module DiscourseChat::Provider::SlackProvider
  class SlackCommandController < DiscourseChat::Provider::HookController
    requires_provider ::DiscourseChat::Provider::SlackProvider::PROVIDER_NAME

    before_filter :slack_token_valid?, only: :command

    skip_before_filter :check_xhr,
                       :preload_json,
                       :verify_authenticity_token,
                       :redirect_to_login_if_required,
                       only: :command

    def command
      message = process_command(params)

      render json: message
    end

    def process_command(params)

      tokens = params[:text].split(" ")

      # channel name fix
      channel_id =
        case params[:channel_name]
        when 'directmessage'
          "@#{params[:user_name]}"
        when 'privategroup'
          params[:channel_id]
        else
          "##{params[:channel_name]}"
        end

      provider = DiscourseChat::Provider::SlackProvider::PROVIDER_NAME

      channel = DiscourseChat::Channel.with_provider(provider).with_data_value('identifier', channel_id).first

      # Create channel if doesn't exist
      channel ||= DiscourseChat::Channel.create!(provider: provider, data: { identifier: channel_id })

      if tokens[0] == 'post'
        return process_post_request(channel, tokens, params[:channel_id])
      end

      return { text: ::DiscourseChat::Helper.process_command(channel, tokens) }

    end

    def process_post_request(channel, tokens, slack_channel_id)
      if SiteSetting.chat_integration_slack_access_token.empty?
        return I18n.t("chat_integration.provider.slack.api_required")
      end

      messages_to_load = 10

      if tokens.size > 1
        begin
          messages_to_load = Integer(tokens[1], 10)
        rescue ArgumentError
          return { text: I18n.t("chat_integration.provider.slack.parse_error") }
        end
      end

      transcript = SlackTranscript.load_transcript(slack_channel_id, messages_to_load)

      return { text: I18n.t("chat_integration.provider.slack.transcript_error") } unless transcript

      return transcript.build_slack_ui

    end

    def slack_token_valid?
      params.require(:token)

      if SiteSetting.chat_integration_slack_incoming_webhook_token.blank? ||
         SiteSetting.chat_integration_slack_incoming_webhook_token != params[:token]

        raise Discourse::InvalidAccess.new
      end
    end
  end

  class SlackEngine < ::Rails::Engine
    engine_name DiscourseChat::PLUGIN_NAME + "-slack"
    isolate_namespace DiscourseChat::Provider::SlackProvider
  end

  SlackEngine.routes.draw do
    post "command" => "slack_command#command"
  end

end