discourse/script/import_scripts/mbox/importer.rb

# frozen_string_literal: true

require_relative "../base"
require_relative "support/database"
require_relative "support/indexer"
require_relative "support/settings"

module ImportScripts::Mbox
  class Importer < ImportScripts::Base
    def initialize(settings_filename)
      @settings = Settings.load(settings_filename)
      super()

      @database = Database.new(@settings.data_dir, @settings.batch_size)
    end

    def get_site_settings_for_import
      settings = super
      settings[:enable_staged_users] = true
      settings[:incoming_email_prefer_html] = @settings.prefer_html
      settings
    end

    protected

    def execute
      index_messages

      if @settings.index_only
        @skip_updates = true
      else
        SiteSetting.tagging_enabled = true if @settings.tags.present?

        import_categories
        import_users
        import_posts
      end
    end

    def index_messages
      puts "", "creating index"
      indexer = Indexer.new(@database, @settings)
      indexer.execute
    end

    def import_categories
      puts "", "creating categories"
      rows = @database.fetch_categories

      create_categories(rows) do |row|
        {
          id: row["name"],
          name: row["name"],
          parent_category_id: row["parent_category_id"].presence,
        }
      end
    end

    def import_users
      puts "", "creating users"
      total_count = @database.count_users
      last_email = ""

      batches do |offset|
        rows, last_email = @database.fetch_users(last_email)
        break if rows.empty?

        next if all_records_exist?(:users, rows.map { |row| row["email"] })

        create_users(rows, total: total_count, offset: offset) do |row|
          {
            id: row["email"],
            email: row["email"],
            name: row["name"],
            trust_level: @settings.trust_level,
            staged: @settings.staged,
            active: !@settings.staged,
            created_at: to_time(row["date_of_first_message"]),
          }
        end
      end
    end

    def batches
      super(@settings.batch_size)
    end

    def import_posts
      puts "", "creating topics and posts"
      total_count = @database.count_messages
      last_row_id = 0

      batches do |offset|
        rows, last_row_id = @database.fetch_messages(last_row_id)
        break if rows.empty?

        next if all_records_exist?(:posts, rows.map { |row| row["msg_id"] })

        create_posts(rows, total: total_count, offset: offset) do |row|
          begin
            if row["email_date"].blank?
              puts "Date is missing. Skipping #{row["msg_id"]}"
              nil
            elsif row["in_reply_to"].blank?
              map_first_post(row)
            else
              map_reply(row)
            end
          rescue => e
            puts "Failed to map post for #{row["msg_id"]}", e, e.backtrace.join("\n")
          end
        end
      end
    end

    def map_post(row)
      user_id = user_id_from_imported_user_id(row["from_email"]) || Discourse::SYSTEM_USER_ID

      {
        id: row["msg_id"],
        user_id: user_id,
        created_at: to_time(row["email_date"]),
        raw: format_raw(row, user_id),
        raw_email: row["raw_message"],
        via_email: true,
        post_create_action: proc { |post| create_incoming_email(post, row) },
      }
    end

    def format_raw(row, user_id)
      body = row["body"] || ""
      elided = row["elided"]

      if row["attachment_count"].positive?
        receiver = Email::Receiver.new(row["raw_message"])
        user = User.find(user_id)
        body = receiver.add_attachments(body, user)
      end

      if elided.present? && @settings.show_trimmed_content
        body = "#{body}#{Email::Receiver.elided_html(elided)}"
      end

      body
    end

    def map_first_post(row)
      subject = row["subject"]
      tags = remove_tags!(subject)

      mapped = map_post(row)
      mapped[:category] = category_id_from_imported_category_id(row["category"])
      mapped[:title] = subject.strip[0...255]
      mapped[:tags] = tags if tags.present?
      mapped
    end

    def map_reply(row)
      parent = @lookup.topic_lookup_from_imported_post_id(row["in_reply_to"])

      if parent.blank?
        puts "Parent message #{row["in_reply_to"]} doesn't exist. Skipping #{row["msg_id"]}: #{row["subject"][0..40]}"
        return nil
      end

      mapped = map_post(row)
      mapped[:topic_id] = parent[:topic_id]
      mapped
    end

    def remove_tags!(subject)
      tag_names = []
      remove_prefixes!(subject)

      loop do
        old_length = subject.length

        @settings.tags.each do |tag|
          tag_names << tag[:name] if subject.sub!(tag[:regex], "") && tag[:name].present?
        end

        remove_prefixes!(subject) if subject.length != old_length
        break if subject.length == old_length
      end

      tag_names.uniq
    end

    def remove_prefixes!(subject)
      # There could be multiple prefixes...
      loop do
        if subject.sub!(@settings.subject_prefix_regex, "")
          subject.strip!
        else
          break
        end
      end
    end

    def create_incoming_email(post, row)
      IncomingEmail.create(
        message_id: row["msg_id"],
        raw: row["raw_message"],
        subject: row["subject"],
        from_address: row["from_email"],
        user_id: post.user_id,
        topic_id: post.topic_id,
        post_id: post.id,
      )
    end

    def to_time(timestamp)
      Time.zone.at(timestamp) if timestamp
    end
  end
end