[Feature] integrate email to invitation requests

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/event/CompetitionValidatedDataEvent.java

@@ -0,0 +1,9 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.event;
+
+import lombok.Builder;
+
+@Builder
+public record CompetitionValidatedDataEvent(
+    String competitionTitle,
+    String stageTitle) {
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/event/InvitationRequestEvent.java

@@ -0,0 +1,10 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.event;
+
+import com.itasocialacademy.oitassist.user.api.dto.UserProfileDetails;
+import java.util.List;
+
+public record InvitationRequestEvent(
+    String competitionTitle,
+    String stageTitle,
+    List<UserProfileDetails> users) {
+}

src/main/java/com/itasocialacademy/oitassist/participation/sender/AsyncEmailSender.java

@@ -3,7 +3,9 @@
 import com.itasocialacademy.oitassist.core.properties.WebClientProperties;
 import com.itasocialacademy.oitassist.core.service.interfaces.EmailService;
 import com.itasocialacademy.oitassist.participation.dao.dto.event.ApplicationDecisionEvent;
+import com.itasocialacademy.oitassist.participation.dao.dto.event.InvitationRequestEvent;
 import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
+import com.itasocialacademy.oitassist.user.api.dto.UserProfileDetails;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.scheduling.annotation.Async;
@@ -44,6 +46,8 @@ public class AsyncEmailSender {
     public void sendDecisionEmail(ApplicationDecisionEvent event) {
         String email = event.email();
         RequestStatus status = event.status();
+        String competitionLink = buildLink(COMPETITION_PATH);
+        String profileLink = buildLink(PROFILE_PATH);
         log.info("Handling ApplicationDecisionEvent for email={}, status={}", email, status);
 
         String template = switch (status) {
@@ -56,19 +60,8 @@ public void sendDecisionEmail(ApplicationDecisionEvent event) {
             if (event.rejectionReason() != null && !event.rejectionReason().isBlank()) {
                 extraParams.put("rejectionReason", event.rejectionReason());
             }
-            String profileLink = UriComponentsBuilder
-                .fromUriString(webClientProperties.origin())
-                .path(PROFILE_PATH)
-                .build()
-                .toUriString();
             extraParams.put("profileLink", profileLink);
         }
-
-        String competitionLink = UriComponentsBuilder
-            .fromUriString(webClientProperties.origin())
-            .path(COMPETITION_PATH)
-            .build()
-            .toUriString();
         Map<String, String> root = new HashMap<>(Map.of(
             "firstName", event.firstName(),
             "competitionTitle", event.competitionTitle(),
@@ -82,4 +75,41 @@ public void sendDecisionEmail(ApplicationDecisionEvent event) {
             "Статус заявки",
             root);
     }
+
+    /**
+     * Handles asynchronously an {@link InvitationRequestEvent} after the publishing
+     * transaction has committed. Builds the URLs and sends an invitation email for
+     * each student.
+     *
+     * @param event the event carrying the titles of competition and stage, the list
+     *              of recipients with emails and first names
+     */
+    @Async
+    public void sendInvitationEmail(InvitationRequestEvent event) {
+        log.info("Handling InvitationRequestEvent for {} users", event.users().size());
+
+        String competitionLink = buildLink(COMPETITION_PATH);
+        String profileLink = buildLink(PROFILE_PATH);
+        for (UserProfileDetails user : event.users()) {
+            Map<String, String> root = Map.of(
+                "firstName", user.firstName(),
+                "competitionTitle", event.competitionTitle(),
+                "stageTitle", event.stageTitle(),
+                "competitionLink", competitionLink,
+                "profileLink", profileLink);
+            emailService.sendTemplateEmail(
+                user.email(),
+                "invitation-request.html",
+                "Запрошення на олімпіаду",
+                root);
+        }
+    }
+
+    private String buildLink(String link) {
+        return UriComponentsBuilder
+            .fromUriString(webClientProperties.origin())
+            .path(link)
+            .build()
+            .toUriString();
+    }
 }

src/main/java/com/itasocialacademy/oitassist/participation/service/InvitationServiceImpl.java

@@ -9,6 +9,8 @@
 import com.itasocialacademy.oitassist.competition.exceptions.StageNotFoundException;
 import com.itasocialacademy.oitassist.core.enums.ErrorCode;
 import com.itasocialacademy.oitassist.core.exceptions.AuthorizationException;
+import com.itasocialacademy.oitassist.participation.dao.dto.event.CompetitionValidatedDataEvent;
+import com.itasocialacademy.oitassist.participation.dao.dto.event.InvitationRequestEvent;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.FailedInvitationResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.SucceededInvitationResponse;
 import com.itasocialacademy.oitassist.participation.dao.model.Participation;
@@ -24,9 +26,11 @@
 import com.itasocialacademy.oitassist.participation.exceptions.*;
 import com.itasocialacademy.oitassist.participation.mapper.ParticipationMapper;
 import com.itasocialacademy.oitassist.participation.mapper.interfaces.ProcessInvitationMapper;
+import com.itasocialacademy.oitassist.participation.sender.AsyncEmailSender;
 import com.itasocialacademy.oitassist.participation.service.interfaces.InvitationService;
 import com.itasocialacademy.oitassist.security.api.interfaces.SecurityFacade;
 import com.itasocialacademy.oitassist.user.api.dto.UserAuthDetails;
+import com.itasocialacademy.oitassist.user.api.dto.UserProfileDetails;
 import com.itasocialacademy.oitassist.user.api.interfaces.UserFacade;
 import com.itasocialacademy.oitassist.user.dao.enums.Role;
 import jakarta.transaction.Transactional;
@@ -52,10 +56,13 @@ public class InvitationServiceImpl implements InvitationService {
     private final ParticipationMapper participationMapper;
     private final ProcessInvitationMapper processInvitationMapper;
     private final CompetitionFacade competitionFacade;
+    private final AsyncEmailSender sender;
 
     @Override
     public CreateInvitationResponse sendEnrollmentRequest(CreateInvitationRequest request) {
-        validateCompetitionAndStageInfo(request.getCompetitionId(), request.getStageId());
+        Long competitionId = request.getCompetitionId();
+        Long stageId = request.getStageId();
+        CompetitionValidatedDataEvent competitionData = validateCompetitionAndStageInfo(competitionId, stageId);
         List<Long> studentIds = validateNoDuplicatesOrThrow(request.getStudentIds());
 
         List<UserAuthDetails> foundUsers = userFacade.findByIds(studentIds);
@@ -89,14 +96,20 @@ public CreateInvitationResponse sendEnrollmentRequest(CreateInvitationRequest re
                 }
             }
         }
-        return CreateInvitationResponse.builder()
-            .competitionId(request.getCompetitionId())
-            .stageId(request.getStageId())
+        CreateInvitationResponse response = CreateInvitationResponse.builder()
+            .competitionId(competitionId)
+            .stageId(stageId)
             .succeeded(succeeded)
             .failed(failed)
             .issuedBy(getCurrentUserIdOrThrow())
             .issuedAt(Instant.now())
             .build();
+
+        if (!succeeded.isEmpty()) {
+            scheduleInvitationEmail(competitionData, succeeded);
+        }
+
+        return response;
     }
 
     @Override
@@ -162,17 +175,19 @@ private List<Long> validateNoDuplicatesOrThrow(List<Long> rawIds) {
         return rawIds;
     }
 
-    private void validateCompetitionAndStageInfo(Long competitionId, Long stageId) {
-        CompetitionDetail competitionDetail = competitionFacade.findCompetitionById(competitionId)
-            .orElseThrow(() -> new CompetitionNotFoundException(competitionId));
-        StageDetail stageDetail = competitionFacade.findStageById(stageId)
-            .orElseThrow(() -> new StageNotFoundException(stageId));
+    private CompetitionValidatedDataEvent validateCompetitionAndStageInfo(Long competitionId, Long stageId) {
+        CompetitionDetail competitionDetail = getCompetitionInfoOrThrow(competitionId);
+        StageDetail stageDetail = getStageInfoOrThrow(stageId);
         if (competitionDetail.competitionStatus() != CompetitionStatus.ENROLLMENT) {
             throw new UserInvitationRequestException("The competition cannot be enrolled");
         }
         if (!stageDetail.competitionId().equals(competitionId)) {
             throw new CompetitionHierarchyValidationException("Specified stage does not belong to this competition");
         }
+        return CompetitionValidatedDataEvent.builder()
+            .competitionTitle(competitionDetail.title())
+            .stageTitle(stageDetail.title())
+            .build();
     }
 
     private Invitation getPendingInvitationOrThrow(Long applicationId) {
@@ -225,4 +240,29 @@ private boolean isPendingInvitationConstraintViolation(DataIntegrityViolationExc
         }
         return false;
     }
+
+    private void scheduleInvitationEmail(
+        CompetitionValidatedDataEvent competitionData,
+        List<SucceededInvitationResponse> succeeded) {
+        List<UserProfileDetails> users = getUserProfiles(succeeded);
+        InvitationRequestEvent event = new InvitationRequestEvent(
+            competitionData.competitionTitle(), competitionData.stageTitle(), users);
+        sender.sendInvitationEmail(event);
+    }
+
+    private CompetitionDetail getCompetitionInfoOrThrow(Long competitionId) {
+        return competitionFacade.findCompetitionById(competitionId)
+            .orElseThrow(() -> new CompetitionNotFoundException(competitionId));
+    }
+
+    private StageDetail getStageInfoOrThrow(Long stageId) {
+        return competitionFacade.findStageById(stageId)
+            .orElseThrow(() -> new StageNotFoundException(stageId));
+    }
+
+    private List<UserProfileDetails> getUserProfiles(List<SucceededInvitationResponse> succeeded) {
+        List<Long> userIds = succeeded.stream()
+            .map(SucceededInvitationResponse::studentId).toList();
+        return userFacade.findProfilesByIds(userIds);
+    }
 }

src/main/resources/templates/application-accepted.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <title>Сповіщення про підтверджену заявку</title>
     <style>
-        <#include "fragments/application-status-style.ftl">
+        <#include "fragments/participation-template-style.ftl">
     </style>
 </head>
 <body>

src/main/resources/templates/application-rejected.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <title>Сповіщення про відхилену заявку</title>
     <style>
-        <#include "fragments/application-status-style.ftl">
+        <#include "fragments/participation-template-style.ftl">
     </style>
 </head>
 <body>

src/main/resources/templates/invitation-request.html

@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html lang="uk">
+<head>
+    <meta charset="UTF-8">
+    <title>Сповіщення про підтверджену заявку</title>
+    <style>
+        <#include "fragments/participation-template-style.ftl">
+    </style>
+</head>
+<body>
+<div class="container">
+    <h1>Привіт, ${firstName}!</h1>
+    <p>Вас було запрошено для участі в олімпіаді <strong>"${competitionTitle}"</strong>,
+        етапі <strong>"${stageTitle}"</strong>!🎉<br>
+        Вам потрібно підтвердити вашу участь в особистому кабінеті.
+        Щоб перейти в кабінет, натисніть на кнопку нижче:</p>
+    <a href="${profileLink}" class="button">Особистий кабінет ↗</a>
+    <p>Або можете переглянути деталі олімпіади:</p>
+    <a href="${competitionLink}" class="button">Переглянути деталі ↗</a>
+    <h3>Бажаємо успіхів!</h3>
+
+    <p>Якщо вам цей лист було надіслано помилково — проігноруйте його.</p>
+
+    <div class="footer">
+        © 2026 OIT Assist. Усі права захищені.
+    </div>
+</div>
+</body>
+</html>

src/test/java/com/itasocialacademy/oitassist/participation/service/InvitationServiceTest.java

@@ -9,6 +9,8 @@
 import com.itasocialacademy.oitassist.competition.exceptions.CompetitionNotFoundException;
 import com.itasocialacademy.oitassist.competition.exceptions.StageNotFoundException;
 import com.itasocialacademy.oitassist.core.exceptions.AuthorizationException;
+import com.itasocialacademy.oitassist.core.service.interfaces.EmailService;
+import com.itasocialacademy.oitassist.participation.dao.dto.event.InvitationRequestEvent;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.CreateInvitationRequest;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.RejectEnrollmentRequest;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.CreateInvitationResponse;
@@ -25,14 +27,17 @@
 import com.itasocialacademy.oitassist.participation.mapper.ParticipationMapper;
 import com.itasocialacademy.oitassist.participation.mapper.interfaces.ProcessInvitationMapper;
 import com.itasocialacademy.oitassist.participation.saver.InvitationRequestsSaver;
+import com.itasocialacademy.oitassist.participation.sender.AsyncEmailSender;
 import com.itasocialacademy.oitassist.security.api.interfaces.SecurityFacade;
 import com.itasocialacademy.oitassist.user.api.dto.UserAuthDetails;
+import com.itasocialacademy.oitassist.user.api.dto.UserProfileDetails;
 import com.itasocialacademy.oitassist.user.api.interfaces.UserFacade;
 import com.itasocialacademy.oitassist.user.dao.enums.Role;
 import org.hibernate.exception.ConstraintViolationException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
@@ -46,7 +51,7 @@
 import static org.mockito.Mockito.*;
 
 @ExtendWith(MockitoExtension.class)
-public class InvitationServiceTest {
+class InvitationServiceTest {
     @Mock
     private ParticipationRepository participationRepository;
     @Mock
@@ -63,6 +68,10 @@ public class InvitationServiceTest {
     private ProcessInvitationMapper processInvitationMapper;
     @Mock
     private CompetitionFacade competitionFacade;
+    @Mock
+    private AsyncEmailSender sender;
+    @Mock
+    private EmailService emailService;
 
     @InjectMocks
     private InvitationServiceImpl invitationService;
@@ -91,11 +100,13 @@ void setUp() {
 
         competitionDetail = CompetitionDetail.builder()
             .id(2L)
+            .title("Olympiad")
             .competitionStatus(CompetitionStatus.ENROLLMENT)
             .build();
 
         stageDetail = StageDetail.builder()
             .id(3L)
+            .title("First stage")
             .competitionId(2L)
             .scope(StageScope.DISTRICT)
             .build();
@@ -498,4 +509,54 @@ private static ProcessInvitationResponse getProcessInvitationResponse(RequestSta
             .status(status)
             .build();
     }
+
+    // ---- emailSending part ----
+
+    @Test
+    void sendEnrollmentRequest_withSucceededInvitations_shouldScheduleInvitationEmail() {
+        when(securityFacade.getCurrentUserId()).thenReturn(Optional.of(4L));
+        when(invitationRepository.findByStudentIdInAndCompetitionIdAndStageIdAndStatus(
+            List.of(10L), 2L, 3L, RequestStatus.PENDING)).thenReturn(List.of());
+        when(participationRepository.findAllByUserIdInAndCompetitionIdAndStageId(List.of(10L), 2L, 3L))
+            .thenReturn(List.of());
+        when(invitationRequestsSaver.saveSingleInvitation(10L, createInvitationRequest)).thenReturn(invitation);
+        when(userFacade.findByIds(List.of(10L))).thenReturn(List.of(validUser));
+        when(competitionFacade.findCompetitionById(2L)).thenReturn(Optional.of(competitionDetail));
+        when(competitionFacade.findStageById(3L)).thenReturn(Optional.of(stageDetail));
+        when(userFacade.findProfilesByIds(List.of(10L))).thenReturn(
+            List.of(new UserProfileDetails(10L, "Test", "test@mail.com")));
+        when(invitationRequestsSaver.saveSingleInvitation(10L, createInvitationRequest)).thenReturn(invitation);
+        invitationService.sendEnrollmentRequest(createInvitationRequest);
+
+        ArgumentCaptor<InvitationRequestEvent> eventCaptor = ArgumentCaptor.forClass(InvitationRequestEvent.class);
+        verify(sender).sendInvitationEmail(eventCaptor.capture());
+
+        InvitationRequestEvent event = eventCaptor.getValue();
+        assertEquals("Olympiad", event.competitionTitle());
+        assertEquals("First stage", event.stageTitle());
+        assertEquals(1, event.users().size());
+        assertEquals("test@mail.com", event.users().getFirst().email());
+    }
+
+    @Test
+    void sendEnrollmentRequest_whenAllStudentsFail_shouldNotScheduleInvitationEmail() {
+        UserAuthDetails orgUser = new UserAuthDetails(10L, "email1@mail.com", "password1", Role.ORG);
+        when(securityFacade.getCurrentUserId()).thenReturn(Optional.of(4L));
+        when(competitionFacade.findCompetitionById(2L)).thenReturn(Optional.of(competitionDetail));
+        when(competitionFacade.findStageById(3L)).thenReturn(Optional.of(stageDetail));
+        when(userFacade.findByIds(List.of(10L))).thenReturn(List.of(orgUser));
+
+        invitationService.sendEnrollmentRequest(createInvitationRequest);
+
+        verify(sender, never()).sendInvitationEmail(any());
+    }
+
+    @Test
+    void sendInvitationEmail_noRecipients_shouldSendNothing() {
+        InvitationRequestEvent event = new InvitationRequestEvent("Olympiad", "District Stage", List.of());
+
+        sender.sendInvitationEmail(event);
+
+        verifyNoInteractions(emailService);
+    }
 }