class DiffDirs

# File lib/diff_dirs.rb, line 2
def self.diff_dirs(dir1, dir2)
  raise(ArgumentError, "Directories must be strings.") unless dir1.is_a?(String) && dir2.is_a?(String)
  
  dir1 = expand_path(dir1)
  dir2 = expand_path(dir2)
  
  cmd = "diff -qr #{dir1} #{dir2}"
  diff_result = execute(cmd)
  out = []
  diff_result.each_line do |line|
    line.chomp!
    out << diff_result_line_parse(dir1, dir2, line)
  end
  out
end

# File lib/diff_dirs.rb, line 58
def self.add_slash(path)
  path += "/" unless path[-1..-1] == "/"
  path
end

# File lib/diff_dirs.rb, line 19
def self.diff_result_line_parse(dir1, dir2, line)
  # New/Deleted files
  match = line.match(/^Only in ([^:]*): ([^$]*)$/)
  if match
    if match[1].starts_with?(dir1)
      return [:deleted, remove_dir_from_path("#{match[1]}/#{match[2]}", dir1)] # deleted from second dir
    elsif match[1].starts_with?(dir2)
      return [:new, remove_dir_from_path("#{match[1]}/#{match[2]}", dir2)] # new in second dir
    else
      raise "#{dir1} or #{dir2} didn't match #{match[1]}"
    end
    
  elsif line.match(/^Files\s/) && line.match(/\sdiffer$/) 
    # Example: Files api/Rakefile and testing/Rakefile differ
    # This should be done with a nice regexp but couldn't figure out how to match everything but the word "and"
    files = line.sub(/^Files\s/, "").sub(/\sdiffer$/,"").split(" and ")
    return [:modified] << remove_dir_from_path(files[0], dir1)
  end
  
  raise RuntimeError, "Cannot parse: #{line}"
end

# File lib/diff_dirs.rb, line 41
def self.execute(cmd)
  `#{cmd}`
end

# File lib/diff_dirs.rb, line 50
def self.expand_path(dir)
  if dir[0..0] == "~"
    File.expand_path(dir) 
  else
    dir
  end
end

# File lib/diff_dirs.rb, line 45
def self.remove_dir_from_path(path, dir)
  dir = add_slash(dir)
  path.sub(Regexp.new("^#{dir}"), "")
end