## lib/git_conf.rb
if 'development' == RAILS_ENV
  require 'rubygems'
  require 'grit' # use "mojombo-grit" from github

  ## uncomment if your application is running in an environment
  ## where `git` command cannot be found in the PATH (i.e. Passenger)
  # Grit::Git.git_binary = '/usr/local/git/bin/git'
end

def Rails.repo
  @@repository ||= Grit::Repo.new(Rails.root)
end

# Adjust your environment.rb to use this subclass:
#   Rails::Initializer.run(:process, GitConf.new) do |config|
#     ...
#   end
class GitConf < Rails::Configuration
  def initialize
    super
    @branched_database = false
  end

  def branched_database?() @branched_database end

  # agument the original method in order to append
  # the branch name suffix in certain conditions
  def database_configuration
    @database_configuration ||= begin
      config = super
      if Rails.env == "development"
        head = Rails.repo.head
        branch = head && head.name
        # check if this branch has a special database
        if branch and branch != "master" and branch !~ /\W/ and branch_has_database?(branch)
          development = config["development"]
          # save original configuration
          development["master-database"] = development["database"]
          # append branch name suffix
          base_name, extension = development["database"].split(".", 2)
          development["database"] = "#{base_name}_#{branch}"
          development["database"] += ".#{extension}" if extension
          # finally, indicate that this database has branched
          @branched_database = true
        end
      end
      config
    end
  end

  protected

  def branch_has_database?(branch)
    Rails.repo.config["branch.#{branch}.database"] == "true"
  end
end