const COLORS = {
  "Bil 1": "#ff0000",
  "Bil 2": "#00c853",
  "Bil 3": "#2979ff",
  "Bil 4": "#2979ff",
  "Bil 5": "#2979ff"
};

const map = L.map("map").setView([55.6761, 12.5683], 13);

L.tileLayer("https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", {
  attribution: "© OpenStreetMap contributors",
  maxZoom: 19
}).addTo(map);

const statusEl = document.getElementById("status");
const alertsEl = document.getElementById("presenceAlerts");
const playBtn = document.getElementById("playBtn");
const pauseBtn = document.getElementById("pauseBtn");
const resetBtn = document.getElementById("resetBtn");

function carIcon(color) {
  return L.divIcon({
    className: "",
    iconSize: [24, 24],
    iconAnchor: [12, 12],
    html: `
      <div class="car" data-role="car">
        <svg viewBox="0 0 24 24" aria-hidden="true">
          <path
            d="M12 2 L20 22 L12 18 L4 22 Z"
            fill="${color}"
            stroke="#ffffff"
            stroke-width="1.5"
          />
        </svg>
      </div>
    `
  });
}

function setHeading(marker, deg) {
  const el = marker.getElement();
  if (!el) return;
  const car = el.querySelector("[data-role=car]");
  if (!car) return;
  car.style.transform = `rotate(${deg}deg)`;
}

function fmtTs(ts) {
  return `${ts}s`;
}

function popupHtml(name, state) {
  return `
    <div style="font:13px/1.4 system-ui,sans-serif;min-width:190px;">
      <div style="font-weight:600;margin-bottom:6px;">${name}</div>
      <div><strong>Tid:</strong> ${fmtTs(state.current.ts)}</div>
      <div><strong>Lat:</strong> ${state.displayLat.toFixed(5)}</div>
      <div><strong>Lon:</strong> ${state.displayLon.toFixed(5)}</div>
      <div><strong>Hastighed:</strong> ${state.current.speedMps} m/s</div>
      <div><strong>Retning:</strong> ${state.displayHeading.toFixed(0)}°</div>
      <div><strong>Usikkerhed:</strong> ${state.current.uncertaintyM} m</div>
      <div><strong>På kortet:</strong> ${state.presenceStateLabel || "ja"}</div>
    </div>
  `;
}

function smoothstep(t) {
  t = Math.max(0, Math.min(1, t));
  return t * t * (3 - 2 * t);
}

function lerp(a, b, t) {
  return a + (b - a) * t;
}

function lerpAngleDeg(a, b, t) {
  let d = ((b - a + 540) % 360) - 180;
  return (a + d * t + 360) % 360;
}

function buildVehicleBuckets(events) {
  const out = {};
  for (const e of events) {
    if (!out[e.vehicle]) out[e.vehicle] = [];
    out[e.vehicle].push({ ...e });
  }
  for (const k of Object.keys(out)) {
    out[k].sort((a, b) => a.ts - b.ts);
  }
  return out;
}

function metersBetween(lat1, lon1, lat2, lon2) {
  const meanLatRad = ((lat1 + lat2) / 2) * Math.PI / 180;
  const metersPerDegLat = 111320;
  const metersPerDegLon = 111320 * Math.cos(meanLatRad);

  const dLatM = (lat2 - lat1) * metersPerDegLat;
  const dLonM = (lon2 - lon1) * metersPerDegLon;

  return Math.hypot(dLatM, dLonM);
}

function clamp(value, min, max) {
  return Math.max(min, Math.min(max, value));
}

function distanceToBoundsMeters(lat, lon, bounds) {
  const south = bounds.getSouth();
  const north = bounds.getNorth();
  const west = bounds.getWest();
  const east = bounds.getEast();

  const clampedLat = clamp(lat, south, north);
  const clampedLon = clamp(lon, west, east);

  return metersBetween(lat, lon, clampedLat, clampedLon);
}

function getPresenceState(lat, lon, uncertaintyM) {
  const bounds = map.getBounds();
  const centerInside = bounds.contains([lat, lon]);

  if (centerInside) {
    return {
      code: "inside",
      label: "ja"
    };
  }

  if (uncertaintyM > 0) {
    const distToBounds = distanceToBoundsMeters(lat, lon, bounds);
    if (distToBounds <= uncertaintyM) {
      return {
        code: "possible",
        label: "muligvis"
      };
    }
  }

  return {
    code: "outside",
    label: "nej"
  };
}

const vehicleEvents = buildVehicleBuckets(VEHICLE_EVENTS);
const vehicleNames = Object.keys(vehicleEvents);

const vehicles = {};

for (const name of vehicleNames) {
  const first = vehicleEvents[name][0];
  const color = COLORS[name] || "#2979ff";

  const marker = L.marker([first.lat, first.lon], {
    icon: carIcon(color)
  }).addTo(map);

  const trail = L.polyline([[first.lat, first.lon]], {
    color,
    weight: 3,
    opacity: 0.85
  }).addTo(map);

  let uncertaintyCircle = null;
  if (name === "Bil 2") {
    uncertaintyCircle = L.circle([first.lat, first.lon], {
      radius: first.uncertaintyM,
      color: color,
      weight: 2,
      dashArray: "6,6",
      opacity: 0.7,
      fillColor: color,
      fillOpacity: 0.08
    }).addTo(map);
  }

  vehicles[name] = {
    name,
    color,
    events: vehicleEvents[name],
    marker,
    trail,
    uncertaintyCircle,
    currentIndex: 0,
    current: first,
    next: vehicleEvents[name][1] || null,
    displayLat: first.lat,
    displayLon: first.lon,
    displayHeading: first.headingDeg,
    lastTrailLat: first.lat,
    lastTrailLon: first.lon,
    presenceState: "inside",
    presenceStateLabel: "ja"
  };

  marker.bindPopup(popupHtml(name, vehicles[name]));
  setHeading(marker, first.headingDeg);
}

let simTime = 0;
let lastFrameTime = null;
let running = true;
const TIME_SCALE = 0.175;

function resetDemo() {
  simTime = 0;
  lastFrameTime = null;

  for (const name of vehicleNames) {
    const v = vehicles[name];
    const first = v.events[0];

    v.currentIndex = 0;
    v.current = first;
    v.next = v.events[1] || null;
    v.displayLat = first.lat;
    v.displayLon = first.lon;
    v.displayHeading = first.headingDeg;
    v.lastTrailLat = first.lat;
    v.lastTrailLon = first.lon;
    v.presenceState = "inside";
    v.presenceStateLabel = "ja";

    v.marker.setLatLng([first.lat, first.lon]);
    setHeading(v.marker, first.headingDeg);
    v.marker.setPopupContent(popupHtml(name, v));

    v.trail.setLatLngs([[first.lat, first.lon]]);
    v.trail.setStyle({ opacity: 0.85 });

    if (v.uncertaintyCircle) {
      v.uncertaintyCircle.setLatLng([first.lat, first.lon]);
      v.uncertaintyCircle.setRadius(first.uncertaintyM);
      v.uncertaintyCircle.setStyle({ opacity: 0.7, fillOpacity: 0.08 });
    }

    if (!map.hasLayer(v.marker)) {
      v.marker.addTo(map);
    }
  }

  updateStatus();
}

function advanceVehiclePointers(v) {
  while (v.next && simTime >= v.next.ts) {
    v.currentIndex += 1;
    v.current = v.events[v.currentIndex];
    v.next = v.events[v.currentIndex + 1] || null;

    v.trail.addLatLng([v.current.lat, v.current.lon]);
    v.lastTrailLat = v.current.lat;
    v.lastTrailLon = v.current.lon;
  }
}

function updateVehicleDisplay(v) {
  advanceVehiclePointers(v);

  let lat = v.current.lat;
  let lon = v.current.lon;
  let heading = v.current.headingDeg;

  if (v.next) {
    const dt = v.next.ts - v.current.ts;
    const raw = dt > 0 ? (simTime - v.current.ts) / dt : 1;
    const t = smoothstep(raw);

    lat = lerp(v.current.lat, v.next.lat, t);
    lon = lerp(v.current.lon, v.next.lon, t);
    heading = lerpAngleDeg(v.current.headingDeg, v.next.headingDeg, t);
  } else {
    const age = simTime - v.current.ts;
    const predictFor = Math.min(age, 8);
    const meters = v.current.speedMps * predictFor;

    const rad = v.current.headingDeg * Math.PI / 180;
    const northM = Math.cos(rad) * meters;
    const eastM = Math.sin(rad) * meters;

    const metersPerDegLat = 111320;
    const metersPerDegLon = 111320 * Math.cos(v.current.lat * Math.PI / 180);

    lat = v.current.lat + northM / metersPerDegLat;
    lon = v.current.lon + eastM / metersPerDegLon;
    heading = v.current.headingDeg;
  }

  v.displayLat = lat;
  v.displayLon = lon;
  v.displayHeading = heading;

  const presence = getPresenceState(lat, lon, v.current.uncertaintyM);
  v.presenceState = presence.code;
  v.presenceStateLabel = presence.label;

  if (presence.code === "inside") {
    if (!map.hasLayer(v.marker)) {
      v.marker.addTo(map);
    }
    v.marker.setLatLng([lat, lon]);
    setHeading(v.marker, heading);
    v.trail.setStyle({ opacity: 0.85 });
  } else {
    if (map.hasLayer(v.marker)) {
      map.removeLayer(v.marker);
    }
    v.trail.setStyle({ opacity: 0.25 });
  }

  v.marker.setPopupContent(popupHtml(v.name, v));

  if (v.uncertaintyCircle) {
    v.uncertaintyCircle.setLatLng([lat, lon]);
    v.uncertaintyCircle.setRadius(v.current.uncertaintyM);

    if (presence.code === "inside") {
      v.uncertaintyCircle.setStyle({ opacity: 0.7, fillOpacity: 0.08 });
    } else if (presence.code === "possible") {
      v.uncertaintyCircle.setStyle({ opacity: 0.35, fillOpacity: 0.03 });
    } else {
      v.uncertaintyCircle.setStyle({ opacity: 0.15, fillOpacity: 0.01 });
    }
  }
}

function updateAlerts() {
  const possibleVehicles = vehicleNames
    .map(name => vehicles[name])
    .filter(v => v.presenceState === "possible");

  if (possibleVehicles.length === 0) {
    alertsEl.innerHTML = "";
    return;
  }

  alertsEl.innerHTML = possibleVehicles.map(v => `
    <div class="alert-item">
      <strong>${v.name}: mulig tilstedeværelse</strong>
      Estimatet er udenfor kortet, men usikkerheden overlapper det viste område.
    </div>
  `).join("");
}

function updateStatus() {
  const total = VEHICLE_EVENTS.length;
  const passed = VEHICLE_EVENTS.filter(e => e.ts <= simTime).length;

  statusEl.textContent =
    `Simuleret tid: ${simTime.toFixed(1)} s\n` +
    `Events passeret: ${passed} / ${total}\n` +
    `Afspilning: 2x`;

  updateAlerts();
}

function tick(now) {
  if (!running) return;

  if (lastFrameTime === null) {
    lastFrameTime = now;
  }

  const dtReal = (now - lastFrameTime) / 1000;
  lastFrameTime = now;
  simTime += dtReal / TIME_SCALE;

  for (const name of vehicleNames) {
    updateVehicleDisplay(vehicles[name]);
  }

  updateStatus();
  requestAnimationFrame(tick);
}

playBtn.addEventListener("click", () => {
  if (running) return;
  running = true;
  lastFrameTime = null;
  requestAnimationFrame(tick);
});

pauseBtn.addEventListener("click", () => {
  running = false;
});

resetBtn.addEventListener("click", () => {
  running = false;
  resetDemo();
  running = true;
  requestAnimationFrame(tick);
});

map.on("moveend zoomend", () => {
  for (const name of vehicleNames) {
    updateVehicleDisplay(vehicles[name]);
  }
  updateStatus();
});

resetDemo();
requestAnimationFrame(tick);