#!/usr/bin/env ruby

require 'yaml'
require 'optparse'

require 'mustache'
require 'mustache/version'

class Mustache
  class CLI
    # Return a structure describing the options.
    def self.parse_options(args)
      opts = OptionParser.new do |opts|
        opts.banner = "Usage: mustache [-c] [-t] [-r library] FILE ..."

        opts.separator " "

        opts.separator "Examples:"
        opts.separator "  $ mustache data.yml template.mustache"
        opts.separator "  $ cat data.yml | mustache - template.mustache"
        opts.separator "  $ mustache -c template.mustache"

        opts.separator " "

        opts.separator "  See mustache(1) or " +
          "http://mustache.github.com/mustache.1.html"
        opts.separator "  for more details."

        opts.separator " "
        opts.separator "Options:"

        opts.on("-c", "--compile FILE",
          "Print the compiled Ruby for a given template.") do |file|
          puts Mustache::Template.new(File.read(file)).compile
          exit
        end

        opts.on("-t", "--tokens FILE",
          "Print the tokenized form of a given template.") do |file|
          require 'pp'
          pp Mustache::Template.new(File.read(file)).tokens
          exit
        end

        opts.on('-r', '--require LIB', 'Require a Ruby library before running.') do |lib|
          require lib
        end

        opts.separator "Common Options:"

        opts.on("-v", "--version", "Print the version") do |v|
          puts "Mustache v#{Mustache::Version}"
          exit
        end

        opts.on_tail("-h", "--help", "Show this message") do
          puts opts
          exit
        end
      end

      opts.separator ""

      opts.parse!(args)
    end

    # Does the dirty work of reading files from the command line then
    # processing them. The meat of this script, if you will.
    def self.process_files(input_files)
      doc = input_files.file.read

      yaml = nil
      begin
        yaml = YAML.load_stream(doc)
      rescue
        abort "Unable to parse yaml!"
      end

      if yaml.nil?
        puts Mustache.render(doc)
      else
        template = input_files.skip.file.read

        puts Mustache.render template, yaml.compact.reduce(&:merge)
      end
    end
  end
end

# Help is the default.
ARGV << '-h' if ARGV.empty? && $stdin.tty?

# Process options
Mustache::CLI.parse_options(ARGV) if $stdin.tty?

# Still here - process rest of ARGF
Mustache::CLI.process_files(ARGF)