src/engine/steps/similarity.ts

import type { Page, Frame, Locator } from 'playwright';
import { logger } from '../../utils/logger';
import {
  readScopeDeepText,
  resolveAssignmentScope,
  SELECTORS,
} from '../selectors';
import { acceptEulaEverywhere } from './login';

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export interface SimilarityResult {
  similarityPercent: number | null;
  viewerUrl: string | null;
  scope?: Page | Frame;
  locator?: Locator;
}

export interface WaitForSimilarityOptions {
  timeoutMs: number;
  pollMs: number;
  refreshAfterMs: number;
  inputFileName?: string;
}

// ---------------------------------------------------------------------------
// Public API
// ---------------------------------------------------------------------------

function getSubmissionButtonLocator(scope: Page | Frame, inputTitle: string): Locator {
  const viewButtons = scope.locator(SELECTORS.similarity.viewSubmissionButton);
  if (inputTitle) {
    return viewButtons.filter({ hasText: inputTitle }).first();
  }
  return viewButtons.first();
}

/**
 * Poll for the similarity score to appear on the submission card.
 *
 * After `refreshAfterMs` with no result, refreshes the assignment launch URL
 * once. Returns the similarity percent (if readable) and viewer URL.
 */
export async function waitForSimilarity(
  page: Page,
  assignmentLaunchUrl: string,
  options: WaitForSimilarityOptions,
): Promise<SimilarityResult> {
  const { timeoutMs, pollMs, refreshAfterMs } = options;
  const inputTitle = options.inputFileName
    ? options.inputFileName.replace(/\.[^.]+$/, '').trim()
    : '';
  const started = Date.now();
  let lastText = '';
  // BUG-11 FIX: Allow multiple refreshes (every refreshAfterMs from first refresh)
  let refreshCount = 0;
  const MAX_REFRESHES = 2;
  let lastRefreshAt = 0;

  while (Date.now() - started < timeoutMs) {
    // ---- Deep text scan across all scopes ----
    const scopes: (Page | Frame)[] = [
      page,
      ...page.frames().filter((f) => !f.url().includes('cookie-shim')),
    ];

    for (const candidateScope of scopes) {
      const deepText = await readScopeDeepText(candidateScope);
      const percentMatch = deepText.match(
        /\b(?:Similarity:\s*)?(\d{1,3})%\b/i,
      );
      // BUG-4 FIX: Validate bounds — regex now matches 0-999 so we clamp to 0-100
      const percentRaw = percentMatch ? parseInt(percentMatch[1], 10) : NaN;
      const percent = Number.isFinite(percentRaw) && percentRaw >= 0 && percentRaw <= 100
        ? percentRaw : NaN;
      const percentOk = !isNaN(percent);
      const titleVisible =
        Boolean(inputTitle) &&
        deepText.toLowerCase().includes(inputTitle.toLowerCase());

      if (
        percentOk &&
        (titleVisible || /Submitted|Similarity|Your work/i.test(deepText))
      ) {
        const text = percentMatch![0].includes('Similarity')
          ? percentMatch![0]
          : `Similarity: ${percent}%`;
        logger.info('Similarity detected from deep text', {
          text,
          percent,
        });
        return {
          similarityPercent: percent,
          viewerUrl: null,
          scope: candidateScope,
          locator: getSubmissionButtonLocator(candidateScope, inputTitle),
        };
      }

      // After refresh, if submission row is visible even without percent, proceed
      if (
        refreshCount > 0 &&
        titleVisible &&
        /Your work/i.test(deepText)
      ) {
        logger.info(
          'Submission row visible after refresh; proceeding without similarity value',
        );
        return {
          similarityPercent: null,
          viewerUrl: null,
          scope: candidateScope,
          locator: getSubmissionButtonLocator(candidateScope, inputTitle),
        };
      }
    }

    // ---- Locator-based scan ----
    const scope = await resolveAssignmentScope(page);
    const candidates = [
      {
        kind: 'similarity',
        locator: scope
          .locator(
            'span[part="tii-grn-badge-label"]:has-text("Similarity:")',
          )
          .first(),
      },
      {
        kind: 'similarity',
        locator: scope.locator(SELECTORS.similarity.similaritySpan).first(),
      },
      {
        kind: 'similarity',
        locator: scope.locator(SELECTORS.similarity.similarityDisplay).first(),
      },
      {
        kind: 'title',
        locator: scope.locator(SELECTORS.similarity.viewSubmissionButton).first(),
      },
    ];

    for (const candidateEntry of candidates) {
      const candidate = candidateEntry.locator;
      if (
        await candidate.isVisible({ timeout: 1500 }).catch(() => false)
      ) {
        const text = (
          await candidate.innerText().catch(() => '')
        ).trim();
        const aria = (
          (await candidate
            .getAttribute('aria-label')
            .catch(() => '')) || ''
        ).trim();
        const visibleText = text || aria;

        if (visibleText && visibleText !== lastText) {
          lastText = visibleText;
          logger.info('Submission state', { visibleText });
        }

        if (
          candidateEntry.kind === 'title' &&
          visibleText &&
          refreshCount > 0
        ) {
          return {
            similarityPercent: null,
            viewerUrl: null,
            scope,
            locator: candidate,
          };
        }

        const simMatch = visibleText.match(
          /Similarity:\s*(\d+)%/i,
        );
        if (simMatch) {
          const percent = parseInt(simMatch[1], 10);
          logger.info('Similarity detected from locator', {
            visibleText,
            percent,
          });
          return {
            similarityPercent: percent,
            viewerUrl: null,
            scope,
            locator: getSubmissionButtonLocator(scope, inputTitle),
          };
        }
      }
    }

    // ---- Log body text for diagnostics ----
    const bodyText = await scope
      .locator('body')
      .innerText({ timeout: 3000 })
      .catch(() => '');
    const shortText = bodyText.replace(/\s+/g, ' ').trim().slice(0, 240);
    if (shortText && shortText !== lastText) {
      lastText = shortText;
      logger.debug('Waiting for submission/similarity', {
        bodySnippet: shortText,
      });
    }

    // ---- Refresh assignment launch URL periodically ----
    // BUG-11 FIX: Allow up to MAX_REFRESHES refreshes, each triggered after
    // refreshAfterMs has passed since the previous refresh (or since start).
    const elapsedSinceLastRefresh = lastRefreshAt === 0
      ? Date.now() - started
      : Date.now() - lastRefreshAt;
    const currentUrl = page.url();
    const urlSeemsFine =
      currentUrl.includes('turnitin.com') &&
      (currentUrl.includes('/assignment/') || currentUrl.includes('/class/'));
    const shouldRefresh =
      refreshCount < MAX_REFRESHES &&
      elapsedSinceLastRefresh >= refreshAfterMs &&
      (!urlSeemsFine || currentUrl.includes('/assignment/type/tool/launch'));

    if (shouldRefresh) {
      refreshCount++;
      lastRefreshAt = Date.now();
      logger.info(
        `Similarity not visible; refreshing assignment launch URL (refresh ${refreshCount}/${MAX_REFRESHES})`,
        { currentUrl },
      );
      await page
        .reload({ waitUntil: 'domcontentloaded', timeout: 60000 })
        .catch(() => {});
      await page.waitForTimeout(5000);

      // ── Handle 502/503/504 error pages after refresh ──
      for (let refreshRetry = 0; refreshRetry < 2; refreshRetry++) {
        const bodyAfterRefresh = await page
          .locator('body')
          .innerText({ timeout: 3000 })
          .catch(() => '');
        if (/502 Bad Gateway|503 Service|504 Gateway/i.test(bodyAfterRefresh)) {
          logger.warn(
            `Server error detected after refresh ${refreshCount} (attempt ${refreshRetry + 1}/2); retrying reload`,
            { bodySnippet: bodyAfterRefresh.slice(0, 200) },
          );
          await page.waitForTimeout(5000);
          await page
            .reload({ waitUntil: 'domcontentloaded', timeout: 60000 })
            .catch(() => {});
          await page.waitForTimeout(5000);
        } else {
          break;
        }
      }

      continue;
    }

    await page.waitForTimeout(pollMs);
  }

  throw new Error(
    `Submission card/similarity did not become ready within ${timeoutMs}ms`,
  );
}