function Color (r,g,b,a) {
  this.r = r
  this.g = g
  this.b = b
  this.a = a || 1.0
}
Color.prototype.toString = function(){
  return "rgba(" + Math.round(this.r) + "," + Math.round(this.g) + "," + Math.round(this.b) + "," + this.a + ")";
}
Color.prototype.rgb = function(){
  return [ this.r, this.g, this.b ];
}
Color.prototype.rgba = function(){
  return [ this.r, this.g, this.b, this.a ];
}
Color.prototype.clone = function(){
  return new Color(this.r, this.g, this.b, this.a);
}
Color.prototype.alpha = function(a){
  var c = this.copy()
  c.a = a;
  return c;
}
Color.prototype.add = function(n){
  if (! n) return
  this.r = clamp(Math.round(this.r + n), 0, 255)
  this.g = clamp(Math.round(this.g + n), 0, 255)
  this.b = clamp(Math.round(this.b + n), 0, 255)
  return this
}
Color.prototype.mottle = function(n){
  n = n || 30
  this.r = clamp(this.r + randrange(-n, n), 0, 255)
  this.g = clamp(this.g + randrange(-n, n), 0, 255)
  this.b = clamp(this.b + randrange(-n, n), 0, 255)
  return this
}
Color.prototype.mottleRGB = function(r,g,b){
  r = r || 0 ; g = g || 0 ; b = b || 0
  this.r = clamp(this.r + randrange(-r, r), 0, 255)
  this.g = clamp(this.g + randrange(-g, g), 0, 255)
  this.b = clamp(this.b + randrange(-b, b), 0, 255)
  return this
}
Color.prototype.swatch = function(){
  var el = document.createElement("div");
  el.style.className = "swatch";
  el.style.width = 16 + "px";
  el.style.height = 16 + "px";
  el.style.backgroundColor = this.toString();
  $(el).data("color", this);
  return el;
}

var COLORS = {
  plain: new Color(230,240,240),
  ivory: new Color(240,240,235),
  pink: new Color(240,223,235),
  red: new Color(240,224,223),
  orange: new Color(240,232,223),
  yellow: new Color(240,240,231),
  green: new Color(233,240,231),
  blue: new Color(224,226,240),
  purple: new Color(235,231,240),
  black: new Color(32,32,37),
}

var DARK_COLORS = {
  plain: new Color(24,10,10),
  ivory: new Color(18,18,18),
  pink: new Color(40,23,35),
  red: new Color(40,24,23),
  orange: new Color(40,32,23),
  yellow: new Color(40,40,31),
  green: new Color(33,40,31),
  blue: new Color(24,26,40),
  purple: new Color(35,31,40),
  black: new Color(0,0,0),
}

function nighttime_quotient() {
  var q = -10;
  var date = new Date()
  var x;
  var h = date.getHours()
  var m = date.getMinutes()
  if (h < 5 || h > 23)
    { return q; }
  if (h >= 5 && h <= 7)
    { x = 60*60*3 - 60 * (h - 5) + m; }
  if (h >= 21 && h <= 23)
    { x = 60 * (h - 21) + m; }
  x /= 60*60*3;
  return q * x;
}
function get_color_from_time(){
  var date = new Date()
  var h = date.getHours()
  var m = date.getMinutes()
  var c;
  if ((h == 4 || h == 16) && m == 20)
    { c = "green"; }
  else if (h < 5)
    { c = "blue"; }
  else if (h >= 5 && h < 6)
    { c = "red"; }
  else if (h >= 6 && h < 9)
    { c = "orange"; }
  else if (h >= 9 && h < 12)
    { c = "yellow"; }
  else if (h >= 12 && h < 18)
    { c = "plain"; }
  else if (h >= 18 && h < 21)
    { c = "blue"; }
  else if (h >= 21)
    { c = "blue"; }
  else
    { c = "plain"; }
  return c;
}
function set_background_color_from_time(){
  var color_name = get_color_from_time()
  set_background_color(color_name)
}
function set_background_color(color_name){
  color_name = color_name || "plain"
  var color_set = window.matchMedia('prefers-color-scheme: dark').matches ? DARK_COLORS : COLORS
  var color = color_set[color_name]
    .clone()
    .mottleRGB(4,4,8)
//     .add(nighttime_quotient())
  document.body.style.backgroundColor = color.toString()
  $(document.body).toggleClass("black", color_name === "black")
}