import { Popup } from "/vendor/maplibre-gl/maplibre-gl.mjs";

const TREE_URL = "/api/gpx/tree";
const UPLOAD_URL = "/api/gpx";
const TRACK_COLOR = "#e63946";

// A MapLibre IControl: a "GPX" button that opens a side panel for
// uploading GPX files (stored server-side in a folder hierarchy) and
// toggling their tracks/waypoints on and off the map.
export class GpxPanelControl {
  constructor(map) {
    this._map = map;
    this._visible = new Set(); // file paths currently shown on the map
    this._interactiveLayers = new Set(); // point layer ids with click/hover wired up

    // setStyle() (switching the Online/Offline base map) tears down all
    // custom sources and layers — put visible GPX layers back afterwards.
    map.on("style.load", () => {
      this._visible.forEach((path) => this._addLayers(path));
    });
  }

  onAdd() {
    this._button = document.createElement("div");
    this._button.className = "maplibregl-ctrl maplibregl-ctrl-group gpx-toggle";
    this._button.innerHTML = `<button type="button">GPX</button>`;
    this._button
      .querySelector("button")
      .addEventListener("click", () => this._togglePanel());

    this._panel = document.getElementById("gpx-panel");
    this._treeContainer = this._panel.querySelector(".gpx-tree");
    this._uploadForm = this._panel.querySelector(".gpx-upload");
    this._uploadStatus = this._panel.querySelector(".gpx-upload__status");
    this._panel
      .querySelector(".gpx-panel__close")
      .addEventListener("click", () => this._togglePanel(false));
    this._uploadForm.addEventListener("submit", (event) => this._handleUpload(event));

    this._loadTree();

    return this._button;
  }

  onRemove() {
    this._button.remove();
  }

  _togglePanel(force) {
    this._panel.hidden = force === undefined ? !this._panel.hidden : !force;
  }

  async _loadTree() {
    const response = await fetch(TREE_URL);
    const tree = await response.json();
    this._renderTree(tree);
  }

  _renderTree(node) {
    this._treeContainer.innerHTML = "";
    this._treeContainer.appendChild(this._renderChildren(node.children));
  }

  _renderChildren(children) {
    const ul = document.createElement("ul");
    if (children.length === 0) {
      const li = document.createElement("li");
      li.className = "gpx-tree__empty";
      li.textContent = "No files yet";
      ul.appendChild(li);
      return ul;
    }

    children.forEach((child) => {
      const li = document.createElement("li");
      if (child.type === "folder") {
        const details = document.createElement("details");
        details.open = true;
        const summary = document.createElement("summary");
        summary.textContent = child.name;
        details.appendChild(summary);
        details.appendChild(this._renderChildren(child.children));
        li.appendChild(details);
      } else {
        const label = document.createElement("label");
        label.className = "gpx-tree__file";
        const checkbox = document.createElement("input");
        checkbox.type = "checkbox";
        checkbox.checked = this._visible.has(child.path);
        checkbox.addEventListener("change", () => this._toggleFile(child.path, checkbox.checked));
        label.appendChild(checkbox);
        label.append(` ${child.name}`);
        li.appendChild(label);
      }
      ul.appendChild(li);
    });

    return ul;
  }

  _toggleFile(path, visible) {
    if (visible) {
      this._visible.add(path);
      this._addLayers(path);
    } else {
      this._visible.delete(path);
      this._removeLayers(path);
    }
  }

  _addLayers(path) {
    const id = sourceId(path);
    if (this._map.getSource(id)) return;

    this._map.addSource(id, { type: "geojson", data: gpxFileUrl(path) });
    this._map.addLayer({
      id: `${id}-line`,
      type: "line",
      source: id,
      filter: ["==", ["geometry-type"], "LineString"],
      layout: { "line-cap": "round", "line-join": "round" },
      paint: { "line-color": TRACK_COLOR, "line-width": 3 },
    });
    this._map.addLayer({
      id: `${id}-points`,
      type: "circle",
      source: id,
      filter: ["==", ["geometry-type"], "Point"],
      paint: {
        "circle-radius": 5,
        "circle-color": TRACK_COLOR,
        "circle-stroke-color": "#fff",
        "circle-stroke-width": 1.5,
      },
    });

    this._registerPointInteractivity(`${id}-points`);
  }

  // Registered once per layer id, ever — map.on(type, layerId, fn) is a
  // delegated listener that lives on the map itself and keeps matching
  // that layer id after setStyle() removes and (via _addLayers) re-adds
  // it, so re-registering on every re-add would stack duplicate popups.
  _registerPointInteractivity(layerId) {
    if (this._interactiveLayers.has(layerId)) return;
    this._interactiveLayers.add(layerId);

    this._map.on("click", layerId, (event) => {
      const feature = event.features[0];
      if (!feature) return;
      new Popup({ closeButton: true, maxWidth: "260px" })
        .setLngLat(event.lngLat)
        .setHTML(popupHtml(feature.properties))
        .addTo(this._map);
    });
    this._map.on("mouseenter", layerId, () => {
      this._map.getCanvas().style.cursor = "pointer";
    });
    this._map.on("mouseleave", layerId, () => {
      this._map.getCanvas().style.cursor = "";
    });
  }

  _removeLayers(path) {
    const id = sourceId(path);
    [`${id}-line`, `${id}-points`].forEach((layerId) => {
      if (this._map.getLayer(layerId)) this._map.removeLayer(layerId);
    });
    if (this._map.getSource(id)) this._map.removeSource(id);
  }

  async _handleUpload(event) {
    event.preventDefault();
    const formData = new FormData(this._uploadForm);
    this._setStatus("Uploading…");

    try {
      const response = await fetch(UPLOAD_URL, { method: "POST", body: formData });
      if (!response.ok) throw new Error("upload failed");
      const { tree } = await response.json();
      this._renderTree(tree);
      this._uploadForm.reset();
      this._setStatus("Uploaded.");
    } catch (err) {
      this._setStatus("Upload failed.");
    }
  }

  _setStatus(text) {
    this._uploadStatus.hidden = false;
    this._uploadStatus.textContent = text;
  }
}

function sourceId(path) {
  return `gpx-${path}`;
}

function gpxFileUrl(path) {
  return `/api/gpx/file/${path.split("/").map(encodeURIComponent).join("/")}`;
}

// properties come straight from an uploaded GPX file — untrusted input —
// so every value is escaped before landing in the popup's HTML.
function popupHtml({ name, description, time }) {
  const parts = [];
  if (name) parts.push(`<strong>${escapeHtml(name)}</strong>`);
  if (description) parts.push(`<p>${linkify(description).replace(/\n/g, "<br>")}</p>`);
  if (time) {
    const parsed = new Date(time);
    if (!Number.isNaN(parsed.getTime())) {
      parts.push(`<p class="gpx-popup__time">${escapeHtml(parsed.toLocaleString())}</p>`);
    }
  }
  return parts.length > 0 ? parts.join("") : "<em>No details</em>";
}

function escapeHtml(text) {
  const div = document.createElement("div");
  div.textContent = text;
  return div.innerHTML;
}

// Turns bare URLs in untrusted text into safe <a> links: the string is
// split on the URL pattern and every piece is escaped — including the URL
// itself, both as href and as link text — before any HTML is assembled, so
// nothing bypasses escaping. The URL pattern excludes quote characters, so
// a matched URL can never break out of the href="..." attribute.
const URL_PATTERN = /(https?:\/\/[^\s<>"']+)/g;

function linkify(text) {
  return text
    .split(URL_PATTERN)
    .map((part, i) => (i % 2 === 1 ? urlToLink(part) : escapeHtml(part)))
    .join("");
}

function urlToLink(url) {
  // Keep trailing sentence punctuation (e.g. "...place/1234.") out of the
  // link itself.
  const [, core, trailing] = url.match(/^(.*?)([.,;:!?]*)$/);
  const href = escapeHtml(core);
  return `<a href="${href}" target="_blank" rel="noopener noreferrer">${href}</a>${escapeHtml(trailing)}`;
}