require 'ise'
require 'cgi'
require 'nokogiri'
require 'tmpdir'

module ISE

  class Project < XMLFile
    
    GoalProperty = 'Last Applied Goal'
    ShortNameProperty = 'PROP_DesignName'
    OutputNameProperty = 'Output File Name'
    TopLevelFileProperty = 'Implementation Top File'
    WorkingDirectoryProperty = 'Working Directory'

    attr_reader :filename

    #
    # Returns the value of a project property.
    #
    def get_property(name)

      #Retreive the value of the node with the given property.
      node = get_property_node(name)
      node.attribute("value").value

    end

    #
    # Sets the value of an ISE project property.
    #
    def set_property(name, value, mark_non_default=true)
 
      #Set the node's property, as specified.
      node = get_property_node(name)
      node.attribute("value").value = value

      #If the mark non-default option is set, mark the state is not a default value.
      node.attribute("valueState").value = 'non-default' if mark_non_default

    end

    #
    # Attempts to minimize synthesis runtime of a _single run_. 
    #
    # This will place all intermediary files in RAM- which means that synthesis
    # results won't be preserved between reboots!
    #
    def minimize_runtime!

      #Compute the path in which temporary synthesis files should be created.
      shortname = CGI::escape(get_property(ShortNameProperty))
      temp_path = Dir::mktmpdir([shortname, ''])
  
      #Synthesize from RAM.
      set_property(WorkingDirectoryProperty, temp_path)

      #Ask the project to focus on runtime over performance.
      set_property(GoalProperty, 'Minimum Runtime')

    end

    #
    # Returns a path to the top-level file in the given project. 
    #
    # absoulute_path: If set when the project file's path is known, an absolute path will be returned.
    #
    def top_level_file(absolute_path=true)
     
      path = get_property(TopLevelFileProperty)

      #If the absolute_path flag is set, and we know how, expand the file path.
      if absolute_path
        path = File.expand_path(path, @base_path) 
      end

      #Return the relevant path.
      path

    end

    #
    # Returns the project's working directory.
    #
    def working_directory
      File.expand_path(get_property(WorkingDirectoryProperty), @base_path)
    end

    #
    # Returns the best-guess path to the most recently generated bit file,
    # or nil if we weren't able to find one.
    #
    def bit_file

      #Determine ISE's working directory.
      working_directory = get_property(WorkingDirectoryProperty)

      #Find an absolute path at which the most recently generated bit file should reside.
      name = get_property(OutputNameProperty)
      name = File.expand_path("#{working_directory}/#{name}.bit", @base_path)

      #If it exists, return it.
      File::exists?(name) ? name : nil

    end

    private

    #
    # Retreives the node with the given property name.
    #
    def get_property_node(name)
      @xml.at_css("property[xil_pn|name=\"#{name}\"]")
    end


  end


end