Add chatRoom service

chat-service/src/main/java/com/relay/chatservice/chatroom/ChatRoom.java

@@ -0,0 +1,20 @@
+package com.relay.chatservice.chatroom;
+
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+@Document
+public class ChatRoom {
+    @Id
+    private String id;
+    private String chatId;
+    private String senderId;
+    private String recipientId;
+
+}

chat-service/src/main/java/com/relay/chatservice/chatroom/ChatRoomRepository.java

@@ -0,0 +1,10 @@
+package com.relay.chatservice.chatroom;
+
+import org.springframework.data.mongodb.repository.MongoRepository;
+
+import java.util.Optional;
+
+public interface ChatRoomRepository extends MongoRepository<ChatRoom, String> {
+
+    Optional<ChatRoom> findBySenderIdAndRecipientId(String senderId, String recipientId);
+}

chat-service/src/main/java/com/relay/chatservice/chatroom/ChatRoomService.java

@@ -0,0 +1,53 @@
+package com.relay.chatservice.chatroom;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.Optional;
+
+@Service
+@RequiredArgsConstructor
+public class ChatRoomService {
+
+    private final ChatRoomRepository chatRoomRepository;
+
+
+    public Optional<String> getChatRoomId(
+            String senderId,
+            String recipientId,
+            boolean createNewRoomIfNotExists
+    ) {
+        return chatRoomRepository.findBySenderIdAndRecipientId(senderId, recipientId)
+                .map(ChatRoom::getChatId)
+                .or(
+                        () -> {
+                            if (createNewRoomIfNotExists) {
+                                var chatId = createChatId(senderId, recipientId);
+                                return Optional.of(chatId);
+                            }
+                            return Optional.empty();
+                        }
+                );
+    }
+
+    private String createChatId(String senderId, String recipientId) {
+        var chatId = String.format("%s_%s", senderId, recipientId);
+
+        ChatRoom senderRecipient = ChatRoom.builder()
+                .chatId(chatId)
+                .senderId(senderId)
+                .recipientId(recipientId)
+                .build();
+
+        ChatRoom recipientSender = ChatRoom.builder()
+                .chatId(chatId)
+                .senderId(recipientId)
+                .recipientId(senderId)
+                .build();
+
+        chatRoomRepository.save(senderRecipient);
+        chatRoomRepository.save(recipientSender);
+
+        return chatId;
+    }
+}