# Copyright (C) 2011-2012 RightScale, Inc, All Rights Reserved Worldwide.
#
# THIS PROGRAM IS CONFIDENTIAL AND PROPRIETARY TO RIGHTSCALE
# AND CONSTITUTES A VALUABLE TRADE SECRET. Any unauthorized use,
# reproduction, modification, or disclosure of this program is
# strictly prohibited. Any use of this program by an authorized
# licensee is strictly subject to the terms and conditions,
# including confidentiality obligations, set forth in the applicable
# License Agreement between RightScale.com, Inc. and
# the licensee

require 'shellwords'

module RightConf

  class Command

    include Singleton
    include ProgressReporter

    # Execute given command with given arguments
    #
    # === Parameters
    # command(String):: Command to run
    # args(Array):: Command arguments
    #
    # === Options
    # abort_on_failure(bool):: Whether to raise an exception in case command
    #                          returns an error (false by default)
    # env:: Hash of environment variables keyed by name
    #
    # === Return
    # result(CommandResult):: Result of execution (output and exit status)
    def execute(command, *args)
      opts = {}
      if !args.empty? && args[-1].is_a?(Hash)
        opts = args[-1]
        args = args[0..-2]
      end
      res = Platform.dispatch(command, opts[:env], *args) { :execute }
      if @verbose
        msg = ([command] + args).compact.join(' ') + ' => ' +
          res.status.to_s + ': ' + res.output
        report("[rconf] " + msg)
      end
      if !res.success? && msg = opts[:abort_on_failure]
        report_fatal("#{msg}: '#{command} #{args.join(' ')}' returned\n#{res.output}")
      end
      res
    end

    # Execute command in context of activated ruby
    #
    # === Parameters
    # command(String):: Command to run
    # args(Array):: Command arguments
    #
    # === Options
    # abort_on_failure(bool):: Whether to raise an exception in case command
    #                          returns an error (false by default)
    # env:: Hash of environment variables keyed by name
    #
    # === Return
    # result(CommandResult):: Result of execution (output and exit status)
    def execute_in_ruby(command, *args)
      report_fatal('Failed to run in ruby context, no ruby specified') unless @ruby_version
      opts = {}; env = {}
      if args[-1].is_a?(Hash)
        opts = args.pop
        env = opts[:env] || {}
      end
      env.merge!({ 'RBENV_VERSION' => @ruby_version })
      opts.merge!({ :env => env })
      args.push(opts)

      execute(command, *args)
    end

    # Execute given command with given arguments using 'sudo'
    #
    # === Parameters
    # command(String):: Command to run
    # args(Array):: Command arguments
    #
    # === Return
    # result(CommandResult):: Result of execution (output and exit status)
    def sudo(*args)
      args = args.unshift('/usr/bin/sudo')
      Command.execute(*args)
    end

    # Execute given command on *nix systems
    #
    # === Parameters
    # command(String):: Command name
    # env(Hash):: Hash of environment variables keyed by name
    # params(Array):: List of parameters to pass to command
    #
    # === Return
    # result(CommandResult):: Result of execution (output and exit status)
    def execute_linux(command, env, *args)
      env ||= {}
      old_envs = env.keys.inject({}) { |o, k| o[k] = ENV[k]; o }
      env.each { |k, v| ENV[k] = v.to_s }
      out = `#{Shellwords.join([command, *args])} 2>&1`
      old_envs.each { |k, v| ENV[k] = v }
      result = CommandResult.new(out, $?.exitstatus)
    end
    alias :execute_darwin :execute_linux

    # Execute given command on Windows systems
    #
    # === Parameters
    # command(String):: Command name
    # env(Hash):: Hash of environment variables keyed by name
    # params(Array):: List of parameters to pass to command
    #
    # === Return
    # result(CommandResult):: Result of execution (output and exit status)
    def execute_windows(command, env, *args)
      raise 'TBD!'
    end

    # Set ruby to be used by 'execute_in_ruby'
    #
    # === Parameters
    # version(String):: rbenv ruby version
    #
    # === Return
    # true:: Always return true
    def set_ruby(version)
      @ruby_version = version
      true
    end

    # Enable debug output
    #
    # === Return
    # true:: Always return true
    def set_verbose
      @verbose = true
    end

  end

  # Command results
  class CommandResult

    # Process output
    attr_reader :output

    # Process exit status
    attr_reader :status

    # Initialize output and exit status
    #
    # === Parameters
    # output(String):: Process output
    # status(Fixnum):: Process exit status
    def initialize(output, status)
      @output = output
      @status = status
    end

    # Whether process exited successfully
    #
    # === Return
    # true:: If process exited with status code 0
    # false:: Otherwise
    def success?
      @status == 0
    end

  end

end