import { factory } from '../../utils/factory'
import { deepMap } from '../../utils/collection'
import { expNumber } from '../../plain/number'

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

export const createExp = /* #__PURE__ */ factory(name, dependencies, ({ typed }) => {
  /**
   * Calculate the exponent of a value.
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.exp(x)
   *
   * Examples:
   *
   *    math.exp(2)                  // returns number 7.3890560989306495
   *    math.pow(math.e, 2)          // returns number 7.3890560989306495
   *    math.log(math.exp(2))        // returns number 2
   *
   *    math.exp([1, 2, 3])
   *    // returns Array [
   *    //   2.718281828459045,
   *    //   7.3890560989306495,
   *    //   20.085536923187668
   *    // ]
   *
   * See also:
   *
   *    expm1, log, pow
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x  A number or matrix to exponentiate
   * @return {number | BigNumber | Complex | Array | Matrix} Exponent of `x`
   */
  const exp = typed(name, {
    number: expNumber,

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

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

    'Array | Matrix': function (x) {
      // TODO: exp(sparse) should return a dense matrix since exp(0)==1
      return deepMap(x, exp)
    }
  })

  return exp
})
