// Small progressive enhancements. Kept deliberately tiny - HTMX does the work.

(function () {
  "use strict";

  // Register the service worker so logging survives a sleeping server.
  if ("serviceWorker" in navigator) {
    window.addEventListener("load", function () {
      navigator.serviceWorker.register("/static/sw.js", { scope: "/" })
        .catch(function () { /* offline support is best-effort */ });
    });
  }

  // A 303 redirect from an HTMX form would otherwise swap the whole page.
  document.body.addEventListener("htmx:afterRequest", function (event) {
    var target = event.detail && event.detail.elt;
    if (target && target.closest && target.closest("form[hx-swap='none']")) {
      var day = document.getElementById("day");
      if (day && window.htmx) {
        window.htmx.ajax("GET", "/partials/day", { target: "#day", swap: "innerHTML" });
      }
    }
  });
})();

// Photo preview. Exposed globally because it is wired up via an inline handler
// on the file input, which is the simplest thing that works on iOS Safari.
//
// There are two file inputs (library and camera) sharing one preview. Picking a
// file in one clears the other, so the form never submits two candidate images.
function ntPick(input, otherId) {
  var other = document.getElementById(otherId);
  if (other) other.value = "";
  ntPreview(input);
}

function ntPreview(input) {
  var image = document.getElementById("preview");
  var button = document.getElementById("analyze-btn");
  if (!image) return;
  var file = input.files && input.files[0];
  if (!file) {
    image.hidden = true;
    if (button) button.disabled = true;
    return;
  }
  image.src = URL.createObjectURL(file);
  image.hidden = false;
  if (button) button.disabled = false;
}

// --------------------------------------------------------------------------
// Barcode scanning
//
// Uses MediaDevices + ZXing. Camera access needs a secure context: it works on
// the Tailscale https:// address and on http://127.0.0.1 (browsers treat
// localhost as secure), but NOT on a plain http:// LAN IP. The photo and
// manual-entry paths exist so a user who lands in that case still has a way
// through rather than a dead end.
// --------------------------------------------------------------------------

var ntReader = null;
var ntLastCode = null;

function ntSetStatus(message, isError) {
  var node = document.getElementById("scan-status");
  if (!node) return;
  node.textContent = message || "";
  node.style.color = isError ? "var(--bad)" : "var(--muted)";
}

function ntScanFormats() {
  return [
    ZXing.BarcodeFormat.EAN_13, ZXing.BarcodeFormat.EAN_8,
    ZXing.BarcodeFormat.UPC_A, ZXing.BarcodeFormat.UPC_E,
    ZXing.BarcodeFormat.CODE_128, ZXing.BarcodeFormat.CODE_39,
    ZXing.BarcodeFormat.ITF
  ];
}

function ntLookupBarcode(code) {
  var cleaned = (code || "").replace(/\D/g, "");
  if (cleaned.length < 6) {
    ntSetStatus("That does not look like a barcode.", true);
    return;
  }
  ntStopScan();
  ntSetStatus("Looking up " + cleaned + "...");
  var meal = document.getElementById("meal");
  var url = "/scan/lookup?barcode=" + encodeURIComponent(cleaned) +
            "&meal=" + encodeURIComponent(meal ? meal.value : "");
  if (window.htmx) {
    window.htmx.ajax("GET", url, { target: "#results", swap: "innerHTML" });
  } else {
    window.location = url;
  }
}

function ntLookupManual() {
  var field = document.getElementById("manual");
  if (field) ntLookupBarcode(field.value);
}

function ntStartScan() {
  var video = document.getElementById("scan-video");
  var startButton = document.getElementById("scan-start");
  var stopButton = document.getElementById("scan-stop");

  if (!window.ZXing) {
    ntSetStatus("The scanner library did not load. Use a photo or type the number.", true);
    return;
  }
  if (!navigator.mediaDevices || !navigator.mediaDevices.getUserMedia) {
    ntSetStatus(
      "This browser will not open the camera here. On a plain http:// address " +
      "the camera is blocked; use https, or use a photo below.", true);
    return;
  }

  video.hidden = false;
  if (startButton) startButton.hidden = true;
  if (stopButton) stopButton.hidden = false;
  ntSetStatus("Point the camera at the barcode.");

  var hints = new Map();
  hints.set(ZXing.DecodeHintType.POSSIBLE_FORMATS, ntScanFormats());
  hints.set(ZXing.DecodeHintType.TRY_HARDER, true);

  ntReader = new ZXing.BrowserMultiFormatReader(hints, { delayBetweenScanAttempts: 200 });
  var constraints = {
    video: {
      facingMode: { ideal: "environment" },
      width: { ideal: 1280 },
      height: { ideal: 720 }
    }
  };

  ntReader.decodeFromConstraints(constraints, video, function (result) {
    if (!result) return;
    var text = result.getText();
    if (text && text !== ntLastCode) {
      ntLastCode = text;
      ntLookupBarcode(text);
    }
  }).catch(function (error) {
    ntStopScan();
    var message = (error && error.name === "NotAllowedError")
      ? "Camera permission was declined. Use a photo below instead."
      : "Could not open the camera. Use a photo below instead.";
    ntSetStatus(message, true);
  });
}

function ntStopScan() {
  if (ntReader) {
    try { ntReader.reset(); } catch (error) { /* already stopped */ }
    ntReader = null;
  }
  var video = document.getElementById("scan-video");
  if (video && video.srcObject) {
    video.srcObject.getTracks().forEach(function (track) { track.stop(); });
    video.srcObject = null;
  }
  var startButton = document.getElementById("scan-start");
  var stopButton = document.getElementById("scan-stop");
  if (startButton) startButton.hidden = false;
  if (stopButton) stopButton.hidden = true;
}

function ntDecodePhoto(input) {
  var file = input.files && input.files[0];
  if (!file || !window.ZXing) return;
  var image = document.getElementById("scan-image");
  image.src = URL.createObjectURL(file);
  image.hidden = false;
  image.onload = function () {
    var reader = new ZXing.BrowserMultiFormatReader();
    reader.decodeFromImageElement(image).then(function (result) {
      ntLookupBarcode(result.getText());
    }).catch(function () {
      ntSetStatus(
        "No barcode found in that photo. Get closer, fill the frame, and keep it in focus.",
        true);
    });
  };
}

// Release the camera when navigating away, otherwise the indicator stays lit.
window.addEventListener("pagehide", function () { ntStopScan(); });