/* globals fullHex, compToHex */

/*

Color {
  constructor (a, b, c, space) {
    space: 'hsl'
    a: 30
    b: 20
    c: 10
  },

  toRgb () { return new Color in rgb space }
  toHsl () { return new Color in hsl space }
  toLab () { return new Color in lab space }

  toArray () { [space, a, b, c] }
  fromArray () { convert it back }
}

// Conversions aren't always exact because of monitor profiles etc...
new Color(h, s, l, 'hsl') !== new Color(r, g, b).hsl()
new Color(100, 100, 100, [space])
new Color('hsl(30, 20, 10)')

// Sugar
SVG.rgb(30, 20, 50).lab()
SVG.hsl()
SVG.lab('rgb(100, 100, 100)')
*/

// Module for color convertions
SVG.Color = function (color, g, b) {
  var match

  // initialize defaults
  this.r = 0
  this.g = 0
  this.b = 0

  if (!color) return

  // parse color
  if (typeof color === 'string') {
    if (SVG.regex.isRgb.test(color)) {
      // get rgb values
      match = SVG.regex.rgb.exec(color.replace(SVG.regex.whitespace, ''))

      // parse numeric values
      this.r = parseInt(match[1])
      this.g = parseInt(match[2])
      this.b = parseInt(match[3])
    } else if (SVG.regex.isHex.test(color)) {
      // get hex values
      match = SVG.regex.hex.exec(fullHex(color))

      // parse numeric values
      this.r = parseInt(match[1], 16)
      this.g = parseInt(match[2], 16)
      this.b = parseInt(match[3], 16)
    }
  } else if (Array.isArray(color)) {
    this.r = color[0]
    this.g = color[1]
    this.b = color[2]
  } else if (typeof color === 'object') {
    this.r = color.r
    this.g = color.g
    this.b = color.b
  } else if (arguments.length === 3) {
    this.r = color
    this.g = g
    this.b = b
  }
}

SVG.extend(SVG.Color, {
  // Default to hex conversion
  toString: function () {
    return this.toHex()
  },
  toArray: function () {
    return [this.r, this.g, this.b]
  },
  fromArray: function (a) {
    return new SVG.Color(a)
  },
  // Build hex value
  toHex: function () {
    return '#' +
      compToHex(Math.round(this.r)) +
      compToHex(Math.round(this.g)) +
      compToHex(Math.round(this.b))
  },
  // Build rgb value
  toRgb: function () {
    return 'rgb(' + [this.r, this.g, this.b].join() + ')'
  },
  // Calculate true brightness
  brightness: function () {
    return (this.r / 255 * 0.30) +
      (this.g / 255 * 0.59) +
      (this.b / 255 * 0.11)
  },
  // Make color morphable
  morph: function (color) {
    this.destination = new SVG.Color(color)

    return this
  },
  // Get morphed color at given position
  at: function (pos) {
    // make sure a destination is defined
    if (!this.destination) return this

    // normalise pos
    pos = pos < 0 ? 0 : pos > 1 ? 1 : pos

    // generate morphed color
    return new SVG.Color({
      r: ~~(this.r + (this.destination.r - this.r) * pos),
      g: ~~(this.g + (this.destination.g - this.g) * pos),
      b: ~~(this.b + (this.destination.b - this.b) * pos)
    })
  }

})

// Testers

// Test if given value is a color string
SVG.Color.test = function (color) {
  color += ''
  return SVG.regex.isHex.test(color) ||
    SVG.regex.isRgb.test(color)
}

// Test if given value is a rgb object
SVG.Color.isRgb = function (color) {
  return color && typeof color.r === 'number' &&
    typeof color.g === 'number' &&
    typeof color.b === 'number'
}

// Test if given value is a color
SVG.Color.isColor = function (color) {
  return SVG.Color.isRgb(color) || SVG.Color.test(color)
}