discourse/script/import_scripts/flarum_import.rb

# frozen_string_literal: true

require "mysql2"
require "time"
require "date"

require File.expand_path(File.dirname(__FILE__) + "/base.rb")

class ImportScripts::FLARUM < ImportScripts::Base
  #SET THE APPROPRIATE VALUES FOR YOUR MYSQL CONNECTION
  FLARUM_HOST = ENV["FLARUM_HOST"] || "db_host"
  FLARUM_DB = ENV["FLARUM_DB"] || "db_name"
  BATCH_SIZE = 1000
  FLARUM_USER = ENV["FLARUM_USER"] || "db_user"
  FLARUM_PW = ENV["FLARUM_PW"] || "db_user_pass"

  def initialize
    super

    @client =
      Mysql2::Client.new(
        host: FLARUM_HOST,
        username: FLARUM_USER,
        password: FLARUM_PW,
        database: FLARUM_DB,
      )
  end

  def execute
    import_users
    import_categories
    import_posts
  end

  def import_users
    puts "", "creating users"
    total_count = mysql_query("SELECT count(*) count FROM users;").first["count"]

    batches(BATCH_SIZE) do |offset|
      results =
        mysql_query(
          "SELECT id, username, email, joined_at, last_seen_at
         FROM users
         LIMIT #{BATCH_SIZE}
         OFFSET #{offset};",
        )

      break if results.size < 1

      next if all_records_exist? :users, results.map { |u| u["id"].to_i }

      create_users(results, total: total_count, offset: offset) do |user|
        {
          id: user["id"],
          email: user["email"],
          username: user["username"],
          name: user["username"],
          created_at: user["joined_at"],
          last_seen_at: user["last_seen_at"],
        }
      end
    end
  end

  def import_categories
    puts "", "importing top level categories..."

    categories =
      mysql_query(
        "
                              SELECT id, name, description, position
                              FROM tags
                              ORDER BY position ASC
                            ",
      ).to_a

    create_categories(categories) { |category| { id: category["id"], name: category["name"] } }

    puts "", "importing children categories..."

    children_categories =
      mysql_query(
        "
                                       SELECT id, name, description, position
                                       FROM tags
                                       ORDER BY position
                                      ",
      ).to_a

    create_categories(children_categories) do |category|
      {
        id: "child##{category["id"]}",
        name: category["name"],
        description: category["description"],
      }
    end
  end

  def import_posts
    puts "", "creating topics and posts"

    total_count = mysql_query("SELECT count(*) count from posts").first["count"]

    batches(BATCH_SIZE) do |offset|
      results =
        mysql_query(
          "
        SELECT p.id id,
               d.id topic_id,
               d.title title,
               d.first_post_id first_post_id,
               p.user_id user_id,
               p.content raw,
               p.created_at created_at,
               t.tag_id category_id
        FROM posts p,
             discussions d,
             discussion_tag t
        WHERE p.discussion_id = d.id
          AND t.discussion_id = d.id
        ORDER BY p.created_at
        LIMIT #{BATCH_SIZE}
        OFFSET #{offset};
      ",
        ).to_a

      break if results.size < 1
      next if all_records_exist? :posts, results.map { |m| m["id"].to_i }

      create_posts(results, total: total_count, offset: offset) do |m|
        skip = false
        mapped = {}

        mapped[:id] = m["id"]
        mapped[:user_id] = user_id_from_imported_user_id(m["user_id"]) || -1
        mapped[:raw] = process_FLARUM_post(m["raw"], m["id"])
        mapped[:created_at] = Time.zone.at(m["created_at"])

        if m["id"] == m["first_post_id"]
          mapped[:category] = category_id_from_imported_category_id("child##{m["category_id"]}")
          mapped[:title] = CGI.unescapeHTML(m["title"])
        else
          parent = topic_lookup_from_imported_post_id(m["first_post_id"])
          if parent
            mapped[:topic_id] = parent[:topic_id]
          else
            puts "Parent post #{m["first_post_id"]} doesn't exist. Skipping #{m["id"]}: #{m["title"][0..40]}"
            skip = true
          end
        end

        skip ? nil : mapped
      end
    end
  end

  def process_FLARUM_post(raw, import_id)
    s = raw.dup

    s
  end

  def mysql_query(sql)
    @client.query(sql, cache_rows: false)
  end
end

ImportScripts::FLARUM.new.perform