feat: add admin notices

src/Admin/AdminNotice.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * Admin notice value object.
+ *
+ * @package WPContentSync
+ */
+
+namespace WPContentSync\Admin;
+
+final class AdminNotice {
+	private const TYPES = array( 'success', 'warning', 'error', 'info' );
+
+	private string $type;
+	private string $message;
+
+	public function __construct( string $type, string $message ) {
+		$this->type    = in_array( $type, self::TYPES, true ) ? $type : 'info';
+		$this->message = sanitize_text_field( $message );
+	}
+
+	public function type(): string {
+		return $this->type;
+	}
+
+	public function message(): string {
+		return $this->message;
+	}
+}

src/Admin/AdminNoticeRepository.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ * Builds admin notices from redirect query args.
+ *
+ * @package WPContentSync
+ */
+
+namespace WPContentSync\Admin;
+
+final class AdminNoticeRepository {
+	/**
+	 * @return array<int, AdminNotice>
+	 */
+	public function current(): array {
+		$notices = array();
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_imported'] ) ) {
+			$notices[] = new AdminNotice( 'success', __( 'The package JSON file was imported successfully.', 'wp-content-sync' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_import_error'] ) ) {
+			$notices[] = new AdminNotice( 'error', $this->queryValue( 'wpcs_import_error' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_settings_saved'] ) ) {
+			$notices[] = new AdminNotice( 'success', __( 'Settings saved.', 'wp-content-sync' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_connection_ok'] ) ) {
+			$notices[] = new AdminNotice( 'success', __( 'REST connection succeeded.', 'wp-content-sync' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_logs_cleared'] ) ) {
+			$notices[] = new AdminNotice( 'success', __( 'Logs cleared.', 'wp-content-sync' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_connection_error'] ) ) {
+			$notices[] = new AdminNotice( 'error', $this->queryValue( 'wpcs_connection_error' ) );
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		if ( isset( $_GET['wpcs_export_error'] ) ) {
+			$notices[] = new AdminNotice( 'error', $this->queryValue( 'wpcs_export_error' ) );
+		}
+
+		return $notices;
+	}
+
+	private function queryValue( string $key ): string {
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Reads redirect-only admin notice query args.
+		return sanitize_text_field( wp_unslash( $_GET[ $key ] ?? '' ) );
+	}
+}