Add first pass at upgrade warnings

composer.json

@@ -18,7 +18,8 @@
 	"autoload": {
 		"files": [
 			"inc/namespace.php",
-			"inc/about/namespace.php"
+			"inc/about/namespace.php",
+			"inc/upgrades/namespace.php"
 		],
 		"classmap": [
 			"inc/"

inc/namespace.php

@@ -14,6 +14,36 @@
  */
 function bootstrap() {
 	About\bootstrap();
+	Upgrades\bootstrap();
+}
+
+/**
+ * Get the major version of Altis in use.
+ *
+ * @return int|null Major version if available, or null if invalid or development version.
+ */
+function get_version() : ?int {
+	$data = get_composer_data();
+	$core = $data['altis/core'] ?? null;
+	if ( ! $core ) {
+		// Uh… I guess there's no Altis here then!
+		return false;
+	}
+
+	// Is this a dev version?
+	if ( substr( $core['version'], 0, 4 ) === 'dev-' ) {
+		return false;
+	}
+
+	$version = $core['version_normalized'];
+	$parts = explode( '.', $version, 2 );
+	if ( count( $parts ) < 2 ) {
+		// Invalid version, probably another development version.
+		return false;
+	}
+
+	$major = intval( $parts[0] );
+	return $major;
 }
 
 /**

inc/upgrades/namespace.php

@@ -0,0 +1,178 @@
+<?php
+
+namespace Altis\Upgrades;
+
+use Altis;
+
+/**
+ * Bootstrap the actions.
+ */
+function bootstrap() {
+	add_action( 'wp_network_dashboard_setup', __NAMESPACE__ . '\\register_widget' );
+	add_action( 'wp_dashboard_setup', __NAMESPACE__ . '\\register_widget' );
+}
+
+/**
+ * Register our dashboard widget.
+ */
+function register_widget() {
+	if ( ! current_user_can( 'edit_options' ) ) {
+		return;
+	}
+
+	if ( is_version_supported() ) {
+		return;
+	}
+
+	add_action( 'admin_head-index.php', function () {
+?>
+<style>
+#altis-upgrade-warning {
+    position: relative;
+    margin: 40px 0 10px;
+    padding: 6px 10px;
+    border: 2px solid #df3232;
+    box-shadow: 0 1px 1px rgba(0, 0, 0, 0.04);
+    background: #fff;
+    font-size: 13px;
+    line-height: 1.7;
+}
+
+#altis-upgrade-warning h1 {
+	background: #df3232;
+	color: #f0f0f0;
+	padding: 6px 10px;
+	margin: -6px -10px 0;
+}
+
+#altis-upgrade-warning h1 .dashicons {
+	color: #df3232;
+	color: #f0f0f0;
+	font-size: 23px;
+	height: 23px;
+	width: 23px;
+	line-height: 1.3;
+}
+
+#altis-upgrade-warning p {
+	font-size: 14px;
+}
+
+#altis-upgrade-warning .button .dashicons-external {
+    line-height: 43px;
+}
+</style>
+<?php
+	} );
+
+	add_action( 'all_admin_notices', function () {
+		global $pagenow;
+		if ( $pagenow !== 'index.php' ) {
+			return;
+		}
+
+		render_widget();
+	} );
+}
+
+/**
+ * Get the supported version information from altis-dxp.com
+ *
+ * @param bool $skip_cache True to override the cache.
+ * @return array Data from altis-dxp.com
+ */
+function get_supported_version_info() {
+	return [
+		'supported' => [
+			4,
+			5,
+			6,
+			7,
+		],
+		'latest' => [
+			'version' => 7,
+			'date' => '2021-05-04',
+			'blog' => 'https://www.altis-dxp.com/foo/',
+		],
+	];
+}
+
+/**
+ * Is this site on the latest version of Altis?
+ *
+ * @return bool
+ */
+function is_version_latest() : bool {
+	$version = Altis\get_version();
+	$support = get_supported_version_info();
+	return $version === $support['latest']['version'];
+}
+
+/**
+ * Is this site on a supported version of Altis?
+ *
+ * @return bool
+ */
+function is_version_supported() : bool {
+	$version = Altis\get_version();
+	$support = get_supported_version_info();
+	return in_array( $version, $support['supported'], true );
+}
+
+/**
+ * Render the unsupported version widget.
+ *
+ * @return void
+ */
+function render_widget() {
+	$version = Altis\get_version();
+	$info = get_supported_version_info();
+
+	?>
+	<div class="wrap">
+	<div id="altis-upgrade-warning">
+		<h1>
+			<span aria-hidden="true" class="dashicons dashicons-warning"></span>
+			<span class="screen-reader-text"><?php esc_html_e( 'Warning:', 'altis' ) ?></span>
+			<?php esc_html_e( 'Altis Upgrade Required', 'altis' ) ?>
+		</h1>
+		<p><?php
+		echo esc_html( sprintf(
+			__( 'You are running an unsupported version of Altis (Altis v%d).', 'altis' ),
+			$version
+		) );
+		?></p>
+
+		<p><?php
+		echo clean_html( sprintf(
+			__( 'The latest version of Altis is <a href="%s">Altis v%d</a>, released on %s.', 'altis' ),
+			$info['latest']['blog'],
+			$info['latest']['version'],
+			date_i18n( get_option( 'date_format' ), strtotime( $info['latest']['date'] ) )
+		), 'a' );
+		?></p>
+
+		<p><?php esc_html_e( 'Newer versions of Altis are faster and come with new features included in your existing licensing cost.', 'altis' ) ?></p>
+
+		<p class="button-container">
+			<a
+				class="button button-primary button-hero"
+				href="https://docs.altis-dxp.com/guides/upgrading/"
+				target="_blank"
+				rel="noopener noreferrer"
+			>
+				<?php
+					echo clean_html( sprintf(
+						'%1$s <span class="screen-reader-text">%2$s</span>',
+						__( 'Learn more about Altis upgrades' ),
+						/* translators: Accessibility text. */
+						__( '(opens in a new tab)' )
+					), 'span' );
+				?>
+				<span aria-hidden="true" class="dashicons dashicons-external"></span>
+			</a>
+		</p>
+	</div>
+	</div>
+	<?php
+}