"use strict";

let trail_chart_number = 0;

const create_map = (map_element) => {
  const open_street_map_mapnik = L.tileLayer.provider("OpenStreetMap.Mapnik", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const open_street_map_de = L.tileLayer.provider("OpenStreetMap.DE", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const open_street_map_france = L.tileLayer.provider("OpenStreetMap.France", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const opnv_karte = L.tileLayer.provider("OPNVKarte", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const open_topo_map = L.tileLayer.provider("OpenTopoMap", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const cycl_osm = L.tileLayer.provider("CyclOSM", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });
  const mtb_map = L.tileLayer.provider("MtbMap", {
    referrerPolicy: "strict-origin-when-cross-origin",
  });

  const map = L.map(map_element, {
    center: [49.75, 6.1],
    zoom: 8,
    zoomControl: true,
    scrollWheelZoom: true,
    keyboard: true,
    layers: [open_street_map_mapnik],
  });

  L.control
    .layers(
      {
        OpenStreetMap: open_street_map_mapnik,
        OpenStreetMapDE: open_street_map_de,
        OpenStreetMapFrance: open_street_map_france,
        OPNVKarte: opnv_karte,
        OpenTopoMap: open_topo_map,
        CycleOSM: cycl_osm,
        MtbMap: mtb_map,
      },
      null,
      {
        collapsed: true,
        position: "topright",
      },
    )
    .addTo(map);

  L.control
    .scale({
      imperial: false,
      metric: true,
      position: "bottomleft",
    })
    .addTo(map);

  new L.Control.FullScreen({
    position: "topleft",
    title: "View map fullscreen",
    titleCancel: "Exit fullscreen",
  }).addTo(map);

  return map;
};

const create_parking_icon = () =>
  L.icon({
    iconUrl: "/static/images/trail/parking.svg",
    iconSize: [32, 32],
    iconAnchor: [16, 32],
    popupAnchor: [0, -32],
    tooltipAnchor: [0, -28],
    className: "trail-parking-marker",
  });

const create_display_control = (map, chart_element) => {
  if (!chart_element.id) {
    trail_chart_number += 1;
    chart_element.id = `trail-chart-${trail_chart_number}`;
  }

  const parking_icon = create_parking_icon();

  const display_control = L.control.elevation({
    theme: "trail-theme",

    detached: true,
    elevationDiv: `#${chart_element.id}`,

    altitude: true,
    distance: true,
    time: "summary",
    speed: "summary",
    pace: "summary",
    slope: "summary",
    acceleration: false,

    summary: false,
    downloadLink: false,
    legend: true,
    ruler: false,

    autofitBounds: true,
    followMarker: false,

    marker: "position-marker",
    distanceMarkers: false,
    hotline: false,

    waypoints: "markers",
    wptLabels: "markers",

    wptIcons: {
      Parking: parking_icon,
      parking: parking_icon,
      "Parking Area": parking_icon,
      "parking area": parking_icon,
      "parking-area": parking_icon,
      Car: parking_icon,
      car: parking_icon,
    },

    trkStart: false,
    trkEnd: false,
    closeBtn: false,
  });

  display_control.addTo(map);

  return display_control;
};

const create_summary_control = () => {
  const map_element = document.createElement("div");

  map_element.hidden = true;
  document.body.append(map_element);

  const map = L.map(map_element, {
    center: [0, 0],
    zoom: 1,
    zoomControl: false,
    attributionControl: false,
    keyboard: false,
    dragging: false,
    scrollWheelZoom: false,
    doubleClickZoom: false,
    boxZoom: false,
    touchZoom: false,
  });

  const summary_control = L.control.elevation({
    detached: false,
    collapsed: true,

    altitude: "summary",
    distance: "summary",
    time: "summary",
    speed: "summary",
    pace: "summary",
    slope: "summary",
    acceleration: false,

    summary: false,
    downloadLink: false,
    legend: false,
    ruler: false,

    autofitBounds: false,
    followMarker: false,

    marker: false,
    distanceMarkers: false,
    hotline: false,

    waypoints: false,
    wptLabels: false,

    trkStart: false,
    trkEnd: false,
    closeBtn: false,
  });

  summary_control.addTo(map);

  return {
    control: summary_control,
    destroy: () => {
      map.remove();
      map_element.remove();
    },
  };
};

function visit_leaflet_layer(layer, callback) {
  if (!layer) {
    return;
  }

  if (typeof layer.eachLayer === "function") {
    layer.eachLayer((child_layer) => {
      visit_leaflet_layer(child_layer, callback);
    });

    return;
  }

  callback(layer);
}

const create_trail_icon = (type, label) =>
  L.divIcon({
    className: `trail-marker trail-marker-${type}`,
    html:
      '<span class="trail-marker-symbol" aria-hidden="true"></span>' +
      `<span class="visually-hidden">${label}</span>`,
    iconSize: [30, 30],
    iconAnchor: [15, 15],
    popupAnchor: [0, -16],
    tooltipAnchor: [0, -16],
  });

function add_trail_marker(map, position, type, label) {
  const marker = L.marker(position, {
    icon: create_trail_icon(type, label),
    keyboard: true,
    title: label,
    alt: label,
  });

  marker.bindTooltip(label, {
    direction: "top",
  });

  marker.addTo(map);
}

const add_endpoint_markers = (map, loaded_layer) => {
  const lat_lngs = [];

  visit_leaflet_layer(loaded_layer, (layer) => {
    if (typeof layer.getLatLngs !== "function") {
      return;
    }

    lat_lngs.push(
      ...layer
        .getLatLngs()
        .flat(Infinity)
        .filter(
          (item) =>
            item &&
            typeof item.lat === "number" &&
            typeof item.lng === "number",
        ),
    );
  });

  if (lat_lngs.length < 2) {
    console.warn(
      "The loaded GPX did not contain enough track points for endpoint markers.",
    );
    return;
  }

  const start = lat_lngs[0];
  const finish = lat_lngs[lat_lngs.length - 1];

  if (start.distanceTo(finish) <= 50) {
    add_trail_marker(map, start, "loop", "Start and finish");
    return;
  }

  add_trail_marker(map, start, "start", "Start");

  add_trail_marker(map, finish, "finish", "Finish");
};

const format_duration = (milliseconds) => {
  if (!Number.isFinite(milliseconds) || milliseconds < 0) {
    return "–";
  }

  const total_seconds = Math.floor(milliseconds / 1000);

  const days = Math.floor(total_seconds / 86400);

  const hours = Math.floor((total_seconds % 86400) / 3600);

  const minutes = Math.floor((total_seconds % 3600) / 60);

  const seconds = total_seconds % 60;

  const time = [hours, minutes, seconds]
    .map((value) => String(value).padStart(2, "0"))
    .join(":");

  if (days === 0) {
    return time;
  }

  const day_label = days === 1 ? "day" : "days";

  return `${days} ${day_label} ${time}`;
};

const format_pace = (time_milliseconds, distance_kilometres) => {
  if (
    !Number.isFinite(time_milliseconds) ||
    !Number.isFinite(distance_kilometres) ||
    time_milliseconds < 0 ||
    distance_kilometres <= 0
  ) {
    return "–";
  }

  const seconds_per_kilometre = Math.round(
    time_milliseconds / 1000 / distance_kilometres,
  );

  const minutes = Math.floor(seconds_per_kilometre / 60);

  const seconds = seconds_per_kilometre % 60;

  return `${minutes}:${String(seconds).padStart(2, "0")} min/km`;
};

const initialize_trail_map = (trail) => {
  const map_element = trail.querySelector("[data-trail-map]");

  const chart_element = trail.querySelector("[data-trail-chart]");

  const message_element = trail.querySelector("[data-trail-message]");

  const trail_gpx_url = trail.dataset.trailGpxUrl;

  const activity_gpx_url = trail.dataset.activityGpxUrl;

  if (!map_element || !chart_element || (!trail_gpx_url && !activity_gpx_url)) {
    console.error(
      "Could not initialize trail map.",
      new Error(
        "The trail block requires a map, a chart and at least one GPX file.",
      ),
    );

    if (map_element) {
      map_element.hidden = true;
    }

    if (chart_element) {
      chart_element.hidden = true;
    }

    if (message_element) {
      message_element.hidden = false;
    }

    return;
  }

  const display_gpx_url = trail_gpx_url || activity_gpx_url;

  const summary_gpx_url = activity_gpx_url || trail_gpx_url;

  const summary_uses_separate_gpx = summary_gpx_url !== display_gpx_url;

  try {
    const map = create_map(map_element);

    const display_control = create_display_control(map, chart_element);

    const set_summary_values = (track_info) => {
      const set_value = (selector, value) => {
        const element = trail.querySelector(selector);

        if (element) {
          element.textContent = value;
        }
      };

      set_value(
        "[data-trail-distance]",
        `${track_info.distance.toFixed(2)} km`,
      );

      set_value("[data-trail-time]", format_duration(track_info.time));

      set_value(
        "[data-trail-pace]",
        format_pace(track_info.time, track_info.distance),
      );

      set_value(
        "[data-trail-maximum-elevation]",
        `${track_info.elevation_max.toFixed(0)} m`,
      );

      set_value(
        "[data-trail-minimum-elevation]",
        `${track_info.elevation_min.toFixed(0)} m`,
      );

      set_value(
        "[data-trail-average-elevation]",
        `${track_info.elevation_avg.toFixed(0)} m`,
      );

      set_value("[data-trail-ascent]", `${track_info.ascent.toFixed(0)} m`);

      set_value("[data-trail-descent]", `${track_info.descent.toFixed(0)} m`);

      set_value(
        "[data-trail-average-speed]",
        `${track_info.speed_avg.toFixed(2)} km/h`,
      );

      set_value(
        "[data-trail-maximum-speed]",
        `${track_info.speed_max.toFixed(2)} km/h`,
      );
    };

    display_control.once("eledata_loaded", ({ layer, track_info }) => {
      add_endpoint_markers(map, layer);

      if (!summary_uses_separate_gpx) {
        set_summary_values(track_info);
      }

      map.invalidateSize(false);
      display_control.redraw();
    });

    display_control.load(display_gpx_url);

    if (summary_uses_separate_gpx) {
      const { control: summary_control, destroy: destroy_summary_control } =
        create_summary_control();

      summary_control.once("eledata_loaded", ({ track_info }) => {
        set_summary_values(track_info);

        destroy_summary_control();
      });

      summary_control.load(summary_gpx_url);
    }
  } catch (error) {
    console.error("Could not initialize trail map.", error);

    map_element.hidden = true;
    chart_element.hidden = true;

    if (message_element) {
      message_element.hidden = false;
    }
  }
};

document.addEventListener("DOMContentLoaded", () => {
  L.registerLocale("en:trail", {
    "x: ": "Distance: ",
    "y: ": "Elevation: ",
    Altitude: "Elevation",
  });

  L.setLocale("en:trail");

  const trails = document.querySelectorAll(".trail");

  for (const trail of trails) {
    initialize_trail_map(trail);
  }
});