/**
 * Address autocomplete via Django /api/address-suggest/ (Nominatim proxy).
 * Never calls Nominatim from the browser.
 *
 * Markup: wrap fields in [data-address-autocomplete][data-suggest-url="..."].
 * Mark inputs with data-ac="line1|line2|city|state|zip|country".
 * The line1 input is the typeahead trigger.
 */
(function () {
  "use strict";

  var DEBOUNCE_MS = 280;
  var MIN_CHARS = 3;

  function debounce(fn, wait) {
    var t;
    return function () {
      var ctx = this;
      var args = arguments;
      clearTimeout(t);
      t = setTimeout(function () {
        fn.apply(ctx, args);
      }, wait);
    };
  }

  function field(root, key) {
    return root.querySelector('[data-ac="' + key + '"]');
  }

  function ensureList(root) {
    var list = root.querySelector(".address-ac-list");
    if (list) {
      return list;
    }
    list = document.createElement("ul");
    list.className = "address-ac-list";
    list.hidden = true;
    list.setAttribute("role", "listbox");
    var line1 = field(root, "line1");
    var wrap = line1 && line1.closest(".form-wrap, .field");
    (wrap || root).appendChild(list);
    if (wrap) {
      wrap.classList.add("address-ac-wrap");
    } else {
      root.classList.add("address-ac-wrap");
    }
    return list;
  }

  function hide(list) {
    list.hidden = true;
    list.innerHTML = "";
  }

  function fill(root, item) {
    var map = {
      line1: item.line1 || "",
      line2: item.line2 || "",
      city: item.city || "",
      state: item.state || "",
      zip: item.zip || "",
      country: item.country || "US",
    };
    Object.keys(map).forEach(function (key) {
      var el = field(root, key);
      if (el) {
        el.value = map[key];
        el.dispatchEvent(new Event("input", { bubbles: true }));
        el.dispatchEvent(new Event("change", { bubbles: true }));
      }
    });
  }

  function render(root, list, results) {
    list.innerHTML = "";
    if (!results.length) {
      hide(list);
      return;
    }
    results.forEach(function (item, index) {
      var li = document.createElement("li");
      li.className = "address-ac-item";
      li.setAttribute("role", "option");
      li.setAttribute("tabindex", "-1");
      li.dataset.index = String(index);
      li.textContent = item.label || item.line1 || "Address";
      li.addEventListener("mousedown", function (ev) {
        ev.preventDefault();
        fill(root, item);
        hide(list);
      });
      list.appendChild(li);
    });
    list.hidden = false;
  }

  function bind(root) {
    var url = root.getAttribute("data-suggest-url");
    var input = field(root, "line1");
    if (!url || !input) {
      return;
    }
    var list = ensureList(root);
    input.setAttribute("autocomplete", "off");
    input.setAttribute("aria-autocomplete", "list");

    var fetchSuggest = debounce(function () {
      var q = (input.value || "").trim();
      if (q.length < MIN_CHARS) {
        hide(list);
        return;
      }
      var req = url + (url.indexOf("?") >= 0 ? "&" : "?") + "q=" + encodeURIComponent(q) + "&limit=5";
      fetch(req, { headers: { Accept: "application/json" }, credentials: "same-origin" })
        .then(function (res) {
          return res.json();
        })
        .then(function (data) {
          render(root, list, (data && data.results) || []);
        })
        .catch(function () {
          hide(list);
        });
    }, DEBOUNCE_MS);

    input.addEventListener("input", fetchSuggest);
    input.addEventListener("keydown", function (ev) {
      if (ev.key === "Escape") {
        hide(list);
      }
    });
    document.addEventListener("click", function (ev) {
      if (!root.contains(ev.target)) {
        hide(list);
      }
    });
  }

  function init() {
    document.querySelectorAll("[data-address-autocomplete]").forEach(bind);
  }

  if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", init);
  } else {
    init();
  }
})();