/* global Canvas, module */

// Word cloud layout by Jason Davies, http://www.jasondavies.com/word-cloud/
// Algorithm due to Jonathan Feinberg, http://static.mrfeinberg.com/bv_ch03.pdf
define([
    'd3'
  ],
  function(d3) {

  	'use strict';

    (function() {
      function cloud() {
        var size = [256, 256],
          text = cloudText,
          font = cloudFont,
          fontSize = cloudFontSize,
          fontStyle = cloudFontNormal,
          fontWeight = cloudFontNormal,
          rotate = cloudRotate,
          padding = cloudPadding,
          spiral = archimedeanSpiral,
          words = [],
          timeInterval = Infinity,
          event = d3.dispatch("word", "end"),
          timer = null,
          cloud = {}; // jshint ignore:line

        cloud.start = function() {

          var step = function() {
            var start = +new Date,
              d;
            while (+new Date - start < timeInterval && ++i < n && timer) {
              d = data[i];
              d.x = (size[0] * (Math.random() + 0.5)) >> 1;
              d.y = (size[1] * (Math.random() + 0.5)) >> 1;
              cloudSprite(d, data, i);
              if (d.hasText && place(board, d, bounds)) {
                tags.push(d);
                event.word(d);
                if (bounds) { cloudBounds(bounds, d); }
                else {
                   bounds = [{
                    x: d.x + d.x0,
                    y: d.y + d.y0
                  }, {
                    x: d.x + d.x1,
                    y: d.y + d.y1
                  }];
                }
                // Temporary hack
                d.x -= size[0] >> 1;
                d.y -= size[1] >> 1;
              }
            }
            if (i >= n) {
              cloud.stop();
              event.end(tags, bounds);
            }
          },

            board = zeroArray((size[0] >> 5) * size[1]),
            bounds = null,
            n = words.length,
            i = -1,
            tags = [],
            data = words.map(function(d, i) {
              d.text = text.call(this, d, i);
              d.font = font.call(this, d, i);
              d.style = fontStyle.call(this, d, i);
              d.weight = fontWeight.call(this, d, i);
              d.rotate = rotate.call(this, d, i);
              d.size = ~~fontSize.call(this, d, i);
              d.padding = padding.call(this, d, i);
              return d;
            }).sort(function(a, b) {
              return b.size - a.size;
            });

          if (timer) { clearInterval(timer); }
          timer = setInterval(step, 0);
          step();

          return cloud;
        };

        cloud.stop = function() {
          if (timer) {
            clearInterval(timer);
            timer = null;
          }
          return cloud;
        };

        cloud.timeInterval = function(x) {
          if (!arguments.length) { return timeInterval; }
          timeInterval = x == null ? Infinity : x;
          return cloud;
        };

        function place(board, tag, bounds) {
          var startX = tag.x,
            startY = tag.y,
            maxDelta = Math.sqrt(size[0] * size[0] + size[1] * size[1]),
            s = spiral(size),
            dt = Math.random() < 0.5 ? 1 : -1,
            t = -dt,
            dxdy,
            dx,
            dy;

          while (dxdy = s(t += dt)) {
            dx = ~~dxdy[0];
            dy = ~~dxdy[1];

            if (Math.min(dx, dy) > maxDelta) { break; }

            tag.x = startX + dx;
            tag.y = startY + dy;

            if (tag.x + tag.x0 < 0 || tag.y + tag.y0 < 0 ||
              tag.x + tag.x1 > size[0] || tag.y + tag.y1 > size[1]) { continue; }
            // TODO only check for collisions within current bounds.
            if (!bounds || !cloudCollide(tag, board, size[0])) {
              if (!bounds || collideRects(tag, bounds)) {
                var sprite = tag.sprite,
                  w = tag.width >> 5,
                  sw = size[0] >> 5,
                  lx = tag.x - (w << 4),
                  sx = lx & 0x7f,
                  msx = 32 - sx,
                  h = tag.y1 - tag.y0,
                  x = (tag.y + tag.y0) * sw + (lx >> 5),
                  last;
                for (var j = 0; j < h; j++) {
                  last = 0;
                  for (var i = 0; i <= w; i++) {
                    board[x + i] |= (last << msx) | (i < w ? (last = sprite[j * w + i]) >>> sx : 0);
                  }
                  x += sw;
                }
                delete tag.sprite;
                return true;
              }
            }
          }
          return false;
        }

        cloud.words = function(x) {
          if (!arguments.length) { return words; }
          words = x;
          return cloud;
        };

        cloud.size = function(x) {
          if (!arguments.length) { return size; }
          size = [+x[0], +x[1]];
          return cloud;
        };

        cloud.font = function(x) {
          if (!arguments.length) { return font; }
          font = d3.functor(x);
          return cloud;
        };

        cloud.fontStyle = function(x) {
          if (!arguments.length) { return fontStyle; }
          fontStyle = d3.functor(x);
          return cloud;
        };

        cloud.fontWeight = function(x) {
          if (!arguments.length) { return fontWeight; }
          fontWeight = d3.functor(x);
          return cloud;
        };

        cloud.rotate = function(x) {
          if (!arguments.length) { return rotate; }
          rotate = d3.functor(x);
          return cloud;
        };

        cloud.text = function(x) {
          if (!arguments.length) { return text; }
          text = d3.functor(x);
          return cloud;
        };

        cloud.spiral = function(x) {
          if (!arguments.length) { return spiral; }
          spiral = spirals[x + ""] || x;
          return cloud;
        };

        cloud.fontSize = function(x) {
          if (!arguments.length) { return fontSize; }
          fontSize = d3.functor(x);
          return cloud;
        };

        cloud.padding = function(x) {
          if (!arguments.length) { return padding; }
          padding = d3.functor(x);
          return cloud;
        };

        return d3.rebind(cloud, event, "on");
      }

      function cloudText(d) {
        return d.text;
      }

      function cloudFont() {
        return "serif";
      }

      function cloudFontNormal() {
        return "normal";
      }

      function cloudFontSize(d) {
        return Math.sqrt(d.value);
      }

      function cloudRotate() {
        return (~~(Math.random() * 6) - 3) * 30;
      }

      function cloudPadding() {
        return 1;
      }

      // Fetches a monochrome sprite bitmap for the specified text.
      // Load in batches for speed.
      function cloudSprite(d, data, di) {
        if (d.sprite) { return; }
        c.clearRect(0, 0, (cw << 5) / ratio, ch / ratio);
        var x = 0,
          y = 0,
          w = 0,
          h = 0,
          maxh = 0,
          n = data.length;
        --di;
        while (++di < n) {
          d = data[di];
          c.save();
          c.font = d.style + " " + d.weight + " " + ~~((d.size + 1) / ratio) + "px " + d.font;
          w = c.measureText(d.text + "m").width * ratio;
          h = d.size << 1;
          if (d.rotate) {
            var sr = Math.sin(d.rotate * cloudRadians),
              cr = Math.cos(d.rotate * cloudRadians),
              wcr = w * cr,
              wsr = w * sr,
              hcr = h * cr,
              hsr = h * sr;
            w = (Math.max(Math.abs(wcr + hsr), Math.abs(wcr - hsr)) + 0x1f) >> 5 << 5;
            h = ~~Math.max(Math.abs(wsr + hcr), Math.abs(wsr - hcr));
          } else {
            w = (w + 0x1f) >> 5 << 5;
          }
          if (h > maxh) { maxh = h; }
          if (x + w >= (cw << 5)) {
            x = 0;
            y += maxh;
            maxh = 0;
          }
          if (y + h >= ch) { break; }
          c.translate((x + (w >> 1)) / ratio, (y + (h >> 1)) / ratio);
          if (d.rotate) { c.rotate(d.rotate * cloudRadians); }
          c.fillText(d.text, 0, 0);
          if (d.padding) { c.lineWidth = 2 * d.padding, c.strokeText(d.text, 0, 0); }
          c.restore();
          d.width = w;
          d.height = h;
          d.xoff = x;
          d.yoff = y;
          d.x1 = w >> 1;
          d.y1 = h >> 1;
          d.x0 = -d.x1;
          d.y0 = -d.y1;
          d.hasText = true;
          x += w;
        }
        var pixels = c.getImageData(0, 0, (cw << 5) / ratio, ch / ratio).data,
          sprite = [];
        while (--di >= 0) {
          d = data[di];
          if (!d.hasText) { continue; }
          w = d.width;
          var w32 = w >> 5;
          h = d.y1 - d.y0;
          // Zero the buffer
          for (var i = 0; i < h * w32; i++) { sprite[i] = 0; }
          x = d.xoff;
          if (x == null) { return; }
          y = d.yoff;
          var seen = 0,
            seenRow = -1;
          for (var j = 0; j < h; j++) {
            for (i = 0; i < w; i++) {
              var k = w32 * j + (i >> 5),
                m = pixels[((y + j) * (cw << 5) + (x + i)) << 2] ? 1 << (31 - (i % 32)) : 0;
              sprite[k] |= m;
              seen |= m;
            }
            if (seen) { seenRow = j; }
            else {
              d.y0++;
              h--;
              j--;
              y++;
            }
          }
          d.y1 = d.y0 + seenRow;
          d.sprite = sprite.slice(0, (d.y1 - d.y0) * w32);
        }
      }

      // Use mask-based collision detection.
      function cloudCollide(tag, board, sw) {
        sw >>= 5;
        var sprite = tag.sprite,
          w = tag.width >> 5,
          lx = tag.x - (w << 4),
          sx = lx & 0x7f,
          msx = 32 - sx,
          h = tag.y1 - tag.y0,
          x = (tag.y + tag.y0) * sw + (lx >> 5),
          last;
        for (var j = 0; j < h; j++) {
          last = 0;
          for (var i = 0; i <= w; i++) {
            if (((last << msx) | (i < w ? (last = sprite[j * w + i]) >>> sx : 0)) & board[x + i]) { return true; }
          }
          x += sw;
        }
        return false;
      }

      function cloudBounds(bounds, d) {
        var b0 = bounds[0],
          b1 = bounds[1];
        if (d.x + d.x0 < b0.x) { b0.x = d.x + d.x0; }
        if (d.y + d.y0 < b0.y) { b0.y = d.y + d.y0; }
        if (d.x + d.x1 > b1.x) { b1.x = d.x + d.x1; }
        if (d.y + d.y1 > b1.y) { b1.y = d.y + d.y1; }
      }

      function collideRects(a, b) {
        return a.x + a.x1 > b[0].x && a.x + a.x0 < b[1].x && a.y + a.y1 > b[0].y && a.y + a.y0 < b[1].y;
      }

      function archimedeanSpiral(size) {
        var e = size[0] / size[1];
        return function(t) {
          return [e * (t *= 0.1) * Math.cos(t), t * Math.sin(t)];
        };
      }

      function rectangularSpiral(size) {
        var dy = 4,
          dx = dy * size[0] / size[1],
          x = 0,
          y = 0;
        return function(t) {
          var sign = t < 0 ? -1 : 1;
          // See triangular numbers: T_n = n * (n + 1) / 2.
          switch ((Math.sqrt(1 + 4 * sign * t) - sign) & 3) {
            case 0:
              x += dx;
              break;
            case 1:
              y += dy;
              break;
            case 2:
              x -= dx;
              break;
            default:
              y -= dy;
              break;
          }
          return [x, y];
        };
      }

      // TODO reuse arrays?
      function zeroArray(n) {
        var a = [],
          i = -1;
        while (++i < n) { a[i] = 0; }
        return a;
      }

      var cloudRadians = Math.PI / 180,
        cw = 1 << 11 >> 5,
        ch = 1 << 11,
        canvas,
        ratio = 1;

      if (typeof document !== "undefined") {
        canvas = document.createElement("canvas");
        canvas.width = 1;
        canvas.height = 1;
        ratio = Math.sqrt(canvas.getContext("2d").getImageData(0, 0, 1, 1).data.length >> 2);
        canvas.width = (cw << 5) / ratio;
        canvas.height = ch / ratio;
      } else {
        // Attempt to use node-canvas.
        canvas = new Canvas(cw << 5, ch);
      }

      var c = canvas.getContext("2d"),
        spirals = {
          archimedean: archimedeanSpiral,
          rectangular: rectangularSpiral
        };
      c.fillStyle = c.strokeStyle = "red";
      c.textAlign = "center";

      if (typeof module === "object" && module.exports) { module.exports = cloud; }
//      else (d3.layout || (d3.layout = {})).cloud = cloud;
      else {
      	(d3.layout || (d3.layout = {})).cloud = cloud;
      }

    })();
  });
