Feature | Group question answer - cmd handler and repo (#18)

backend/src/app.ts

@@ -34,6 +34,7 @@ import { MongoQuestionsRepository } from './modules/questions/infrastructure/rep
 import { InMemoryQuestionsRepository } from './modules/questions/infrastructure/repository/inmemory/InMemoryQuestionsRepository';
 import { QuestionsRestApiModule } from './modules/questions/presentation/rest-api/QuestionsRestApiModule';
 import { InMemoryGroupQuestionsRepository } from './modules/questions/infrastructure/repository/inmemory/InMemoryGroupQuestionsRepository';
+import { InMemoryAnswerGroupQuestionRepository } from './modules/group-question-answer/infrastructure/repository/inmemory/InMemoryAnswerGroupQuestionRepository';
 
 config();
 
@@ -50,8 +51,9 @@ export async function IntegramicApplication(
     await connectToMongoDb();
   }
 
+  const answerGroupQuestionRepository = AnswerGroupQuestionRepository();
   const groupQuestionAnswerModule: Module = {
-    core: AnswerGroupQuestionModuleCore(eventBus, currentTimeProvider),
+    core: AnswerGroupQuestionModuleCore(eventBus, currentTimeProvider, answerGroupQuestionRepository),
     restApi: GroupQuestionAnswerRestApiModule(commandBus, eventBus, queryBus),
   };
 
@@ -152,3 +154,7 @@ function QuestionsRepository() {
 function GroupQuestionsRepository() {
   return new InMemoryGroupQuestionsRepository();
 }
+
+function AnswerGroupQuestionRepository() {
+  return new InMemoryAnswerGroupQuestionRepository();
+}

backend/src/modules/group-question-answer/core/AnswerGroupQuestionModuleCore.ts

@@ -3,13 +3,18 @@ import { AnswerGroupQuestionCommandHandler } from './application/command/AnswerG
 import { AnswerGroupQuestion } from './application/command/AnswerGroupQuestion';
 import { DomainEventPublisher } from '../../../shared/core/application/event/DomainEventBus';
 import { CurrentTimeProvider } from '../../../shared/core/CurrentTimeProvider';
+import { AnswerGroupQuestionRepository } from './application/AnswerGroupQuestionRepository';
 
-export function AnswerGroupQuestionModuleCore(eventPublisher: DomainEventPublisher, currentTimeProvider: CurrentTimeProvider): ModuleCore {
+export function AnswerGroupQuestionModuleCore(
+  eventPublisher: DomainEventPublisher,
+  currentTimeProvider: CurrentTimeProvider,
+  repository: AnswerGroupQuestionRepository,
+): ModuleCore {
   return {
     commandHandlers: [
       {
         commandType: AnswerGroupQuestion,
-        handler: new AnswerGroupQuestionCommandHandler(eventPublisher, currentTimeProvider),
+        handler: new AnswerGroupQuestionCommandHandler(eventPublisher, currentTimeProvider, repository),
       },
     ],
     eventHandlers: [],

backend/src/modules/group-question-answer/core/application/AnswerGroupQuestionRepository.ts

@@ -0,0 +1,9 @@
+import { QuestionAnswer } from './domain/QuestionAnswer';
+
+export interface AnswerGroupQuestionRepository {
+  save(answeredGroupQuestion: QuestionAnswer): Promise<void>;
+
+  findByGroupId(groupId: string): Promise<QuestionAnswer | undefined>;
+
+  findAllByQuestionId(questionId: string): Promise<QuestionAnswer[]>;
+}

backend/src/modules/group-question-answer/core/application/command/AnswerGroupQuestionCommandHandler.ts

@@ -3,12 +3,21 @@ import { AnswerGroupQuestion } from './AnswerGroupQuestion';
 import { CommandResult } from '../../../../../shared/core/application/command/CommandResult';
 import { DomainEventPublisher } from '../../../../../shared/core/application/event/DomainEventBus';
 import { CurrentTimeProvider } from '../../../../../shared/core/CurrentTimeProvider';
-import { PlayerId } from '../../../../../shared/core/domain/PlayerId';
+import { AnswerGroupQuestionRepository } from '../AnswerGroupQuestionRepository';
+import { answerGroupQuestion } from '../domain/QuestionAnswer';
 
 export class AnswerGroupQuestionCommandHandler implements CommandHandler<AnswerGroupQuestion> {
-  constructor(private readonly eventPublisher: DomainEventPublisher, private readonly currentTimeProvider: CurrentTimeProvider) {}
+  constructor(
+    private readonly eventPublisher: DomainEventPublisher,
+    private readonly currentTimeProvider: CurrentTimeProvider,
+    private readonly repository: AnswerGroupQuestionRepository,
+  ) {}
 
   async execute(command: AnswerGroupQuestion): Promise<CommandResult> {
+    const { state, events } = answerGroupQuestion(command, this.currentTimeProvider);
+
+    await this.repository.save(state);
+    this.eventPublisher.publishAll(events);
     return CommandResult.success();
   }
 }

backend/src/modules/group-question-answer/core/application/domain/QuestionAnswer.ts

@@ -0,0 +1,38 @@
+import { CurrentTimeProvider } from '../../../../../shared/core/CurrentTimeProvider';
+import { DomainCommandResult } from '../../../../../shared/core/domain/DomainCommandResult';
+import { GroupQuestionWasAnswered } from './event/GroupQuestionWasAnswered';
+
+export class QuestionAnswer {
+  readonly questionId: string;
+  readonly groupId: string;
+  readonly answerAuthorId: string;
+  readonly text: string;
+
+  constructor(props: { questionId: string; groupId: string; answerAuthorId: string; text: string }) {
+    this.questionId = props.questionId;
+    this.groupId = props.groupId;
+    this.answerAuthorId = props.answerAuthorId;
+    this.text = props.text;
+  }
+}
+
+export function answerGroupQuestion(
+  command: { questionId: string; groupId: string; answerAuthorId: string; text: string },
+  currentTimeProvider: CurrentTimeProvider,
+): DomainCommandResult<QuestionAnswer> {
+  if (command.text.trim().length <= 0) {
+    throw new Error('An answer cannot be empty!');
+  }
+
+  const groupQuestionWasAnswered = new GroupQuestionWasAnswered({
+    occurredAt: currentTimeProvider(),
+    ...command,
+  });
+
+  const questionAnswer = new QuestionAnswer({ ...command });
+
+  return {
+    state: questionAnswer,
+    events: [groupQuestionWasAnswered],
+  };
+}

backend/src/modules/group-question-answer/core/application/domain/event/GroupQuestionWasAnswered.ts

@@ -0,0 +1,14 @@
+export class GroupQuestionWasAnswered {
+  readonly occurredAt: Date;
+  readonly questionId: string;
+  readonly groupId: string;
+  readonly answerAuthorId: string;
+  readonly text: string;
+
+  constructor(props: { occurredAt: Date; questionId: string; groupId: string; answerAuthorId: string; text: string }) {
+    this.questionId = props.questionId;
+    this.groupId = props.groupId;
+    this.answerAuthorId = props.answerAuthorId;
+    this.text = props.text;
+  }
+}

backend/src/modules/group-question-answer/infrastructure/repository/inmemory/InMemoryAnswerGroupQuestionRepository.ts

@@ -0,0 +1,22 @@
+import { AnswerGroupQuestionRepository } from '../../../core/application/AnswerGroupQuestionRepository';
+import { QuestionAnswer } from '../../../core/application/domain/QuestionAnswer';
+
+export class InMemoryAnswerGroupQuestionRepository implements AnswerGroupQuestionRepository {
+  private readonly entities: { [id: string]: QuestionAnswer } = {};
+
+  findByGroupId(groupId: string): Promise<QuestionAnswer | undefined> {
+    return Promise.resolve(this.entities[groupId]);
+  }
+
+  async save(question: QuestionAnswer): Promise<void> {
+    this.entities[question.questionId] = question;
+  }
+
+  findAllByQuestionId(questionId: string): Promise<QuestionAnswer[]> {
+    return Promise.resolve(
+      Object.keys(this.entities)
+        .filter((id) => this.entities[id].groupId === questionId)
+        .map((id) => this.entities[id]),
+    );
+  }
+}

backend/src/modules/group-question-answer/presentation/rest-api/GroupQuestionAnswerRouter.ts

@@ -1,6 +1,5 @@
 import { CommandPublisher } from '../../../../shared/core/application/command/CommandBus';
 import { DomainEventPublisher } from '../../../../shared/core/application/event/DomainEventBus';
-import { QueryPublisherMock } from '../../../../../test/test-support/shared/core/QueryPublisherMock';
 import { QueryPublisher } from '../../../../shared/core/application/query/QueryBus';
 import express, { Request, Response } from 'express';
 import { AnswerGroupQuestion } from '../../core/application/command/AnswerGroupQuestion';