#!/usr/bin/env ruby

# Copyright (C) 2005 SIPfoundry Inc.
# Licensed by SIPfoundry under the LGPL license.
# 
# Copyright (C) 2005 Pingtel Corp.
# Licensed to SIPfoundry under a Contributor Agreement.

require 'getoptlong'
require 'tempfile'

class Setup

  attr_accessor :previous
  attr_accessor :current

  # Default implementation is a Redhat system
  def initialize(system)
    @system = system
  end

  def verbose=(enabled)
    @system.verbose = enabled
  end
  

  def upgrade
    raise "previous and current parameters required" unless previous && current

    @system.unresolved(current).each do |file|
      if resolve(file)
        @system.mark_resolved(file)
      end
    end
  end

  def show_unresolved
    raise "current parameters required" unless current
    @system.unresolved(current).each do |file|
      @system.console file
    end
  end

  def resolve(file)
    patch = create_patch(file)
    if patch != ''
      if @system.test_patch(file, patch)
        @system.apply_patch(file, patch)
        return true
      end
    end
    return false
  end

  def create_patch(file)
    tar_file=file[1..-1]
    current_file = @system.extract_file(current, tar_file)
    previous_file = @system.extract_file(previous, tar_file)
    patch = @system.create_patch(previous_file, current_file)
    @system.delete_file(current_file)
    @system.delete_file(previous_file)
    return patch
  end

end

# commands AND so calls can be stubbed out for unitttests 
class SystemService
  @@patch = 'patch'
  @@diff = 'diff'
  @@tar = 'tar'

  attr_accessor :verbose

  def initialize()
    verbose = false
  end

  alias oldBackquote `
  def `(cmd)
    if verbose
      puts cmd
    end
    return oldBackquote(cmd)
  end

  def unresolved(archive)
    unresolved = []
    raise "File missing #{archive}" unless File.exists?(archive)
    `tar -tzf #{archive}`.each do |file|
       filename = '/' + file.chomp
       if File.exist?(filename + '.rpmnew')
         unresolved.push filename
       end
    end
    return unresolved
  end

  def console(msg)
    puts msg if verbose
    return msg
  end

  def mark_resolved(file)
    File.delete(file + '.rpmnew')
  end

  def create_patch(file1, file2)
    patch = `#{@@diff} --unified #{file1} #{file2} 2>/dev/null`
    rc = "#{$?}"
    return rc != '2' ? patch : ''
  end

  def delete_file(file) 
    File.delete(file)
  end

  def test_patch(file, patch)
    cmd = console("#{@@patch} --unified --forward --dry-run #{file} 1>& 2>/dev/null")
    IO.popen(cmd, "w") {|pipe|
      pipe.puts patch
    }
    rc = "#{$?}"

    return rc == '0'
  end

  def apply_patch(file, patch)
    stat = File.stat(file)
    cmd = console("#{@@patch} --unified --forward \"#{file}\" 1>& 2>/dev/null")
    IO.popen(cmd, "w") {|pipe|
      pipe.puts patch
    }
    File.chown(stat.uid, stat.gid, file)
  end

  def extract_file(archive, file)
    extract = Tempfile.new('pkg-upgrade').path
    `tar --to-stdout -xzf "#{archive}" "#{file}" > #{extract} 2>/dev/null`
    return extract
  end
    
end

def usage_exit(error_code=1)
      usage = <<__EOU__

  Usage: #{ $0 } parameters

    Utilities to upgrade a package's configuration files

  Parameters:
     --help             This help text
     --verbose          Verbose output
     --previous         Name of archive containing pristine copies of
                          previous configuration
     --current          Name of archive containing pristine copies of
                          current configuration
__EOU__

      STDERR << usage
      exit error_code
end

if __FILE__ == $0
  # XPB-863 - used to ensure patch command forces config files to
  # -rw-r--r-- permission bits
  File.umask(022)

  OptSet = [
    ['--previous','-p', GetoptLong::REQUIRED_ARGUMENT],
    ['--current','-c', GetoptLong::REQUIRED_ARGUMENT],
    ['--show-unresolved','-u', GetoptLong::NO_ARGUMENT],
    ['--verbose','-v', GetoptLong::NO_ARGUMENT],
    ['--help','-h', GetoptLong::NO_ARGUMENT],
  ]

  setup = Setup.new(SystemService.new)
  opts = GetoptLong.new(*OptSet)
  begin
    action = 'upgrade'
    opts.each do |name, arg|
      case name
        when '--help'
          usage_exit 0
        when '--previous'
          setup.previous = arg
        when '--current'
          setup.current = arg
        when '--show-unresolved'
          action = 'show_unresolved'
        when '--verbose'
          setup.verbose = true
        else
          usage_exit
        end
    end
    
  rescue
    usage_exit
  end

  begin
  setup.send(action)

  end
end