add smart random

src/modules/decks/use-cases/save-grade-use-case.ts

@@ -0,0 +1,41 @@
+import { CommandHandler, ICommandHandler } from '@nestjs/cqrs'
+import { CardsRepository } from '../../cards/infrastructure/cards.repository'
+import { ForbiddenException, NotFoundException } from '@nestjs/common'
+import { DecksRepository } from '../infrastructure/decks.repository'
+import { GradesRepository } from '../infrastructure/grades.repository'
+
+export class SaveGradeCommand {
+  constructor(
+    public readonly userId: string,
+    public readonly args: {
+      cardId: string
+      grade: number
+    }
+  ) {}
+}
+
+@CommandHandler(SaveGradeCommand)
+export class SaveGradeHandler implements ICommandHandler<SaveGradeCommand> {
+  constructor(
+    private readonly cardsRepository: CardsRepository,
+    private readonly decksRepository: DecksRepository,
+    private readonly gradesRepository: GradesRepository
+  ) {}
+
+  async execute(command: SaveGradeCommand) {
+    const deck = await this.decksRepository.findDeckByCardId(command.args.cardId)
+    if (!deck)
+      throw new NotFoundException(`Deck containing card with id ${command.args.cardId} not found`)
+
+    if (deck.userId !== command.userId && deck.isPrivate) {
+      throw new ForbiddenException(`You can't save cards to  a private deck that you don't own`)
+    }
+
+    return await this.gradesRepository.createGrade({
+      userId: command.userId,
+      grade: command.args.grade,
+      cardId: command.args.cardId,
+      deckId: deck.id,
+    })
+  }
+}