var assert = require('assert');
var BN = require('../').BN;
var fixtures = require('./fixtures');

describe('BN.js/Utils', function() {
  describe('.toString()', function() {
    describe('binary padding', function() {
      it('should have a length of 256', function() {
        var a = new BN(0);
        assert.equal(a.toString(2, 256).length, 256);
      });
    });
    describe('hex padding', function() {
      it('should have length of 8 from leading 15', function() {
        var a = new BN('ffb9602', 16);
        var b = new Buffer(a.toString('hex', 2), 'hex');
        assert.equal(a.toString('hex', 2).length, 8);
      });

      it('should have length of 8 from leading zero', function() {
        var a = new BN('fb9604', 16);
        var b = new Buffer(a.toString('hex', 8), 'hex');
        assert.equal(a.toString('hex', 8).length, 8);
      });

      it('should have length of 8 from leading zeros', function() {
        var a = new BN(0);
        var b = new Buffer(a.toString('hex', 8), 'hex');
        assert.equal(a.toString('hex', 8).length, 8);
      });

      it('should have length of 64 from leading 15', function() {
        var a = new BN(
            'ffb96ff654e61130ba8422f0debca77a0ea74ae5ea8bca9b54ab64aabf01003',
            16);
        var b = new Buffer(a.toString('hex', 2), 'hex');
        assert.equal(a.toString('hex', 2).length, 64);
      });

      it('should have length of 64 from leading zero', function() {
        var a = new BN(
            'fb96ff654e61130ba8422f0debca77a0ea74ae5ea8bca9b54ab64aabf01003',
            16);
        var b = new Buffer(a.toString('hex', 64), 'hex');
        assert.equal(a.toString('hex', 64).length, 64);
      });
    });
  });

  describe('.isNeg()', function() {
    it('should return true for negative numbers', function() {
      assert.equal(new BN(-1).isNeg(), true);
      assert.equal(new BN(1).isNeg(), false);
      assert.equal(new BN(0).isNeg(), false);
      assert.equal(new BN('-0', 10).isNeg(), false);
    });
  });

  describe('.isOdd()', function() {
    it('should return true for odd numbers', function() {
      assert.equal(new BN(0).isOdd(), false);
      assert.equal(new BN(1).isOdd(), true);
      assert.equal(new BN(2).isOdd(), false);
      assert.equal(new BN('-0', 10).isOdd(), false);
      assert.equal(new BN('-1', 10).isOdd(), true);
      assert.equal(new BN('-2', 10).isOdd(), false);
    });
  });

  describe('.isEven()', function() {
    it('should return true for even numbers', function() {
      assert.equal(new BN(0).isEven(), true);
      assert.equal(new BN(1).isEven(), false);
      assert.equal(new BN(2).isEven(), true);
      assert.equal(new BN('-0', 10).isEven(), true);
      assert.equal(new BN('-1', 10).isEven(), false);
      assert.equal(new BN('-2', 10).isEven(), true);
    });
  });

  describe('.bitLength()', function() {
    it('should return proper bitLength', function() {
      assert.equal(new BN(0).bitLength(), 0);
      assert.equal(new BN(0x1).bitLength(), 1);
      assert.equal(new BN(0x2).bitLength(), 2);
      assert.equal(new BN(0x3).bitLength(), 2);
      assert.equal(new BN(0x4).bitLength(), 3);
      assert.equal(new BN(0x8).bitLength(), 4);
      assert.equal(new BN(0x10).bitLength(), 5);
      assert.equal(new BN(0x100).bitLength(), 9);
      assert.equal(new BN(0x123456).bitLength(), 21);
      assert.equal(new BN('123456789', 16).bitLength(), 33);
      assert.equal(new BN('8023456789', 16).bitLength(), 40);
    });
  });

  describe('.byteLength()', function() {
    it('should return proper byteLength', function() {
      assert.equal(new BN(0).byteLength(), 0);
      assert.equal(new BN(0x1).byteLength(), 1);
      assert.equal(new BN(0x2).byteLength(), 1);
      assert.equal(new BN(0x3).byteLength(), 1);
      assert.equal(new BN(0x4).byteLength(), 1);
      assert.equal(new BN(0x8).byteLength(), 1);
      assert.equal(new BN(0x10).byteLength(), 1);
      assert.equal(new BN(0x100).byteLength(), 2);
      assert.equal(new BN(0x123456).byteLength(), 3);
      assert.equal(new BN('123456789', 16).byteLength(), 5);
      assert.equal(new BN('8023456789', 16).byteLength(), 5);
    });
  });

  describe('.toArray()', function() {
    it('should zero pad to desired lengths', function() {
      var n = new BN(0x123456);
      assert.deepEqual(n.toArray('be', 5), [ 0x00, 0x00, 0x12, 0x34, 0x56 ]);
      assert.deepEqual(n.toArray('le', 5), [ 0x56, 0x34, 0x12, 0x00, 0x00 ]);
    });

    it('should throw when naturally larger than desired length', function() {
      var n = new BN(0x123456);
      assert.throws(function() {
        n.toArray('be', 2);
      });
    });
  });

  describe('.toNumber()', function() {
    it('should return proper Number if below the limit', function() {
      var n = new BN(0x123456);
      assert.deepEqual(n.toNumber(), 0x123456);
    });

    it('should throw when number exceeds 53 bits', function() {
      var n = new BN(1).iushln(54);
      assert.throws(function() {
        n.toNumber();
      });
    });
  });

  describe('.zeroBits()', function() {
    it('should return proper zeroBits', function() {
      assert.equal(new BN(0).zeroBits(), 0);
      assert.equal(new BN(0x1).zeroBits(), 0);
      assert.equal(new BN(0x2).zeroBits(), 1);
      assert.equal(new BN(0x3).zeroBits(), 0);
      assert.equal(new BN(0x4).zeroBits(), 2);
      assert.equal(new BN(0x8).zeroBits(), 3);
      assert.equal(new BN(0x10).zeroBits(), 4);
      assert.equal(new BN(0x100).zeroBits(), 8);
      assert.equal(new BN(0x1000000).zeroBits(), 24);
      assert.equal(new BN(0x123456).zeroBits(), 1);
    });
  });

  describe('.toJSON', function() {
    it('should return hex string', function() {
      assert.equal(new BN(0x123).toJSON(), '123');
    });
  });
});
