var assert = require('assert'),
    error = require('../../../lib/error/index'),
    math = require('../../../index'),
    approx = require('../../../tools/approx'),
    pi = math.pi,
    asinh = math.asinh,
    sinh = math.sinh,
    complex = math.complex,
    matrix = math.matrix,
    unit = math.unit,
    bigmath = math.create({number: 'bignumber', precision: 20}),
    biggermath = math.create({precision: 21}),
    asinhBig = bigmath.asinh,
    Big = bigmath.bignumber;

describe('asinh', function() {
  it('should return the hyperbolic arcsin of a boolean', function () {
    approx.equal(asinh(true), 0.8813735870195430);
    assert.equal(asinh(false), 0);
  });

  it('should return the hyperbolic arcsin of null', function () {
    assert.equal(asinh(null), 0);
  });

  it('should return the hyperbolic arcsin of a number', function() {
    approx.equal(asinh(-2), -1.44363547517881034249327674027311);
    approx.equal(asinh(-1), -0.88137358701954302523260932497979);
    approx.equal(asinh(0), 0);
    approx.equal(asinh(1), 0.88137358701954302523260932497979);
    approx.equal(asinh(2), 1.44363547517881034249327674027311);
    approx.equal(asinh(pi), 1.8622957433108482198883613251826);
  });

  it('should return the hyperbolic arcsin of a bignumber', function() {
    var arg = Big(-2);
    assert.deepEqual(asinhBig(arg), Big('-1.4436354751788103425'));
    assert.deepEqual(asinhBig(Big(-1)), Big('-0.88137358701954302523'));
    assert.deepEqual(asinhBig(Big(0)), Big(0));
    assert.deepEqual(asinhBig(Big(1)), Big('0.88137358701954302523'));
    assert.deepEqual(asinhBig(Big(2)), Big('1.4436354751788103425'));
    assert.deepEqual(asinhBig(bigmath.pi).toString(), '1.8622957433108482199');

    //Make sure arg was not changed
    assert.deepEqual(arg, Big(-2));
  });

  it('should be the inverse function of hyperbolic sin', function() {
    approx.equal(asinh(sinh(-1)), -1);
    approx.equal(asinh(sinh(0)), 0);
    approx.equal(asinh(sinh(0.1)), 0.1);
    approx.equal(asinh(sinh(0.5)), 0.5);
    approx.equal(asinh(sinh(2)), 2);
  });

  it('should be the inverse function of bignumber sinh', function() {
    assert.deepEqual(asinhBig(bigmath.sinh(Big(-1))), Big(-1));
    assert.deepEqual(asinhBig(bigmath.sinh(Big(0))), Big(0));
    assert.deepEqual(asinhBig(bigmath.sinh(Big(0.5))), Big(0.5));
    assert.deepEqual(asinhBig(bigmath.sinh(Big(2))), Big(2));

    /* Pass in more digits to pi. */
    assert.deepEqual(asinhBig(biggermath.sinh(Big(0.1))), Big(0.1));
  });

  it('should return the arcsinh of a complex number', function() {
    approx.deepEqual(asinh(complex('2+3i')), complex(1.9686379257931, 0.9646585044076028));
    approx.deepEqual(asinh(complex('2-3i')), complex(1.9686379257931, -0.9646585044076028));
    approx.deepEqual(asinh(complex('-2+3i')), complex(-1.9686379257931, 0.9646585044076028));
    approx.deepEqual(asinh(complex('-2-3i')), complex(-1.9686379257931, -0.9646585044076028));
    approx.deepEqual(asinh(complex('1+i')), complex(1.0612750619050357, 0.6662394324925153));
    approx.deepEqual(asinh(complex('i')), complex(0, pi / 2));
    approx.deepEqual(asinh(complex('1')), complex(0.881373587019543025, 0));
    assert.deepEqual(asinh(complex('0')), complex(0, 0));
  });

  it('should throw an error if called with a unit', function() {
    assert.throws(function () {asinh(unit('45deg'))});
    assert.throws(function () {asinh(unit('5 celsius'))});
  });

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

  it('should calculate the arcsin element-wise for arrays and matrices', function() {
    var asinh123 = [0.881373587019543025, 1.4436354751788103, 1.8184464592320668];
    approx.deepEqual(asinh([1,2,3]), asinh123);
    approx.deepEqual(asinh(matrix([1,2,3])), matrix(asinh123));
  });

  it('should throw an error in case of invalid number of arguments', function() {
    assert.throws(function () {asinh()}, error.ArgumentsError);
    assert.throws(function () {asinh(1, 2)}, error.ArgumentsError);
  });

});