const form = document.querySelector("#uploadForm");
const pdfInput = document.querySelector("#pdfInput");
const fileName = document.querySelector("#fileName");
const startButton = document.querySelector("#startButton");
const statusText = document.querySelector("#statusText");
const batchText = document.querySelector("#batchText");
const progressBar = document.querySelector("#progressBar");
const jobIdText = document.querySelector("#jobIdText");
const pageCounter = document.querySelector("#pageCounter");
const tabCounter = document.querySelector("#tabCounter");
const messageText = document.querySelector("#messageText");
const downloadLink = document.querySelector("#downloadLink");
const downloadCsvLink = document.querySelector("#downloadCsvLink");
const previewBody = document.querySelector("#previewBody");
const rowCount = document.querySelector("#rowCount");
const browserViewStatus = document.querySelector("#browserViewStatus");
const browserViewImage = document.querySelector("#browserViewImage");
const browserViewEmpty = document.querySelector("#browserViewEmpty");

let pollTimer = null;

pdfInput.addEventListener("change", () => {
  fileName.textContent = pdfInput.files[0]?.name || "Choose a bank statement PDF";
});

form.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearInterval(pollTimer);
  downloadLink.hidden = true;
  downloadCsvLink.hidden = true;
  startButton.disabled = true;
  setStatus({ id: "", status: "uploading", message: "Uploading PDF", progress: 2, completed_batches: 0, total_batches: 0 });

  const formData = new FormData(form);
  try {
    const response = await fetch("/api/jobs", { method: "POST", body: formData });
    if (!response.ok) throw new Error(await readError(response));
    const payload = await response.json();
    pollJob(payload.job_id);
    pollTimer = setInterval(() => pollJob(payload.job_id), 2500);
  } catch (error) {
    setStatus({ status: "error", message: error.message, progress: 100, completed_batches: 0, total_batches: 0 });
    startButton.disabled = false;
  }
});

async function pollJob(jobId) {
  try {
    const response = await fetch(`/api/jobs/${jobId}`);
    if (!response.ok) throw new Error(await readError(response));
    const job = await response.json();
    setStatus(job);
    updateBrowserView(job);

    if (job.status === "done") {
      clearInterval(pollTimer);
      startButton.disabled = false;
      downloadLink.hidden = false;
      downloadLink.href = `/api/jobs/${jobId}/download`;
      downloadCsvLink.hidden = false;
      downloadCsvLink.href = `/api/jobs/${jobId}/download.csv`;
      renderPreview(job.data_preview || []);
    }

    if (job.status === "error") {
      clearInterval(pollTimer);
      startButton.disabled = false;
    }
  } catch (error) {
    clearInterval(pollTimer);
    startButton.disabled = false;
    setStatus({ status: "error", message: error.message, progress: 100, completed_batches: 0, total_batches: 0 });
  }
}

function setStatus(job) {
  statusText.textContent = titleCase(job.status || "ready");
  jobIdText.textContent = job.id ? `Job ${job.id}` : "No job started";
  pageCounter.textContent = `${job.completed_pages || 0} / ${job.total_pages || 0} pages`;
  tabCounter.textContent = `${job.active_tabs || 0} active tabs`;
  const pageText = job.current_pages ? ` Current pages: ${job.current_pages}.` : "";
  messageText.textContent = `${job.error || job.message || ""}${pageText}`;
  batchText.textContent = `${job.completed_batches || 0} / ${job.total_batches || 0} waves`;
  progressBar.style.width = `${Math.max(0, Math.min(job.progress || 0, 100))}%`;
}

function updateBrowserView(job) {
  if (!job.id || !job.latest_screenshot) {
    browserViewStatus.textContent = "Waiting";
    return;
  }
  browserViewStatus.textContent = "Latest screenshot";
  browserViewImage.hidden = false;
  browserViewEmpty.hidden = true;
  browserViewImage.src = `/api/jobs/${job.id}/browser-view/latest?t=${Date.now()}`;
}

function renderPreview(rows) {
  rowCount.textContent = rows.length ? `First ${rows.length} rows` : "No rows returned";
  if (!rows.length) {
    previewBody.innerHTML = '<tr><td colspan="5" class="empty">No preview rows were returned.</td></tr>';
    return;
  }

  previewBody.innerHTML = rows.map((row) => `
    <tr>
      <td>${escapeHtml(row.date || "")}</td>
      <td>${escapeHtml(row.description || "")}</td>
      <td>${escapeHtml(row.voucher_type || "")}</td>
      <td>${escapeHtml(row.amount || "")}</td>
      <td>${escapeHtml(row.closing || "")}</td>
    </tr>
  `).join("");
}

async function readError(response) {
  try {
    const payload = await response.json();
    return payload.detail || response.statusText;
  } catch {
    return response.statusText;
  }
}

function titleCase(value) {
  return value.charAt(0).toUpperCase() + value.slice(1);
}

function escapeHtml(value) {
  return String(value)
    .replaceAll("&", "&amp;")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#039;");
}