epess-web-backend/src/Message/message.schema.ts

import { Inject, Injectable, Logger } from '@nestjs/common'
import { ChatRoomType, Message, MessageContextType, MessageType } from '@prisma/client'
import { Pothos, PothosRef, PothosSchema, SchemaBuilderToken } from '@smatch-corp/nestjs-pothos'
import { Builder, SchemaContext } from '../Graphql/graphql.builder'
import { PrismaService } from '../Prisma/prisma.service'
import { PubSubEvent } from '../common/pubsub/pubsub-event'
import { DateTimeUtils } from '../common/utils/datetime.utils'

@Injectable()
export class MessageSchema extends PothosSchema {
  constructor(
    @Inject(SchemaBuilderToken) private readonly builder: Builder,
    private readonly prisma: PrismaService,
  ) {
    super()
  }

  @PothosRef()
  message() {
    return this.builder.prismaObject('Message', {
      description: 'A message in the system.',
      fields: (t) => ({
        id: t.exposeID('id', {
          description: 'The ID of the message.',
        }),
        senderId: t.exposeID('senderId', {
          description: 'The ID of the sender.',
        }),
        chatRoomId: t.exposeID('chatRoomId', {
          description: 'The ID of the chat room.',
        }),
        type: t.expose('type', {
          type: MessageType,
          description: 'The type of the message.',
        }),
        content: t.exposeString('content', {
          description: 'The message content.',
        }),
        sentAt: t.expose('sentAt', {
          type: 'DateTime',
          description: 'The date and time the message was sent.',
        }),
        context: t.expose('context', {
          type: MessageContextType,
          description: 'The context of the message.',
        }),
        metadata: t.expose('metadata', {
          type: 'Json',
          nullable: true,
          description: 'The metadata of the message.',
        }),
        sender: t.relation('sender', {
          description: 'The sender of the message.',
        }),
        chatRoom: t.relation('chatRoom', {
          description: 'The chat room.',
        }),
      }),
    })
  }

  @Pothos()
  init(): void {
    this.builder.queryFields((t) => ({
      message: t.prismaField({
        type: this.message(),
        description: 'Retrieve a single message by its unique identifier.',
        args: this.builder.generator.findUniqueArgs('Message'),
        resolve: async (query, _root, args) => {
          return await this.prisma.message.findUnique({
            ...query,
            where: args.where,
          })
        },
      }),
      messages: t.prismaField({
        type: [this.message()],
        description: 'Retrieve a list of messages with optional filtering, ordering, and pagination.',
        args: this.builder.generator.findManyArgs('Message'),
        resolve: async (query, _root, args, ctx, _info) => {
          if (ctx.isSubscription) {
            throw new Error('Not allowed')
          }
          if (args.filter?.context && typeof args.filter.context === 'object') {
            // if args.context is NOTIFICATION or SYSTEM, filter by recipientId
            if (
              args.filter.context.in?.toString().includes(MessageContextType.NOTIFICATION) ||
              args.filter.context.in?.toString().includes(MessageContextType.SYSTEM)
            ) {
              args.filter.recipientId = ctx.http.me?.id
            }
          }
          return await this.prisma.message.findMany({
            ...query,
            skip: args.skip ?? undefined,
            take: args.take ?? undefined,
            orderBy: args.orderBy ?? undefined,
            where: args.filter ?? undefined,
          })
        },
      }),
      messagesByChatRoomId: t.prismaField({
        type: [this.message()],
        description: 'Retrieve a list of messages by chat room ID.',
        args: this.builder.generator.findManyArgs('Message'),
        resolve: async (query, _root, args) => {
          return await this.prisma.message.findMany({
            ...query,
            where: args.filter ?? undefined,
          })
        },
      }),
    }))

    // mutations
    this.builder.mutationFields((t) => ({
      sendMessage: t.prismaField({
        type: this.message(),
        description: 'Send a message to a chat room.',
        args: {
          input: t.arg({
            type: this.builder.generator.getCreateInput('Message', [
              'id',
              'senderId',
              'sender',
              'sentAt',
              'context',
              'recipient',
              'recipientId',
            ]),
            description: 'The message to send.',
            required: true,
          }),
        },
        resolve: async (query, _root, args, ctx, _info) => {
          if (ctx.isSubscription) {
            throw new Error('Not allowed')
          }
          const messageContext = MessageContextType.CHAT
          // get the sender from the context and add it to the input
          args.input.sender = {
            connect: {
              id: ctx.http.me?.id,
            },
          }
          if (!args.input.sender) {
            throw new Error('Cannot get sender from context')
          }
          let userIds: string[] = []
          // get the recipient if messageContext is CHAT
          if (messageContext === MessageContextType.CHAT) {
            // get chatRoomId from input
            const chatRoomId = args.input.chatRoom?.connect?.id
            if (!chatRoomId) {
              throw new Error('Cannot get chatRoomId from input')
            }
            // if chatroom type is SUPPORT, user 1 is mentorId, user 2 is customerId
            // query the chatRoom to get the userIds
            const chatRoom = await this.prisma.chatRoom.findUnique({
              where: {
                id: chatRoomId,
              },
            })
            if (chatRoom?.type === ChatRoomType.SUPPORT) {
              userIds = [chatRoom.mentorId!, chatRoom.customerId!]
            }
          }
          // check if content is empty
          if (!args.input.content || args.input.content.trim() === '') {
            throw new Error('Content cannot be empty')
          }
          const lastActivity = DateTimeUtils.now()
          const message = await this.prisma.$transaction(async (tx) => {
            const message = await tx.message.create({
              ...query,
              data: {
                ...args.input,
                context: MessageContextType.CHAT,
              },
            })
            await tx.chatRoom.update({
              where: {
                id: message.chatRoomId!,
              },
              data: {
                lastActivity: lastActivity.toJSDate(),
              },
            })
            return message
          })
          ctx.http.pubSub.publish(`${PubSubEvent.MESSAGE_SENT}.${message.chatRoomId}`, message)
          // publish to new message subscribers
          userIds.forEach((userId: string) => {
            ctx.http.pubSub.publish(`${PubSubEvent.NEW_MESSAGE}.${userId}`, message)
          })
          return message
        },
      }),
    }))

    this.builder.subscriptionFields((t) => ({
      messageSent: t.field({
        description: 'Subscribe to messages sent by users.',
        type: this.message(),
        args: {
          chatRoomId: t.arg({
            type: 'String',
            description: 'The ID of the chat room to subscribe to.',
          }),
        },
        subscribe: (_, args, ctx: SchemaContext) => {
          if (!ctx.isSubscription) {
            throw new Error('Not allowed')
          }
          return ctx.websocket.pubSub.asyncIterator([
            `${PubSubEvent.MESSAGE_SENT}.${args.chatRoomId}`,
          ]) as unknown as AsyncIterable<Message>
        },
        resolve: (payload: Message) => payload,
      }),
    }))
  }
}