From 6a2914f5fcc8d546b97e843ea8ee85e25b1b2e48 Mon Sep 17 00:00:00 2001
From: Viktor Miller <viktor.miller@vihais.com>
Date: Wed, 14 Jan 2026 21:09:01 +0900
Subject: [PATCH] feat(06-03): implement async batch email processor callback

Add process_mentor_notification_batch() method to process Action
Scheduler callbacks. Sends German email notifications with job details
(title, location, type, permalink) to batches of opted-in mentors.
Includes rate limit delay (0.1s between emails), error logging for
failures, and unsubscribe hint in email body. Registered callback for
'ddhh_jm_send_mentor_notification_batch' hook.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 includes/class-scheduler.php | 108 ++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 1 deletion(-)

diff --git a/includes/class-scheduler.php b/includes/class-scheduler.php
index 565059a..9760837 100644
--- a/includes/class-scheduler.php
+++ b/includes/class-scheduler.php
@@ -22,7 +22,8 @@ class DDHH_JM_Scheduler {
 	 * Initialize hooks.
 	 */
 	public static function setup_hooks() {
-		// Phase 06-03 will register async action callbacks here.
+		// Register async action callback for mentor notification batches
+		add_action( 'ddhh_jm_send_mentor_notification_batch', array( __CLASS__, 'process_mentor_notification_batch' ), 10, 2 );
 	}
 
 	/**
@@ -81,4 +82,109 @@ class DDHH_JM_Scheduler {
 
 		return $batch_count;
 	}
+
+	/**
+	 * Process mentor notification batch (async callback).
+	 *
+	 * Sends emails to batch of users about a newly published job.
+	 * Includes rate limiting delay between sends to avoid provider limits.
+	 *
+	 * @param array $user_ids Array of user IDs in this batch.
+	 * @param int   $job_id   Job post ID.
+	 */
+	public static function process_mentor_notification_batch( $user_ids, $job_id ) {
+		// Validate inputs
+		if ( empty( $user_ids ) || empty( $job_id ) ) {
+			error_log( 'DDHH_JM_Scheduler: Cannot process batch - missing user IDs or job ID' );
+			return;
+		}
+
+		// Get job post
+		$post = get_post( $job_id );
+		if ( ! $post || 'job_offer' !== $post->post_type ) {
+			error_log( sprintf( 'DDHH_JM_Scheduler: Invalid job_id %d in batch processing', $job_id ) );
+			return;
+		}
+
+		// Get job details
+		$job_title    = $post->post_title;
+		$job_location = get_field( 'job_location', $job_id );
+		$job_type     = get_field( 'job_type', $job_id );
+		$job_link     = get_permalink( $job_id );
+
+		// Track successful sends
+		$sent_count = 0;
+
+		// Process each user in batch
+		foreach ( $user_ids as $user_id ) {
+			// Get user data
+			$user = get_userdata( $user_id );
+			if ( ! $user ) {
+				error_log( sprintf( 'DDHH_JM_Scheduler: User ID %d not found, skipping', $user_id ) );
+				continue;
+			}
+
+			// Get user email
+			$user_email = $user->user_email;
+			if ( empty( $user_email ) ) {
+				error_log( sprintf( 'DDHH_JM_Scheduler: User ID %d has no email, skipping', $user_id ) );
+				continue;
+			}
+
+			// Prepare German email subject
+			$subject = sprintf( 'Neues Stellenangebot: %s', $job_title );
+
+			// Prepare German email body
+			$body = sprintf(
+				"Hallo,\n\n" .
+				"ein neues Stellenangebot wurde veröffentlicht:\n\n" .
+				"Stelle: %s\n" .
+				"Standort: %s\n" .
+				"Art: %s\n\n" .
+				"Sie können das Angebot hier ansehen:\n%s\n\n" .
+				"Um keine weiteren Benachrichtigungen zu erhalten, können Sie diese in Ihrem Profil deaktivieren.\n\n" .
+				"---\n" .
+				"Diese E-Mail wurde automatisch gesendet.",
+				$job_title,
+				$job_location ? $job_location : 'Nicht angegeben',
+				$job_type ? $job_type : 'Nicht angegeben',
+				$job_link
+			);
+
+			// Set email headers
+			$headers = array( 'Content-Type: text/html; charset=UTF-8' );
+
+			// Convert plain text to HTML with line breaks
+			$html_body = nl2br( esc_html( $body ) );
+
+			// Send email
+			$sent = wp_mail( $user_email, $subject, $html_body, $headers );
+
+			// Log failures
+			if ( ! $sent ) {
+				error_log(
+					sprintf(
+						'DDHH_JM_Scheduler: Failed to send mentor notification to user %d for job %d',
+						$user_id,
+						$job_id
+					)
+				);
+			} else {
+				$sent_count++;
+			}
+
+			// Rate limit delay: 0.1 seconds between emails
+			usleep( 100000 );
+		}
+
+		// Log batch completion
+		error_log(
+			sprintf(
+				'DDHH_JM_Scheduler: Processed notification batch: %d emails sent for job %d "%s"',
+				$sent_count,
+				$job_id,
+				$job_title
+			)
+		);
+	}
 }