#!/usr/bin/env ruby
#
# Generates code for a command line application
#
# Usage: generate
#

class MainClass
  
  attr_accessor :name, :outfile, :opts

  def initialize
    @opts = []
  end

  def add_opt(name,takes_argument,description)
    @opts << Opt.new(name,takes_argument,description)
  end
end

class Opt
  attr_accessor :name,:takes_argument,:description
  def initialize(name,takes_argument,description)
    @name = name
    @takes_argument = takes_argument
    @description = description
  end
end

class Generate

  attr_writer :verbose

  def initialize
    @verbose = false
  end

  def start(args)
    begin
      validate_args args
    rescue Exception => e
      STDERR.puts e
      print_help
      return
    end

    v = MainClass.new
    puts "Please enter the following infomation or type \'q\' to quit...\n\n"

    # class name
    v.name = make_classname(args.empty? ? prompt('classname') : args.shift)

    # output file
    v.outfile = make_filename(prompt('outfile or \'stdout\'',make_filename(v.name)))

    # options
    while true
      pre = 'option #' + (v.opts.length+1).to_s + ' '
      name = prompt pre + 'name (blank for none)'
      break if !name || name == ''
      takes_arg = make_boolean(prompt(pre + 'takes argument [y/N]'))
      description = prompt pre + 'description'
      v.add_opt name,takes_arg,description
    end

    # output file
    output_make_class v
  end

  def print_help
    STDERR.puts 'Usage: ' + File.basename(__FILE__) + " <option>? <argument>?"
    STDERR.puts 'where <options> include:'
    STDERR.puts ' -h || --help        print this message'
    STDERR.puts ' -v || --verbose     use verbose logging statements'
    STDERR.puts 'and <arguments> include:'
    STDERR.puts ' <classname>? name of the class to create'
  end

  private

  # writes 'v' to v.outfile or STDOUT if v.outfile = 'stdout'
  def output_make_class(v)
    s = gen_output v
    if v.outfile == 'stdout.rb'
      puts s
    else
      File.open v.outfile, "w" do |f|
        f.puts s
      end
      begin
        system "chmod +x " + v.outfile
      rescue
      end
    end
  end

  # Returns the output string for main class
  def gen_output(v)
    s = ''
    
    # main class
    s += <<HERE;
#!/usr/bin/env ruby

class #{v.name}
  
  attr_writer :verbose
HERE
  
  s += v.opts.map { |opt| "  attr_writer :#{opt.name}" }.join("\n")
  s += "\n"

  s += <<HERE;

  def initialize
    @verbose = false
HERE

    s += v.opts.map { |opt| "    @" + opt.name + " = " + (opt.takes_argument ? "nil" : "false") }.join("\n")
    s += "\n"

    s += <<HERE;
  end

  def start(args)
    begin
      validate_args args
    rescue Exception => e
      STDERR.puts e
      print_help
      return
    end

    # TODO: Start here
  end

  def print_help
    STDERR.puts 'Usage: ' + File.basename(__FILE__) + " <option>? <argument>?"
    STDERR.puts 'where <options> include:'
    STDERR.puts ' -h     || --help            print this message'
    STDERR.puts ' -v     || --verbose         use verbose logging statements'
HERE
    
    v.opts.each do |opt|
      opt_str = '    STDERR.puts \' -' + opt.name[0,1] + ' '
      opt_str += opt.takes_argument ? '<s>' : '   '
      opt_str += ' || --' + opt.name + ' '
      opt_str += opt.takes_argument ? '<s>' : '   '
      while opt_str.length < 46
        opt_str += ' '
      end
      opt_str += opt.description + '\''
      s += opt_str + "\n"
    end

    s += <<HERE;
    STDERR.puts 'and <arguments> include:'
    # TODO: fill in arguments
HERE

    s += <<HERE;
  end

  def validate_args(args)
    # TODO: validate args
  end

  def log(s)
    STDERR.puts s if @verbose
  end

end
HERE

    # main method
    s += <<HERE;

# --------------------------------------------------
# Main
# --------------------------------------------------

def main(argv)

  v = #{v.name}.new

  args = []
  while !argv.empty?
    arg = argv.shift
    if arg == '-h' || arg =~ /-help/
      v.print_help
      exit 0
    elsif arg == '-v' || arg =~ /-verbose/
      v.verbose = true
HERE

    v.opts.each do |opt|
        s += "    elsif arg == '-" + opt.name[0,1] + "' || arg =~ /-" + opt.name + "/\n"
        s += "      v.#{opt.name} = "
        if opt.takes_argument
          s += "argv.shift"
        else
          s += "true"
        end
        s += "\n"
    end

      s += <<HERE;
    else
      args.push arg
    end
  end

  v.start args

end

main ARGV
HERE

    return s
  end

  # http://api.rubyonrails.com/classes/Inflector.html#M001629
  def camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)
    if first_letter_in_uppercase
      lower_case_and_underscored_word.to_s.gsub(/\/(.?)/) { "::" + $1.upcase }.gsub(/(^|_)(.)/) { $2.upcase }
    else
      lower_case_and_underscored_word.first + camelize(lower_case_and_underscored_word)[1..-1]
    end
  end

  # Returns a boolean is 's' is 'yes', 'true', etc
  def make_boolean(s)
    return false if !s
    return false if s == ''
    t = s.downcase
    nos = ['y','yes','t','true']
    nos.each do |no|
      return true if t == no
    end
    return false
  end
  
  # Returns a name that is better for a class
  def make_classname(s)
    return s if !s
    return s if s == ''
    res = camelize s.downcase.gsub(/\s/,'_')
    log 'Using class ' + res
    return res
  end

  # Returns a file name for given class name
  def make_filename(s)
    res = s.downcase.gsub(/\.rb.*/,'') + '.rb'
    log 'Using file ' + res
    return res
  end

  def prompt(msg,default_value=nil)
    s = ''
    while s == ''
      print msg
      print ' [' + default_value + ']' if default_value
      print '> '
      s = gets
      if s == 'q' || s == 'quit'
        log 'Quitting...'
        exit 0
      end
      s.strip!
      if s == ''
        s = default_value
      end
    end
    return s
  end

  def note(s)
    puts s
  end

  def validate_args(args)

  end

  def log(s)
    STDERR.puts s if @verbose
  end
end

# --------------------------------------------------
# Main
# --------------------------------------------------

def main(argv)

  v = Generate.new

  args = []
  while !argv.empty?
    arg = argv.shift
    if arg == '-h' || arg =~ /-help/
      v.print_help
      exit 0
    elsif arg == '-v' || arg =~ /-verbose/
      v.verbose = true
    else
      args.push arg
    end
  end

  v.start args

end

main ARGV