chore: import DH V2 D5.6.4 production baseline

api-v3/src/inspection-closing/inspection-signature-file.ts

@@ -0,0 +1,49 @@
+import { BadRequestException } from '@nestjs/common';
+
+export const MAX_INSPECTION_SIGNATURE_BYTES = 1024 * 1024;
+
+export interface UploadedInspectionSignatureFile {
+  originalname: string;
+  mimetype: string;
+  size: number;
+  buffer: Buffer;
+}
+
+export interface InspectedInspectionSignatureFile {
+  originalName: string;
+  mimeType: 'image/png';
+  extension: '.png';
+}
+
+export function inspectInspectionSignatureFile(
+  file: UploadedInspectionSignatureFile | undefined,
+): InspectedInspectionSignatureFile {
+  if (!file?.buffer?.length) {
+    throw new BadRequestException({
+      code: 'INSPECTION_SIGNATURE_FILE_REQUIRED',
+      message: 'La firma manuscrita en formato PNG es obligatoria',
+    });
+  }
+  if (file.buffer.length > MAX_INSPECTION_SIGNATURE_BYTES) {
+    throw new BadRequestException({
+      code: 'INSPECTION_SIGNATURE_FILE_TOO_LARGE',
+      message: 'La firma no puede superar 1 MB',
+    });
+  }
+  const pngSignature = Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]);
+  if (
+    file.mimetype !== 'image/png'
+    || file.buffer.length < pngSignature.length
+    || !file.buffer.subarray(0, pngSignature.length).equals(pngSignature)
+  ) {
+    throw new BadRequestException({
+      code: 'INSPECTION_SIGNATURE_PNG_REQUIRED',
+      message: 'La firma debe ser una imagen PNG válida',
+    });
+  }
+  return {
+    originalName: (file.originalname || 'firma.png').slice(0, 255),
+    mimeType: 'image/png',
+    extension: '.png',
+  };
+}