Watermark Extract

import { useRef, useState } from 'react';

const API_BASE = 'https://api.bizmori.com/api/v2';
const API_TOKEN = import.meta.env.VITE_MORI_API_TOKEN;

const ACCEPT_FORMATS = '.jpg,.jpeg,.png,.webp,.tiff,.bmp,.pdf';

const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function api(path, { method = 'GET', body, idempotencyKey } = {}) {
  // Retries reuse the caller's idempotency key, so a retried create can never
  // produce a second order. Auth failures surface as `AUTH_*` codes — retrying
  // those will not help, so they fall through to the throw below.
  for (let attempt = 0; ; attempt++) {
    const res = await fetch(`${API_BASE}${path}`, {
      method,
      headers: {
        Authorization: `Bearer ${API_TOKEN}`,
        ...(body && { 'Content-Type': 'application/json' }),
      },
      body: body && JSON.stringify({ idempotencyKey, ...body }),
    });

    if (!res.ok) {
      const { code } = await res.json().catch(() => ({}));
      // 429 covers two cases: a transient rate limit, and PLAN_LIMIT_EXCEEDED,
      // which means the plan quota is spent and will never clear on retry.
      if (res.status === 429 && code !== 'PLAN_LIMIT_EXCEEDED' && attempt < 3) {
        await sleep(2 ** attempt * 1000);
        continue;
      }
      throw new Error(code ?? `HTTP_${res.status}`);
    }
    return (await res.json()).data;
  }
}

function putFile(file, uploadUrl, onProgress) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open('PUT', uploadUrl);
    xhr.setRequestHeader('Content-Type', file.type);

    xhr.upload.onprogress = (event) => {
      if (event.lengthComputable) onProgress(event.loaded / event.total);
    };
    xhr.onload = () =>
      xhr.status < 300 ? resolve() : reject(new Error(`UPLOAD_FAILED_${xhr.status}`));
    xhr.onerror = () => reject(new Error('UPLOAD_NETWORK_ERROR'));

    xhr.send(file);
  });
}


async function pollOrder(orderId, { onStatus, timeoutMs = 10 * 60 * 1000 } = {}) {
  const deadline = Date.now() + timeoutMs;
  let delay = 2000;

  while (Date.now() < deadline) {
    const order = await api(`/orders/${orderId}`);
    onStatus?.(order.status);
    if (['complete', 'failed', 'expired'].includes(order.status)) return order;

    await sleep(delay);
    delay = Math.min(delay * 1.5, 15000);
  }
  throw new Error('ORDER_POLL_TIMEOUT');
}

export default function WatermarkExtractChecker() {
  const [file, setFile] = useState(null);
  const [progress, setProgress] = useState(0);
  const [status, setStatus] = useState('idle');
  const [result, setResult] = useState(null);
  const [error, setError] = useState(null);
  const [orderId, setOrderId] = useState(null);
  const inFlight = useRef(false);

  const busy = status !== 'idle' && status !== 'complete';

  async function checkWatermark(event) {
    event.preventDefault();
    if (inFlight.current || !file) return;
    inFlight.current = true;

    // Snapshot the selection. The user can swap files while requests are in
    // flight, and `selected` has to stay paired with the order's upload URL.
    const selected = file;
    setError(null);
    setOrderId(null);
    setResult(null);
    setProgress(0);

    try {
      setStatus('creating order');
      const order = await api('/orders/wtr-extract', {
        method: 'POST',
        idempotencyKey: crypto.randomUUID(),
        body: { file: { fileName: selected.name } },
      });

      setOrderId(order.orderId);
      setStatus('uploading');
      await putFile(selected, order.file.uploadUrl, setProgress);

      const finished = await pollOrder(order.orderId, { onStatus: setStatus });
      // `expired` is terminal too: the cleanup job drops the files after 7 days.
      if (finished.status !== 'complete') throw new Error(`ORDER_${finished.status.toUpperCase()}`);

      setResult(finished);
      setStatus('complete');
    } catch (caught) {
      setError(caught.message);
      setStatus('idle');
    } finally {
      inFlight.current = false;
    }
  }

  return (
    <form onSubmit={checkWatermark}>
      <input
        type="file"
        accept={ACCEPT_FORMATS}
        disabled={busy}
        onChange={(event) => {
          setFile(event.target.files[0] ?? null);
          setError(null);
          setProgress(0);
          setResult(null);
        }}
      />
      <button type="submit" disabled={busy || !file}>
        Check for watermark
      </button>

      {status !== 'idle' && <p>Status: {status}</p>}
      {status === 'uploading' && <p>Uploading: {Math.round(progress * 100)}%</p>}

      {/* `status` says the job finished; `statusCode` says what was found. */}
      {result?.statusCode === 'detected' && (
        <p>
          Watermark detected: <strong>{result.watermarkText}</strong>
        </p>
      )}
      {result?.statusCode === 'undetected' && <p>No watermark was found in this image.</p>}
      {error && <p role="alert">Failed: {error}{orderId && ` (orderId: ${orderId})`}</p>}
    </form>
  );
}