refactor: organize backend by business responsibility

src/modules/auth/presentation/auth.dto.ts

@@ -0,0 +1,57 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { Transform } from 'class-transformer';
+import {
+  IsString,
+  MinLength,
+  Validate,
+  ValidatorConstraint,
+} from 'class-validator';
+
+@ValidatorConstraint({ name: 'email' })
+class EmailConstraint {
+  validate(value: unknown): boolean {
+    return (
+      typeof value === 'string' &&
+      value.length <= 254 &&
+      value.split('@').length === 2 &&
+      !value
+        .split('')
+        .some(
+          (character) =>
+            /\s/.test(character) ||
+            character.charCodeAt(0) < 32 ||
+            character.charCodeAt(0) === 127,
+        ) &&
+      value.split('@').every(Boolean)
+    );
+  }
+  defaultMessage(): string {
+    return 'must be a valid email address';
+  }
+}
+
+@ValidatorConstraint({ name: 'passwordBytes' })
+class PasswordBytesConstraint {
+  validate(value: unknown): boolean {
+    return typeof value === 'string' && Buffer.byteLength(value, 'utf8') <= 72;
+  }
+  defaultMessage(): string {
+    return 'must not exceed 72 UTF-8 bytes';
+  }
+}
+
+export class CredentialsDto {
+  @ApiProperty({ example: 'user@example.com' })
+  @IsString()
+  @Transform(({ value }: { value: unknown }) =>
+    typeof value === 'string' ? value.trim().toLowerCase() : value,
+  )
+  @Validate(EmailConstraint)
+  declare email: string;
+
+  @ApiProperty({ minLength: 12, maxLength: 72, example: 'a secure password' })
+  @IsString()
+  @MinLength(12)
+  @Validate(PasswordBytesConstraint)
+  declare password: string;
+}