=begin

  Subversion tag support for Capistrano 2.

  * Place this file somewhere in your Rails app (for example in lib/tasks/capistrano_svn_tags.rb).
  * Load it in your Capfile, for example 
      load 'lib/tasks/capistrano_svn_tags'
    If you load the default Capistrano recipe (load 'config/deploy') make sure 
    this file is loaded before it!
  * Create a tag of a stable version of your code, for example 
      svn cp http://dev.example.com/svn/pimpr/trunk \
                 http://dev.example.com/svn/pimpr/tags/v1.5
    The library assumes standard subversion repository layout, i.e. tags reside in 'tags' directory.
    If you keep your releasable versions in another directory, for example stable_releases,
    set appropriately svn_tag_dir variable in your recipe:
      set :svn_tag_dir, 'stable_releases'
  * 'cap deploy' finds automatically the latest (in alphabetical order!) tag and deploys it.
    'cap deploy TAG=v2.3' deploys a specific tag.
  * 'cap deploy:rollback' works too, reverting to the preceding (in alphabetical order!) 
     already deployed tag.
  * For questions and comments write to sava@tutuf.com

  Copyright (c) 2008, Sava Chankov , Tutuf Ltd.
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
      * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
      * Neither the name of the Tutuf Ltd. nor the names of its contributors 
        may be used to endorse or promote products derived from this software
        without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY Tutuf Ltd. ``AS IS'' AND ANY
  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL Tutuf Ltd. BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=end

namespace :deploy do
  # The standard subversion repository dir in which tags reside.
  set :svn_tag_dir, 'tags'

  desc "Pull source code with the provided (or latest if none given) tag to the remote servers."
  task :update_tag do
    set_release_tag
    logger.info "deploying tag #{release_name}"
    set :repository, "#{repository}/#{svn_tag_dir}/#{release_name}"
  end

  before "deploy:update_code", "deploy:update_tag"

  def set_release_tag
    set :release_name, ENV['TAG']
    unless release_name
      logger.info "no tag specified, assuming latest"
      set(:release_name) {source.latest_tag}
    end
  end
end

require 'capistrano/recipes/deploy/scm/subversion'
Capistrano::Deploy::SCM::Subversion.class_eval do
  #Find the last in alphabetical order tag
  def latest_tag
    logger.debug "querying latest tag ..." unless @latest_revision
    tags_dir = configuration.repository + '/' + configuration.svn_tag_dir + '/'
    @latest_revision = ls(tags_dir).split("\n").last.chomp('/')
  end
  alias_method :latest_revision, :latest_tag

  def ls(path)
    `#{scm} ls #{path}`
  end
end