unreal-chat/apps/api/src/resolvers/message.ts

import { GraphQLError } from 'graphql';
import { IResolvers, withFilter } from 'mercurius';
import { MutationResolvers, QueryResolvers } from '../generated/graphql';
import { withAuth } from '../utils';

export const MESSAGE_ADDED = 'MESSAGE_ADDED';

export const messageResolvers: IResolvers = {
  Query: {
    messages: withAuth<QueryResolvers['messages']>(
      async (_, { roomId }, { prisma, jwt }) => {
        const room = await prisma.room.findUnique({
          where: { id: roomId, members: { some: { id: jwt.sub } } },
        });

        if (!room) {
          throw new GraphQLError('Room not found', {
            extensions: {
              code: 'NOT_FOUND',
            },
          });
        }

        return prisma.message.findMany({
          where: { roomId },
          orderBy: { createdAt: 'asc' },
        });
      }
    ),
  },
  Mutation: {
    sendMessage: withAuth<MutationResolvers['sendMessage']>(
      async (_, { content, roomId }, { prisma, jwt, pubsub }) => {
        const room = await prisma.room.findUnique({
          where: { id: roomId, members: { some: { id: jwt.sub } } },
        });

        if (!room) {
          throw new GraphQLError('Room not found', {
            extensions: {
              code: 'NOT_FOUND',
            },
          });
        }

        const message = await prisma.message.create({
          data: {
            content,
            user: {
              connect: { id: jwt.sub },
            },
            room: {
              connect: { id: roomId },
            },
          },
          include: {
            user: true,
            room: true,
          },
        });

        pubsub.publish({
          topic: MESSAGE_ADDED,
          payload: { messageAdded: message, roomId },
        });

        return message;
      }
    ),
  },
  Subscription: {
    messageAdded: {
      subscribe: withFilter(
        (_, __, { pubsub }) => pubsub.subscribe([MESSAGE_ADDED]),
        (payload, variables) => {
          return payload.roomId === variables.roomId;
        }
      ),
    },
  },
  Message: {
    user: async (parent, _, { prisma }) =>
      parent.user
        ? parent.user
        : prisma.user.findUnique({
            where: { id: parent.userId },
          }),
    room: async (parent, _, { prisma }) =>
      parent.room
        ? parent.room
        : prisma.room.findUnique({
            where: { id: parent.roomId },
          }),
  },
};