# Copyright (C) 2011 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

module RightConf

  class EnvironmentUpdater

    include ProgressReporter

    # Update bash resource or profile file to define given environment variable
    # or append to existing environment variable
    #
    # === Parameters
    # code(String):: Code to be inserted in bash resource file
    # dependencies(Array):: List of environment variables that code will update
    #                       (Use to put code after these env var are set in the
    #                       existing bash resource file)
    #
    # === Return
    # true:: If bash resource or profile file was updated
    # false:: Otherwise
    def self.update(code, dependencies=[])
      new.do_update(code, dependencies)
    end

    # Update bash resource or profile file to define given environment variable
    # or append to existing environment variable
    #
    # === Parameters
    # code(String):: Code to be inserted in bash resource file
    # dependencies(Array):: List of environment variables that code will update
    #                       (Use to put code after these env var are set in the
    #                       existing bash resource file)
    #
    # === Return
    # true:: If bash resource or profile file was updated
    # false:: Otherwise
    def do_update(code, dependencies=[])
      if Platform.darwin?
        candidates = [ '.bash_profile' ]
      else
        candidates = ['.bash_profile', '.bashrc']
      end
      candidates.map! { |c| File.join(ENV['HOME'], c) }
      bashrc_path = candidates.detect { |c| File.exist?(c) }
      updated = false
      if bashrc_path
        content = IO.read(bashrc_path)
        unless content.include?(code) 
          i = dependencies.inject(nil) do |m, d|
            index = content.index(/^\s*#{d}=/)
            m = if m.nil?
              index
            else
              if index.nil?
                m
              else
                [ index, m ].max
              end
            end
          end
          if i
            next_line = content.index("\n", i + 1)
            if next_line
              content.insert(next_line + 1, code + "\n")
            else
              content += "\n" + code
            end
          else
            content = code + "\n" + content
          end
          FileUtils.mv(bashrc_path, bashrc_path + '.old')
          File.open(bashrc_path, 'w') { |f| f.puts content }
          updated = true
        end
      else
        report_error "Failed to update bash resource or profile: file not found"
      end
    end

  end
end