import * as THREE from "three";

import { CONFIG, PATHS, VESSEL_CONFIG } from "./constants.js";
import { createInteractableLayer } from "./interactable.js";
import { latLonToVector3 } from "./utils.js";

let showVessels = false;
let activeTrackLine = null;
let vesselDataByKey = new Map();
let vesselSnapshotGeneration = 0;
let vesselRealtimeStats = {
  connected: false,
  updates: 0,
  lastUpdateAt: null,
  lastBatchSize: 0,
};

const VESSEL_RENDER_ORDER = 4.4;
const VESSEL_POINT_SIZE = 34;
const VESSEL_ATLAS_CELL_SIZE = 128;
const VESSEL_COURSE_BINS = 32;
const VESSEL_TRACK_ENDPOINT_EPSILON = 0.001;

function getVesselDedupeKey(feature, markerData) {
  const props = feature?.properties || {};
  const mmsi = props.mmsi ?? feature?.id ?? markerData?.mmsi;
  if (mmsi !== undefined && mmsi !== null && String(mmsi).trim() !== "") {
    return `mmsi:${String(mmsi).trim()}`;
  }
  return [
    "position",
    Number(markerData.latitude).toFixed(5),
    Number(markerData.longitude).toFixed(5),
    String(props.name || markerData.name || "").trim().toLowerCase(),
  ].join(":");
}

function dedupeVesselFeatures(features) {
  const seen = new Set();
  const markerData = [];
  features.forEach((feature) => {
    const marker = buildVesselMarkerData(feature);
    if (!marker) return;
    const key = getVesselDedupeKey(feature, marker);
    if (seen.has(key)) return;
    seen.add(key);
    markerData.push(marker);
  });
  return markerData;
}

function markerDataToDedupeKey(item) {
  const mmsi = item?.mmsi;
  if (mmsi !== undefined && mmsi !== null && String(mmsi).trim() !== "") {
    return `mmsi:${String(mmsi).trim()}`;
  }
  return [
    "position",
    Number(item.latitude).toFixed(5),
    Number(item.longitude).toFixed(5),
    String(item.name || "").trim().toLowerCase(),
  ].join(":");
}

function normalizeVesselType(value, code) {
  const type = String(value || "").trim().toLowerCase();
  const numericCode = Number(code);
  if (type.includes("cargo") || (numericCode >= 70 && numericCode <= 79)) return "cargo";
  if (type.includes("tanker") || (numericCode >= 80 && numericCode <= 89)) return "tanker";
  if (type.includes("passenger") || (numericCode >= 60 && numericCode <= 69)) return "passenger";
  if (type.includes("fishing") || numericCode === 30) return "fishing";
  if (type.includes("military") || numericCode === 35) return "military";
  return "other";
}

function formatVesselTypeLabel(type, fallback = "") {
  const rawFallback = String(fallback || "").trim();
  const normalized = String(type || "").trim().toLowerCase();
  if (normalized === "cargo") return "Cargo";
  if (normalized === "tanker") return "Tanker";
  if (normalized === "passenger") return "Passenger";
  if (normalized === "fishing") return "Fishing";
  if (normalized === "military") return "Military";
  return rawFallback && rawFallback.toLowerCase() !== "other" ? rawFallback : "Other";
}

function drawVesselShape(context, anchored, glow, color = "#ffffff") {
  context.fillStyle = color;
  context.globalAlpha = anchored ? 0.55 : 0.96;
  if (glow) {
    context.shadowColor = color;
    context.shadowBlur = anchored ? 8 : 14;
  }
  context.beginPath();
  if (anchored) {
    context.arc(0, 0, 24, 0, Math.PI * 2);
  } else {
    context.moveTo(0, -37);
    context.lineTo(28, 32);
    context.lineTo(0, 17);
    context.lineTo(-28, 32);
    context.closePath();
  }
  context.fill();
}

function buildVesselMarkerData(feature) {
  const props = feature?.properties || {};
  const coordinates = feature?.geometry?.coordinates || [];
  const longitude = Number(coordinates[0]);
  const latitude = Number(coordinates[1]);
  if (!Number.isFinite(latitude) || !Number.isFinite(longitude)) return null;

  const type = normalizeVesselType(props.vessel_type_name, props.vessel_type);
  const vesselTypeLabel = formatVesselTypeLabel(type, props.vessel_type_name);
  const navStatus = Number(props.nav_status);
  const speed = Number(props.sog);
  const anchored = navStatus === 1 || navStatus === 5 || (Number.isFinite(speed) && speed < 0.5);
  const mmsiString = props.mmsi !== undefined && props.mmsi !== null && String(props.mmsi).trim() !== ""
    ? String(props.mmsi)
    : null;

  return {
    ...props,
    mmsi: mmsiString,
    mmsi_display: props.mmsi_display ? String(props.mmsi_display) : mmsiString,
    latitude,
    longitude,
    type,
    vessel_type_display: vesselTypeLabel,
    anchored,
    course: Number(props.cog ?? props.heading ?? 0),
  };
}

function getCourseBin(marker) {
  if (marker.userData.anchored) return 0;
  const course = Number(marker.userData.course || 0);
  const normalized = ((course % 360) + 360) % 360;
  return Math.round((normalized / 360) * VESSEL_COURSE_BINS) % VESSEL_COURSE_BINS;
}

function buildTrackPoint(lon, lat) {
  const latitude = Number(lat);
  const longitude = Number(lon);
  if (!Number.isFinite(latitude) || !Number.isFinite(longitude)) return null;
  return latLonToVector3(
    latitude,
    longitude,
    CONFIG.earthRadius + VESSEL_CONFIG.track.altitudeOffset,
  );
}

function appendCurrentMarkerTrackPoint(points, marker) {
  if (!(marker?.position instanceof THREE.Vector3)) return;
  const markerPosition = marker.position.clone();
  const lastPoint = points[points.length - 1];
  if (!lastPoint || lastPoint.distanceToSquared(markerPosition) > VESSEL_TRACK_ENDPOINT_EPSILON) {
    points.push(markerPosition);
  }
}

const vesselIconLayer = createInteractableLayer({
  id: "vessels",
  objectType: "vessel",
  renderOrder: VESSEL_RENDER_ORDER,
  altitudeOffset: VESSEL_CONFIG.altitudeOffset,
  pointSize: VESSEL_POINT_SIZE,
  atlasCellSize: VESSEL_ATLAS_CELL_SIZE,
  colors: {
    byKind: VESSEL_CONFIG.colors,
    normal: VESSEL_CONFIG.colors.other,
  },
  opacity: {
    normal: VESSEL_CONFIG.marker.baseOpacity,
    dimmed: VESSEL_CONFIG.marker.dimmedOpacity,
    hover: 0.98,
    locked: 1,
  },
  stateScale: {
    hover: VESSEL_CONFIG.marker.hoverScale,
    locked: VESSEL_CONFIG.marker.lockedScale,
    dimmed: VESSEL_CONFIG.marker.dimmedScale,
  },
  avoidance: false,
  icon: {
    draw(context, { marker, rotationBin = 0, glow = false, color = "#ffffff" }) {
      const anchored = Boolean(marker?.userData?.anchored);
      if (!anchored) {
        context.rotate((rotationBin / VESSEL_COURSE_BINS) * Math.PI * 2);
      }
      drawVesselShape(context, anchored, glow, color);
    },
  },
  getPosition: (item) => ({
    latitude: item.latitude,
    longitude: item.longitude,
  }),
  getKind: (item) => item.type || "other",
  getRotationBin: getCourseBin,
  getBucketKey: (marker) => {
    const anchored = Boolean(marker.userData.anchored);
    const courseBin = getCourseBin(marker);
    return `${anchored ? "anchored" : "moving"}:${courseBin}`;
  },
  getUserData: (item) => ({
    ...item,
    vessel_kind: item.type,
    baseScale: VESSEL_CONFIG.marker.baseScale,
  }),
  cluster: false,
});

const GLOBAL_VESSEL_VIEWPORT = {
  bbox: [-180, -85.05112878, 180, 85.05112878],
  zoom: 4,
};

export function getVesselMarkers() {
  return vesselIconLayer.getMarkers();
}

export function getVesselCount() {
  return vesselIconLayer.getCount();
}

export function getVesselRealtimeStats() {
  return { ...vesselRealtimeStats };
}

export function getShowVessels() {
  return showVessels;
}

export function toggleVessels(show) {
  showVessels = Boolean(show);
  vesselIconLayer.setVisible(showVessels);
  if (activeTrackLine) {
    activeTrackLine.visible = showVessels;
  }
}

export function clearVesselSelection() {
  getVesselMarkers().forEach((marker) => setVesselMarkerState(marker, "normal"));
  clearVesselTrack();
}

function clearVesselTrack() {
  if (activeTrackLine?.parent) {
    activeTrackLine.parent.remove(activeTrackLine);
  }
  activeTrackLine?.geometry?.dispose?.();
  activeTrackLine?.material?.dispose?.();
  activeTrackLine = null;
}

export function setVesselMarkerState(marker, state = "normal") {
  vesselIconLayer.setMarkerState(marker, state);
}

export function getVesselPointerIntersections(options) {
  return vesselIconLayer.getPointerIntersections(options);
}

export function clearVesselData(earth) {
  clearVesselSelection();
  vesselDataByKey.clear();
  vesselIconLayer.clearData(earth);
}

export async function loadVessels(_scene, earth, options = {}) {
  const requestGeneration = ++vesselSnapshotGeneration;
  const requestedLimit = Number(options.limit ?? VESSEL_CONFIG.maxRenderedMarkers);
  const bbox = Array.isArray(options.bbox) && options.bbox.length === 4
    ? options.bbox
    : GLOBAL_VESSEL_VIEWPORT.bbox;
  const zoom = Number.isFinite(Number(options.zoom))
    ? Number(options.zoom)
    : GLOBAL_VESSEL_VIEWPORT.zoom;
  const params = new URLSearchParams({ bbox: bbox.join(","), zoom: String(zoom) });
  if (Number.isFinite(requestedLimit) && requestedLimit > 0) {
    params.set("limit", String(requestedLimit));
  }
  const response = await fetch(`${PATHS.vesselsApi}?${params.toString()}`, { cache: "no-store" });
  if (!response.ok) throw new Error(`Vessels HTTP ${response.status}`);
  const payload = await response.json();
  const features = Array.isArray(payload?.features) ? payload.features : [];
  if (requestGeneration !== vesselSnapshotGeneration) {
    return { totalCount: getVesselCount(), stats: {} };
  }

  clearVesselData(earth);
  let markerData = dedupeVesselFeatures(features);
  if (Number.isFinite(requestedLimit) && requestedLimit > 0) {
    markerData = markerData.slice(0, requestedLimit);
  }
  vesselDataByKey = new Map(markerData.map((item) => [markerDataToDedupeKey(item), item]));
  vesselIconLayer.setData(markerData);

  vesselIconLayer.attach(earth);
  vesselIconLayer.setVisible(showVessels);

  return {
    totalCount: getVesselCount(),
    stats: payload?.stats || {},
  };
}

export function startVesselRealtime(_earth, { onUpdate } = {}) {
  onUpdate?.({ totalCount: getVesselCount(), stream: getVesselRealtimeStats() });
}

export function stopVesselRealtime() {
  vesselSnapshotGeneration += 1;
  vesselRealtimeStats = {
    connected: false,
    updates: 0,
    lastUpdateAt: null,
    lastBatchSize: 0,
  };
}

export async function showVesselTrack(marker, earth) {
  clearVesselTrack();
  if (!marker?.userData?.mmsi || !earth) return null;

  const response = await fetch(PATHS.vesselTrackApi(marker.userData.mmsi));
  if (!response.ok) {
    throw new Error(`Vessel track HTTP ${response.status}`);
  }
  const payload = await response.json();
  const coordinates = payload?.features?.[0]?.geometry?.coordinates || [];
  if (coordinates.length < 2) return null;

  const points = coordinates
    .map(([lon, lat]) => buildTrackPoint(lon, lat))
    .filter(
      (point) =>
        point &&
        Number.isFinite(point.x) &&
        Number.isFinite(point.y) &&
        Number.isFinite(point.z),
    );
  appendCurrentMarkerTrackPoint(points, marker);
  if (points.length < 2) return null;

  const geometry = new THREE.BufferGeometry().setFromPoints(points);
  const material = new THREE.LineBasicMaterial({
    color: VESSEL_CONFIG.track.color,
    transparent: true,
    opacity: VESSEL_CONFIG.track.opacity,
    depthWrite: false,
  });
  activeTrackLine = new THREE.Line(geometry, material);
  activeTrackLine.renderOrder = VESSEL_RENDER_ORDER - 0.1;
  earth.add(activeTrackLine);
  return activeTrackLine;
}

export function getVesselLegendItems() {
  return [
    { label: "货轮", color: VESSEL_CONFIG.colors.cargo, shape: "vessel" },
    { label: "油轮", color: VESSEL_CONFIG.colors.tanker, shape: "vessel" },
    { label: "客船", color: VESSEL_CONFIG.colors.passenger, shape: "vessel" },
    { label: "渔船", color: VESSEL_CONFIG.colors.fishing, shape: "vessel" },
    { label: "军舰", color: VESSEL_CONFIG.colors.military, shape: "vessel" },
    { label: "停泊/低速", color: VESSEL_CONFIG.colors.other, shape: "dot" },
    { label: "其他船只", color: VESSEL_CONFIG.colors.other, shape: "vessel" },
  ];
}

export function updateVesselVisualState(lockedObjectType, lockedObject, camera) {
  vesselIconLayer.updateVisualState(lockedObjectType, lockedObject, camera);
}