require 'pathname'

module BuildMaster
  class SiteSpec
    def self.get_instance
      self.new()
    end

    attr_accessor :output_dir, :content_dir, :template, :template_file
    
    def properties
      @properties = Hash.new unless @properties
      return @properties
    end
    
    def validate_inputs
      validate_dir(@content_dir, :content_dir)
    end
    
    def load_template
      if (@template)
        return XTemplate.new(@template)
      else
        return XTemplate.new(File.open(@template_file))
      end
    end

    def relative_to_root(path)
      to = path_name(path)
      from = path_name(@content_dir)
      return to.relative_path_from(from)
    end
    
    def evaluate(expression, path)
      value_from_properties = properties()[expression]
      if (value_from_properties)
        return value_from_properties
      end
      if (!respond_to?(expression, true))
        raise "Neither property nor method found with name '#{expression}'"
      end
      relative_path = relative_to_root(path)
      if (expression == 'relative_to_root')
        return relative_path
      else
        send(expression, relative_to_root(path).to_s)
      end
    end
    
    def add_property(name, value)
      properties()[name] = value
    end
    
    private
    def path_name(path)
      return Pathname.new(path.gsub(/\\/, '/'))
    end
    
    def validate_dir(directory, symbol)
      if not directory
        raise "Directory for #{symbol.id2name} not specified"
      end
      if not File.exists? directory
        raise "Directory for #{symbol.id2name} -- <#{directory}> does not exist"
      end
      if not File.directory? directory
        raise "<#{directory}> should be a directory for #{symbol.id2name}"
      end
    end
    
    def validate_file(file, symbol)
      if not file
        raise "File for #{symbol.id2name} not specified"
      end
      if (not File.exists? file)
        raise "File for #{symbol.id2name} -- <#{file}> does not exist"
      end
      if not File.file? file
        raise "#<{file} should be a file for #{symbol.id2name}"
      end
    end
  end
  
end