require 'optparse'

# Run the command given by the first argument.  Right
# now all we have is deployments. We hope to have other
# kinds of events here later.
$LOAD_PATH << "#{File.dirname(__FILE__)}/.."
module NewRelic
  class Command
    attr_accessor :leftover
    # Capture a failure to execute the command.
    class CommandFailure < StandardError
      attr_reader :options
      def initialize message, opt_parser=nil
        super message
        @options = opt_parser
      end
    end

    def info(message)
      STDOUT.puts message
    end

    def err(message)
      STDERR.puts message
    end

    def initialize(command_line_args)
      if Hash === command_line_args
        # command line args is an options hash
        command_line_args.each do | key, value |
          instance_variable_set "@#{key}", value.to_s if value
        end
      else
        # parse command line args.  Throw an exception on a bad arg.
        @options = options do | opts |
          opts.on("-h", "Show this help") {  raise CommandFailure, opts.to_s }
        end
        @leftover = @options.parse(command_line_args)
      end
    rescue OptionParser::ParseError => e
      raise CommandFailure.new(e.message, @options)
    end

    @commands = []
    def self.inherited(subclass)
      @commands << subclass
    end

    cmds = File.expand_path(File.join(File.dirname(__FILE__), 'commands', '*.rb'))
    Dir[cmds].each{|command| require command }

    def self.run

      @command_names = @commands.map{ |c| c.command }

      extra = []
      options = ARGV.options do |opts|
        script_name = File.basename($0)
        if script_name =~ /newrelic_cmd$/
          $stdout.puts "warning: the 'newrelic_cmd' script has been renamed 'newrelic'"
          script_name = 'newrelic'
        end
        opts.banner = "Usage: #{script_name} [ #{ @command_names.join(" | ")} ] [options]"
        opts.separator "use '#{script_name} <command> -h' to see detailed command options"
        opts
      end
      extra = options.order!
      command = extra.shift
      # just make it a little easier on them
      command = 'deployments' if command =~ /deploy/
      if command.nil?
        STDERR.puts options
      elsif !@command_names.include?(command)
        STDERR.puts "Unrecognized command: #{command}"
        STDERR.puts options
      else
        command_class = @commands.find{ |c| c.command == command}
        command_class.new(extra).run
      end
    rescue OptionParser::InvalidOption => e
      raise NewRelic::Command::CommandFailure, e.message
    end
  end

end