feat: adding email notification when certian revalidation threshold is met

• feat: adding email notification when certian revalidation threshold is met

Resolves #149 (closed)

src/main/java/org/eclipsefoundation/git/eca/service/impl/DefaultMailerService.java

+/**
+ * Copyright (c) 2025 Eclipse Foundation
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * Author: Jordi Gómez <jordi.gomez@eclipse-foundation.org>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipsefoundation.git.eca.service.impl;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.eclipsefoundation.git.eca.dto.GithubWebhookTracking;
+import org.eclipsefoundation.git.eca.service.MailerService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import io.quarkus.mailer.Mail;
+import io.quarkus.mailer.Mailer;
+import io.quarkus.qute.Location;
+import io.quarkus.qute.Template;
+import io.smallrye.config.ConfigMapping;
+import jakarta.enterprise.context.ApplicationScoped;
+
+@ApplicationScoped
+public class DefaultMailerService implements MailerService {
+  public static final Logger LOGGER = LoggerFactory.getLogger(DefaultMailerService.class);
+  private final EclipseMailerConfig config;
+  private final Mailer mailer;
+
+  @Location("emails/revalidation-alert")
+  Template revalidationAlertTemplate;
+
+  public DefaultMailerService(EclipseMailerConfig config, Mailer mailer) {
+    this.config = config;
+    this.mailer = mailer;
+  }
+
+  @Override
+  public void sendRevalidationAlert(GithubWebhookTracking tracking, Integer threshold) {
+    var revalidationAlertConfig = config.revalidationAlert();
+
+    if (revalidationAlertConfig.to().isEmpty()) {
+      LOGGER.warn("No recipients configured for revalidation alert. Skipping email notification.");
+      return;
+    }
+
+    String subject = "GitHub Webhook Revalidation Alert";
+
+    Mail messageBuilder = new Mail();
+
+    messageBuilder.setSubject(subject);
+    messageBuilder.setText(revalidationAlertTemplate.data("attempts", threshold)
+        .data("requestId", tracking.getId())
+        .data("repository", tracking.getRepositoryFullName())
+        .data("pullRequest", tracking.getPullRequestNumber())
+        .data("lastState", tracking.getLastKnownState())
+        .data("lastUpdated", tracking.getLastUpdated().toString())
+        .render());
+
+    messageBuilder.addTo(revalidationAlertConfig.to().toArray(String[]::new));
+    revalidationAlertConfig.authorMessage().replyTo()
+        .ifPresent(messageBuilder::addReplyTo);
+    revalidationAlertConfig.authorMessage().bcc()
+        .ifPresent(bcc -> messageBuilder.addBcc(bcc.toArray(String[]::new)));
+
+    mailer.send(messageBuilder);
+    LOGGER.info("Revalidation alert sent to: {}", revalidationAlertConfig.to());
+  }
+
+  /**
+   * Represents configuration for the default mailer service.
+   * 
+   * @author Martin Lowe
+   *
+   */
+  @ConfigMapping(prefix = "eclipse.mailer")
+  public interface EclipseMailerConfig {
+
+    public RevalidationAlert revalidationAlert();
+
+    /**
+     * This interface defines the contract for specifying recipients and message
+     * configuration when sending revalidation alerts within the ECA validation
+     * process.
+     */
+    public interface RevalidationAlert {
+      public List<String> to();
+
+      public MessageConfiguration authorMessage();
+    }
+
+    public interface MessageConfiguration {
+      public Optional<String> replyTo();
+
+      public Optional<List<String>> bcc();
+    }
+  }
+
+}