module Mustache::Sinatra::Helpers

def mustache(template, options={}, locals={})
  render :mustache, template, options, locals
end

def render_mustache(template, data, opts, locals, &block)
  name = Mustache.classify(template.to_s)
  # This is a horrible hack but we need it to know under which namespace
  # Views is located. If you have Hurl::App::Views, namespace should be
  # set to Hurl:App.
  namespace = options.namespace
  if namespace.const_defined?(:Views) && namespace::Views.const_defined?(name)
    # First try to find the existing view,
    # e.g. Hurl::Views::Index
    klass = namespace::Views.const_get(name)
  elsif File.exists?(file = "#{options.mustaches}/#{template}.rb")
    # Couldn't find it - try to require the file if it exists, then
    # load in the view.
    require "#{file}".chomp('.rb')
    klass = namespace::Views.const_get(name)
    # compile and cache the template
    klass.template = data
  else
    # Still nothing. Use the stache.
    klass = Mustache
  end
  # Tell the view class its extension and path so finding partials
  # works as expected.
  if klass.template_extension != 'mustache'
    klass.template_extension = 'mustache'
  end
  # Confusingly Sinatra's `views` setting tells Mustache where the
  # templates are found. It's fine, blame Chris.
  if klass.template_path != options.views
    klass.template_path = options.views
  end
  # Create a new instance for playing with
  instance = klass.new
  # Copy instance variables set in Sinatra to the view
  instance_variables.each do |name|
    instance.instance_variable_set(name, instance_variable_get(name))
  end
  # Locals get added to the view's context
  locals.each do |local, value|
    instance[local] = value
  end
  # If we're paseed a block it's a subview. Sticking it in yield
  # lets us use {{yield}} in layout.html to render the actual page.
  instance[:yield] = block.call if block
  instance.template = data unless instance.compiled?
  instance.to_html
end