# encoding: utf-8

module Prawn
  module ManualBuilder
    # The Prawn::ManualBuilder ExampleFile class is a utility class to ease 
    # the manipulation and extraction of source code and comments from the 
    # actual example files
    #
    class ExampleFile
      attr_reader :package, :filename
      
      # Stores the file data, filename and parent, which will be either an
      # ExampleSection or an ExamplePackage.
      #
      # Available boolean options are:
      # 
      # <tt>:eval_source</tt>:: Evals the example source code (default: true)
      # <tt>:full_source</tt>:: Extract the full source code when true. Extract
      # only the code between the generate block when false (default: false)
      #
      def initialize(parent, filename, options={})
        @parent   = parent.is_a?(String) ? ExamplePackage.new(parent) : parent
        
        @filename = filename
        @data     = read_file(@parent.folder_name, filename)
        
        @options  = {:eval_source => true, :full_source => false}.merge(options)
      end
      
      # Return the example source code excluding the initial comments and
      # require calls
      #
      def full_source
        @data.gsub(/# encoding.*?\n.*require.*?\n\n/m, "\n").strip
      end
      
      # Return the example source contained inside the first generate block or
      # the full source if no generate block is found
      #
      def generate_block_source
        block = @data.slice(/\w+\.generate.*? do\n(.*)end/m, 1)
          
        return full_source unless block
        
        block.gsub(/^( ){2}/, "")
      end
      
      # Return either the full_source or the generate_block_source according
      # to the options
      #
      def source
        @options[:full_source] ? full_source : generate_block_source
      end
      
      # Return true if the example source should be evaluated inline within
      # the manual according to the options
      #
      def eval?
        @options[:eval_source]
      end
      
      # Retrieve the comments between the encoding declaration and the require
      # call for example_helper.rb
      #
      # Then removes the '#' signs, reflows the line breaks and return the result
      #
      def introduction_text
        intro_lines
          .map do |line|
            line
              .gsub(/\A\s*# (?=\S)/m, ' ')
              .gsub(/\A\s*#/, '')
              .strip
          end
          .join("\n")
      end
      
      # Returns a human friendly version of the example file name
      #
      def name
        @name ||= @filename[/(.*)\.rb/, 1].gsub("_", " ").capitalize
      end
      
      # Returns this example's parent original folder name
      #
      def parent_folder_name
        @parent.folder_name
      end
      
      # Returns the human friendly version of this example parent name
      #
      def parent_name
        @parent.name
      end
      
      # Renders this example to a pdf
      #
      def render(pdf)
        pdf.render_example(self)
      end
      
    private
    
      # Read the data from a file in a given package
      #
      def read_file(folder_name, filename)
        data = File.read(File.expand_path(File.join(
          Prawn::ManualBuilder.manual_dir, folder_name, filename)))

        data.encode(::Encoding::UTF_8)
      end

      def intro_lines
        @data
          .lines
          .grep(/^#/)
          .reject do |line|
            line.start_with?('#!') ||
              /coding:/.match(line) ||
              /\A\s*#\s*frozen_string_literal:/.match(line) ||
              /\A\s*#\s*rubocop:/.match(line)
          end
      end
    end
  end
end