<?php
/**
 * Durable job queue rows synced with transient job state.
 *
 * @package SpinxQuickMigrate
 */

namespace SpinxQM;

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

// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Job queue: reads/writes its own custom queue table directly ($wpdb); there is no Core API for a custom table and queue state must reflect LIVE rows (caching would surface stale job status). All identifiers/values are prepared (%i/%s).
/**
 * Persists job rows in the custom queue table, mirroring transient job state.
 */
class Job_Queue {

	/**
	 * Fully prefixed queue table name.
	 *
	 * @var string
	 */
	private $table_name;

	/**
	 * Resolve the prefixed queue table name.
	 */
	public function __construct() {
		global $wpdb;
		$this->table_name = $wpdb->prefix . 'spinxqm_queue';
	}

	/**
	 * Whether the queue table exists.
	 */
	public function table_ready(): bool {
		global $wpdb;
		$like  = $wpdb->esc_like( $this->table_name );
		$found = $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $like ) ); // phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.UnquotedComplexPlaceholder
		return ! empty( $found );
	}

	/**
	 * Upsert a row from the in-memory transient job (same job_id UUID).
	 *
	 * @param string $job_id Job ID (UUID) shared by the transient and the queue row.
	 */
	public function sync_from_transient( string $job_id ): void {
		if ( ! $this->table_ready() ) {
			return;
		}

		$job = Helpers::get_job( $job_id );
		if ( empty( $job ) ) {
			return;
		}

		global $wpdb;

		$status = self::normalize_status( (string) ( $job['status'] ?? 'running' ) );
		$now    = current_time( 'mysql' );

		$row = array(
			'operation_type'         => sanitize_key( (string) ( $job['type'] ?? '' ) ),
			'status'                 => $status,
			'priority'               => 50,
			'payload'                => wp_json_encode( $job ),
			'result'                 => isset( $job['result'] ) ? wp_json_encode( $job['result'] ) : null,
			'error_message'          => null,
			'dependencies'           => wp_json_encode( array() ),
			'dependencies_satisfied' => 1,
			'updated_at'             => $now,
		);

		if ( in_array( $status, array( 'failed', 'error' ), true ) ) {
			$row['error_message'] = (string) ( $job['message'] ?? '' );
		}

		if ( in_array( $status, array( 'completed', 'failed', 'success', 'error', 'cancelled' ), true ) ) {
			$row['completed_at'] = $now;
		}

		$existing = $wpdb->get_var( $wpdb->prepare( 'SELECT id FROM %i WHERE job_id = %s', $this->table_name, $job_id ) );

		if ( $existing ) {
			$wpdb->update( $this->table_name, $row, array( 'job_id' => $job_id ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
			return;
		}

		$row['job_id']     = $job_id;
		$row['created_at'] = $now;
		$row['started_at'] = $now;
		$wpdb->insert( $this->table_name, $row ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
	}

	/**
	 * Return the job_id of the most recent active (queued/running/paused) row,
	 * or an empty string when nothing is in flight.
	 */
	public function find_active(): string {
		if ( ! $this->table_ready() ) {
			return '';
		}

		global $wpdb;
		$job_id = $wpdb->get_var(
			$wpdb->prepare(
				"SELECT job_id FROM %i WHERE status IN ( 'queued', 'running', 'paused' ) ORDER BY created_at DESC LIMIT 1",
				$this->table_name
			)
		);

		return is_string( $job_id ) ? $job_id : '';
	}

	/**
	 * Count queue rows that are running or queued.
	 *
	 * @return array<string,int>
	 */
	public function count_by_status(): array {
		if ( ! $this->table_ready() ) {
			return array(
				'running' => 0,
				'queued'  => 0,
			);
		}

		global $wpdb;
		$running = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE status = %s', $this->table_name, 'running' ) );
		$queued  = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE status = %s', $this->table_name, 'queued' ) );

		return array(
			'running' => $running,
			'queued'  => $queued,
		);
	}

	/**
	 * Fetch a filtered, paginated page of queue rows.
	 *
	 * @param array<string,mixed> $filters  Optional `type` and `status` filters.
	 * @param int                 $page     1-based page number.
	 * @param int                 $per_page Rows per page.
	 * @return array<string,mixed>
	 */
	public function list_jobs( array $filters, int $page, int $per_page ): array {
		if ( ! $this->table_ready() ) {
			return array(
				'operations' => array(),
				'pagination' => array(
					'total'        => 0,
					'pages'        => 0,
					'current_page' => $page,
					'per_page'     => $per_page,
				),
			);
		}

		global $wpdb;

		// Sentinel pass-through guards keep the query a single literal string.
		$type   = ! empty( $filters['type'] ) ? sanitize_key( (string) $filters['type'] ) : '';
		$status = ! empty( $filters['status'] ) ? sanitize_key( (string) $filters['status'] ) : '';
		$offset = max( 0, ( $page - 1 ) * $per_page );

		$total = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT(*) FROM %i WHERE ( %s = '' OR operation_type = %s ) AND ( %s = '' OR status = %s )",
				$this->table_name,
				$type,
				$type,
				$status,
				$status
			)
		);

		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT job_id, operation_type, status, error_message, created_at, completed_at, updated_at FROM %i WHERE ( %s = '' OR operation_type = %s ) AND ( %s = '' OR status = %s ) ORDER BY created_at DESC LIMIT %d OFFSET %d",
				$this->table_name,
				$type,
				$type,
				$status,
				$status,
				$per_page,
				$offset
			),
			ARRAY_A
		);

		return array(
			'operations' => is_array( $rows ) ? $rows : array(),
			'pagination' => array(
				'total'        => $total,
				'pages'        => $per_page > 0 ? (int) ceil( $total / $per_page ) : 0,
				'current_page' => $page,
				'per_page'     => $per_page,
			),
		);
	}

	/**
	 * Map a job status to a known queue status (unknown values become "running").
	 *
	 * @param string $status Raw job status.
	 * @return string
	 */
	private static function normalize_status( string $status ): string {
		$status = strtolower( $status );
		if ( in_array( $status, array( 'queued', 'running', 'completed', 'failed', 'paused', 'success', 'error', 'cancelled' ), true ) ) {
			return $status;
		}
		if ( 'complete' === $status ) {
			return 'completed';
		}
		return 'running';
	}
}