require 'barber'
require 'coffee-script'
require 'fileutils'
require 'sass'

# Public: Define an Asset.
#
# Examples
#
#   Asset.new(file: "#{@working_dir}/#{args[:src]}",
#        build_dir: @build_dir,
#      working_dir: @working_dir,
#      helper_args: args)
module Pyro
  class Asset
    attr_accessor :file, :build_dir, :working_dir, :helper_args

    # Public: Set args to attrs on new().
    #
    # Examples
    #
    #   Asset.new(file: "#{@working_dir}/#{args[:src]}",
    #        build_dir: @build_dir,
    #      working_dir: @working_dir,
    #      helper_args: args)
    #
    # Returns an Asset instance.
    def initialize(args)
      args.each { |k, v| instance_variable_set("@#{k}", v) }
    end

    # Public: Map File methods to an Asset.
    #
    # * Maybe Asset should inheret from File?
    #
    # Examples
    #
    #   @asset.mtime
    #
    # * See the File class for more info.
    def mtime
      File.mtime file
    end
    def basename
      File.basename file
    end
    def dirname
      File.dirname file
    end
    def extname
      File.extname file
    end

    # Public: Strip the extension from the basename.
    #
    # Examples
    #
    #   @asset.name
    #
    # Retunrs a String of the basename without the extension.
    #   ('my_file.rb' -> 'myfile')
    def name
      basename.sub(extname, '')
    end

    # Public: Format the mtime as a timestamp String.
    #
    # Examples
    #
    #   @asset.timestamp
    #
    # Returns a String.
    def timestamp
      mtime.strftime "%Y%m%d%H%M%S"
    end

    # Public: Find the relative target path of an Asset.
    #
    # Examples
    #
    #   @asset.relative_dir
    #
    # Returns a path as a String.
    def relative_dir
      dirname.sub("#{working_dir}/", '')
    end

    # Public: Find the relative target file path of an Asset.
    #
    # Examples
    #
    #   @asset.relative_file
    #
    # Returns a filepath as a String.
    def relative_file
      if helper_args[:target]
        helper_args[:target]
      else
        "#{relative_dir}/#{name}#{compiled_ext}"
      end
    end

    # Public: Determine the target extension of an Asset.
    #
    # Examples
    #
    #   @asset.compiled_ext
    #
    # Returns a String.
    def compiled_ext
      case extname
      when '.coffee', '.hbs', '.handlebars'
        '.js'
      when '.scss'
        '.css'
      else
        extname
      end
    end

    # Public: Compile the contents of an Asset.
    #
    # Examples
    #
    #   @asset.contents
    #
    # Returns the compiled contents.
    def contents
      contents = File.read file
      case extname
      when '.coffee'
        contents = CoffeeScript.compile(contents, bare: true)
      when '.scss'
        contents = Sass::Engine.new(contents, { syntax: :scss }).render
      when '.hbs', '.handlebars'
        contents = Barber::Ember::FilePrecompiler.call(contents)
        contents = "Ember.TEMPLATES['#{template_name}'] = #{contents}"
      end
      contents
    end

    # Public: Find the name to use for a Handlebars template.
    #
    # * Use the name: arg in the template() helper to override the default.
    #
    # Examples
    #
    #   @asset.template_name
    #
    # Returns the relative template path and filename unless told otherwise.
    def template_name
      if helper_args[:name]
        helper_args[:name]
      elsif helper_args[:src]
        name
      elsif helper_args[:dir]
        file.sub("#{working_dir}/#{helper_args[:dir]}/", '').sub(extname, '')
      else
        'name-not-found'
      end
    end

    # Public: Generate a compiled Asset.
    #
    # Examples
    #
    #   @asset.generate_file
    #
    # Generates a compiled Asset file into a target file.
    def generate_file
      FileUtils.mkdir_p "#{build_dir}/#{relative_dir}"
      File.open("#{build_dir}/#{relative_file}", 'a+') { |f| f.write contents }
    end

    # Public: Generate link to a generated Asset.
    #
    # Examples
    #
    #   @asset.generate_link
    #
    # Retunrs a <script> or <link> tag.
    def generate_link
      case compiled_ext
      when '.js'
        "<script type='text/javascript' src='#{relative_file}?#{timestamp}'></script>\n"
      when '.css'
        "<link type='text/css' rel='stylesheet' href='#{relative_file}?#{timestamp}' />\n"
      end
    end
  end
end