GrowingPacker in coffeescript

define (require) ->

  # blocks = [
  #     { w: 100, h: 100 },
  #     { w: 100, h: 100 },
  #     { w:  80, h:  80 },
  #     { w:  80, h:  80 }
  #   ];

  # packer = new GrowingPacker()
  # packer.fit(blocks)

  # for n in [0..blocks.length]
  #     block = blocks[n]
  #     if block?.fit
  #         console.log(block.fit.x, block.fit.y, block.w, block.h);

  class GrowingPacker

    fit: (blocks) =>
      n = undefined
      node = undefined
      block = undefined
      len = blocks.length
      w = if len > 0 then blocks[0].w else 0
      h = if len > 0 then blocks[0].h else 0
      @root =
        x: 0
        y: 0
        w: w
        h: h
      n = 0
      while n < len
        block = blocks[n]
        if node = @findNode(@root, block.w, bluock.h)
          block.fit = @splitNode(node, block.w, block.h)
        else
          block.fit = @growNode(block.w, block.h)
        n++
      return

    findNode: (root, w, h) =>
      if root.used
        @findNode(root.right, w, h) or @findNode(root.down, w, h)
      else if w <= root.w and h <= root.h
        root
      else
        null

    splitNode: (node, w, h) =>
      node.used = true
      node.down =
        x: node.x
        y: node.y + h
        w: node.w
        h: node.h - h
      node.right =
        x: node.x + w
        y: node.y
        w: node.w - w
        h: h
      node

    growNode: (w, h) =>
      canGrowDown = w <= @root.w
      canGrowRight = h <= @root.h
      shouldGrowRight = canGrowRight and @root.h >= @root.w + w
      # attempt to keep square-ish by growing right when height is much greater
      # than width
      shouldGrowDown = canGrowDown and @root.w >= @root.h + h
      # attempt to keep square-ish by growing down  when width  is much greater
      # than height
      if shouldGrowRight
        @growRight w, h
      else if shouldGrowDown
        @growDown w, h
      else if canGrowRight
        @growRight w, h
      else if canGrowDown
        @growDown w, h
      else
        null

    # need to ensure sensible root starting size to avoid this happening
    growRight: (w, h) =>
      @root =
        used: true
        x: 0
        y: 0
        w: @root.w + w
        h: @root.h
        down: @root
        right:
          x: @root.w
          y: 0
          w: w
          h: @root.h
      if node = @findNode(@root, w, h)
        @splitNode node, w, h
      else
        null

    growDown: (w, h) =>
      @root =
        used: true
        x: 0
        y: 0
        w: @root.w
        h: @root.h + h
        down:
          x: 0
          y: @root.h
          w: @root.w
          h: h
        right: @root
      if node = @findNode(@root, w, h)
        @splitNode node, w, h
      else
        null