var MircColor = (function(){
  var COLORS = [
    [255,255,255],
    [0,0,0],
    [0,0,127],
    [0,147,0],
    [255,0,0],
    [127,0,0],
    [156,0,156],
    [252,127,0],
    [255,255,0],
    [0,252,0],
    [0,147,147],
    [0,255,255],
    [0,0,252],
    [255,0,255],
    [127,127,127],
    [210,210,210]
  ]

  function closest_to(pixel){
    return COLORS.reduce(function(prev, curr, index) {
      var d = distance(pixel, curr)
      if (prev[0] > d) {
        prev[0] = d
        prev[1] = index
      }
      return prev
    }, [Infinity, -1])[1]
  }

  function distance(u, v){
    var r = u[0] - v[0]
    var g = u[1] - v[1]
    var b = u[2] - v[2]
    return Math.sqrt(r*r+g*g+b*b)
  }

  function fromImageData (pixels, cb){
    var rows = [],
        pixel = new Array (4),
        data = pixels.data,
        t
    for (var i = 0, h = pixels.height; i < h; i++) {
      var row = []
      rows.push(row)
      for (var j = 0, w = pixels.width; j < w; j++) {
        t = (i*w+j)*4
        pixel[0] = data[t]
        pixel[1] = data[t+1]
        pixel[2] = data[t+2]
        pixel[3] = data[t+3]
        row[j] = closest_to(pixel)
      }
    }
    if (! cb) return rows
    else cb (rows)
  }

  function neighbor (canvas, ctx, img) {
    var scratch = document.createElement("canvas")
    var scratchCtx = scratch.getContext('2d')
    scratch.width = img.naturalWidth
    scratch.height = img.naturalHeight
    scratchCtx.drawImage(img, 0, 0, img.naturalWidth, img.naturalHeight)
    var srcImageData = scratchCtx.getImageData(0,0,scratch.width,scratch.height)
    var destImageData = ctx.createImageData(canvas.width,canvas.height)
    var src = srcImageData.data, dest = destImageData.data
    var dt, dw = destImageData.width, dh = destImageData.height
    var st, sw = srcImageData.width, sh = srcImageData.height
    for (var i = 0; i < dh; i++) {
      for (var j = 0; j < dw; j++) {
        var y = i * sh/dh
        var x = j * sw/dw
        dt = ((i*dw) + j) * 4
        st = Math.floor( Math.floor(y)*sw + x ) * 4
        dest[dt] = src[st]
        dest[dt+1] = src[st+1]
        dest[dt+2] = src[st+2]
        dest[dt+3] = src[st+3]
      }
    }

    return destImageData
  }
  var img = new Image ()
  function fromUrl (url, cb, opt) {
    img.onload = function(){
      var canvas = document.createElement("canvas"), ctx = canvas.getContext('2d'), pixels
      if (opt.width) {
        canvas.width = opt.width
        if (opt.height) {
          canvas.height = opt.height
        } else if (opt.ratio) {
          canvas.height = opt.width / opt.ratio
        } else {
          canvas.height = (img.naturalHeight * width / img.naturalWidth) / 2
        }
      }
      else {
        canvas.width = img.naturalWidth * 2
        canvas.height = img.naturalHeight
      }
      if (opt.neighbor) {
        pixels = neighbor(canvas, ctx, img)
      }
      else {
        ctx.drawImage(img,0,0,img.naturalWidth,img.naturalHeight,0,0,canvas.width,canvas.height)
        pixels = ctx.getImageData(0,0,canvas.width,canvas.height)
      }
      fromImageData(pixels, cb)
    }
    if (img.src == url) { return img.onload() }
    img.src = url
    if (img.complete) { return img.onload() }
  }
  function ascii (rows) {
    var lines = rows.map(function(str){
      return str.map(function(index){ return "\\x03" + index + "," + index + "x\\x03" }).join("")
    }).join("\\n")
    var txt = '/exec -out printf "' + lines + '"\n'
    return txt
  }
  function asciiFromUrl (url, cb, opt) {
    fromUrl(url, function(rows){
      cb(ascii(rows), rows)
    }, width)
  }
  function stringFromUrl (url, cb, opt) {
    fromUrl(url, function(rows){
      cb(rows.map(function(str){
        return str.map(function(index){ return "\C-c" + index + "," + index + "x\C-c" }).join("")
      }).join("\n"))
    }, width)
  }

  return {
    colors: COLORS,
    closest_to: closest_to,
    distance: distance,
    fromUrl: fromUrl,
    fromImageData: fromImageData,
    stringFromUrl: stringFromUrl,
    asciiFromUrl: asciiFromUrl,
    ascii: ascii,
    neighbor: neighbor,
  }

})()