var assert = require('assert'),
    error = require('../../../lib/error/index'),
    math = require('../../../index'),
    approx = require('../../../tools/approx'),
    pi = math.pi,
    complex = math.complex,
    matrix = math.matrix,
    unit = math.unit,
    tanh = math.tanh,
    bigmath = math.create({number: 'BigNumber', precision: 20});

describe('tanh', function() {
  it('should return the tanh of a boolean', function () {
    approx.equal(tanh(true), 0.76159415595576);
    approx.equal(tanh(false), 0);
  });

  it('should return the tanh of null', function () {
    approx.equal(tanh(null), 0);
  });

  it('should return the tanh of a number', function() {
    approx.equal(tanh(0), 0);
    approx.equal(tanh(pi), 0.99627207622075);
    approx.equal(tanh(1), 0.76159415595576);
    approx.equal(tanh(2), 0.96402758007582);
    approx.equal(tanh(3), 0.99505475368673);
  });

  it('should return the tanh of a bignumber', function() {
    var tanhBig = bigmath.tanh;
    var Big = bigmath.bignumber;

    var arg1 = Big(-Infinity);
    var arg2 = Big(-3);
    var arg10 = Big(Infinity);
    assert.deepEqual(tanhBig(arg1), Big(-1));
    assert.deepEqual(tanhBig(arg2), Big('-0.99505475368673045133'));
    assert.deepEqual(tanhBig(Big(-2)), Big('-0.96402758007581688395'));
    assert.deepEqual(tanhBig(Big(-1)), Big('-0.76159415595576488812'));
    assert.deepEqual(tanhBig(Big(0)), Big(0));
    assert.deepEqual(tanhBig(Big(1)), Big('0.76159415595576488812'));
    assert.deepEqual(tanhBig(Big(2)), Big('0.96402758007581688395'));
    assert.deepEqual(tanhBig(Big(3)), Big('0.99505475368673045133'));
    assert.deepEqual(tanhBig(bigmath.pi).toString(), '0.99627207622074994426');
    assert.deepEqual(tanhBig(arg10), Big(1));

    // Make sure args were not changed
    assert.deepEqual(arg1.toString(), '-Infinity');
    assert.deepEqual(arg2, Big(-3));
    assert.deepEqual(arg10.toString(), 'Infinity');
  });

  it('should return the tanh of a complex number', function() {
    approx.deepEqual(tanh(complex('1')), complex(0.76159415595576, 0));
    approx.deepEqual(tanh(complex('i')), complex(0, 1.5574077246549));
    approx.deepEqual(tanh(complex('2 + i')), complex(1.0147936161466, 0.033812826079897));
  });

  it('should return the tanh of an angle', function() {
    approx.equal(tanh(unit('90deg')), 0.91715233566727);
    approx.equal(tanh(unit('-45deg')), -0.65579420263267);

    assert(math.type.isBigNumber(tanh(unit(math.bignumber(90), 'deg'))));
    approx.equal(tanh(unit(math.bignumber(90), 'deg')).toNumber(), 0.91715233566727);

    approx.deepEqual(tanh(unit(complex('2 + i'), 'rad')), complex(1.0147936161466, 0.033812826079897));
  });

  it('should throw an error if called with an invalid unit', function() {
    assert.throws(function () {tanh(unit('5 celsius'))});
  });

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

  var tanh123 = [0.76159415595576, 0.96402758007582, 0.99505475368673];

  it('should return the tanh of each element of an array', function() {
    approx.deepEqual(tanh([1,2,3]), tanh123);
  });

  it('should return the tanh of each element of a matrix', function() {
    approx.deepEqual(tanh(matrix([1,2,3])), matrix(tanh123));
  });

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

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