/* global assert, JSBI, pow */

const {
  calcTarget,
  incrementNonce,
  bufferToBase64,
  bigIntToUint8Array,
  greaterThan,
} = pow;

describe('Proof of Work', () => {
  describe('#incrementNonce', () => {
    it('should increment a Uint8Array nonce correctly', () => {
      const arr1Before = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0]);
      const arr1After = incrementNonce(arr1Before);
      assert.strictEqual(arr1After[0], 0);
      assert.strictEqual(arr1After[1], 0);
      assert.strictEqual(arr1After[2], 0);
      assert.strictEqual(arr1After[3], 0);
      assert.strictEqual(arr1After[4], 0);
      assert.strictEqual(arr1After[5], 0);
      assert.strictEqual(arr1After[6], 0);
      assert.strictEqual(arr1After[7], 1);
    });

    it('should increment a Uint8Array nonce correctly in a loop', () => {
      let arr = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0]);
      assert.deepEqual(
        incrementNonce(arr),
        new Uint8Array([0, 0, 0, 0, 0, 0, 0, 1])
      );
      arr = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0]);
      for (let i = 0; i <= 255; i += 1) {
        arr = incrementNonce(arr);
      }
      assert.deepEqual(arr, new Uint8Array([0, 0, 0, 0, 0, 0, 1, 0]));
      arr = new Uint8Array([255, 255, 255, 255, 255, 255, 255, 255]);
      assert.deepEqual(
        incrementNonce(arr),
        new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0])
      );
    });
  });

  describe('#calcTarget', () => {
    it('should calculate a correct difficulty target', () => {
      // These values will need to be updated if we adjust the difficulty settings
      let payloadLen = 625;
      const ttl = 86400;
      let expectedTarget = new Uint8Array([0, 4, 119, 164, 35, 224, 222, 64]);

      let actualTarget = calcTarget(ttl, payloadLen, 10);
      assert.deepEqual(actualTarget, expectedTarget);
      payloadLen = 6597;
      expectedTarget = new Uint8Array([0, 0, 109, 145, 174, 146, 124, 3]);
      actualTarget = calcTarget(ttl, payloadLen, 10);
      assert.deepEqual(actualTarget, expectedTarget);
    });
  });

  describe('#greaterThan', () => {
    it('should correclty compare two Uint8Arrays', () => {
      let arr1 = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0, 0, 1]);
      let arr2 = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0, 0, 1]);
      assert.isFalse(greaterThan(arr1, arr2));
      arr1 = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0, 0, 2]);
      arr2 = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0, 0, 1]);
      assert.isTrue(greaterThan(arr1, arr2));
      arr1 = new Uint8Array([255, 255, 255, 255, 255, 255, 255, 255, 255, 255]);
      arr2 = new Uint8Array([255, 255, 255, 255, 255, 255, 255, 255, 255, 254]);
      assert.isTrue(greaterThan(arr1, arr2));
      arr1 = new Uint8Array([254, 255, 255, 255, 255, 255, 255, 255, 255, 255]);
      arr2 = new Uint8Array([255, 255, 255, 255, 255, 255, 255, 255, 255, 255]);
      assert.isFalse(greaterThan(arr1, arr2));
      arr1 = new Uint8Array([0]);
      arr2 = new Uint8Array([0, 0]);
      assert.isFalse(greaterThan(arr1, arr2));
    });
  });

  describe('#bufferToBase64', () => {
    it('should correclty convert a Uint8Array to a base64 string', () => {
      let arr = new Uint8Array([1, 2, 3]);
      let expected = 'AQID';
      assert.strictEqual(bufferToBase64(arr), expected);
      arr = new Uint8Array([123, 25, 3, 121, 45, 87, 24, 111]);
      expected = 'exkDeS1XGG8=';
      assert.strictEqual(bufferToBase64(arr), expected);
      arr = new Uint8Array([]);
      expected = '';
      assert.strictEqual(bufferToBase64(arr), expected);
    });
  });

  describe('#bigIntToUint8Array', () => {
    it('should correclty convert a BigInteger to a Uint8Array', () => {
      let bigInt = JSBI.BigInt(Number.MAX_SAFE_INTEGER);
      let expected = new Uint8Array([0, 31, 255, 255, 255, 255, 255, 255]);
      assert.deepEqual(bigIntToUint8Array(bigInt), expected);
      bigInt = JSBI.BigInt('0');
      expected = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0]);
      assert.deepEqual(bigIntToUint8Array(bigInt), expected);
      bigInt = JSBI.BigInt('255');
      expected = new Uint8Array([0, 0, 0, 0, 0, 0, 0, 255]);
      assert.deepEqual(bigIntToUint8Array(bigInt), expected);
      bigInt = JSBI.BigInt('256');
      expected = new Uint8Array([0, 0, 0, 0, 0, 0, 1, 0]);
      assert.deepEqual(bigIntToUint8Array(bigInt), expected);
    });
  });
});
