import {
	ForbiddenException,
	forwardRef,
	Inject,
	Injectable,
} from "@nestjs/common";
import { EventsGateway } from "../realtime/events.gateway";
import { UsersService } from "../users/users.service";
import type { CreateMessageDto } from "./dto/create-message.dto";
import { MessagesRepository } from "./repositories/messages.repository";

@Injectable()
export class MessagesService {
	constructor(
		private readonly messagesRepository: MessagesRepository,
		private readonly eventsGateway: EventsGateway,
		@Inject(forwardRef(() => UsersService))
		private readonly usersService: UsersService,
	) {}

	async sendMessage(senderId: string, dto: CreateMessageDto) {
		let conversation = await this.messagesRepository.findConversationBetweenUsers(
			senderId,
			dto.recipientId,
		);

		if (!conversation) {
			const newConv = await this.messagesRepository.createConversation();
			await this.messagesRepository.addParticipant(newConv.id, senderId);
			await this.messagesRepository.addParticipant(newConv.id, dto.recipientId);
			conversation = newConv;
		}

		const message = await this.messagesRepository.createMessage({
			conversationId: conversation.id,
			senderId,
			text: dto.text,
		});

		// Notify recipient via WebSocket
		this.eventsGateway.sendToUser(dto.recipientId, "new_message", {
			conversationId: conversation.id,
			message,
		});

		return message;
	}

	async getConversations(userId: string) {
		return this.messagesRepository.findAllConversations(userId);
	}

	async getUnreadCount(userId: string) {
		return this.messagesRepository.countUnreadMessages(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,
			userId,
		);
		if (!isParticipant) {
			throw new ForbiddenException("You are not part of this conversation");
		}

		// Récupérer les préférences de l'utilisateur actuel
		const user = await this.usersService.findOne(userId);

		// Marquer comme lus seulement si l'utilisateur l'autorise
		if (user?.showReadReceipts) {
			await this.messagesRepository.markAsRead(conversationId, userId);

			// Notifier l'expéditeur que les messages ont été lus
			const participants =
				await this.messagesRepository.getParticipants(conversationId);
			const otherParticipant = participants.find((p) => p.userId !== userId);
			if (otherParticipant) {
				this.eventsGateway.sendToUser(otherParticipant.userId, "messages_read", {
					conversationId,
					readerId: 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");
		}

		const user = await this.usersService.findOne(userId);
		if (!user?.showReadReceipts) return;

		const result = await this.messagesRepository.markAsRead(
			conversationId,
			userId,
		);

		// Notifier l'autre participant
		const participants =
			await this.messagesRepository.getParticipants(conversationId);
		const otherParticipant = participants.find((p) => p.userId !== userId);
		if (otherParticipant) {
			this.eventsGateway.sendToUser(otherParticipant.userId, "messages_read", {
				conversationId,
				readerId: userId,
			});
		}

		return result;
	}
}