class Opal::Builder

def self.build(name)
  Builder.new.build name
end

def append_path(path)
  @paths << path
end

def build(path)
  @segments = []
  require_asset path
  @segments.join
end

def build_asset(path)
  ext = File.extname path
  unless builder = BUILDERS[ext]
    raise "Unknown builder for #{ext}"
  end
  @segments << __send__(builder, path)
end

def build_erb(path)
  ::ERB.new(File.read(path)).result binding
end

def build_js(path)
  File.read(path)
end

def build_ruby(path)
  compile_ruby File.read(path), @options.clone
end

def build_str(str, options = {})
  @segments = []
  @segments << compile_ruby(str, options)
  @segments.join
end

def compile_ruby(str, options = nil)
  options ||= @options.clone
  compiler = Compiler.new
  result = compiler.compile str, options
  compiler.requires.each do |r|
    require_asset r
  end
  result
end

def find_asset(path)
  path.untaint if path =~ /\A(\w[-.\w]*\/?)+\Z/
  file_types = %w[.rb .js .js.erb]
  @paths.each do |root|
    file_types.each do |type|
      test = File.join root, "#{path}#{type}"
      if File.exist? test
        return test
      end
    end
  end
  raise "Could not find asset: #{path}"
end

def initialize(options = {})
  @paths = options.delete(:paths) || Opal.paths.clone
  @options = options
  @handled = {}
end

def require_asset(path)
  location = find_asset path
  unless @handled[location]
    @handled[location] = true
    build_asset location
  end
end