require 'attached/processor'

module Attached
  
  class Image < Processor
    
    
    attr_reader :path
    attr_reader :extension
    
    attr_reader :width
    attr_reader :height
    attr_reader :operation

    # Create a processor.
    #
    # Parameters:
    # 
    # * file       - The file to be processed.
    # * options    - The options to be applied to the processing.
    # * attachment - The attachment the processor is being run for.
    
    def initialize(file, options = {}, attachment = nil)
      super
        
      @path      = self.file.path
      
      @size      = options[:size]
      @extension = options[:extension]
      
      @width, @height, @operation = @size.match(/(\d*)x?(\d*)(.*)/)[1..3] if @size
      
      @width     ||= options[:width]
      @height    ||= options[:height]
      @operation ||= options[:operation]
      
      @extension ||= File.extname(self.file.path)
      
      @width     = Integer(self.width)
      @height    = Integer(self.height)
      
      raise "Image processor requires specification of 'width' or 'size'"  unless self.width
      raise "Image processor requires specification of 'height' or 'size'" unless self.height
    end
    
    
    # Helper function for calling processors.
    #
    # Usage:
    #
    #   self.process
    
    def process
      result = Tempfile.new(["", self.extension])
      result.binmode
      
      begin
        parameters = []
        
        parameters << self.path
        
        case operation
        when '#' then parameters << "-resize #{width}x#{height}^ -gravity center -extent #{width}x#{height}"
        when '<' then parameters << "-resize #{width}x#{height}\\<"
        when '>' then parameters << "-resize #{width}x#{height}\\>"
        else          parameters << "-resize #{width}x#{height}"
        end
        
        parameters << result.path
        
        parameters = parameters.join(" ").squeeze(" ")
        
        `convert #{parameters}`
        
        raise "Command 'convert' failed. Ensure upload file is an image and options are correct." unless $?.exitstatus == 0
        
      rescue Errno::ENOENT  
        
        raise "Command 'convert' not found. Ensure 'Image Magick' is installed."
      
      end
      
      return result
    end
    
    
  end
end