// test atan2
var assert = require('assert'),
    math = require('../../../index'),
    approx = require('../../../tools/approx'),
    pi = math.pi,
    complex = math.complex,
    matrix = math.matrix,
    sparse = math.sparse,
    unit = math.unit,
    divide = math.divide,
    atan2 = math.atan2,
    bigmath = math.create({precision: 20}),
    Big = bigmath.bignumber,
    atan2Big = bigmath.atan2;

describe('atan2', function() {

  it('should calculate atan2 correctly', function() {
    assert.equal(atan2(0, 0) / pi, 0);
    assert.equal(atan2(0, 1) / pi, 0);
    assert.equal(atan2(1, 1) / pi, 0.25);
    assert.equal(atan2(1, 0) / pi, 0.5);
    assert.equal(atan2(1, -1) / pi, 0.75);
    assert.equal(atan2(0, -1) / pi, 1);
    assert.equal(atan2(-1, -1) / pi, -0.75);
    assert.equal(atan2(-1, 0) / pi, -0.5);
    assert.equal(atan2(-1, 1) / pi, -0.25);
  });

  it('should calculate atan2 for booleans', function() {
    assert.equal(atan2(true, true), 0.25 * pi);
    assert.equal(atan2(true, false), 0.5 * pi);
    assert.equal(atan2(false, true), 0);
    assert.equal(atan2(false, false), 0);
  });

  it('should calculate atan2 with mixed numbers and booleans', function() {
    assert.equal(atan2(1, true), 0.25 * pi);
    assert.equal(atan2(1, false), 0.5 * pi);
    assert.equal(atan2(true, 1), 0.25 * pi);
    assert.equal(atan2(false, 1), 0);
  });

  it('should calculate atan2 with mixed numbers and null', function() {
    assert.equal(atan2(1, null), 0.5 * pi);
    assert.equal(atan2(null, 1), 0);
  });

  it('should return the arctan of for bignumbers', function() {
    assert.deepEqual(atan2Big(Big(0), Big(0)), Big(NaN));
    assert.deepEqual(atan2Big(Big(0), Big(1)), Big(0));
    assert.deepEqual(atan2Big(Big(1), Big(1)), Big('0.7853981633974483096'));
    assert.deepEqual(atan2Big(Big(1), Big(0)), Big('1.5707963267948966192'));
    assert.deepEqual(atan2Big(Big(1), Big(-1)), Big('2.3561944901923449288'));
    assert.deepEqual(atan2Big(Big(0), Big(-1)), Big('3.1415926535897932385'));
    assert.deepEqual(atan2Big(Big(-1), Big(-1)), Big('-2.3561944901923449288'));
    assert.deepEqual(atan2Big(Big(-1), Big(0)), Big('-1.5707963267948966192'));
    assert.deepEqual(atan2Big(Big(-1), Big(1)), Big('-0.7853981633974483096'));
  });

  it('should return the arctan of for mixed numbers and bignumbers', function() {
    assert.deepEqual(atan2Big(1, Big(1)), Big('0.7853981633974483096'));
    assert.deepEqual(atan2Big(Big(1), 1), Big('0.7853981633974483096'));
  });

  it('should return the arctan of for mixed bignumbers and booleans', function() {
    assert.deepEqual(atan2Big(Big(1), true), Big('0.7853981633974483096'));
    assert.deepEqual(atan2Big(Big(1), false), Big('1.5707963267948966192'));
    assert.deepEqual(atan2Big(true, Big(1)), Big('0.7853981633974483096'));
    assert.deepEqual(atan2Big(false, Big(1)), Big(0));
  });

  it('should calculate atan2 with mixed bignumbers and null', function() {
    assert.deepEqual(atan2Big(Big(1), null), Big('1.5707963267948966192'));
    assert.deepEqual(atan2Big(null, Big(1)), Big(0));
  });

  it('should throw an error if called with a complex', function() {
    assert.throws(function () {atan2(complex('2+3i'), complex('1-2i')); });
  });

  it('should throw an error if called with a string', function() {
    assert.throws(function () {atan2('string', 1);});
  });

  it('should throw an error if called with a unit', function() {
    assert.throws(function () {atan2(unit('5cm'), 1);});
  });
  
  describe('Array', function () {

    it('should calculate atan2 array - scalar', function () {
      assert.deepEqual(divide(atan2(1, [1, -1, 0]), pi), [0.25, 0.75, 0.5]);
      assert.deepEqual(divide(atan2([1, -1, 0], 1), pi), [0.25, -0.25, 0]);
    });

    it('should calculate atan2 array - array', function () {
      assert.deepEqual(divide(atan2([[1, -1, 0], [1, -1, 0]], [[-1, 0, 1], [1, 1, 1]]), pi), [[0.75, -0.5, 0], [0.25, -0.25, 0]]);
    });

    it('should calculate atan2 array - dense matrix', function () {
      assert.deepEqual(divide(atan2([[1, -1, 0], [1, -1, 0]], matrix([[-1, 0, 1], [1, 1, 1]])), pi), matrix([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });

    it('should calculate atan2 array - sparse matrix', function () {
      assert.deepEqual(divide(atan2([[1, -1, 0], [1, -1, 0]], sparse([[-1, 0, 1], [1, 1, 1]])), pi), matrix([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });
  });

  describe('DenseMatrix', function () {

    it('should calculate atan2 dense matrix - scalar', function () {
      assert.deepEqual(divide(atan2(1, matrix([1, -1, 0])), pi), matrix([0.25, 0.75, 0.5]));
      assert.deepEqual(divide(atan2(matrix([1, -1, 0]), 1), pi), matrix([0.25, -0.25, 0]));
    });

    it('should calculate atan2 dense matrix - array', function () {
      assert.deepEqual(divide(atan2(matrix([[1, -1, 0], [1, -1, 0]]), [[-1, 0, 1], [1, 1, 1]]), pi), matrix([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });

    it('should calculate atan2 dense matrix - dense matrix', function () {
      assert.deepEqual(divide(atan2(matrix([[1, -1, 0], [1, -1, 0]]), matrix([[-1, 0, 1], [1, 1, 1]])), pi), matrix([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });

    it('should calculate atan2 dense matrix - sparse matrix', function () {
      assert.deepEqual(divide(atan2(matrix([[1, -1, 0], [1, -1, 0]]), sparse([[-1, 0, 1], [1, 1, 1]])), pi), matrix([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });
  });

  describe('SparseMatrix', function () {

    it('should calculate atan2 sparse matrix - scalar', function () {
      assert.deepEqual(divide(atan2(1, sparse([[1, -1], [0, 1]])), pi), matrix([[0.25, 0.75], [0.5, 0.25]]));
      assert.deepEqual(divide(atan2(sparse([[1, -1], [0, 1]]), 1), pi), sparse([[0.25, -0.25], [0, 0.25]]));
    });

    it('should calculate atan2 sparse matrix - array', function () {
      assert.deepEqual(divide(atan2(sparse([[1, -1, 0], [1, -1, 0]]), [[-1, 0, 1], [1, 1, 1]]), pi), sparse([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });

    it('should calculate atan2 sparse matrix - dense matrix', function () {
      assert.deepEqual(divide(atan2(sparse([[1, -1, 0], [1, -1, 0]]), matrix([[-1, 0, 1], [1, 1, 1]])), pi), sparse([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });

    it('should calculate atan2 sparse matrix - sparse matrix', function () {
      assert.deepEqual(divide(atan2(sparse([[1, -1, 0], [1, -1, 0]]), sparse([[-1, 0, 1], [1, 1, 1]])), pi), sparse([[0.75, -0.5, 0], [0.25, -0.25, 0]]));
    });
  });

  it('should calculate the atan2 element-wise for arrays and matrices', function() {
    // array, matrix, range
    approx.deepEqual(divide(atan2([1, 0, -1], [1, 0, -1]), pi), [0.25, 0, -0.75]);
    approx.deepEqual(divide(atan2(
        matrix([1,0,-1]),
        matrix([1,0,-1])), pi),
        matrix([0.25, 0, -0.75]));
    assert.equal(atan2(0, 2) / pi, 0);
    assert.equal(atan2(0, -2) / pi, 1);
  });

  it('should throw an error in case of invalid number of arguments', function() {
    assert.throws(function () {atan2(1);}, /TypeError: Too few arguments/);
    assert.throws(function () {atan2(1, 2, 3);}, /TypeError: Too many arguments/);
  });

  it('should LaTeX atan2', function () {
    var expression = math.parse('atan2(1,1)');
    assert.equal(expression.toTex(), '\\mathrm{atan2}\\left(1,1\\right)');
  });
});