import type { Page, BrowserContext, Frame, Locator } from 'playwright';
import { logger } from '../../utils/logger';
import {
  SELECTORS,
  deepClickByText,
  resolveAssignmentScope,
} from '../selectors';

type ViewerScope = Page | Frame;

function ownerPage(scope: ViewerScope): Page {
  return typeof (scope as any).page === 'function'
    ? (scope as Frame).page()
    : (scope as Page);
}

function isReportSubmissionUrl(url: string): boolean {
  return (
    url.includes('reports.integrity.turnitin.com') &&
    /submission-viewer|\/submission\//i.test(url)
  );
}

function findReportViewerScope(context: BrowserContext): ViewerScope | null {
  for (const candidatePage of context.pages()) {
    if (isReportSubmissionUrl(candidatePage.url())) {
      return candidatePage;
    }

    const reportFrame = candidatePage
      .frames()
      .find((frame) => isReportSubmissionUrl(frame.url()));
    if (reportFrame) {
      return reportFrame;
    }
  }

  return null;
}

/**
 * Click the submission title to open the report viewer.
 * Returns the viewer page after it has navigated to reports.integrity.turnitin.com.
 */
export async function openReportViewerPage(
  page: Page,
  context: BrowserContext,
  similarityScope?: ViewerScope,
  similarityLocator?: Locator,
): Promise<ViewerScope> {
  const scope = similarityScope || (await resolveAssignmentScope(page));

  const titleButton = scope
    .locator(SELECTORS.viewer.titleButton)
    .first();

  const specificTargetVisible = similarityLocator
    ? await similarityLocator.isVisible({ timeout: 3000 }).catch(() => false)
    : false;
  const clickTarget = specificTargetVisible
    ? similarityLocator!
    : (await titleButton.isVisible({ timeout: 3000 }).catch(() => false))
      ? titleButton
      : null;

  const [newPage] = await Promise.all([
    context
      .waitForEvent('page', { timeout: 30000 })
      .catch(() => null),
    clickTarget
      ? clickTarget.click({ force: true }).catch(async () => {
          await deepClickByText(scope, ['view submission']);
        })
      : deepClickByText(scope, ['view submission']),
  ]);

  // BUG-6 FIX: Verify the captured page is actually the report viewer before
  // waiting for its load state. context.waitForEvent('page') can fire for any
  // new page (ads, redirects), so we must not blindly wait 30s on a wrong page.
  let viewerScope: ViewerScope;
  if (newPage && isReportSubmissionUrl(newPage.url())) {
    // Correct page — wait for it to load normally
    viewerScope = newPage;
    await (viewerScope as Page)
      .waitForLoadState('domcontentloaded', { timeout: 60000 })
      .catch(() => {});
  } else {
    // Wrong page or no page event — scan existing pages/frames immediately
    if (newPage) {
      logger.warn('waitForEvent(page) captured a non-viewer page; scanning context for viewer', {
        capturedUrl: newPage.url(),
      });
    }
    // Give Turnitin a short moment to open the real viewer page
    const scopeOwner = typeof (scope as any).page === 'function'
      ? (scope as Frame).page()
      : (scope as Page);
    await scopeOwner.waitForTimeout(3000).catch(() => {});
    const existing = findReportViewerScope(context);
    viewerScope = existing ||
      (typeof (scope as any).page === 'function'
        ? (scope as Frame).page()
        : (scope as Page));
  }

  const deadline = Date.now() + 30000;
  while (
    Date.now() < deadline &&
    !isReportSubmissionUrl(viewerScope.url())
  ) {
    const existing = findReportViewerScope(context);
    if (existing) {
      viewerScope = existing;
      break;
    }
    await ownerPage(viewerScope).waitForTimeout(500).catch(() => {});
  }

  await ownerPage(viewerScope).waitForTimeout(2500);

  const viewerUrl = viewerScope.url();
  logger.info('Report viewer opened', { viewerUrl });

  if (!isReportSubmissionUrl(viewerUrl)) {
    throw new Error(
      `Report viewer did not open a submission route correctly. Current URL: ${viewerUrl}`,
    );
  }

  return viewerScope;
}

export async function openReportViewer(
  page: Page,
  context: BrowserContext,
): Promise<string> {
  const viewerPage = await openReportViewerPage(page, context);
  return viewerPage.url();
}