<?php
namespace Rafgrid;

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

/**
 * Audit log: who changed which cell, old -> new. Table: {prefix}rafgrid_audit.
 */
class Audit {

	public static function create_table() {
		global $wpdb;
		$table = $wpdb->prefix . 'rafgrid_audit';
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		$charset = $wpdb->get_charset_collate();
		dbDelta(
			"CREATE TABLE {$table} (
			id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
			user_id BIGINT UNSIGNED NOT NULL,
			post_id BIGINT UNSIGNED NOT NULL,
			column_key VARCHAR(191) NOT NULL DEFAULT '',
			old_value LONGTEXT NULL,
			new_value LONGTEXT NULL,
			created_at DATETIME NOT NULL,
			PRIMARY KEY (id),
			KEY post_id (post_id),
			KEY user_id (user_id)
		) {$charset};"
		);
	}

	/**
	 * @param int    $post_id Post ID.
	 * @param string $column  Column key.
	 * @param mixed  $old     Old value.
	 * @param mixed  $new     New value.
	 */
	private static ?Settings $settings_cache = null;

	public static function log( $post_id, $column, $old, $new ) {
		if ( null === self::$settings_cache ) {
			self::$settings_cache = new Settings();
		}
		if ( ! self::$settings_cache->get( 'enable_history', 1 ) ) {
			return;
		}
		if ( self::stringify( $old ) === self::stringify( $new ) ) {
			return;
		}
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
		$wpdb->insert(
			$wpdb->prefix . 'rafgrid_audit',
			array(
				'user_id'    => get_current_user_id(),
				'post_id'    => absint( $post_id ),
				'column_key' => substr( sanitize_text_field( $column ), 0, 191 ),
				'old_value'  => substr( self::stringify( $old ), 0, 2000 ),
				'new_value'  => substr( self::stringify( $new ), 0, 2000 ),
				'created_at' => current_time( 'mysql' ),
			),
			array( '%d', '%d', '%s', '%s', '%s', '%s' )
		);
	}

	/**
	 * @param mixed $v Value.
	 */
	public static function stringify( $v ): string {
		if ( is_array( $v ) ) {
			return implode( ',', array_map( static fn( $x ) => is_array( $x ) ? wp_json_encode( $x ) : (string) $x, $v ) );
		}
		if ( is_bool( $v ) ) {
			return $v ? '1' : '0';
		}
		return null === $v ? '' : (string) $v;
	}

	/**
	 * Recent entries.
	 *
	 * @param int $limit Limit.
	 * @return array
	 */
	public static function recent( $limit = 50 ) {
		global $wpdb;
		$table = $wpdb->prefix . 'rafgrid_audit';
		// Administrators see the whole log, everyone else only their own changes.
		if ( current_user_can( 'manage_options' ) ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Plugin's own table; live data that must not be served from cache.
			$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i ORDER BY id DESC LIMIT %d', $table, $limit ), ARRAY_A );
		} else {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Plugin's own table; live data that must not be served from cache.
			$rows = $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i WHERE user_id = %d ORDER BY id DESC LIMIT %d', $table, get_current_user_id(), $limit ), ARRAY_A );
		}
		return is_array( $rows ) ? $rows : array();
	}

	/**
	 * Roll back one audit entry (restore old value).
	 *
	 * @param int $id Audit ID.
	 * @return true|\WP_Error
	 */
	public static function rollback( $id ) {
		global $wpdb;
		$table = $wpdb->prefix . 'rafgrid_audit';
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Plugin's own table; live data that must not be served from cache.
		$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE id = %d', $table, absint( $id ) ) );
		if ( ! $row ) {
			return new \WP_Error( 'rafgrid_no_audit', __( 'Audit entry not found.', 'rafgrid' ) );
		}
		if ( ! current_user_can( 'manage_options' ) && (int) $row->user_id !== get_current_user_id() ) {
			return new \WP_Error( 'rafgrid_forbidden', __( 'You cannot edit this item.', 'rafgrid' ) );
		}
		// save_cell checks edit rights on the item and logs the rollback itself.
		return Saving::save_cell( (int) $row->post_id, $row->column_key, $row->old_value );
	}
}