<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Unit tests for the 5 migration phases not covered in MigrationPhaseTest.php
 * (P1-11): Diagnose, Install_Schema, Backfill_Bulk, Backfill_Unserialize,
 * Verify_Sample.
 *
 * All engine dependencies (WPDO_Schema_Manager, WPDO_Migration_Orchestrator,
 * WPDO_Entity_Migration_Engine, WPDO_Hook_Bus) use the real classes loaded via
 * composer autoload. The $wpdb stub returns null/[] for all DB calls, giving
 * zero-row results sufficient to exercise the logic paths under test.
 */
class MigrationPhaseRemainingTest extends TestCase {

	/** @var object Original $wpdb saved for restoration. */
	private object $original_wpdb;

	protected function setUp(): void {
		global $wpdb;
		$this->original_wpdb    = $wpdb;
		$GLOBALS['_wp_options'] = array();
		WPDO_Mode_Manager::reset_cache();

		// Provide a fresh $wpdb with all methods the phases under test require,
		// regardless of which prior test may have left a broken stub.
		$wpdb = new class {
			public string $prefix     = 'wp_';
			public string $users      = 'wp_users';
			public string $usermeta   = 'wp_usermeta';
			public string $postmeta   = 'wp_postmeta';
			public string $options    = 'wp_options';
			public string $last_error = '';
			public array  $queries    = [];
			public function prepare( string $sql, ...$args ): string {
				$i = 0;
				return preg_replace_callback( '/%[sd]/', function () use ( &$i, $args ) {
					return (string) ( $args[ $i++ ] ?? '?' );
				}, $sql );
			}
			public function get_var( string $sql ): ?string { return null; }
			public function get_col( string $sql ): array { return []; }
			public function get_results( string $sql, $output = null ): array { return []; }
			public function query( string $sql ): int|bool { $this->queries[] = $sql; return 1; }
			public function insert( string $t, array $d, $f = null ): int|false { return 1; }
			public function get_charset_collate(): string { return ''; }
		};

		// Reset Schema_Manager request-scoped cache so table_exists() hits $wpdb each test.
		$ref  = new ReflectionClass( WPDO_Schema_Manager::class );
		$prop = $ref->getProperty( 'table_exists_cache' );
		$prop->setAccessible( true );
		$prop->setValue( null, array() );

		// The unit bootstrap loads Member_Fields / Post_Fields, which register entity
		// groups at include time. These phases assert "no groups registered" behaviour,
		// so clear the registry to isolate them from that ambient state.
		$reg = new ReflectionClass( WPDO_Entity_Registry::class );
		foreach ( array( 'groups', 'field_index' ) as $name ) {
			$p = $reg->getProperty( $name );
			$p->setAccessible( true );
			$p->setValue( null, array() );
		}

		// Install_Schema re-fires wpdo_register_entity_fields, which would re-populate
		// the registry from those same listeners — drop them for the duration.
		$this->saved_field_listeners                            = $GLOBALS['_wp_filter_callbacks']['wpdo_register_entity_fields'] ?? array();
		$GLOBALS['_wp_filter_callbacks']['wpdo_register_entity_fields'] = array();
		WPDO_Entity_Registry::clear_pending_schemas();
	}

	/**
	 * Listeners removed in setUp() and restored in tearDown().
	 *
	 * @var array
	 */
	private array $saved_field_listeners = array();

	protected function tearDown(): void {
		global $wpdb;
		$wpdb = $this->original_wpdb;

		$GLOBALS['_wp_filter_callbacks']['wpdo_register_entity_fields'] = $this->saved_field_listeners;
	}

	private function make_job(): array {
		return array(
			'job_id'           => 'test-job',
			'log'              => array(),
			'state'            => 'running',
			'overall_progress' => 0,
			'metrics'          => array(
				'ratio_start' => 1.5,
				'ratio_now'   => 1.5,
			),
			'options'          => array(),
		);
	}

	// ── WPDO_Phase_Diagnose ───────────────────────────────────────────────────

	public function test_diagnose_name(): void {
		$phase = new WPDO_Phase_Diagnose( 'user' );
		$this->assertSame( 'diagnose', $phase->name() );
	}

	public function test_diagnose_returns_ok(): void {
		$phase  = new WPDO_Phase_Diagnose( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
	}

	public function test_diagnose_records_eav_rows_in_metrics(): void {
		// With $wpdb returning null, count_eav_residue() → 0. Key must exist.
		$phase = new WPDO_Phase_Diagnose( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$this->assertArrayHasKey( 'eav_rows_now', $job['metrics'] );
		$this->assertIsInt( $job['metrics']['eav_rows_now'] );
	}

	public function test_diagnose_records_ratio_in_metrics(): void {
		// 0 users → ratio = 0. Key must exist.
		$phase = new WPDO_Phase_Diagnose( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$this->assertArrayHasKey( 'ratio_now', $job['metrics'] );
	}

	public function test_diagnose_appends_log_entry(): void {
		$phase = new WPDO_Phase_Diagnose( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$this->assertNotEmpty( $job['log'] );
		$this->assertStringContainsString( 'Diagnose', $job['log'][0] );
	}

	// ── WPDO_Phase_Install_Schema ─────────────────────────────────────────────

	public function test_install_schema_name(): void {
		$phase = new WPDO_Phase_Install_Schema( 'user' );
		$this->assertSame( 'install_schema', $phase->name() );
	}

	public function test_install_schema_succeeds_when_no_groups_registered(): void {
		// No groups registered for 'user' in unit-test bootstrap → $missing stays empty.
		$phase  = new WPDO_Phase_Install_Schema( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
	}

	public function test_install_schema_appends_log_entry(): void {
		$phase = new WPDO_Phase_Install_Schema( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$this->assertNotEmpty( $job['log'] );
		$this->assertStringContainsString( 'Schema migration ok', $job['log'][0] );
	}

	// ── WPDO_Phase_Backfill_Bulk ──────────────────────────────────────────────

	public function test_backfill_bulk_name(): void {
		$phase = new WPDO_Phase_Backfill_Bulk( 'user' );
		$this->assertSame( 'backfill_bulk', $phase->name() );
	}

	public function test_backfill_bulk_skips_on_dry_run(): void {
		$phase  = new WPDO_Phase_Backfill_Bulk( 'user' );
		$job    = array_merge( $this->make_job(), array( 'options' => array( 'dry_run' => true ) ) );
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
		$this->assertStringContainsString( 'dry_run', $job['log'][0] ?? '' );
	}

	public function test_backfill_bulk_returns_ok_with_no_groups(): void {
		// No groups → loop body never executes → 0 groups, 0 rows.
		$phase  = new WPDO_Phase_Backfill_Bulk( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
		$found_summary = false;
		foreach ( $job['log'] as $line ) {
			if ( str_contains( $line, 'Bulk backfill' ) ) {
				$found_summary = true;
				$this->assertStringContainsString( '0 groups', $line );
				break;
			}
		}
		$this->assertTrue( $found_summary, 'Log must contain Bulk backfill summary.' );
	}

	// ── WPDO_Phase_Backfill_Unserialize ───────────────────────────────────────

	public function test_backfill_unserialize_name(): void {
		$phase = new WPDO_Phase_Backfill_Unserialize( 'user' );
		$this->assertSame( 'backfill_unserialize', $phase->name() );
	}

	public function test_backfill_unserialize_skips_on_dry_run(): void {
		$phase  = new WPDO_Phase_Backfill_Unserialize( 'user' );
		$job    = array_merge( $this->make_job(), array( 'options' => array( 'dry_run' => true ) ) );
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
		$this->assertStringContainsString( 'dry_run', $job['log'][0] ?? '' );
	}

	public function test_backfill_unserialize_returns_ok_with_no_json_groups(): void {
		// No groups with JSON fields → loop body never executes.
		$phase  = new WPDO_Phase_Backfill_Unserialize( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
	}

	public function test_backfill_unserialize_appends_total_log_entry(): void {
		$phase = new WPDO_Phase_Backfill_Unserialize( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$this->assertNotEmpty( $job['log'] );
		$last = end( $job['log'] );
		$this->assertStringContainsString( 'Row-by-row backfill', $last );
	}

	// ── WPDO_Phase_Verify_Sample ──────────────────────────────────────────────

	public function test_verify_sample_name(): void {
		$phase = new WPDO_Phase_Verify_Sample( 'user' );
		$this->assertSame( 'verify_sample', $phase->name() );
	}

	public function test_verify_sample_24h_starts_window_when_no_started_at(): void {
		$phase  = new WPDO_Phase_Verify_Sample( 'user' );
		$job    = array_merge( $this->make_job(), array( 'options' => array( 'verify_24h' => true ) ) );
		$result = $phase->execute( $job );
		$this->assertSame( 'in_progress', $result['status'] );
		$this->assertArrayHasKey( 'phase_started_at', $job );
	}

	public function test_verify_sample_24h_stays_in_progress_during_window(): void {
		$phase = new WPDO_Phase_Verify_Sample( 'user' );
		$job   = array_merge(
			$this->make_job(),
			array(
				'options'          => array( 'verify_24h' => true ),
				'phase_started_at' => time() - 3600, // 1 hour ago — still within 24h window
			)
		);
		$result = $phase->execute( $job );
		$this->assertSame( 'in_progress', $result['status'] );
	}

	public function test_verify_sample_succeeds_with_zero_users(): void {
		// $wpdb->get_var() returns null → 0 users → 0 samples → 0 diffs → ok.
		$phase  = new WPDO_Phase_Verify_Sample( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
	}

	public function test_verify_sample_log_contains_compare_summary(): void {
		$phase = new WPDO_Phase_Verify_Sample( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );
		$found = false;
		foreach ( $job['log'] as $line ) {
			if ( str_contains( $line, 'Verify' ) ) {
				$found = true;
				break;
			}
		}
		$this->assertTrue( $found, 'Log must contain Verify summary.' );
	}

	public function test_verify_sample_constants(): void {
		$this->assertSame( 500, WPDO_Phase_Verify_Sample::VERIFY_SAMPLE_MIN );
		$this->assertEqualsWithDelta( 0.10, WPDO_Phase_Verify_Sample::VERIFY_SAMPLE_RATIO, 0.0001 );
	}
}