<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Unit tests for WPDO_Migration_Phase_Base and WPDO_Phase_Completed.
 *
 * WPDO_Phase_Completed is the simplest phase — no external class calls — so it
 * exercises the full interface contract without mocking infrastructure.
 */
class MigrationPhaseTest extends TestCase {

	private function make_job( float $ratio_start = 1.5, float $ratio_now = 0.8 ): array {
		return array(
			'job_id'           => 'test-job',
			'log'              => array(),
			'state'            => 'running',
			'overall_progress' => 0,
			'metrics'          => array(
				'ratio_start' => $ratio_start,
				'ratio_now'   => $ratio_now,
			),
		);
	}

	// ── WPDO_Phase_Completed ──────────────────────────────────────────────────

	public function test_completed_returns_done_status(): void {
		$phase  = new WPDO_Phase_Completed( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'done', $result['status'] );
	}

	public function test_completed_sets_state_to_completed(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );

		$this->assertSame( 'completed', $job['state'] );
	}

	public function test_completed_sets_overall_progress_to_100(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$job   = $this->make_job();
		$phase->execute( $job );

		$this->assertSame( 100, $job['overall_progress'] );
	}

	public function test_completed_sets_completed_at_timestamp(): void {
		$before = time();
		$phase  = new WPDO_Phase_Completed( 'user' );
		$job    = $this->make_job();
		$phase->execute( $job );

		$this->assertGreaterThanOrEqual( $before, $job['completed_at'] );
		$this->assertLessThanOrEqual( time(), $job['completed_at'] );
	}

	public function test_completed_appends_log_entry(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$job   = $this->make_job( 1.5, 0.75 );
		$phase->execute( $job );

		$this->assertNotEmpty( $job['log'] );
		$last_line = end( $job['log'] );
		$this->assertStringContainsString( 'Migration complete', $last_line );
	}

	public function test_completed_name_is_completed(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$this->assertSame( 'completed', $phase->name() );
	}

	// ── WPDO_Migration_Phase_Base log truncation ──────────────────────────────

	public function test_log_truncates_at_max_log_lines(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$job   = $this->make_job();

		// Each execute() appends exactly one log entry — call it MAX+5 times.
		$max = WPDO_Migration_Phase_Base::MAX_LOG_LINES;
		for ( $i = 0; $i < $max + 5; $i++ ) {
			$phase->execute( $job );
		}

		$this->assertCount( $max, $job['log'] );
	}

	public function test_log_keeps_most_recent_lines_when_truncating(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		$job   = $this->make_job();

		$max = WPDO_Migration_Phase_Base::MAX_LOG_LINES;
		for ( $i = 0; $i < $max + 10; $i++ ) {
			$phase->execute( $job );
		}

		// Log contains exactly MAX lines with truncation keeping the most recent.
		$this->assertCount( $max, $job['log'] );
		// First kept line was written after at least 10 entries were discarded.
		$first_line = $job['log'][0];
		$this->assertStringContainsString( 'Migration complete', $first_line );
	}

	// ── Phase interface contract ───────────────────────────────────────────────

	public function test_phase_implements_interface(): void {
		$phase = new WPDO_Phase_Completed( 'user' );
		// Interfaces cannot be class_alias()'d; the phase contract is core-internal
		// (only the 11 built-in phases implement it), so assert the canonical name.
		$this->assertInstanceOf( TMDO_Migration_Phase_Interface::class, $phase );
	}

	public function test_phase_entity_type_injectable(): void {
		$phase_user = new WPDO_Phase_Completed( 'user' );
		$phase_term = new WPDO_Phase_Completed( 'term' );

		// Both are independent instances — no shared state.
		$job_a = $this->make_job();
		$job_b = $this->make_job();
		$phase_user->execute( $job_a );
		$phase_term->execute( $job_b );

		$this->assertSame( 'completed', $job_a['state'] );
		$this->assertSame( 'completed', $job_b['state'] );
	}

	// ── Phase_Cleanup — RuntimeException guards (P1-11, highest priority) ────────

	protected function setUp(): void {
		$GLOBALS['_wp_options'] = [];
		WPDO_Mode_Manager::reset_cache();
	}

	private function make_mode_option( string $entity_type, string $mode ): void {
		$GLOBALS['_wp_options']['wpdo_bridge_modes'] = array( $entity_type => $mode );
		WPDO_Mode_Manager::reset_cache();
	}

	public function test_cleanup_throws_when_mode_not_aeav_only(): void {
		$this->make_mode_option( 'user', 'dual_write' );
		$phase = new WPDO_Phase_Cleanup( 'user' );
		$job   = $this->make_job();

		$this->expectException( \RuntimeException::class );
		$this->expectExceptionMessageMatches( '/must be aeav_only/' );
		$phase->execute( $job );
	}

	public function test_cleanup_throws_when_auto_backup_requested_but_no_path(): void {
		$this->make_mode_option( 'user', 'aeav_only' );
		$phase = new WPDO_Phase_Cleanup( 'user' );
		$job   = array_merge(
			$this->make_job(),
			array(
				'options'     => array( 'auto_backup' => true ),
				'backup_path' => '', // empty — simulates backup that never ran
			)
		);

		$this->expectException( \RuntimeException::class );
		$this->expectExceptionMessageMatches( '/no backup_path on record/' );
		$phase->execute( $job );
	}

	public function test_cleanup_skips_when_dry_run(): void {
		$this->make_mode_option( 'user', 'dual_write' ); // wrong mode, but dry_run should short-circuit first
		$phase = new WPDO_Phase_Cleanup( '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] ?? '' );
	}

	// ── Phase_Demote ──────────────────────────────────────────────────────────────

	public function test_demote_skips_when_not_aeav_only(): void {
		$this->make_mode_option( 'user', 'shadow_read' );
		$phase  = new WPDO_Phase_Demote( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		$this->assertStringContainsString( 'skipped', $job['log'][0] ?? '' );
	}

	public function test_demote_transitions_aeav_only_to_dual_write(): void {
		$this->make_mode_option( 'user', 'aeav_only' );
		$phase  = new WPDO_Phase_Demote( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		$this->assertSame( 'dual_write', WPDO_Mode_Manager::get( 'user' ) );
	}

	// ── Phase_Backup — skip when auto_backup=false ────────────────────────────────

	public function test_backup_skips_when_auto_backup_false(): void {
		$phase = new WPDO_Phase_Backup( 'user' );
		$job   = array_merge( $this->make_job(), array( 'options' => array( 'auto_backup' => false ) ) );

		$result = $phase->execute( $job );
		$this->assertSame( 'ok', $result['status'] );
		$this->assertStringContainsString( 'skipped', $job['log'][0] ?? '' );
	}

	// ── Phase_Promote_Aeav ────────────────────────────────────────────────────────

	public function test_promote_aeav_skips_when_already_aeav_only(): void {
		$this->make_mode_option( 'user', 'aeav_only' );
		$phase  = new WPDO_Phase_Promote_Aeav( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		$this->assertStringContainsString( 'Already', $job['log'][0] ?? '' );
	}

	public function test_promote_aeav_transitions_from_shadow_read(): void {
		$this->make_mode_option( 'user', 'shadow_read' );
		$phase  = new WPDO_Phase_Promote_Aeav( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		$this->assertSame( 'aeav_only', WPDO_Mode_Manager::get( 'user' ) );
	}

	// ── Phase_Promote_Shadow ──────────────────────────────────────────────────────

	public function test_promote_shadow_transitions_from_dual_write(): void {
		$this->make_mode_option( 'user', 'dual_write' );
		$phase  = new WPDO_Phase_Promote_Shadow( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		$this->assertSame( 'shadow_read', WPDO_Mode_Manager::get( 'user' ) );
	}

	public function test_promote_shadow_skips_when_already_at_shadow_or_higher(): void {
		$this->make_mode_option( 'user', 'aeav_only' );
		$phase  = new WPDO_Phase_Promote_Shadow( 'user' );
		$job    = $this->make_job();
		$result = $phase->execute( $job );

		$this->assertSame( 'ok', $result['status'] );
		// Mode should be unchanged (already past shadow_read).
		$this->assertSame( 'aeav_only', WPDO_Mode_Manager::get( 'user' ) );
	}

	// ── Phase name() contract ─────────────────────────────────────────────────────

	public function test_all_phases_return_expected_names(): void {
		$cases = array(
			array( new WPDO_Phase_Backup( 'user' ), 'backup' ),
			array( new WPDO_Phase_Cleanup( 'user' ), 'cleanup' ),
			array( new WPDO_Phase_Demote( 'user' ), 'demote' ),
			array( new WPDO_Phase_Promote_Aeav( 'user' ), 'promote_aeav' ),
			array( new WPDO_Phase_Promote_Shadow( 'user' ), 'promote_shadow' ),
		);
		foreach ( $cases as [ $phase, $expected ] ) {
			$this->assertSame( $expected, $phase->name() );
		}
	}
}