require 'pandorified/result'

module Pandorified
  # Raised when Pandorabots returns an API result with a non-zero status.
  class PandorabotsError < StandardError; end

  class Session
    # A new session for conversing with a bot.
    #
    # @note If you choose not to specify a {custid}, one will be automatically chosen and remembered throughout the session.
    #
    # @param [String] botid A valid Pandorabots botid.
    # @param [String] custid An identifier used to keep track of this conversation.
    def initialize(botid, custid = nil)
      @botid = botid
      @custid = custid
    end

    # Send a message to this session's bot and receive a response.
    #
    # See {Pandorified::Result} for how to check for an error response and get the error message.
    # Alternatively, you can use {#talk!} instead of this method, which raises an exception when Pandorabots API returns an error.
    #
    # @param [String] input Text to say to the bot.
    #
    # @return [Pandorified::Result] The bot's response as a result object.
    def talk(input)
      result = Pandorified::Result.new(botid: @botid, custid: @custid, input: input)
      @custid ||= result.custid if result.success?
      result
    end

    # Send a message to this session's bot and receive a response (if successful).
    #
    # If Pandorabots API responds with an error, {Pandorified::PandorabotsError} is raised with the specific error message.
    # If you'd like to check for and handle the error yourself, you can use {#talk} instead of this method.
    #
    # @param [String] input Text to say to the bot.
    #
    # @return [String] The bot's response text.
    def talk!(input)
      result = self.talk(input)
      raise Pandorified::PandorabotsError, "Pandorabots returned status #{result.status}: #{result.message}" if result.error?
      result.that
    end
  end
end