# pgen.rb
# by Jesse H-K on Thursday, June 15 2006

require 'optparse'

class Array
    def random_choice
        self[rand(self.length)]
    end
end

def parse_options(args)
    options = {}
 
    options[:length] = 10

    opts = OptionParser.new do |opts|
        opts.banner = "Usage: pgen.rb [options]"

        opts.on("-n",
                "--numbers",
                "Include the digits [0-9] in the password.") do |n|
                    options[:numb] = n
                end
        
        opts.on("-p",
                "--punctuation",
                "Include common punctuation characters in the password.") do |p|
                    options[:punct] = p
                end
        
        opts.on("-u",
                "--uppercase",
                "Include uppercase letters in the password.") do |u|
                    options[:upcase] = u
                end

        opts.on("-l",
                "--length=[LENGTH]",
                Integer,
                "The length of the password. Default is 10 characters.") do |l|
                    options[:length] = l
                end
    end

    opts.parse!
    options
end

class PasswordGenerator
    @@options = { :numb  => ('0'..'9').to_a,
                  :punct    => %w(. , ! ? @ & :),
                  :upcase   => ('A'..'Z').to_a }

    def initialize(length, *opts)
        @possible = *('a'..'z')
        @length = length

        parse_content_options(opts) 
    end

    def parse_content_options(opts)
        opts.each { |opt| @possible.concat(@@options[opt]) if @@options.key? opt }
    end 

    def generate
        (1..@length).inject("") { |passwd, e| passwd << @possible.random_choice }
    end

    private :parse_content_options
end
        
options = parse_options(ARGV)

puts PasswordGenerator.new(options[:length], *options.keys).generate