<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * TMDO_Entity_Migration_Engine::migrate_group() must not invent values for keys
 * the object has no native row for.
 *
 * Bug (dev36 R-2.1, 2026-09-26): the engine REPLACEs only the columns it found
 * native rows for, so every other column fell back to its DDL default —
 * user activity.session_count / account_flags (nullable, DEFAULT 0) became 0
 * for every backfilled user, and the checker's "extra" count went 60 → 123.
 *
 * Fixture (user entity, group md_act):
 *   login_count   integer, default 0, nullable
 *   session_count integer, default 0, nullable
 *   note          text
 *   req_flag      integer, required (NOT NULL DEFAULT 0)
 */
class EntityMigrationEngineDefaultsTest extends TestCase {

	private const TABLE  = 'wp_itest_wpdo_user_md_act';
	private const STATUS = 'wp_itest_wpdo_migration_status';

	public static function setUpBeforeClass(): void {
		foreach ( array(
			'includes/adapters/interface-entity-adapter.php',
			'includes/engine/class-tmdo-type-caster.php',
			'includes/engine/class-tmdo-schema-manager.php',
			'includes/engine/class-tmdo-entity-registry.php',
			'includes/engine/class-tmdo-entity-migration-engine.php',
			'includes/adapters/class-tmdo-adapter-user.php',
		) as $file ) {
			require_once WPDO_PLUGIN_DIR . $file;
		}
	}

	protected function setUp(): void {
		global $wpdb;
		self::drop();
		$wpdb->query( "CREATE TABLE `{$wpdb->usermeta}` ( umeta_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id BIGINT UNSIGNED NOT NULL DEFAULT 0, meta_key VARCHAR(255) DEFAULT NULL, meta_value LONGTEXT, PRIMARY KEY (umeta_id), KEY user_id (user_id) ) ENGINE=InnoDB" );
		$wpdb->query( 'CREATE TABLE `' . self::TABLE . '` ( id BIGINT NOT NULL AUTO_INCREMENT, user_id BIGINT NOT NULL, login_count BIGINT(20) DEFAULT 0, session_count BIGINT(20) DEFAULT 0, note VARCHAR(255) DEFAULT NULL, req_flag BIGINT(20) NOT NULL DEFAULT 0, PRIMARY KEY (id), UNIQUE KEY uk_entity (user_id) ) ENGINE=InnoDB' );
		$wpdb->query( 'CREATE TABLE `' . self::STATUS . "` ( id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT, entity_type VARCHAR(50) NOT NULL, group_name VARCHAR(50) NOT NULL, last_id BIGINT UNSIGNED NOT NULL DEFAULT 0, total_migrated BIGINT UNSIGNED NOT NULL DEFAULT 0, status VARCHAR(20) NOT NULL DEFAULT 'pending', started_at DATETIME DEFAULT NULL, completed_at DATETIME DEFAULT NULL, PRIMARY KEY (id), UNIQUE KEY entity_group (entity_type, group_name) ) ENGINE=InnoDB" );

		$GLOBALS['_wp_cache'] = array();
		WPDO_Entity_Registry::init();
		WPDO_Entity_Registry::register_adapter( 'user', new WPDO_Adapter_User() );
		WPDO_Entity_Registry::register_group(
			'user',
			'md_act',
			array(
				array( 'key' => 'login_count', 'type' => 'integer', 'default' => 0 ),
				array( 'key' => 'session_count', 'type' => 'integer', 'default' => 0 ),
				array( 'key' => 'note', 'type' => 'text' ),
				array( 'key' => 'req_flag', 'type' => 'integer', 'default' => 0, 'required' => true ),
			)
		);
		WPDO_Schema_Manager::flush_table_exists_cache();
	}

	protected function tearDown(): void {
		self::drop();
		WPDO_Entity_Registry::init();
	}

	private static function drop(): void {
		global $wpdb;
		foreach ( array( $wpdb->usermeta, self::TABLE, self::STATUS ) as $table ) {
			$wpdb->query( "DROP TABLE IF EXISTS `{$table}`" );
		}
	}

	private function native( int $user_id, string $key, string $value ): void {
		global $wpdb;
		$wpdb->insert( $wpdb->usermeta, array( 'user_id' => $user_id, 'meta_key' => $key, 'meta_value' => $value ) );
	}

	/** @return array<string, string|null> */
	private function flat_row( int $user_id ): array {
		global $wpdb;
		return (array) $wpdb->get_row( $wpdb->prepare( 'SELECT login_count, session_count, note, req_flag FROM `' . self::TABLE . '` WHERE user_id = %d', $user_id ), ARRAY_A );
	}

	private function migrate(): array {
		return TMDO_Entity_Migration_Engine::migrate_group( 'user', 'md_act', array( 'resume' => false, 'sleep_ms' => 0 ) );
	}

	public function test_keys_without_a_native_row_stay_null_instead_of_the_column_default(): void {
		$this->native( 1, 'login_count', '7' );

		$report = $this->migrate();

		$this->assertSame( 1, $report['migrated'] );
		$row = $this->flat_row( 1 );
		$this->assertSame( '7', $row['login_count'] );
		$this->assertNull( $row['session_count'], 'no native session_count — must not become the DEFAULT 0' );
		$this->assertNull( $row['note'] );
	}

	public function test_a_native_value_equal_to_the_default_is_still_written(): void {
		$this->native( 1, 'session_count', '0' );

		$this->migrate();

		$this->assertSame( '0', $this->flat_row( 1 )['session_count'] );
	}

	public function test_a_stale_flat_value_is_cleared_when_the_native_row_is_gone(): void {
		global $wpdb;
		$wpdb->insert( self::TABLE, array( 'user_id' => 1, 'login_count' => 3, 'session_count' => 5, 'note' => 'old' ) );
		$this->native( 1, 'login_count', '4' );

		$this->migrate();

		$row = $this->flat_row( 1 );
		$this->assertSame( '4', $row['login_count'] );
		$this->assertNull( $row['session_count'] );
		$this->assertNull( $row['note'] );
	}

	public function test_a_required_column_without_a_native_row_keeps_its_default(): void {
		$this->native( 1, 'login_count', '1' );

		$report = $this->migrate();

		$this->assertSame( 0, $report['errors'] );
		$this->assertSame( '0', $this->flat_row( 1 )['req_flag'], 'NOT NULL column cannot hold NULL — its default is the documented stand-in' );
	}

	public function test_the_cron_batch_path_does_not_invent_defaults_either(): void {
		$this->native( 1, 'login_count', '2' );

		$result = TMDO_Entity_Migration_Engine::migrate_group_batch( 'user', 'md_act' );

		$this->assertSame( 1, $result['migrated'] );
		$this->assertNull( $this->flat_row( 1 )['session_count'] );
	}
}