# From rails (http://rubyonrails.com)
#
# Improved by murphy
class CodeStatistics

  TEST_TYPES = /\btest/i

  # Create a new Code Statistic.
  #
  # Rakefile Example:
  #
  #  desc 'Report code statistics (LOC) from the application'
  #  task :stats => :copy_files do
  #    require 'rake_helpers/code_statistics'
  #    CodeStatistics.new(
  #      ["Main", "lib"],
  #      ["Tests", "test"],
  #      ["Demos", "demo"]
  #    ).to_s
  #   end
  def initialize(*pairs)
    @pairs = pairs
    @statistics = calculate_statistics
    @total = if pairs.empty? then nil else calculate_total end
  end

  # Print a textual table viewing the stats
  #
  # Intended for console output.
  def print
    print_header
    @pairs.each { |name, path| print_line name, @statistics[name] }
    print_splitter

    if @total
      print_line 'Total', @total
      print_splitter
    end

    print_code_test_stats
  end

private

  DEFAULT_FILE_PATTERN = /\.rb$/

  def calculate_statistics
    @pairs.inject({}) do |stats, (name, path, pattern, is_ruby_code)|
      pattern ||= DEFAULT_FILE_PATTERN
      path = File.join path, '*.rb'
      stats[name] = calculate_directory_statistics path, pattern, is_ruby_code
      stats
    end
  end

  def calculate_directory_statistics directory, pattern = DEFAULT_FILE_PATTERN, is_ruby_code = true
    is_ruby_code = true if is_ruby_code.nil?
    stats = Hash.new 0

    Dir[directory].each do |file_name|
      p "Scanning #{file_name}..." if $VERBOSE
      next unless file_name =~ pattern

      lines = codelines = classes = modules = methods = 0
      empty_lines = comment_lines = 0
      in_comment_block = false

      File.readlines(file_name).each do |line|
        lines += 1
        if line[/^\s*$/]
          empty_lines += 1
        elsif is_ruby_code
          case line
          when /^=end\b/
            comment_lines += 1
            in_comment_block = false
          when in_comment_block
            comment_lines += 1
          when /^\s*class\b/
            classes += 1
          when /^\s*module\b/
            modules += 1
          when /^\s*def\b/
            methods += 1
          when /^\s*#/
            comment_lines += 1
          when /^=begin\b/
            in_comment_block = false
            comment_lines += 1
          when /^__END__$/
            in_comment_block = true
          end
        end
      end

      codelines = lines - comment_lines - empty_lines

      stats[:lines] += lines
      stats[:comments] += comment_lines
      stats[:codelines] += codelines
      stats[:classes] += classes
      stats[:modules] += modules
      stats[:methods] += methods
      stats[:files] += 1
    end

    stats
  end

  def calculate_total
    total = Hash.new 0
    @statistics.each_value { |pair| pair.each { |k, v| total[k] += v } }
    total
  end

  def calculate_code
    code_loc = 0
    @statistics.each { |k, v| code_loc += v[:codelines] unless k[TEST_TYPES] }
    code_loc
  end

  def calculate_tests
    test_loc = 0
    @statistics.each { |k, v| test_loc += v[:codelines] if k[TEST_TYPES] }
    test_loc
  end

  def print_header
    print_splitter
    puts "| T=Test  Name              | Files | Lines |   LOC | Comments | Classes | Modules | Methods | M/C | LOC/M |"
    print_splitter
  end

  def print_splitter
    puts "+---------------------------+-------+-------+-------+----------+---------+---------+---------+-----+-------+"
  end

  def print_line name, statistics
    m_over_c = (statistics[:methods] / (statistics[:classes] + statistics[:modules])) rescue m_over_c = 0
    loc_over_m = (statistics[:codelines] / statistics[:methods]) - 2 rescue loc_over_m = 0

    if name[TEST_TYPES]
      name = "T #{name}"
    else
      name = "  #{name}"
    end

    line = "| %-25s | %5d | %5d | %5d | %8d | %7d | %7d | %7d | %3d | %5d |" % (
      [name, *statistics.values_at(:files, :lines, :codelines, :comments, :classes, :modules, :methods)] +
      [m_over_c, loc_over_m] )

    puts line
  end

  def print_code_test_stats
    code = calculate_code
    tests = calculate_tests

    puts "  Code LOC = #{code}     Test LOC = #{tests}     Code:Test Ratio = [1 : #{sprintf("%.2f", tests.to_f / code)}]"
    puts ""
  end

end

# Run a test script.
if $0 == __FILE__
  $VERBOSE = true
  CodeStatistics.new(
    ['This dir', File.dirname(__FILE__)]
  ).print
end