SnapOtter/apps/api/src/routes/tools/barcode-read.ts

import { basename } from "node:path";
import type { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
import jsQR from "jsqr";
import sharp from "sharp";
import { validateImageBuffer } from "../../lib/file-validation.js";

/**
 * Read QR codes and barcodes from uploaded images.
 */
export function registerBarcodeRead(app: FastifyInstance) {
  app.post("/api/v1/tools/barcode-read", async (request: FastifyRequest, reply: FastifyReply) => {
    let fileBuffer: Buffer | null = null;
    let filename = "image";

    try {
      const parts = request.parts();
      for await (const part of parts) {
        if (part.type === "file") {
          const chunks: Buffer[] = [];
          for await (const chunk of part.file) {
            chunks.push(chunk);
          }
          fileBuffer = Buffer.concat(chunks);
          filename = basename(part.filename ?? "image");
        }
      }
    } catch (err) {
      return reply.status(400).send({
        error: "Failed to parse multipart request",
        details: err instanceof Error ? err.message : String(err),
      });
    }

    if (!fileBuffer || fileBuffer.length === 0) {
      return reply.status(400).send({ error: "No image file provided" });
    }

    // Validate the uploaded image
    const validation = await validateImageBuffer(fileBuffer);
    if (!validation.valid) {
      return reply.status(400).send({ error: `Invalid image: ${validation.reason}` });
    }

    try {
      // Convert to RGBA raw pixel data for jsQR
      const image = sharp(fileBuffer);
      const metadata = await image.metadata();
      const width = metadata.width ?? 0;
      const height = metadata.height ?? 0;

      const rawData = await image.ensureAlpha().raw().toBuffer();

      const code = jsQR(
        new Uint8ClampedArray(rawData.buffer, rawData.byteOffset, rawData.length),
        width,
        height,
      );

      if (!code) {
        return reply.send({
          filename,
          found: false,
          text: null,
          message: "No QR code found in the image",
        });
      }

      return reply.send({
        filename,
        found: true,
        text: code.data,
        location: {
          topLeft: code.location.topLeftCorner,
          topRight: code.location.topRightCorner,
          bottomLeft: code.location.bottomLeftCorner,
          bottomRight: code.location.bottomRightCorner,
        },
      });
    } catch (err) {
      return reply.status(422).send({
        error: "Barcode reading failed",
        details: err instanceof Error ? err.message : "Unknown error",
      });
    }
  });
}