module CompassRails

def configuration
  config = Compass::Configuration::Data.new('rails')
  config.extend(CompassRails::Configuration)
  config
end

def configure_rails!(app)
  return unless app.config.respond_to?(:sass)
  sass_config = app.config.sass
  compass_config = app.config.compass
  sass_config.load_paths.concat(compass_config.sass_load_paths)
  { :output_style => :style,
    :line_comments => :line_comments,
    :cache => :cache,
    :disable_warnings => :quiet,
    :preferred_syntax => :preferred_syntax
  }.each do |compass_option, sass_option|
    set_maybe sass_config, compass_config, sass_option, compass_option
  end
  if compass_config.sass_options
    compass_config.sass_options.each do |config, value|
      sass_config.send("#{config}=", value)
    end
  end
end

def context
  @context ||= begin
    sprockets.version = ::Rails.env + "-#{sprockets.version}"
    setup_fake_rails_env_paths(sprockets)
    context = ::CompassRails.sprockets.context_class
    context.extend(::Sprockets::Helpers::IsolatedHelper)
    context.extend(::Sprockets::Helpers::RailsHelper)
    context.extend(::Sass::Rails::Railtie::SassContext)
    context.sass_config = sass_config
    context
  end
end

def prefix
  ::Rails.application.config.assets.prefix
end

def rails31?
  return false unless defined?(::Rails)
  version_match RAILS_31
end

def rails32?
  return false unless defined?(::Rails)
  version_match RAILS_32
end

def rails_loaded?
  defined?(::Rails)
end

def rails_version
  rails_spec = (Gem.loaded_specs["railties"] || Gem.loaded_specs["rails"])
  raise "You have to require Rails before compass" unless rails_spec
  rails_spec.version.to_s
end

def sass_config
  ::Rails.application.config.sass
end

def set_maybe(sass_config, compass_config, sass_option, compass_option)
  if compass_value = compass_config.send(:"#{compass_option}_without_default")
    sass_config.send(:"#{sass_option}=", compass_value)
  end
end

def setup_fake_rails_env_paths(sprockets_env)
  return unless rails_loaded?
  if sprockets_env.respond_to?(:trail, true)
    sprockets_trail = sprockets_env.send(:trail)
  else
    sprockets_trail = sprockets_env.index
  end
  keys = ['app/assets', 'lib/assets', 'vendor/assets']
  local = keys.map {|path| ::Rails.root.join(path) }.map { |path| [File.join(path, 'images'), File.join(path, 'stylesheets')] }.flatten!
  sprockets_trail.paths.unshift(*local)
  paths = []
  ::Rails::Engine.subclasses.each do |subclass|
    paths = subclass.paths
    keys.each do |key|
      sprockets_trail.paths.unshift(*paths[key].existent_directories)
    end
  end
end

def sprockets
  @sprockets ||= Rails.application.assets || ::Sprockets::Railtie.build_environment(Rails.application)
end

def version_match(version)
  !(rails_version =~ version).nil?
end