import assert from 'assert'
import approx from '../../../../tools/approx.js'
import math from '../../../../src/defaultInstance.js'
const arg = math.arg

describe('arg', function () {
  it('should compute the argument of a boolean', function () {
    assert.strictEqual(arg(true), 0)
    assert.strictEqual(arg(false), 0)
  })

  it('should compute the argument of a number', function () {
    assert.strictEqual(arg(1), 0)
    assert.strictEqual(arg(2), 0)
    assert.strictEqual(arg(0), 0)
    approx.equal(arg(-2), 3.141592653589793)
  })

  it('should compute the argument of a bignumber', function () {
    assert.deepStrictEqual(arg(math.bignumber(1)), math.bignumber(0))
    assert.deepStrictEqual(arg(math.bignumber(-2)),
      math.bignumber('3.141592653589793238462643383279502884197169399375105820974944592'))
  })

  it('should compute the argument of a complex number correctly', function () {
    assert.strictEqual(arg(math.complex('0')) / math.pi, 0)
    assert.strictEqual(arg(math.complex('1 + 0i')) / math.pi, 0)
    assert.strictEqual(arg(math.complex('1 + i')) / math.pi, 0.25)
    assert.strictEqual(arg(math.complex('0 + i')) / math.pi, 0.5)
    assert.strictEqual(arg(math.complex('-1 + i')) / math.pi, 0.75)
    assert.strictEqual(arg(math.complex('-1 + 0i')) / math.pi, 1)
    assert.strictEqual(arg(math.complex('-1 - i')) / math.pi, -0.75)
    assert.strictEqual(arg(math.complex('0 - i')) / math.pi, -0.5)
    assert.strictEqual(arg(math.complex('1 - i')) / math.pi, -0.25)
    assert.strictEqual(arg(math.i) / math.pi, 0.5)
  })

  it('should calculate the argument for each element in a matrix', function () {
    assert.deepStrictEqual(math.divide(arg([
      math.i, math.unaryMinus(math.i), math.add(1, math.i)
    ]), math.pi), [
      0.5, -0.5, 0.25
    ])
    assert.deepStrictEqual(math.matrix(math.divide(arg([
      math.i, math.unaryMinus(math.i), math.add(1, math.i)
    ]), math.pi)).valueOf(), [
      0.5, -0.5, 0.25
    ])
  })

  it('should compute the argument of a real number correctly', function () {
    assert.strictEqual(arg(2) / math.pi, 0)
    assert.strictEqual(arg(-2) / math.pi, 1)
  })

  it('should throw an error if used with a string', function () {
    assert.throws(function () { arg('string') })
  })

  it('should throw an error if used with a unit', function () {
    assert.throws(function () { arg(math.unit('5cm')) })
  })

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

  it('should LaTeX arg', function () {
    const expression = math.parse('arg(1+i)')
    assert.strictEqual(expression.toTex(), '\\arg\\left(1+ i\\right)')
  })
})