module Xmvc
  
  ##
  # A base thor-extension for which to build vendors/plugins for the Xmvc framework
  # Extensions must impmlement several methods including :install and :secretary.
  # Vendors are run in a root-dir named after themselves through the Xmvc::Vendor class-method
  # #vendor_name.  A Vendor must at least provide a file named 'vendor.yml' in the root of its
  # template namespace
  # this file is used to define asset and meta-data
  # 
  #   name: some-vendor
  #   javascripts:
  #   - App.js
  #   - app/view/**/*.js
  #   - app/model/*.js
  #   - app/controller/*.js
  #
  
  class Vendor < Thor
    include Thor::Actions
    
    class Error < StandardError
    end

    class SpecNotFound < Error
    end
    
    ##
    # all vendors must implement vendor.yml in the same directory their extension lives
    #
    CONFIG_FILENAME = "vendor.yml"
    
    attr_accessor :config
    attr_accessor :js
    attr_accessor :css
    
    class << self
      
      ##
      # get / set the vendor name
      #
      def vendor_name(name=nil)
        @name ||= name
      end
      
      ##
      # Install a vendor
      # @return {Xmvc::Vendor}
      #
      def install(options)
        unless vendor_name
          raise Vendor::Error.new("Vendors must specify a name using the class-method vendor_name")
        end
        
        prepare_vendor(options) do |vendor|
          vendor.say_status("install", vendor.class.to_s)
          vendor.invoke(:install)
          begin
            vendor.copy_file(CONFIG_FILENAME, CONFIG_FILENAME) unless File.exists? CONFIG_FILENAME
          rescue StandardError => e
            raise SpecNotFound.new("Vendors must have available in their source-directory, a file named 'vendor.yml' or the class-method #source_root defined, which provides the base-path to the location of vendor.yml.  Xmvc::Vendor attempted to automatically copy this file into the installation directory.")
          end
        end  
      end
    
      ##
      # Loads and configures an Xmvc::Vendor instance
      # @return {Xmvc::Vendor}
      #
      def load(options)
        prepare_vendor(options)
      end
      
      ##
      # @param {Xmvc::Vendor} vendor
      # @param {Symbol} environment
      # @param {Symbol} ext File-extension of requested resource, :js, :css, etc
      # @param {String} host
      #
      def asset_urls(vendor, environment = :development, ext = :js, host=nil)
        config = vendor.config
        host = config['host'] unless host
        type = Xmvc.asset_dir(ext)
        rs = []
        # Note, we check config['host'] here, not host as defined above, since cachefly urls
        # override host requested as function param.  Host as in http://extjs.cachefly.net/...
        if config['host'].include?("http://") 
          config[type].each do |file|
            rs << cachefly_url(environment, config['host'], config['name'], file, config['version'], ext)
          end
        elsif host != Xmvc::PUBLIC_PATH
          rs << File.join("/#{host}", "#{config['name']}.#{ext.to_s}")
        else
          rs << Xmvc.build_path(environment, host, config['name'], config['version'], ext)
        end
        rs
      end
      
      def bundle_js(vendor, sec, root=Xmvc::PUBLIC_PATH)
        config = vendor.config
        vendor.destination_root = root
        path = ""
        vendor.inside "javascripts" do  
          vendor.empty_directory(config['name']) unless File.exists? config['name']
          vendor.inside config['name'] do |dir|
            path = File.expand_path(File.join(dir, Xmvc.build_name(vendor.options[:environment]||:development, config['name'], config['version'], :js)))
            sec.concatenation.save_to(path)
          end
        end
        path
      end
      
      def bundle_css(vendor)
        vendor.destination_root = Xmvc::PUBLIC_PATH
        vendor.inside "stylesheets" do
          Xmvc.ui.warn(' - bundle css -- no implementation')
        end
      end
      
    protected
      
      def cachefly_url(environment, host, name, file, version, ext)
        version = (version.nil? or version.empty?) ? "" : "-#{version}"
        File.join(host, "#{name}#{version}", "#{file}.#{ext.to_s}")
      end
        
      def prepare_vendor(options)
        vendor = new([], options)
        vendor.inside(File.expand_path(options[:root])) do
          vendor.inside vendor_name do |root|
            vendor.destination_root = root
            yield vendor if block_given?
            configure(vendor)
          end
        end
        vendor
      end
      
      def defaults
        @defaults ||= {
          "name" => "",
          "host" => "public",  # <-- http://foo.cachefly.net, /sprockets, /public, (defaults to /public)
          "version" => "",
          "javascripts" => [],
          "stylesheets" => []
        }
      end
      
      def configure(vendor)
        begin
          vendor.config = defaults.merge(YAML.load_file(File.join(vendor.destination_root, CONFIG_FILENAME)))
          
          # Enforce config name to that defined in the class, ignoring that
          # defined in YAML, which can't be trusted.  #vendor_name in the class-extension is the only
          # way to ID a vendor.
          vendor.config.update("name" => vendor_name)
        rescue StandardError => e
          raise SpecNotFound.new("Tried to load vendor #{vendor_name} but found no #{CONFIG_FILENAME} in the directory #{vendor.destination_root}")
        end
        vendor
      end
    end # end Vendor class
    
    desc "secretary", "Return this vendor's Sprockets::Secretary"
    def secretary(type = :js)
      say_status "secretary", self.class.to_s
      case type
        when :js then @secretary ||= Sprockets::Secretary.new({
          :root => destination_root,
          :source_files => config["javascripts"]
        })
      end
    end
    
    desc "bundle", "Bundle a vendor's assets"
    def bundle(sec = secretary(:js))
      # ugly hack for root in order to satisfy both Sprockts helper and CLI.
      root = (self.class.vendor_name == :app) ? Xmvc::PUBLIC_PATH : "../#{Xmvc::PUBLIC_PATH}"
      
      self.class.bundle_js(self, sec, root) unless config['host'].include?('http://')
      self.class.bundle_css(self) unless config['host'].include?('http://')
    end
  end
end