import { LIVETRACK_ICON } from "/js/icons.js";
import { notifySidePanelOpen, onlyOneSidePanelOpen } from "/js/panels.js";

const SESSIONS_URL = "/api/livetrack/sessions";
const TRACK_SOURCE = "livetrack-track";
const TRACK_COLOR = "#7209b7";

// A sidebar icon that opens a side panel listing Garmin LiveTrack sessions
// received via the webhook (see docs/deployment.adoc). Clicking one fetches
// and draws its track on the map (only one shown at a time — clicking the
// active one again hides it).
export class LiveTrackPanelControl {
  constructor(map) {
    this._map = map;
    this._activeSessionId = null;
    this._geojson = null;

    // setStyle() (switching the Online/Offline base map) tears down all
    // custom sources and layers — put the track back afterwards, same as
    // GpxPanelControl does for visible GPX files.
    map.on("style.load", () => {
      if (this._geojson) this._showTrack(this._geojson, { fit: false });
    });
  }

  mount(sidebar) {
    this._container = document.createElement("div");
    this._container.className = "sidebar-item";
    this._container.innerHTML = `<button type="button" class="sidebar-icon" title="LiveTrack" aria-label="LiveTrack">${LIVETRACK_ICON}</button>`;
    this._icon = this._container.querySelector(".sidebar-icon");
    this._icon.addEventListener("click", () => this._togglePanel());

    this._panel = document.getElementById("livetrack-panel");
    this._list = this._panel.querySelector(".livetrack-panel__list");
    this._panel
      .querySelector(".basemap-panel__close")
      .addEventListener("click", () => this._togglePanel(false));

    onlyOneSidePanelOpen(this._panel, () => this._icon.classList.remove("active"));

    sidebar.appendChild(this._container);
  }

  _togglePanel(force) {
    const open = force === undefined ? this._panel.hidden : force;
    this._panel.hidden = !open;
    this._icon.classList.toggle("active", open);
    if (open) {
      notifySidePanelOpen(this._panel);
      this._loadSessions();
    }
  }

  async _loadSessions() {
    const response = await fetch(SESSIONS_URL);
    const { sessions } = await response.json();
    this._renderSessions(sessions);
  }

  _renderSessions(sessions) {
    this._list.innerHTML = "";

    if (sessions.length === 0) {
      const li = document.createElement("li");
      li.className = "gpx-tree__empty";
      li.textContent = "No sessions yet";
      this._list.appendChild(li);
      return;
    }

    sessions.forEach(({ id, received_at }) => {
      const li = document.createElement("li");
      li.className = "livetrack-panel__item";

      const button = document.createElement("button");
      button.type = "button";
      button.className = "livetrack-panel__row";
      button.classList.toggle("active", id === this._activeSessionId);

      const idSpan = document.createElement("span");
      idSpan.className = "livetrack-panel__id";
      idSpan.textContent = id;

      const timeSpan = document.createElement("span");
      timeSpan.className = "livetrack-panel__time";
      timeSpan.textContent = new Date(received_at).toLocaleString();

      button.append(idSpan, timeSpan);
      button.addEventListener("click", () => this._toggleTrack(id, button));
      li.appendChild(button);
      this._list.appendChild(li);
    });
  }

  async _toggleTrack(id, button) {
    const wasActive = id === this._activeSessionId;
    this._removeTrack();
    this._list.querySelectorAll(".livetrack-panel__row.active").forEach((el) => el.classList.remove("active"));
    if (wasActive) return;

    button.classList.add("loading");
    try {
      const response = await fetch(`/api/livetrack/sessions/${encodeURIComponent(id)}/track`);
      if (!response.ok) {
        const { error } = await response.json().catch(() => ({}));
        window.alert(error || "Could not load track.");
        return;
      }
      this._geojson = await response.json();
      this._showTrack(this._geojson);
      this._activeSessionId = id;
      button.classList.add("active");
    } finally {
      button.classList.remove("loading");
    }
  }

  _showTrack(geojson, { fit = true } = {}) {
    if (this._map.getSource(TRACK_SOURCE)) return;

    this._map.addSource(TRACK_SOURCE, { type: "geojson", data: geojson });
    this._map.addLayer({
      id: `${TRACK_SOURCE}-line`,
      type: "line",
      source: TRACK_SOURCE,
      filter: ["==", ["geometry-type"], "LineString"],
      layout: { "line-cap": "round", "line-join": "round" },
      paint: { "line-color": TRACK_COLOR, "line-width": 3 },
    });
    this._map.addLayer({
      id: `${TRACK_SOURCE}-point`,
      type: "circle",
      source: TRACK_SOURCE,
      filter: ["==", ["geometry-type"], "Point"],
      paint: {
        "circle-radius": 6,
        "circle-color": TRACK_COLOR,
        "circle-stroke-color": "#fff",
        "circle-stroke-width": 1.5,
      },
    });

    if (!fit) return;

    const coordinates = geojson.features[0].geometry.coordinates;
    const bounds = coordinates.reduce(
      ([minLon, minLat, maxLon, maxLat], [lon, lat]) => [
        Math.min(minLon, lon),
        Math.min(minLat, lat),
        Math.max(maxLon, lon),
        Math.max(maxLat, lat),
      ],
      [Infinity, Infinity, -Infinity, -Infinity],
    );
    this._map.fitBounds(
      [
        [bounds[0], bounds[1]],
        [bounds[2], bounds[3]],
      ],
      { padding: 40 },
    );
  }

  _removeTrack() {
    this._activeSessionId = null;
    this._geojson = null;
    [`${TRACK_SOURCE}-line`, `${TRACK_SOURCE}-point`].forEach((layerId) => {
      if (this._map.getLayer(layerId)) this._map.removeLayer(layerId);
    });
    if (this._map.getSource(TRACK_SOURCE)) this._map.removeSource(TRACK_SOURCE);
  }
}