# frozen_string_literal: true

module Gitlab
  module Database
    CI_DATABASE_NAME = 'ci'

    # This constant is used when renaming tables concurrently.
    # If you plan to rename a table using the `rename_table_safely` method, add your table here one milestone before the rename.
    # Example:
    # TABLES_TO_BE_RENAMED = {
    #   'old_name' => 'new_name'
    # }.freeze
    TABLES_TO_BE_RENAMED = {}.freeze

    # Minimum PostgreSQL version requirement per documentation:
    # https://docs.gitlab.com/ee/install/requirements.html#postgresql-requirements
    MINIMUM_POSTGRES_VERSION = 12

    # https://www.postgresql.org/docs/9.2/static/datatype-numeric.html
    MAX_INT_VALUE = 2147483647
    MIN_INT_VALUE = -2147483648

    # The max value between MySQL's TIMESTAMP and PostgreSQL's timestampz:
    # https://www.postgresql.org/docs/9.1/static/datatype-datetime.html
    # https://dev.mysql.com/doc/refman/5.7/en/datetime.html
    # FIXME: this should just be the max value of timestampz
    MAX_TIMESTAMP_VALUE = Time.at((1 << 31) - 1).freeze

    # The maximum number of characters for text fields, to avoid DoS attacks via parsing huge text fields
    # https://gitlab.com/gitlab-org/gitlab-foss/issues/61974
    MAX_TEXT_SIZE_LIMIT = 1_000_000

    # Minimum schema version from which migrations are supported
    # Migrations before this version may have been removed
    MIN_SCHEMA_VERSION = 20190506135400
    MIN_SCHEMA_GITLAB_VERSION = '11.11.0'

    # Schema we store dynamically managed partitions in (e.g. for time partitioning)
    DYNAMIC_PARTITIONS_SCHEMA = :gitlab_partitions_dynamic

    # Schema we store static partitions in (e.g. for hash partitioning)
    STATIC_PARTITIONS_SCHEMA = :gitlab_partitions_static

    # This is an extensive list of postgres schemas owned by GitLab
    # It does not include the default public schema
    EXTRA_SCHEMAS = [DYNAMIC_PARTITIONS_SCHEMA, STATIC_PARTITIONS_SCHEMA].freeze

    DATABASES = ActiveRecord::Base
      .connection_handler
      .connection_pools
      .each_with_object({}) do |pool, hash|
        hash[pool.db_config.name.to_sym] = Connection.new(pool.connection_klass)
      end
      .freeze

    PRIMARY_DATABASE_NAME = ActiveRecord::Base.connection_db_config.name.to_sym

    def self.main
      DATABASES[PRIMARY_DATABASE_NAME]
    end

    def self.has_config?(database_name)
      Gitlab::Application.config.database_configuration[Rails.env].include?(database_name.to_s)
    end

    def self.main_database?(name)
      # The database is `main` if it is a first entry in `database.yml`
      # Rails internally names them `primary` to avoid confusion
      # with broad `primary` usage we use `main` instead
      #
      # TODO: The explicit `== 'main'` is needed in a transition period till
      # the `database.yml` is not migrated into `main:` syntax
      # https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65243
      ActiveRecord::Base.configurations.primary?(name.to_s) || name.to_s == 'main'
    end

    def self.ci_database?(name)
      name.to_s == CI_DATABASE_NAME
    end

    def self.check_postgres_version_and_print_warning
      return if Gitlab::Runtime.rails_runner?

      DATABASES.each do |name, connection|
        next if connection.postgresql_minimum_supported_version?

        Kernel.warn ERB.new(Rainbow.new.wrap(<<~EOS).red).result

                    ██     ██  █████  ██████  ███    ██ ██ ███    ██  ██████ 
                    ██     ██ ██   ██ ██   ██ ████   ██ ██ ████   ██ ██      
                    ██  █  ██ ███████ ██████  ██ ██  ██ ██ ██ ██  ██ ██   ███ 
                    ██ ███ ██ ██   ██ ██   ██ ██  ██ ██ ██ ██  ██ ██ ██    ██ 
                     ███ ███  ██   ██ ██   ██ ██   ████ ██ ██   ████  ██████  

          ******************************************************************************
            You are using PostgreSQL <%= Gitlab::Database.main.version %> for the #{name} database, but PostgreSQL >= <%= Gitlab::Database::MINIMUM_POSTGRES_VERSION %>
            is required for this version of GitLab.
            <% if Rails.env.development? || Rails.env.test? %>
            If using gitlab-development-kit, please find the relevant steps here:
              https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/main/doc/howto/postgresql.md#upgrade-postgresql
            <% end %>
            Please upgrade your environment to a supported PostgreSQL version, see
            https://docs.gitlab.com/ee/install/requirements.html#database for details.
          ******************************************************************************
        EOS
      rescue ActiveRecord::ActiveRecordError, PG::Error
        # ignore - happens when Rake tasks yet have to create a database, e.g. for testing
      end
    end

    def self.nulls_order(field, direction = :asc, nulls_order = :nulls_last)
      raise ArgumentError unless [:nulls_last, :nulls_first].include?(nulls_order)
      raise ArgumentError unless [:asc, :desc].include?(direction)

      case nulls_order
      when :nulls_last then nulls_last_order(field, direction)
      when :nulls_first then nulls_first_order(field, direction)
      end
    end

    def self.nulls_last_order(field, direction = 'ASC')
      Arel.sql("#{field} #{direction} NULLS LAST")
    end

    def self.nulls_first_order(field, direction = 'ASC')
      Arel.sql("#{field} #{direction} NULLS FIRST")
    end

    def self.random
      "RANDOM()"
    end

    def self.true_value
      "'t'"
    end

    def self.false_value
      "'f'"
    end

    def self.sanitize_timestamp(timestamp)
      MAX_TIMESTAMP_VALUE > timestamp ? timestamp : MAX_TIMESTAMP_VALUE.dup
    end

    def self.allow_cross_joins_across_databases(url:)
      # this method is implemented in:
      # spec/support/database/prevent_cross_joins.rb
    end

    def self.add_post_migrate_path_to_rails(force: false)
      return if ENV['SKIP_POST_DEPLOYMENT_MIGRATIONS'] && !force

      Rails.application.config.paths['db'].each do |db_path|
        path = Rails.root.join(db_path, 'post_migrate').to_s

        unless Rails.application.config.paths['db/migrate'].include? path
          Rails.application.config.paths['db/migrate'] << path

          # Rails memoizes migrations at certain points where it won't read the above
          # path just yet. As such we must also update the following list of paths.
          ActiveRecord::Migrator.migrations_paths << path
        end
      end
    end

    def self.db_config_names
      ::ActiveRecord::Base.configurations.configs_for(env_name: Rails.env).map(&:name)
    end

    def self.db_config_name(ar_connection)
      if ar_connection.respond_to?(:pool) &&
          ar_connection.pool.respond_to?(:db_config) &&
          ar_connection.pool.db_config.respond_to?(:name)
        return ar_connection.pool.db_config.name
      end

      'unknown'
    end

    # Monkeypatch rails with upgraded database observability
    def self.install_monkey_patches
      ActiveRecord::Base.prepend(ActiveRecordBaseTransactionMetrics)
    end

    def self.read_only?
      false
    end

    def self.read_write?
      !read_only?
    end

    # MonkeyPatch for ActiveRecord::Base for adding observability
    module ActiveRecordBaseTransactionMetrics
      extend ActiveSupport::Concern

      class_methods do
        # A monkeypatch over ActiveRecord::Base.transaction.
        # It provides observability into transactional methods.
        def transaction(**options, &block)
          ActiveSupport::Notifications.instrument('transaction.active_record', { connection: connection }) do
            super(**options, &block)
          end
        end
      end
    end
  end
end

Gitlab::Database.prepend_mod_with('Gitlab::Database')