config: splits config in multiple files

splits the big appConfig in multiple configs
adds media.config.mock.ts

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/config/database.config.ts

@@ -0,0 +1,75 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import * as Joi from 'joi';
+import { DatabaseDialect } from './database-dialect.enum';
+import { registerAs } from '@nestjs/config';
+
+export interface DatabaseConfig {
+  username: string;
+  password: string;
+  database: string;
+  host: string;
+  port: number;
+  storage: string;
+  dialect: DatabaseDialect;
+}
+
+const databaseSchema = Joi.object({
+  username: Joi.when('dialect', {
+    is: Joi.invalid(DatabaseDialect.SQLITE),
+    then: Joi.string(),
+    otherwise: Joi.optional(),
+  }),
+  password: Joi.when('dialect', {
+    is: Joi.invalid(DatabaseDialect.SQLITE),
+    then: Joi.string(),
+    otherwise: Joi.optional(),
+  }),
+  database: Joi.when('dialect', {
+    is: Joi.invalid(DatabaseDialect.SQLITE),
+    then: Joi.string(),
+    otherwise: Joi.optional(),
+  }),
+  host: Joi.when('dialect', {
+    is: Joi.invalid(DatabaseDialect.SQLITE),
+    then: Joi.string(),
+    otherwise: Joi.optional(),
+  }),
+  port: Joi.when('dialect', {
+    is: Joi.invalid(DatabaseDialect.SQLITE),
+    then: Joi.number(),
+    otherwise: Joi.optional(),
+  }),
+  storage: Joi.when('dialect', {
+    is: Joi.valid(DatabaseDialect.SQLITE),
+    then: Joi.string(),
+    otherwise: Joi.optional(),
+  }),
+  dialect: Joi.string().valid(...Object.values(DatabaseDialect)),
+});
+
+export default registerAs('databaseConfig', async () => {
+  const databaseConfig = databaseSchema.validate(
+    {
+      username: process.env.HD_DATABASE_USER,
+      password: process.env.HD_DATABASE_PASS,
+      database: process.env.HD_DATABASE_NAME,
+      host: process.env.HD_DATABASE_HOST,
+      port: parseInt(process.env.HD_DATABASE_PORT) || undefined,
+      storage: process.env.HD_DATABASE_STORAGE,
+      dialect: process.env.HD_DATABASE_DIALECT,
+    },
+    {
+      abortEarly: false,
+      presence: 'required',
+    },
+  );
+  if (databaseConfig.error) {
+    throw new Error(databaseConfig.error.toString());
+  }
+  return databaseConfig.value;
+});