var _ = require('../util')

/**
 * Stringify value.
 *
 * @param {Number} indent
 */

exports.json = {
  read: function (value, indent) {
    return typeof value === 'string'
      ? value
      : JSON.stringify(value, null, Number(indent) || 2)
  },
  write: function (value) {
    try {
      return JSON.parse(value)
    } catch (e) {
      return value
    }
  }
}

/**
 * 'abc' => 'Abc'
 */

exports.capitalize = function (value) {
  if (!value && value !== 0) return ''
  value = value.toString()
  return value.charAt(0).toUpperCase() + value.slice(1)
}

/**
 * 'abc' => 'ABC'
 */

exports.uppercase = function (value) {
  return (value || value === 0)
    ? value.toString().toUpperCase()
    : ''
}

/**
 * 'AbC' => 'abc'
 */

exports.lowercase = function (value) {
  return (value || value === 0)
    ? value.toString().toLowerCase()
    : ''
}

/**
 * 12345 => $12,345.00
 *
 * @param {String} sign
 */

var digitsRE = /(\d{3})(?=\d)/g
exports.currency = function (value, currency) {
  value = parseFloat(value)
  if (!isFinite(value) || (!value && value !== 0)) return ''
  currency = currency != null ? currency : '$'
  var stringified = Math.abs(value).toFixed(2)
  var _int = stringified.slice(0, -3)
  var i = _int.length % 3
  var head = i > 0
    ? (_int.slice(0, i) + (_int.length > 3 ? ',' : ''))
    : ''
  var _float = stringified.slice(-3)
  var sign = value < 0 ? '-' : ''
  return currency + sign + head +
    _int.slice(i).replace(digitsRE, '$1,') +
    _float
}

/**
 * 'item' => 'items'
 *
 * @params
 *  an array of strings corresponding to
 *  the single, double, triple ... forms of the word to
 *  be pluralized. When the number to be pluralized
 *  exceeds the length of the args, it will use the last
 *  entry in the array.
 *
 *  e.g. ['single', 'double', 'triple', 'multiple']
 */

exports.pluralize = function (value) {
  var args = _.toArray(arguments, 1)
  return args.length > 1
    ? (args[value % 10 - 1] || args[args.length - 1])
    : (args[0] + (value === 1 ? '' : 's'))
}

/**
 * A special filter that takes a handler function,
 * wraps it so it only gets triggered on specific
 * keypresses. v-on only.
 *
 * @param {String} key
 */

var keyCodes = {
  esc: 27,
  tab: 9,
  enter: 13,
  space: 32,
  'delete': 46,
  up: 38,
  left: 37,
  right: 39,
  down: 40
}

exports.key = function (handler, key) {
  if (!handler) return
  var code = keyCodes[key]
  if (!code) {
    code = parseInt(key, 10)
  }
  return function (e) {
    if (e.keyCode === code) {
      return handler.call(this, e)
    }
  }
}

// expose keycode hash
exports.key.keyCodes = keyCodes

exports.debounce = function (handler, delay) {
  if (!handler) return
  if (!delay) {
    delay = 300
  }
  return _.debounce(handler, delay)
}

/**
 * Install special array filters
 */

_.extend(exports, require('./array-filters'))