import { factory } from '../../utils/factory'
import { deepMap } from '../../utils/collection'

const name = 'tan'
const dependencies = ['typed']

export const createTan = /* #__PURE__ */ factory(name, dependencies, ({ typed }) => {
  /**
   * Calculate the tangent of a value. `tan(x)` is equal to `sin(x) / cos(x)`.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.tan(x)
   *
   * Examples:
   *
   *    math.tan(0.5)                    // returns number 0.5463024898437905
   *    math.sin(0.5) / math.cos(0.5)    // returns number 0.5463024898437905
   *    math.tan(math.pi / 4)            // returns number 1
   *    math.tan(math.unit(45, 'deg'))   // returns number 1
   *
   * See also:
   *
   *    atan, sin, cos
   *
   * @param {number | BigNumber | Complex | Unit | Array | Matrix} x  Function input
   * @return {number | BigNumber | Complex | Array | Matrix} Tangent of x
   */
  const tan = typed(name, {
    number: Math.tan,

    Complex: function (x) {
      return x.tan()
    },

    BigNumber: function (x) {
      return x.tan()
    },

    Unit: function (x) {
      if (!x.hasBase(x.constructor.BASE_UNITS.ANGLE)) {
        throw new TypeError('Unit in function tan is no angle')
      }
      return tan(x.value)
    },

    'Array | Matrix': function (x) {
      // deep map collection, skip zeros since tan(0) = 0
      return deepMap(x, tan, true)
    }
  })

  return tan
})
