ?? false,
          enableImageGeneration: body.enableImageGeneration ?? false,
          enableVideoGeneration: body.enableVideoGeneration ?? false,
          enableTTS: body.enableTTS ?? true,
          interactiveMode: body.interactiveMode ?? true,
          taskEngineMode: body.taskEngineMode ?? false,
        }),
        redirect: 'error',
        cache: 'no-store',
        signal: AbortSignal.timeout(30_000),
      });
      const result = (await upstream.json().catch(() => null)) as {
        jobId?: unknown;
        job_id?: unknown;
        status?: unknown;
        message?: unknown;
      } | null;
      if (!upstream.ok) {
        return apiError(
          API_ERROR_CODES.UPSTREAM_ERROR,
          upstream.status >= 400 && upstream.status < 500 ? upstream.status : 502,
          'Works rejected the large-course generation request',
        );
      }
      const remoteJobId =
        typeof result?.jobId === 'string'
          ? result.jobId
          : typeof result?.job_id === 'string'
            ? result.job_id
            : '';
      if (!remoteJobId) {
        return apiError(
          API_ERROR_CODES.UPSTREAM_ERROR,
          502,
          'Works returned an invalid generation response',
        );
      }
      return apiSuccess(
        {
          courseId: remoteJobId,
          jobId: remoteJobId,
          status: typeof result?.status === 'string' ? result.status : 'queued',
          message:
            typeof result?.message === 'string'
              ? result.message
              : 'Course framework generation started',
          detailUrl: `${buildRequestOrigin(req)}/api/courses/${remoteJobId}`,
          pollIntervalMs: 3000,
        },
        202,
      );
    }

    const courseId = nanoid(10);
    const baseUrl = buildRequestOrigin(req);
    await createCourse(courseId, body);
    const detailUrl = `${baseUrl}/api/courses/${courseId}`;

    // Phase 1 only: generate the course framework, then wait for the operator
    // to review and confirm before any module is generated (POST /start).
    after(() => runCourseFrameworkGeneration(courseId, baseUrl));

    return apiSuccess(
      {
        courseId,
        status: 'queued',
        message: 'Course framework generation started; awaiting confirmation before modules',
        detailUrl,
        pollIntervalMs: 3000,
      },
      202,
    );
  } catch (error) {
    log.error(
      `Course creation failed [requirement="${requirementSnippet ?? 'unknown'}..."]:`,
      error,
    );
    return apiError(
      API_ERROR_CODES.INTERNAL_ERROR,
      500,
      'Failed to create course',
      error instanceof Error ? error.message : 'Unknown error',
    );
  }
}

export async function GET(request: NextRequest) {
  const denied = await requireOpsAccess(request);
  if (denied) return denied;

  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 listCourseRecords(limit);
    const items = await Promise.all(
      records.map(async (record) => {
        // Reconcile live state so the list reflects job outcomes without polling.
        const reconciled =
          (await readCourseRecordReconciled(record.id).catch(() => null)) ?? record;
        return {
          courseId: reconciled.id,
          status: reconciled.status,
          title: reconciled.framework?.courseTitle ?? reconciled.requirement.slice(0, 40),
          moduleCount: reconciled.modules.length,
          succeededCount: reconciled.modules.filter((m) => m.status === 'succeeded').length,
          error: reconciled.error,
          createdAt: reconciled.createdAt,
          updatedAt: reconciled.updatedAt,
        };
      }),
    );
    return apiSuccess({ items });
  } catch (error) {
    log.error('Course listing failed:', error);
    return apiError(API_ERROR_CODES.INTERNAL_ERROR, 500, 'Failed to list courses');
  }
}