import {
  type LoremUnit,
  LINE_ENDINGS,
  SUPPORTED_PLATFORMS,
  UNIT_PARAGRAPHS,
  UNIT_SENTENCES,
  UNIT_WORDS,
} from './constants';
import ProcessHelper from '../tests/util/ProcessHelper';

import { veganIpsum } from '.';

/**
 * Unit tests for the `veganIpsum` convenience function validating output
 * units, counts, and formatting across common input combinations.
 */
describe('veganIpsum', () => {
  // Helper to mock and reset the platform during tests.
  const process = new ProcessHelper();

  /**
   * Resets the platform after each test to ensure a clean environment.
   */
  afterEach(() => process.resetPlatform());

  /**
   * Tests that the default behavior of `veganIpsum` generates one sentence.
   */
  test('Should return one sentence by default', () => {
    const result = veganIpsum();
    // Expect the result to be a non-empty string ending with a period.
    expect(result.slice(-1)).toEqual('.');

    // Expect the result to contain exactly one sentence.
    const sentences = result.split('. ');
    expect(sentences).toHaveLength(1);
  });

  /**
   * Tests that `veganIpsum` generates the specified number of paragraphs
   * when the `units` parameter is set to `UNIT_PARAGRAPHS`.
   */
  test('Should return the specified number of paragraphs', () => {
    process.setPlatform(SUPPORTED_PLATFORMS.WIN32);
    const count = 5;
    const someUnits: LoremUnit[] = [UNIT_PARAGRAPHS];
    someUnits.forEach((units) => {
      const results = veganIpsum({ count, units });
      const paragraphs = results.split(LINE_ENDINGS.WIN32);
      // Expect the number of paragraphs to match the specified count.
      expect(paragraphs).toHaveLength(count);
    });
  });

  /**
   * Tests that `veganIpsum` generates the specified number of sentences
   * when the `units` parameter is set to `UNIT_SENTENCES`.
   */
  test('Should return the specified number of sentences', () => {
    const count = 3;
    const someUnits: LoremUnit[] = [UNIT_SENTENCES];
    someUnits.forEach((units) => {
      const results = veganIpsum({ count, units });
      const sentences = results.split('. ');
      // Expect the number of sentences to match the specified count.
      expect(sentences).toHaveLength(count);
    });
  });

  /**
   * Tests that `veganIpsum` generates the specified number of words
   * when the `units` parameter is set to `UNIT_WORDS`.
   */
  test('Should return the specified number of words', () => {
    const count = 7;
    const someUnits: LoremUnit[] = [UNIT_WORDS];
    someUnits.forEach((units) => {
      const results = veganIpsum({ count, units });
      const words = results.split(' ');
      // Expect the number of words to match the specified count.
      expect(words).toHaveLength(count);
    });
  });

  /**
   * Tests that `veganIpsum` returns an empty string when an invalid `units` parameter is provided.
   */
  test('Should return an empty string for invalid units', () => {
    // @ts-expect-error Testing invalid units input
    // Expect the function to return an empty string when units are not recognized.
    expect(veganIpsum({ count: 7, units: 'unknown' })).toEqual('');
  });
});