module Eeml
  include Eeml::Constants

  # One of the component classes of Environment. Represents the location of the environment. Environments can only have a single location object.
  class Location
    attr_accessor :name, :latitude, :longitude, :elevation
    attr_accessor :domain, :exposure, :disposition

    def initialize(options = {})
      @name = options[:name]
      @latitude = options[:latitude]
      @longitude = options[:longitude]
      @elevation = options[:elevation]
      @domain = options[:domain]
      @exposure = options[:exposure]
      @disposition = options[:disposition]
    end
  end

  # One of the component classes of Environment. Represents an individual datastream, and provides access to it's value
  # and other attributes. Environments can have zero or more datastreams.
  class DataStream
    attr_accessor :identifier, :value, :tags, :min_value, :max_value, :unit_symbol, :unit_type, :unit_value

    def initialize(options = {})
      @identifier = options[:identifier]
      @value = options[:value]
      @max_value = options[:max_value]
      @min_value = options[:min_value]
      @tags = []
      @unit_symbol = options[:unit_symbol]
      @unit_type = options[:unit_type]
      @unit_value = options[:unit_value]
    end

    def to_s
      "identifier: '#{@identifier}', value: '#{@value}', min_value: '#{@min_value}', max_value: '#{@max_value}', tags: '#{@tags.join(", ")}'"
    end

  end

  # This class represents the main point of entry to this library. In general we will be creating instances of this class, either
  # by manually specifying the parameters, or probably more commonly, by passing in either an EEML or JSON formatted string which
  # will be parsed to initialize the object.
  class Environment
    attr_accessor :identifier, :updated, :creator
    attr_accessor :title, :description, :feed_url, :website, :email, :icon, :status
    attr_accessor :location
    attr_accessor :datastreams

    # Create a new Environment object by passing parameters in a hash (just like creating an ActiveRecord object)
    def initialize(options = {})
      @datastreams = []
      @identifier = options[:identifier]
      @creator = options[:creator]
      @title = options[:title]
      @status = options[:status]
      @feed_url = options[:feed_url]
      @description = options[:description]
      @website = options[:website]
      @email = options[:email]
      @icon = options[:icon]
    end

    def add_datastream(datastream)
      #TODO: consider checking for unique identifier
      datastreams << datastream
    end

    def remove_last_datastream
      datastreams.pop
    end

    # Create multiple Environment objects from an EEML string containing multiple `environment` stanzas.
    def self.new_list_from_eeml(xml_str)
      parser = ParserRegistry.get_xml_parser_for(xml_str)
      return parser.make_environments_from_xml(xml_str)
    end

    # Create a new Environment object from an EEML string.
    def self.new_from_eeml(xml_str)
      parser = ParserRegistry.get_xml_parser_for(xml_str)
      return parser.make_environment_from_xml(xml_str)
    end

    # Create a new Environment object from a JSON string.
    def self.new_from_json(json_str)
      parser =  ParserRegistry.get_json_parser_for(json_str)
      return parser.make_environment_from_json(json_str)
    end
  
    def update_datastreams_from_csv_values!(csv_values)

      csv_values.each_with_index do |new_val, index|
        datastream = datastreams[index]
        #if we don't have an existing datastream at same index, create new one
        if datastream.nil?
          self.datastreams << DataStream.new(:identifier => index, :value => new_val, :ordering => index)          
        else
          #we had a match, so update the existing datastream
          datastream.value = new_val
        end
      end

      # if the csv specifies FEWER feeds than the env currently has.
      if csv_values.size < self.datastreams.size
        # remove the excess from the end of the env's list.
        num_extra = datastreams.size - csv_values.size
        1.upto(num_extra) { remove_last_datastream }
      end
    end

    def to_eeml(version = Constants::EEML_VERSION)
      outputter = OutputRegistry.get_xml_output_for(version)
      outputter.to_eeml(self)
    end

    def to_json
      outputter = OutputRegistry.get_json_output_for
      outputter.to_json(self)
    end
    
  end

end