namespace :gitlab do
  namespace :db do
    desc 'GitLab | DB | Manually insert schema migration version'
    task :mark_migration_complete, [:version] => :environment do |_, args|
      unless args[:version]
        puts "Must specify a migration version as an argument".color(:red)
        exit 1
      end

      version = args[:version].to_i
      if version == 0
        puts "Version '#{args[:version]}' must be a non-zero integer".color(:red)
        exit 1
      end

      sql = "INSERT INTO schema_migrations (version) VALUES (#{version})"
      begin
        ActiveRecord::Base.connection.execute(sql)
        puts "Successfully marked '#{version}' as complete".color(:green)
      rescue ActiveRecord::RecordNotUnique
        puts "Migration version '#{version}' is already marked complete".color(:yellow)
      end
    end

    desc 'GitLab | DB | Drop all tables'
    task drop_tables: :environment do
      connection = ActiveRecord::Base.connection

      # In PostgreSQLAdapter, data_sources returns both views and tables, so use
      # #tables instead
      tables = connection.tables

      # Removes the entry from the array
      tables.delete 'schema_migrations'
      # Truncate schema_migrations to ensure migrations re-run
      connection.execute('TRUNCATE schema_migrations') if connection.table_exists? 'schema_migrations'

      # Drop any views
      connection.views.each do |view|
        connection.execute("DROP VIEW IF EXISTS #{connection.quote_table_name(view)} CASCADE")
      end

      # Drop tables with cascade to avoid dependent table errors
      # PG: http://www.postgresql.org/docs/current/static/ddl-depend.html
      # Add `IF EXISTS` because cascade could have already deleted a table.
      tables.each { |t| connection.execute("DROP TABLE IF EXISTS #{connection.quote_table_name(t)} CASCADE") }

      # Drop all extra schema objects GitLab owns
      Gitlab::Database::EXTRA_SCHEMAS.each do |schema|
        connection.execute("DROP SCHEMA IF EXISTS #{connection.quote_table_name(schema)}")
      end
    end

    desc 'GitLab | DB | Configures the database by running migrate, or by loading the schema and seeding if needed'
    task configure: :environment do
      # Check if we have existing db tables
      # The schema_migrations table will still exist if drop_tables was called
      if ActiveRecord::Base.connection.tables.count > 1
        Rake::Task['db:migrate'].invoke
      else
        # Add post-migrate paths to ensure we mark all migrations as up
        Gitlab::Database.add_post_migrate_path_to_rails(force: true)
        Rake::Task['db:structure:load'].invoke
        Rake::Task['db:seed_fu'].invoke
      end
    end

    desc 'GitLab | DB | Run database migrations and print `unattended_migrations_completed` if action taken'
    task unattended: :environment do
      no_database = !ActiveRecord::Base.connection.schema_migration.table_exists?
      needs_migrations = ActiveRecord::Base.connection.migration_context.needs_migration?

      if no_database || needs_migrations
        Rake::Task['gitlab:db:configure'].invoke
        puts "unattended_migrations_completed"
      else
        puts "unattended_migrations_static"
      end
    end

    desc 'GitLab | DB | Checks if migrations require downtime or not'
    task :downtime_check, [:ref] => :environment do |_, args|
      abort 'You must specify a Git reference to compare with' unless args[:ref]

      require 'shellwords'

      ref = Shellwords.escape(args[:ref])

      migrations = `git diff #{ref}.. --diff-filter=A --name-only -- db/migrate`.lines
        .map { |file| Rails.root.join(file.strip).to_s }
        .select { |file| File.file?(file) }
        .select { |file| /\A[0-9]+.*\.rb\z/ =~ File.basename(file) }

      Gitlab::DowntimeCheck.new.check_and_print(migrations)
    end

    desc 'GitLab | DB | Sets up EE specific database functionality'

    if Gitlab.ee?
      task setup_ee: %w[geo:db:drop geo:db:create geo:db:schema:load geo:db:migrate]
    else
      task :setup_ee
    end

    desc 'This adjusts and cleans db/structure.sql - it runs after db:structure:dump'
    task :clean_structure_sql do |task_name|
      structure_file = 'db/structure.sql'
      schema = File.read(structure_file)

      File.open(structure_file, 'wb+') do |io|
        Gitlab::Database::SchemaCleaner.new(schema).clean(io)
      end

      # Allow this task to be called multiple times, as happens when running db:migrate:redo
      Rake::Task[task_name].reenable
    end

    desc 'This dumps GitLab specific database details - it runs after db:structure:dump'
    task :dump_custom_structure do |task_name|
      Gitlab::Database::CustomStructure.new.dump

      # Allow this task to be called multiple times, as happens when running db:migrate:redo
      Rake::Task[task_name].reenable
    end

    desc 'This loads GitLab specific database details - runs after db:structure:dump'
    task :load_custom_structure do
      configuration = Rails.application.config_for(:database)

      ENV['PGHOST']     = configuration['host']          if configuration['host']
      ENV['PGPORT']     = configuration['port'].to_s     if configuration['port']
      ENV['PGPASSWORD'] = configuration['password'].to_s if configuration['password']
      ENV['PGUSER']     = configuration['username'].to_s if configuration['username']

      command = 'psql'
      dump_filepath = Gitlab::Database::CustomStructure.custom_dump_filepath.to_path
      args = ['-v', 'ON_ERROR_STOP=1', '-q', '-X', '-f', dump_filepath, configuration['database']]

      unless Kernel.system(command, *args)
        raise "failed to execute:\n#{command} #{args.join(' ')}\n\n" \
          "Please ensure `#{command}` is installed in your PATH and has proper permissions.\n\n"
      end
    end

    # Inform Rake that custom tasks should be run every time rake db:structure:dump is run
    Rake::Task['db:structure:dump'].enhance do
      Rake::Task['gitlab:db:clean_structure_sql'].invoke
      Rake::Task['gitlab:db:dump_custom_structure'].invoke
    end

    # Inform Rake that custom tasks should be run every time rake db:structure:load is run
    Rake::Task['db:structure:load'].enhance do
      Rake::Task['gitlab:db:load_custom_structure'].invoke
    end

    desc 'Create missing dynamic database partitions'
    task :create_dynamic_partitions do
      Gitlab::Database::Partitioning::PartitionCreator.new.create_partitions
    end

    # This is targeted towards deploys and upgrades of GitLab.
    # Since we're running migrations already at this time,
    # we also check and create partitions as needed here.
    Rake::Task['db:migrate'].enhance do
      Rake::Task['gitlab:db:create_dynamic_partitions'].invoke
    end

    # When we load the database schema from db/structure.sql
    # we don't have any dynamic partitions created. We don't really need to
    # because application initializers/sidekiq take care of that, too.
    # However, the presence of partitions for a table has influence on their
    # position in db/structure.sql (which is topologically sorted).
    #
    # Other than that it's helpful to create partitions early when bootstrapping
    # a new installation.
    Rake::Task['db:structure:load'].enhance do
      Rake::Task['gitlab:db:create_dynamic_partitions'].invoke
    end

    # During testing, db:test:load restores the database schema from scratch
    # which does not include dynamic partitions. We cannot rely on application
    # initializers here as the application can continue to run while
    # a rake task reloads the database schema.
    Rake::Task['db:test:load'].enhance do
      Rake::Task['gitlab:db:create_dynamic_partitions'].invoke
    end

    desc 'reindex a regular (non-unique) index without downtime to eliminate bloat'
    task :reindex, [:index_name] => :environment do |_, args|
      unless Feature.enabled?(:database_reindexing, type: :ops)
        puts "This feature (database_reindexing) is currently disabled.".color(:yellow)
        exit
      end

      indexes = if args[:index_name]
                  [Gitlab::Database::PostgresIndex.by_identifier(args[:index_name])]
                else
                  Gitlab::Database::Reindexing.candidate_indexes.random_few(2)
                end

      Gitlab::Database::Reindexing.perform(indexes)
    rescue => e
      Gitlab::AppLogger.error(e)
      raise
    end
  end
end