// Developer: Saksham Pathak (github.com/parthmax2)

let classes = [];
let selectedFile = null;

const dropzone        = document.getElementById("dropzone");
const dropzoneEmpty   = document.getElementById("dropzoneEmpty");
const dropzonePreview = document.getElementById("dropzonePreview");
const previewImage    = document.getElementById("previewImage");
const previewFileName = document.getElementById("previewFileName");
const previewFileInfo = document.getElementById("previewFileInfo");
const changeImageBtn  = document.getElementById("changeImageBtn");
const imageInput      = document.getElementById("imageInput");
const resizeCb        = document.getElementById("resizeCb");
const slidersEl       = document.getElementById("sliders");
const legendEl        = document.getElementById("legend");
const runBtn          = document.getElementById("runBtn");
const scanOverlay     = document.getElementById("scanOverlay");
const step1           = document.querySelector('.step[data-step="1"]');
const step2           = document.querySelector('.step[data-step="2"]');
const line1           = document.getElementById("line1");
const stepEyebrow     = document.getElementById("stepEyebrow");

const toastStack = document.getElementById("toastStack");

function showToast(message, type = "info") {
  const el = document.createElement("div");
  el.className = `toast ${type}`;
  el.textContent = message;
  toastStack.appendChild(el);
  setTimeout(() => el.remove(), 4000);
}

function formatBytes(bytes) {
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(0)} KB`;
  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
}

function readImageDimensions(file) {
  return new Promise((resolve) => {
    const img = new Image();
    img.onload = () => {
      resolve({ width: img.naturalWidth, height: img.naturalHeight });
      URL.revokeObjectURL(img.src);
    };
    img.src = URL.createObjectURL(file);
  });
}

async function init() {
  const res = await fetch("/api/classes");
  const data = await res.json();
  classes = data.classes;
  renderSliders();
  renderLegend();
}

function renderSliders() {
  slidersEl.innerHTML = classes.map((c) => `
    <div class="slider-item">
      <label for="slider-${c.id}">${c.name}</label>
      <input type="range" id="slider-${c.id}" min="0" max="1" step="0.01" value="${c.default_threshold}">
      <span id="slider-${c.id}-val" class="mono">${c.default_threshold}</span>
    </div>
  `).join("");

  classes.forEach((c) => {
    const input = document.getElementById(`slider-${c.id}`);
    const val = document.getElementById(`slider-${c.id}-val`);
    input.addEventListener("input", () => { val.textContent = input.value; });
  });
}

function renderLegend() {
  legendEl.innerHTML = classes.map((c) => `
    <div class="legend-item">
      <span class="swatch" style="background: rgb(${c.color.join(",")})"></span>
      <span>${c.name}</span>
    </div>
  `).join("");
}

function getThresholds() {
  const thresholds = {};
  classes.forEach((c) => {
    thresholds[c.id] = parseFloat(document.getElementById(`slider-${c.id}`).value);
  });
  return thresholds;
}

// ── upload / dropzone ──────────────────────────────────────
async function setSelectedFile(file) {
  if (!file || !file.type.startsWith("image/")) {
    showToast("Please choose a valid image file.", "error");
    return;
  }
  selectedFile = file;
  previewImage.src = URL.createObjectURL(file);
  previewFileName.textContent = file.name;
  previewFileInfo.textContent = formatBytes(file.size);
  dropzoneEmpty.hidden = true;
  dropzonePreview.hidden = false;
  runBtn.disabled = false;

  const { width, height } = await readImageDimensions(file);
  previewFileInfo.textContent = `${width} × ${height} px · ${formatBytes(file.size)}`;
}

dropzone.addEventListener("click", (e) => {
  if (e.target.closest(".dropzone-preview")) return;
  imageInput.click();
});
dropzone.addEventListener("keydown", (e) => {
  if (e.key === "Enter" || e.key === " ") { e.preventDefault(); imageInput.click(); }
});
imageInput.addEventListener("change", () => setSelectedFile(imageInput.files[0]));

changeImageBtn.addEventListener("click", (e) => {
  e.stopPropagation();
  imageInput.click();
});

["dragenter", "dragover"].forEach((evt) =>
  dropzone.addEventListener(evt, (e) => { e.preventDefault(); dropzone.classList.add("dragover"); })
);
["dragleave", "drop"].forEach((evt) =>
  dropzone.addEventListener(evt, (e) => { e.preventDefault(); dropzone.classList.remove("dragover"); })
);
dropzone.addEventListener("drop", (e) => {
  const file = e.dataTransfer.files[0];
  if (file) setSelectedFile(file);
});

// ── run detection ──────────────────────────────────────────
runBtn.addEventListener("click", async () => {
  if (!selectedFile) {
    showToast("Please choose an image first.", "error");
    return;
  }

  runBtn.disabled = true;
  runBtn.textContent = "Analyzing…";
  scanOverlay.classList.add("active");
  step1.classList.add("completed");
  step1.classList.remove("active");
  step2.classList.add("active");
  line1.classList.add("filled");
  stepEyebrow.innerHTML = `<span class="dot"></span> Step 2 of 3`;

  try {
    const formData = new FormData();
    formData.append("image", selectedFile);
    formData.append("resize", resizeCb.checked);
    formData.append("thresholds", JSON.stringify(getThresholds()));

    const res = await fetch("/api/detect", { method: "POST", body: formData });
    if (!res.ok) throw new Error(`Request failed: ${res.status}`);
    const data = await res.json();

    sessionStorage.setItem("cardentiq_result", JSON.stringify(data));
    window.location.href = "report.html";
  } catch (err) {
    showToast(`Detection failed: ${err.message}`, "error");
    scanOverlay.classList.remove("active");
    step1.classList.remove("completed");
    step1.classList.add("active");
    step2.classList.remove("active");
    line1.classList.remove("filled");
    stepEyebrow.innerHTML = `<span class="dot"></span> Step 1 of 3`;
    runBtn.disabled = false;
    runBtn.textContent = "Analyze Image";
  }
});

init();