<?php
/**
 * Migration phase: promote entity mode to shadow_read.
 *
 * @package TMDO
 * @since 3.0.1
 */


if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Transitions mode from dual_write → shadow_read (flat table serves reads).
 */
class TMDO_Phase_Promote_Shadow extends TMDO_Migration_Phase_Base {

	/**
	 * Returns the phase slug.
	 *
	 * @return string
	 */
	public function name(): string {
		return 'promote_shadow';
	}

	/**
	 * Executes the phase.
	 *
	 * @param array $job Job array (by reference).
	 * @return array{status: string}
	 * @throws \RuntimeException If mode transition fails.
	 */
	public function execute( array &$job ): array {
		$current = TMDO_Mode_Manager::get( $this->entity_type );

		if ( TMDO_Mode_Manager::MODE_DUAL_WRITE === $current ) {
			$r = TMDO_Mode_Manager::set( $this->entity_type, TMDO_Mode_Manager::MODE_SHADOW_READ );
			if ( is_wp_error( $r ) ) {
				throw new \RuntimeException( 'Promote to shadow_read failed: ' . $r->get_error_message() );
			}
			$this->log( $job, 'Mode: dual_write → shadow_read (verifying flat reads)' );
		} else {
			$this->log( $job, "↪ Already at {$current}; skip promote_shadow" );
		}

		return array( 'status' => 'ok' );
	}
}