require 'http'

module Senec
  class State
    def initialize(host:)
      @host = host
    end

    attr_reader :host

    # Extract state names from JavaScript file, which is formatted like this:
    #
    # var system_state_name = {
    #   0: "FIRST STATE",
    #   1: "SECOND STATE",
    #   ...
    #  };
    def names
      response.match(FILE_REGEX)[0].split("\n").each_with_object({}) do |line, hash|
        key, value = line.match(LINE_REGEX)&.captures
        next unless key && value

        hash[key.to_i] = value
      end
    end

    private

    FILE_REGEX = /var system_state_name = \{(.*?)\};/m
    LINE_REGEX = /(\d+)\s*:\s*"(.*)"/

    def response
      @response ||= begin
        res = HTTP.get uri
        raise Senec::Error, res.status.to_s unless res.status.success?

        res.body.to_s
      end
    end

    # Use the JavaScript file with German names from the SENEC web interface
    def uri
      URI.parse("http://#{host}/js/DE-de.js")
    end
  end
end