/*
 * quantize.js Copyright 2008 Nick Rabinowitz
 * Ported to node.js by Olivier Lesnicki
 * Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
 */
// fill out a couple protovis dependencies

/*
 * Block below copied from Protovis: http://mbostock.github.com/protovis/
 * Copyright 2010 Stanford Visualization Group
 * Licensed under the BSD License: http://www.opensource.org/licenses/bsd-license.php
 */
if (!pv) {
  var pv = {
    map: function (array, f) {
      var o = {};
      return f ? array.map(function (d, i) {
        o.index = i;
        return f.call(o, d);
      }) : array.slice();
    },
    naturalOrder: function (a, b) {
      return a < b ? -1 : a > b ? 1 : 0;
    },
    sum: function (array, f) {
      var o = {};
      return array.reduce(f ? function (p, d, i) {
        o.index = i;
        return p + f.call(o, d);
      } : function (p, d) {
        return p + d;
      }, 0);
    },
    max: function (array, f) {
      return Math.max.apply(null, f ? pv.map(array, f) : array);
    }
  };
}
/**
 * Basic Javascript port of the MMCQ (modified median cut quantization)
 * algorithm from the Leptonica library (http://www.leptonica.com/).
 * Returns a color map you can use to map original pixels to the reduced
 * palette. Still a work in progress.
 * 
 * @author Nick Rabinowitz
 * @example
 
// array of pixels as [R,G,B] arrays
var myPixels = [[190,197,190], [202,204,200], [207,214,210], [211,214,211], [205,207,207]
                // etc
                ];
var maxColors = 4;
 
var cmap = MMCQ.quantize(myPixels, maxColors);
var newPalette = cmap.palette();
var newPixels = myPixels.map(function(p) { 
    return cmap.map(p); 
});
 
 */


var MMCQ = function () {
  // private constants
  var sigbits = 5,
      rshift = 8 - sigbits,
      maxIterations = 1000,
      fractByPopulations = 0.75; // get reduced-space color index for a pixel

  function getColorIndex(r, g, b) {
    return (r << 2 * sigbits) + (g << sigbits) + b;
  } // Simple priority queue


  function PQueue(comparator) {
    var contents = [],
        sorted = false;

    function sort() {
      contents.sort(comparator);
      sorted = true;
    }

    return {
      push: function (o) {
        contents.push(o);
        sorted = false;
      },
      peek: function (index) {
        if (!sorted) { sort(); }
        if (index === undefined) { index = contents.length - 1; }
        return contents[index];
      },
      pop: function () {
        if (!sorted) { sort(); }
        return contents.pop();
      },
      size: function () {
        return contents.length;
      },
      map: function (f) {
        return contents.map(f);
      },
      debug: function () {
        if (!sorted) { sort(); }
        return contents;
      }
    };
  } // 3d color space box


  function VBox(r1, r2, g1, g2, b1, b2, histo) {
    var vbox = this;
    vbox.r1 = r1;
    vbox.r2 = r2;
    vbox.g1 = g1;
    vbox.g2 = g2;
    vbox.b1 = b1;
    vbox.b2 = b2;
    vbox.histo = histo;
  }

  VBox.prototype = {
    volume: function (force) {
      var vbox = this;

      if (!vbox._volume || force) {
        vbox._volume = (vbox.r2 - vbox.r1 + 1) * (vbox.g2 - vbox.g1 + 1) * (vbox.b2 - vbox.b1 + 1);
      }

      return vbox._volume;
    },
    count: function (force) {
      var vbox = this,
          histo = vbox.histo;

      if (!vbox._count_set || force) {
        var npix = 0,
            i,
            j,
            k,
            index;

        for (i = vbox.r1; i <= vbox.r2; i++) {
          for (j = vbox.g1; j <= vbox.g2; j++) {
            for (k = vbox.b1; k <= vbox.b2; k++) {
              index = getColorIndex(i, j, k);
              npix += histo[index] || 0;
            }
          }
        }

        vbox._count = npix;
        vbox._count_set = true;
      }

      return vbox._count;
    },
    copy: function () {
      var vbox = this;
      return new VBox(vbox.r1, vbox.r2, vbox.g1, vbox.g2, vbox.b1, vbox.b2, vbox.histo);
    },
    avg: function (force) {
      var vbox = this,
          histo = vbox.histo;

      if (!vbox._avg || force) {
        var ntot = 0,
            mult = 1 << 8 - sigbits,
            rsum = 0,
            gsum = 0,
            bsum = 0,
            hval,
            i,
            j,
            k,
            histoindex;

        for (i = vbox.r1; i <= vbox.r2; i++) {
          for (j = vbox.g1; j <= vbox.g2; j++) {
            for (k = vbox.b1; k <= vbox.b2; k++) {
              histoindex = getColorIndex(i, j, k);
              hval = histo[histoindex] || 0;
              ntot += hval;
              rsum += hval * (i + 0.5) * mult;
              gsum += hval * (j + 0.5) * mult;
              bsum += hval * (k + 0.5) * mult;
            }
          }
        }

        if (ntot) {
          vbox._avg = [~~(rsum / ntot), ~~(gsum / ntot), ~~(bsum / ntot)];
        } else {
          //console.log('empty box');
          vbox._avg = [~~(mult * (vbox.r1 + vbox.r2 + 1) / 2), ~~(mult * (vbox.g1 + vbox.g2 + 1) / 2), ~~(mult * (vbox.b1 + vbox.b2 + 1) / 2)];
        }
      }

      return vbox._avg;
    },
    contains: function (pixel) {
      var vbox = this,
          rval = pixel[0] >> rshift;
      gval = pixel[1] >> rshift;
      bval = pixel[2] >> rshift;
      return rval >= vbox.r1 && rval <= vbox.r2 && gval >= vbox.g1 && gval <= vbox.g2 && bval >= vbox.b1 && bval <= vbox.b2;
    }
  }; // Color map

  function CMap() {
    this.vboxes = new PQueue(function (a, b) {
      return pv.naturalOrder(a.vbox.count() * a.vbox.volume(), b.vbox.count() * b.vbox.volume());
    });
  }

  CMap.prototype = {
    push: function (vbox) {
      this.vboxes.push({
        vbox: vbox,
        color: vbox.avg()
      });
    },
    palette: function () {
      return this.vboxes.map(function (vb) {
        return vb.color;
      });
    },
    size: function () {
      return this.vboxes.size();
    },
    map: function (color) {
      var vboxes = this.vboxes;

      for (var i = 0; i < vboxes.size(); i++) {
        if (vboxes.peek(i).vbox.contains(color)) {
          return vboxes.peek(i).color;
        }
      }

      return this.nearest(color);
    },
    nearest: function (color) {
      var vboxes = this.vboxes,
          d1,
          d2,
          pColor;

      for (var i = 0; i < vboxes.size(); i++) {
        d2 = Math.sqrt(Math.pow(color[0] - vboxes.peek(i).color[0], 2) + Math.pow(color[1] - vboxes.peek(i).color[1], 2) + Math.pow(color[2] - vboxes.peek(i).color[2], 2));

        if (d2 < d1 || d1 === undefined) {
          d1 = d2;
          pColor = vboxes.peek(i).color;
        }
      }

      return pColor;
    },
    forcebw: function () {
      // XXX: won't  work yet
      var vboxes = this.vboxes;
      vboxes.sort(function (a, b) {
        return pv.naturalOrder(pv.sum(a.color), pv.sum(b.color));
      }); // force darkest color to black if everything < 5

      var lowest = vboxes[0].color;
      if (lowest[0] < 5 && lowest[1] < 5 && lowest[2] < 5) { vboxes[0].color = [0, 0, 0]; } // force lightest color to white if everything > 251

      var idx = vboxes.length - 1,
          highest = vboxes[idx].color;
      if (highest[0] > 251 && highest[1] > 251 && highest[2] > 251) { vboxes[idx].color = [255, 255, 255]; }
    }
  }; // histo (1-d array, giving the number of pixels in
  // each quantized region of color space), or null on error

  function getHisto(pixels) {
    var histosize = 1 << 3 * sigbits,
        histo = new Array(histosize),
        index,
        rval,
        gval,
        bval;
    pixels.forEach(function (pixel) {
      rval = pixel[0] >> rshift;
      gval = pixel[1] >> rshift;
      bval = pixel[2] >> rshift;
      index = getColorIndex(rval, gval, bval);
      histo[index] = (histo[index] || 0) + 1;
    });
    return histo;
  }

  function vboxFromPixels(pixels, histo) {
    var rmin = 1000000,
        rmax = 0,
        gmin = 1000000,
        gmax = 0,
        bmin = 1000000,
        bmax = 0,
        rval,
        gval,
        bval; // find min/max

    pixels.forEach(function (pixel) {
      rval = pixel[0] >> rshift;
      gval = pixel[1] >> rshift;
      bval = pixel[2] >> rshift;
      if (rval < rmin) { rmin = rval; }else if (rval > rmax) { rmax = rval; }
      if (gval < gmin) { gmin = gval; }else if (gval > gmax) { gmax = gval; }
      if (bval < bmin) { bmin = bval; }else if (bval > bmax) { bmax = bval; }
    });
    return new VBox(rmin, rmax, gmin, gmax, bmin, bmax, histo);
  }

  function medianCutApply(histo, vbox) {
    if (!vbox.count()) { return; }
    var rw = vbox.r2 - vbox.r1 + 1,
        gw = vbox.g2 - vbox.g1 + 1,
        bw = vbox.b2 - vbox.b1 + 1,
        maxw = pv.max([rw, gw, bw]); // only one pixel, no split

    if (vbox.count() == 1) {
      return [vbox.copy()];
    }
    /* Find the partial sum arrays along the selected axis. */


    var total = 0,
        partialsum = [],
        lookaheadsum = [],
        i,
        j,
        k,
        sum,
        index;

    if (maxw == rw) {
      for (i = vbox.r1; i <= vbox.r2; i++) {
        sum = 0;

        for (j = vbox.g1; j <= vbox.g2; j++) {
          for (k = vbox.b1; k <= vbox.b2; k++) {
            index = getColorIndex(i, j, k);
            sum += histo[index] || 0;
          }
        }

        total += sum;
        partialsum[i] = total;
      }
    } else if (maxw == gw) {
      for (i = vbox.g1; i <= vbox.g2; i++) {
        sum = 0;

        for (j = vbox.r1; j <= vbox.r2; j++) {
          for (k = vbox.b1; k <= vbox.b2; k++) {
            index = getColorIndex(j, i, k);
            sum += histo[index] || 0;
          }
        }

        total += sum;
        partialsum[i] = total;
      }
    } else {
      /* maxw == bw */
      for (i = vbox.b1; i <= vbox.b2; i++) {
        sum = 0;

        for (j = vbox.r1; j <= vbox.r2; j++) {
          for (k = vbox.g1; k <= vbox.g2; k++) {
            index = getColorIndex(j, k, i);
            sum += histo[index] || 0;
          }
        }

        total += sum;
        partialsum[i] = total;
      }
    }

    partialsum.forEach(function (d, i) {
      lookaheadsum[i] = total - d;
    });

    function doCut(color) {
      var dim1 = color + '1',
          dim2 = color + '2',
          left,
          right,
          vbox1,
          vbox2,
          d2,
          count2 = 0;

      for (i = vbox[dim1]; i <= vbox[dim2]; i++) {
        if (partialsum[i] > total / 2) {
          vbox1 = vbox.copy();
          vbox2 = vbox.copy();
          left = i - vbox[dim1];
          right = vbox[dim2] - i;
          if (left <= right) { d2 = Math.min(vbox[dim2] - 1, ~~(i + right / 2)); }else { d2 = Math.max(vbox[dim1], ~~(i - 1 - left / 2)); } // avoid 0-count boxes

          while (!partialsum[d2]) { d2++; }

          count2 = lookaheadsum[d2];

          while (!count2 && partialsum[d2 - 1]) { count2 = lookaheadsum[--d2]; } // set dimensions


          vbox1[dim2] = d2;
          vbox2[dim1] = vbox1[dim2] + 1; // console.log('vbox counts:', vbox.count(), vbox1.count(), vbox2.count());

          return [vbox1, vbox2];
        }
      }
    } // determine the cut planes


    return maxw == rw ? doCut('r') : maxw == gw ? doCut('g') : doCut('b');
  }

  function quantize(pixels, maxcolors) {
    // short-circuit
    if (!pixels.length || maxcolors < 2 || maxcolors > 256) {
      // console.log('wrong number of maxcolors');
      return false;
    } // XXX: check color content and convert to grayscale if insufficient


    var histo = getHisto(pixels);
 // check that we aren't below maxcolors already
    histo.forEach(function () {
    });
    // get the beginning vbox from the colors


    var vbox = vboxFromPixels(pixels, histo),
        pq = new PQueue(function (a, b) {
      return pv.naturalOrder(a.count(), b.count());
    });
    pq.push(vbox); // inner function to do the iteration

    function iter(lh, target) {
      var ncolors = lh.size(),
          niters = 0,
          vbox;

      while (niters < maxIterations) {
        if (ncolors >= target) { return; }

        if (niters++ > maxIterations) {
          // console.log("infinite loop; perhaps too few pixels!");
          return;
        }

        vbox = lh.pop();

        if (!vbox.count()) {
          /* just put it back */
          lh.push(vbox);
          niters++;
          continue;
        } // do the cut


        var vboxes = medianCutApply(histo, vbox),
            vbox1 = vboxes[0],
            vbox2 = vboxes[1];

        if (!vbox1) {
          // console.log("vbox1 not defined; shouldn't happen!");
          return;
        }

        lh.push(vbox1);

        if (vbox2) {
          /* vbox2 can be null */
          lh.push(vbox2);
          ncolors++;
        }
      }
    } // first set of colors, sorted by population


    iter(pq, fractByPopulations * maxcolors); // console.log(pq.size(), pq.debug().length, pq.debug().slice());
    // Re-sort by the product of pixel occupancy times the size in color space.

    var pq2 = new PQueue(function (a, b) {
      return pv.naturalOrder(a.count() * a.volume(), b.count() * b.volume());
    });

    while (pq.size()) {
      pq2.push(pq.pop());
    } // next set - generate the median cuts using the (npix * vol) sorting.


    iter(pq2, maxcolors); // calculate the actual colors

    var cmap = new CMap();

    while (pq2.size()) {
      cmap.push(pq2.pop());
    }

    return cmap;
  }

  return {
    quantize: quantize
  };
}();

var quantize = MMCQ.quantize;

export default quantize;
