/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { describe, it, expect } from 'vitest';
import {
  countOccurrences,
  unescapeStringForGeminiBug,
} from './editCorrector.js';

describe('editCorrector', () => {
  describe('countOccurrences', () => {
    it('should return 0 for empty string', () => {
      expect(countOccurrences('', 'a')).toBe(0);
    });

    it('should return 0 for empty substring', () => {
      expect(countOccurrences('abc', '')).toBe(0);
    });

    it('should return 0 if substring is not found', () => {
      expect(countOccurrences('abc', 'd')).toBe(0);
    });

    it('should return 1 if substring is found once', () => {
      expect(countOccurrences('abc', 'b')).toBe(1);
    });

    it('should return correct count for multiple occurrences', () => {
      expect(countOccurrences('ababa', 'a')).toBe(3);
      expect(countOccurrences('ababab', 'ab')).toBe(3);
    });

    it('should count non-overlapping occurrences', () => {
      expect(countOccurrences('aaaaa', 'aa')).toBe(2); // Non-overlapping: aa_aa_
      expect(countOccurrences('ababab', 'aba')).toBe(1); // Non-overlapping: aba_ab -> 1
    });

    it('should correctly count occurrences when substring is longer', () => {
      expect(countOccurrences('abc', 'abcdef')).toBe(0);
    });

    it('should be case sensitive', () => {
      expect(countOccurrences('abcABC', 'a')).toBe(1);
      expect(countOccurrences('abcABC', 'A')).toBe(1);
    });
  });

  describe('unescapeStringForGeminiBug', () => {
    it('should unescape common sequences', () => {
      expect(unescapeStringForGeminiBug('\\n')).toBe('\n');
      expect(unescapeStringForGeminiBug('\\t')).toBe('\t');
      expect(unescapeStringForGeminiBug("\\'")).toBe("'");
      expect(unescapeStringForGeminiBug('\\"')).toBe('"');
      expect(unescapeStringForGeminiBug('\\`')).toBe('`');
    });

    it('should handle multiple escaped sequences', () => {
      expect(unescapeStringForGeminiBug('Hello\\nWorld\\tTest')).toBe(
        'Hello\nWorld\tTest',
      );
    });

    it('should not alter already correct sequences', () => {
      expect(unescapeStringForGeminiBug('\n')).toBe('\n');
      expect(unescapeStringForGeminiBug('Correct string')).toBe(
        'Correct string',
      );
    });

    it('should handle mixed correct and incorrect sequences', () => {
      expect(unescapeStringForGeminiBug('\\nCorrect\t\\`')).toBe(
        '\nCorrect\t`',
      );
    });

    it('should handle backslash followed by actual newline character', () => {
      expect(unescapeStringForGeminiBug('\\\n')).toBe('\n');
      expect(unescapeStringForGeminiBug('First line\\\nSecond line')).toBe(
        'First line\nSecond line',
      );
    });

    it('should handle multiple backslashes before an escapable character', () => {
      expect(unescapeStringForGeminiBug('\\\\n')).toBe('\n'); // \\n -> \n
      expect(unescapeStringForGeminiBug('\\\\\\t')).toBe('\t'); // \\\t -> \t
      expect(unescapeStringForGeminiBug('\\\\\\\\`')).toBe('`'); // \\\\` -> `
    });

    it('should return empty string for empty input', () => {
      expect(unescapeStringForGeminiBug('')).toBe('');
    });

    it('should not alter strings with no targeted escape sequences', () => {
      expect(unescapeStringForGeminiBug('abc def')).toBe('abc def');
      // \\F and \\S are not targeted escapes, so they should remain as \\F and \\S
      expect(unescapeStringForGeminiBug('C:\\Folder\\File')).toBe(
        'C:\\Folder\\File',
      );
    });

    it('should correctly process strings with some targeted escapes', () => {
      // \\U is not targeted, \\n is.
      expect(unescapeStringForGeminiBug('C:\\Users\\name')).toBe(
        'C:\\Users\name',
      );
    });

    it('should handle complex cases with mixed slashes and characters', () => {
      expect(
        unescapeStringForGeminiBug('\\\\\\nLine1\\\nLine2\\tTab\\\\`Tick\\"'),
      ).toBe('\nLine1\nLine2\tTab`Tick"');
    });
  });
});