module Eeml
  # A parser for json environments based on the EEML 5 specification.
  class JsonEnvironmentParserV100 # :nodoc:
    include Exceptions

    def make_environment_from_hash(env_hash)
      env = Environment.new(:title => env_hash["title"],
                            :description => env_hash["description"],
                            :feed_url => env_hash["feed"],
                            :website => env_hash["website"],
                            :email => env_hash["email"],
                            :icon => env_hash["icon"],
                            :status => env_hash["status"],
                            :identifier => env_hash["id"],
                            :private => env_hash["private"])

      env.updated = Time.gm(*ParseDate.parsedate(env_hash['updated'])) unless env_hash['updated'].nil?

      env.location = buildLocation(env_hash)

      env.datastreams = buildDatastreams(env_hash)
  
      return env
    end

    def make_environment_from_json(json_str)
      env_hash = JSON.parse(json_str)
      return make_environment_from_hash(env_hash)
    end

    private

    def buildLocation(env_hash)
      location_hash = env_hash["location"]
      return if location_hash.nil?
      Location.new(:name => location_hash["name"],
                   :latitude => location_hash["lat"],
                   :longitude => location_hash["lon"],
                   :elevation => location_hash["ele"],
                   :domain => location_hash["domain"],
                   :disposition => location_hash["disposition"],
                   :exposure => location_hash["exposure"])
    end

    def buildDatastreams(env_hash)
      datastreams_hash = env_hash["datastreams"]
      return if datastreams_hash.nil?
      datastreams = []
      datastreams_hash.each do |datastream_hash|  
	datastream = DataStream.new
        raise MissingAttribute.new('id', "data") if datastream_hash['id'].nil?
        datastream.identifier = datastream_hash['id']
        datastream.tags = datastream_hash['tags'] unless datastream_hash['tags'].nil?
        
        values_arr = datastream_hash["values"]

        raise DataMissingValue if values_arr.nil?

        values_arr.each do |v|
          value = Value.new(:value => v["value"],
                            :min_value => datastream_hash["min_value"],
                            :max_value => datastream_hash["max_value"],
                            :recorded_at => v["at"])

          datastream.add_value(value)
        end

        unit_hash = datastream_hash["unit"]
        unless unit_hash.nil?
          datastream.unit_symbol = unit_hash["symbol"]
          datastream.unit_type = unit_hash["type"]
          datastream.unit_value = unit_hash["label"]
        end

        datastreams << datastream
      end
      return datastreams
    end
  end
end