module Sprout
  class RemoteFileLoaderError < StandardError #:nodoc:
  end

  class RemoteFileLoader #:nodoc:
    
    def get_remote_file(uri, force=false, md5=nil)
      response = fetch(uri.to_s)
      if(force || response_is_valid?(response, md5))
        return response
      end
    end
    
    def response_is_valid?(response, expected_md5sum=nil)
      if(expected_md5sum)
        md5 = Digest::MD5.new
        md5 << response
        
        if(expected_md5sum != md5.hexdigest)
          puts "The MD5 Sum of the downloaded file (#{md5.hexdigest}) does not match what was expected (#{expected_md5sum})."
          puts "Would you like to install anyway? [Yn]"
          response = $stdin.gets.chomp!
          if(response.downcase == 'y')
            return true
          else
            raise RemoteFileLoaderError.new('MD5 Checksum failed')
          end
        end
      end
      return true
    end
    
    def fetch(uri)
      uri = URI.parse(uri)
      progress = nil
      response = nil
      name = uri.path.split("/").pop
      
      raise RemoteFileLoaderError.new("The RemoteFileTask failed for #{name}. We can only handle HTTP requests at this time, it seems you were trying: '#{uri.scheme}'") if uri.scheme != 'http'
      begin
        open(uri.to_s, :content_length_proc => lambda {|t|
          if t && t > 0
            progress = ProgressBar.new(name, t)
            progress.file_transfer_mode
            progress.set(0)
          else
            progress = ProgressBar.new(name, 0)
            progress.file_transfer_mode
            progress.set(0)
          end
        },
        :progress_proc => lambda {|s|
          progress.set s if progress
        }) do |f|
          response = f.read
          progress.finish
        end
      rescue SocketError => sock_err
        raise RemoteFileLoaderError.new("[ERROR] #{sock_err.to_s}")
      rescue OpenURI::HTTPError => http_err
        raise RemoteFileLoaderError.new("[ERROR] Failed to load file from: '#{uri.to_s}'\n[REMOTE ERROR] #{http_err.io.read.strip}")
      rescue Errno::ECONNREFUSED => econ_err
        raise Errno::ECONNREFUSED.new("[ERROR] Connection refused at: '#{uri.to_s}'")
      end

      return response
    end
    
  end
end