module SlackRubyBot
  module Commands
    class Base
      include Loggable
      class_attribute :routes

      class << self
        def send_message(client, channel, text, options = {})
          logger.warn '[DEPRECATION] `send_message` is deprecated.  Please use `client.say` instead.'
          if text && text.length > 0
            client.say(options.merge(channel: channel, text: text))
          else
            client.say(options.merge(channel: channel, text: 'Nothing to see here.', gif: 'nothing'))
          end
        end

        def send_message_with_gif(client, channel, text, keywords, options = {})
          logger.warn '[DEPRECATION] `send_message_with_gif` is deprecated.  Please use `client.say` instead.'
          client.say(options.merge(channel: channel, text: text, gif: keywords))
        end

        def send_gif(client, channel, keywords, options = {})
          logger.warn '[DEPRECATION] `send_gif` is deprecated.  Please use `client.say` instead.'
          client.say(options.merge(channel: channel, text: '', gif: keywords))
        end

        def default_command_name
          name && name.split(':').last.downcase
        end

        def operator(*values, &block)
          values.each do |value|
            match Regexp.new("^(?<operator>\\#{value})(?<expression>.*)$", Regexp::IGNORECASE), &block
          end
        end

        def command(*values, &block)
          values.each do |value|
            escaped = Regexp.escape(value)
            match Regexp.new("^(?<bot>[[:alnum:][:punct:]@<>]*)[\\s]+(?<command>#{escaped})$", Regexp::IGNORECASE), &block
            match Regexp.new("^(?<bot>[[:alnum:][:punct:]@<>]*)[\\s]+(?<command>#{escaped})[\\s]+(?<expression>.*)$", Regexp::IGNORECASE), &block
          end
        end

        def invoke(client, data)
          finalize_routes!
          expression, text = parse(client, data)
          called = false
          routes.each_pair do |route, method|
            match = route.match(expression)
            match ||= route.match(text) if text
            next unless match
            next if match.names.include?('bot') && !client.name?(match['bot'])
            called = true
            if method
              method.call(client, data, match)
            elsif respond_to?(:call)
              send(:call, client, data, match)
            else
              fail NotImplementedError, data.text
            end
            break
          end
          called
        end

        def match(match, &block)
          self.routes ||= {}
          self.routes[match] = block
        end

        private

        def parse(client, data)
          text = data.text
          return text unless direct_message?(data) && message_from_another_user?(data)
          return text if bot_mentioned_in_message?(text, client.names)
          ["#{client.name} #{text}", text]
        end

        def direct_message?(data)
          data.channel && data.channel[0] == 'D'
        end

        def message_from_another_user?(data)
          data.user && data.user != SlackRubyBot.config.user_id
        end

        def bot_mentioned_in_message?(text, bot_names)
          bot_names = bot_names.join('|')
          !!text.downcase.match(/\A(#{bot_names})\s|\A(#{bot_names})\z/)
        end

        def finalize_routes!
          return if routes && routes.any?
          command default_command_name
        end
      end
    end
  end
end