#!/usr/bin/env ruby
 
# Author: MadX <root+gp2sass@yapok.org>
# License: Public domain
 
require 'optparse'
require 'ostruct'
 
# Command line option parser (relies on optparse)
class G2SOptionParser
 
  Version = [1, 0]
 
  def self.parse(args)
    options = OpenStruct.new
    options.output  = $stdout
    options.mode    = :overwrite
    options.verbose = false
    options.notify  = true
    
    opts = OptionParser.new do |opts|
      opts.banner = "Usage: gp2sass [options] source_file"
      
      opts.separator ""
      opts.separator "Specific options:"
      
      opts.on('-o', '--output [FILE]', 'Output contents in FILE') do |file|
        options.output = file
      end
      
      opts.on('-p', '--prepend', 'Prepend to the selected file') do |p|
        options.mode = :prepend
      end
      
      opts.on('-a', '--append', 'Append to the seleced file') do |a|
        options.mode = :append
      end
      
      opts.on('-n', '--[no-]notify', 'Put a loud comment in the sass output',
        'to notify the success') do |n|
        options.notify = n
      end
      
      opts.on('-v', '--[no-]verbose', 'Run verbosely') do |v|
        options.verbose = v
      end
      
      opts.separator ""
      opts.separator "Common options:"
      
      opts.on_tail("-h", "--help", "Show this message") do
        puts opts
        puts  "\nDescription:",
          "  gp2sass is a command line tool to convert Gimp palette files (gpl)",
          "  to a Sass constant set."
          
        puts "\nExample:",
          "  Try the following command (if you have The Gimp installed):",
          "", "    gp2sass Tango",
          ""
        exit
      end
 
      opts.on_tail("--version", "Show version") do
        puts "gp2sass v#{Version.join('.')}"
        exit
      end
      
    end
    
    opts.parse!(args)
    options
  end # self.parse()
 
end # G2SOptionParser
 
# Parse ARGV :)
source  = ARGV[-1]
options = G2SOptionParser.parse(ARGV[0..(ARGV.length - 1)])
 
# Yes, the program begins \o/
begin
 
  # Guess the source or raise an error if no file matches
  if source.nil? then raise "Usage: gp2sass [options] source_file" end
  searchable_dirs = [
    '.', 
    '~/.gimp-2.4/palettes/',
    '~/.gimp-2.2/palettes/',
    '/usr/share/gimp/2.0/palettes'
  ].collect{|path| File.expand_path(path) }
  path = nil
  source = File.basename(source, '.gpl') + '.gpl'
  if options.verbose  
    puts "Searching %s in" % source
    searchable_dirs.each {|d| puts "  #{File.expand_path(d)}"}
  end
  searchable_dirs.each do |dir|
    path = File.join(dir, source )
    if File.exists?(path) then break else path = nil end
  end
  raise 'File "%s" not found' % source if path.nil?
  
  puts "File found: %s" % path if options.verbose
  
  # Open the palette file and parse it
  header, *data = File.read(path).split('#')
  palette = OpenStruct.new
  palette.name = header.gsub(/.*Name: ([^\n]+).*/m, '\1')
  palette.colors = {}
  data.join.strip.each_line do |line|
    digits, name = line.split("\t")
    name = name.downcase.gsub(/ +/, '_').strip
    palette.colors[name] = digits.scan(/\S+/).collect {|c| "%02x" % c.to_i }
  end
  output = options.notify ? "/* %s palette imported#{$/}" % palette.name : ''
  palette.colors.each do |name, hexes|
    output += "!%s = #%s%s%s#{$/}" % ([name] + hexes)
  end
  if options.verbose
    puts "Palette file parsed, output will look like :"
    puts output.split($/).collect {|l| l = "  #{l}"}.join($/)
  end
  if options.output == $stdout
    puts output
  else
    if options.verbose && !File.exists?(options.output)
      puts "File %s doesn't exist, creating it" % options.output
    end
    if File.exists?(options.output) 
      buf = File.read(options.output) 
      puts "Saving file contents" if options.verbose
    else 
      buf = nil 
    end
    f = File.open(options.output, 'w+')
    puts 'Opening "%s"' % options.output if options.verbose
    case options.mode
      when :prepend
        msg = "Prepending output to file contents"
        output = "#{output}#{$/}#{buf}"
      when :append
        msg = "Appending output to file contents"
        output = "#{buf}#{$/}#{output}"
      else
        msg = "Overwriting file contents"
    end
    puts msg if options.verbose
    f.write(output)
    f.close
    puts "Finished." if options.verbose
  end
  
rescue => e
  puts e.message
  exit
end