import { describe, test, expect } from "bun:test";
import { SudokuGenerator } from "./SudokuGenerator";

describe("SudokuGenerator", () => {
  test("generates an 81-character string of only digits 1–9 for solution", () => {
    const generator = new SudokuGenerator();
    const solution = generator.getSolution();
    expect(solution).toHaveLength(81);
    expect(/^[1-9]+$/.test(solution)).toBe(true);
  });

  test("generates 10 valid boards", () => {
    for (let i = 0; i < 10; i++) {
      const generator = new SudokuGenerator();
      const solution = generator.getSolution();
      expect(solution).toHaveLength(81);
      expect(/^[1-9]+$/.test(solution)).toBe(true);
    }
  });

  test("generates 100 valid boards", () => {
    for (let i = 0; i < 100; i++) {
      const generator = new SudokuGenerator();
      const solution = generator.getSolution();
      expect(solution).toHaveLength(81);
      expect(/^[1-9]+$/.test(solution)).toBe(true);
    }
  });

  test("generates puzzle with correct number of empty cells", () => {
    const easyGen = new SudokuGenerator();
    easyGen.generate('easy');
    const easyPuzzle = easyGen.getPuzzle();
    const easyEmpty = (easyPuzzle.match(/\./g) || []).length;
    expect(easyEmpty).toBe(40);

    const mediumGen = new SudokuGenerator();
    mediumGen.generate('medium');
    const mediumPuzzle = mediumGen.getPuzzle();
    const mediumEmpty = (mediumPuzzle.match(/\./g) || []).length;
    expect(mediumEmpty).toBe(50);

    const hardGen = new SudokuGenerator();
    hardGen.generate('hard');
    const hardPuzzle = hardGen.getPuzzle();
    const hardEmpty = (hardPuzzle.match(/\./g) || []).length;
    expect(hardEmpty).toBe(60);
  });

  test("puzzle and solution have same givens in same positions", () => {
    const generator = new SudokuGenerator();
    generator.generate('medium');
    const puzzle = generator.getPuzzle();
    const solution = generator.getSolution();

    for (let i = 0; i < 81; i++) {
      if (puzzle[i] !== '.') {
        expect(puzzle[i]).toBe(solution[i]);
      }
    }
  });
});