feat: add API for fetching direct conversation with a user

- Added `GET /messages/conversations/with/:userId` endpoint in the backend to retrieve direct conversation data.
- Implemented corresponding method in `MessagesService` and `MessagesRepository`.
- Updated the frontend service to support fetching direct conversations via API.

backend/src/messages/messages.controller.ts

@@ -22,6 +22,17 @@ export class MessagesController {
 		return this.messagesService.getConversations(req.user.sub);
 	}
 
+	@Get("conversations/with/:userId")
+	getConversationWithUser(
+		@Req() req: AuthenticatedRequest,
+		@Param("userId") targetUserId: string,
+	) {
+		return this.messagesService.getConversationWithUser(
+			req.user.sub,
+			targetUserId,
+		);
+	}
+
 	@Get("conversations/:id")
 	getMessages(
 		@Req() req: AuthenticatedRequest,

backend/src/messages/messages.service.ts

@@ -42,6 +42,13 @@ export class MessagesService {
 		return this.messagesRepository.findAllConversations(userId);
 	}
 
+	async getConversationWithUser(userId: string, targetUserId: string) {
+		return this.messagesRepository.findConversationBetweenUsers(
+			userId,
+			targetUserId,
+		);
+	}
+
 	async getMessages(userId: string, conversationId: string) {
 		const isParticipant = await this.messagesRepository.isParticipant(
 			conversationId,
@@ -51,6 +58,20 @@ export class MessagesService {
 			throw new ForbiddenException("You are not part of this conversation");
 		}
 
+		// Marquer comme lus
+		await this.messagesRepository.markAsRead(conversationId, userId);
+
 		return this.messagesRepository.findMessagesByConversationId(conversationId);
 	}
+
+	async markAsRead(userId: string, conversationId: string) {
+		const isParticipant = await this.messagesRepository.isParticipant(
+			conversationId,
+			userId,
+		);
+		if (!isParticipant) {
+			throw new ForbiddenException("You are not part of this conversation");
+		}
+		return this.messagesRepository.markAsRead(conversationId, userId);
+	}
 }

frontend/src/services/message.service.ts

@@ -36,6 +36,13 @@ export const MessageService = {
 		return data;
 	},
 
+	async getConversationWith(userId: string): Promise<Conversation | null> {
+		const { data } = await api.get<Conversation | null>(
+			`/messages/conversations/with/${userId}`,
+		);
+		return data;
+	},
+
 	async sendMessage(recipientId: string, text: string): Promise<Message> {
 		const { data } = await api.post<Message>("/messages", {
 			recipientId,