#!/usr/bin/ruby

require 'find'
require 'getoptlong'

EXTS = Regexp.compile('^.*\.(' + %w[
  h hh hpp H
  c cc cpp cxx C
  m mm M
  rb py pl sh
  lua
  scm hs lisp
  java cs
  js
  l ll y yy].join('|') + ')$')

OPTS = [
  [ '--exclude',        '-x', GetoptLong::REQUIRED_ARGUMENT ],
  [ '--no-blank-lines', '-n', GetoptLong::NO_ARGUMENT ],
  [ '--help',           '-h', GetoptLong::NO_ARGUMENT ]]

HELP = {
  '--exclude' => {
    :argument_placeholder => 'pattern',
    :help_text => 'exclude files matching glob pattern <pattern>'
  },
  '--no-blank-lines' => {
    :help_text => "don't count blank lines in source files"
  },
  '--help' => {
    :help_text => "this help text"
  }
}

opts = GetoptLong.new(*OPTS)

REGEXP_METACHARACTERS = '\\$^*(){}+.?'

exclusions = nil
blank_lines = true

opts.each do |opt, arg|
  if opt == '--exclude' then
    re = ''
    arg.each_byte do |b|
      if b == ?* then
        re += '.*'
      elsif b == ?? then
        re += '.'
      else
        if REGEXP_METACHARACTERS.include?(b) then
          re += '\\'
        end
        re << b
      end
    end
    re += '$'
    if exclusions then
      exclusions += "|(#{re})"
    else
      exclusions = "(#{re})"
    end
  elsif opt == '--no-blank-lines' then
    blank_lines = false
  elsif opt == '--help' then
    puts "Usage: #{$0} [options] [paths to search]\n\nOptions:"
    puts OPTS.map { |option|
      if option[-1] == GetoptLong::REQUIRED_ARGUMENT then
        joiner = " <#{HELP[option[0]][:argument_placeholder]}>\n    "
      elsif option[-1] == GetoptLong::OPTIONAL_ARGUMENT then
        joiner = " [#{HELP[option[0]][:argument_placeholder]}]\n    "
      elsif option[-1] == GetoptLong::NO_ARGUMENT then
        joiner = "\n    "
      end
      
      "    " + option[0..-2].map { |o| o + joiner }.join +
        "            " + HELP[option[0]][:help_text] + "\n"
    }.join("\n")
    puts
    exit
  end
end

if ARGV.size == 0 then
  ARGV << '.'
end

exclusions_re = if exclusions then Regexp.compile(exclusions) else nil end
lc = 0
ARGV.each do |root|
  Find.find(root) do |path|
    if exclusions_re && exclusions_re =~ path then
      Find.prune
      next
    end
    
    if EXTS =~ path then
      begin
        File.read(path).each_line do |line|
          unless line =~ /^\s+$/ && !blank_lines then
            lc += 1
          end
        end
      rescue => e
        $stderr.puts(e)
      end
    end
  end
end
puts lc