#!/usr/bin/env ruby
#
# A Ruby dot plotter created by Nolan Eakins <sneakin@semanticgap.com>.
# Copyright (c) 2008 Nolan Eakins
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#

require 'rubygems'
require 'parse_tree'
require 'rmagick'

#
# This computes a dot plot between @alpha and @beta. It can be accessed using
# either #[] or #data. To create a dot plot you need two arrays which are
# then compared element by element. Each row in the dot plot represents one
# element in @alpha, and each column is an element in @beta. The dot at that
# position will be true if both elements match.
#
class DotPlot
  attr_reader :data
  
  def initialize(alpha, beta)
    @alpha = alpha
    @beta = beta
    
    compute!
  end
  
  def [](x, y)
    @data[y][x]
  end
  
  def width
    @data[0].length
  end
  
  def height
    @data.length
  end
  
  def compute!
    @data = @beta.collect { |a|
      @alpha.collect { |b|
        a == b
      }
    }
  end
end

#
# This DotPlot sends the two initializing strings through ParseTree so that
# Ruby source files can be compared at the token level.
#
class RubyDotPlot < DotPlot
  def initialize(alpha, beta)
    super(ParseTree.translate(alpha).flatten,
          ParseTree.translate(beta).flatten)
  end
end

class LineDotPlot < DotPlot
  def initialize(alpha, beta)
    super(alpha.split("\n"), beta.split("\n"))
  end
end

#
# This uses RMagick to produce a graphic using the data from a DotPlot.
#
class Plotter
  def initialize(plot)
    @plot = plot
  end
 
  #
  # Draws and saves the plot to {path}.
  #
  def plot(path)
    canvas = Magick::ImageList.new
    canvas.new_image(@plot.width, @plot.height)
    
    draw = Magick::Draw.new
    
    @plot.width.times { |x|
      @plot.height.times { |y|
        draw.point(x, y) if @plot[x, y]
      }
    }
    
    draw.draw(canvas)
    canvas.write(path)
  end
end

if __FILE__ == $0
  require 'optparse'
  
  def usage
    "Usage: #{$0} [--help] [options] alpha beta output"
  end
  
  options = {
    :plotter => LineDotPlot
  }
  
  OptionParser.new do |opts|
    opts.banner = usage
    opts.on("-r", "--ruby", "Use the RubyDotPlot") do |v|
      options[:plotter] = RubyDotPlot
    end
    
    opts.on("-l", "--lines", "Use the LineDotPlot") do |v|
      options[:plotter] = LineDotPlot
    end
    
    opts.on("-h", "--help", "Show this help") do |v|
      puts opts
      exit -1
    end
  end.parse!
  
  if ARGV.length != 3
    puts usage
    exit -1
  end

  puts "Plotting #{ARGV[0]} against #{ARGV[1]} to #{ARGV[2]}"
  plot = options[:plotter].new(File.read(ARGV[0]),
                         File.read(ARGV[1]))
  Plotter.new(plot).plot(ARGV[2])
end