// public/js/activityThumbs.js
// Caricamento, parsing e rendering delle anteprime dei percorsi.

(() => {
  "use strict";

  const routeCache = window.activityRouteCache || new Map();
  window.activityRouteCache = routeCache;

  function normalizePoint(point) {
    if (!point) return null;

    if (Number.isFinite(Number(point.lat)) && Number.isFinite(Number(point.lng))) {
      return { lat: Number(point.lat), lng: Number(point.lng) };
    }
    if (Number.isFinite(Number(point.latitude)) && Number.isFinite(Number(point.longitude))) {
      return { lat: Number(point.latitude), lng: Number(point.longitude) };
    }
    if (Number.isFinite(Number(point.lat)) && Number.isFinite(Number(point.lon))) {
      return { lat: Number(point.lat), lng: Number(point.lon) };
    }
    if (Array.isArray(point) && point.length >= 2) {
      const lng = Number(point[0]);
      const lat = Number(point[1]);
      if (Number.isFinite(lat) && Number.isFinite(lng)) return { lat, lng };
    }

    return null;
  }

  function extractDirectPoints(item) {
    const candidates = [
      item.track_preview,
      item.points,
      item.track_points,
      item.coordinates
    ];

    for (const candidate of candidates) {
      if (!Array.isArray(candidate)) continue;
      const points = candidate.map(normalizePoint).filter(Boolean);
      if (points.length >= 2) return points;
    }

    const geojson = item.geojson;
    const coordinates =
      geojson?.type === "LineString"
        ? geojson.coordinates
        : geojson?.type === "Feature" && geojson.geometry?.type === "LineString"
          ? geojson.geometry.coordinates
          : null;

    if (!Array.isArray(coordinates)) return [];
    return coordinates.map(normalizePoint).filter(Boolean);
  }

  function simplifyPoints(points, maxPoints = 350) {
    if (!Array.isArray(points)) return [];
    if (points.length <= maxPoints) return points;

    const step = Math.ceil(points.length / maxPoints);
    const output = [];

    for (let index = 0; index < points.length; index += step) {
      output.push(points[index]);
    }

    const last = points.at(-1);
    const outputLast = output.at(-1);
    if (!outputLast || outputLast.lat !== last.lat || outputLast.lng !== last.lng) {
      output.push(last);
    }

    return output;
  }

  async function fetchActivityText(filePath) {
    const headers = {};
    const token = localStorage.getItem("token");
    if (token) headers.Authorization = `Bearer ${token}`;

    const response = await fetch(filePath, { headers });
    if (!response.ok) {
      throw new Error(`HTTP ${response.status} caricando ${filePath}`);
    }
    return response.text();
  }

  function parseTcxPoints(text) {
    const xml = new DOMParser().parseFromString(text, "application/xml");
    const parseError = xml.getElementsByTagName("parsererror")[0];
    if (parseError) {
      console.warn("[parseTcxPoints] XML parser error", parseError.textContent);
      return [];
    }

    return Array.from(xml.getElementsByTagName("Trackpoint"))
      .map(trackpoint => {
        const lat = Number(trackpoint.getElementsByTagName("LatitudeDegrees")[0]?.textContent);
        const lng = Number(trackpoint.getElementsByTagName("LongitudeDegrees")[0]?.textContent);
        return Number.isFinite(lat) && Number.isFinite(lng) ? { lat, lng } : null;
      })
      .filter(Boolean);
  }

  function parseGpxPoints(text) {
    const xml = new DOMParser().parseFromString(text, "application/xml");
    const parseError = xml.getElementsByTagName("parsererror")[0];
    if (parseError) {
      console.warn("[parseGpxPoints] XML parser error", parseError.textContent);
      return [];
    }

    return Array.from(xml.getElementsByTagName("trkpt"))
      .map(point => {
        const lat = Number(point.getAttribute("lat"));
        const lng = Number(point.getAttribute("lon"));
        return Number.isFinite(lat) && Number.isFinite(lng) ? { lat, lng } : null;
      })
      .filter(Boolean);
  }

  async function getRoutePoints(item) {
    if (!item) return [];

    const cacheKey = item.id || item.path || item.name;
    if (cacheKey && routeCache.has(cacheKey)) return routeCache.get(cacheKey);

    let points = extractDirectPoints(item);

    if (points.length < 2 && item.path) {
      const format = String(item.format || item.file_extension || item.mime_type || "").toLowerCase();
      const lowerPath = String(item.path).toLowerCase();

      if (format === "tcx" || lowerPath.endsWith(".tcx")) {
        points = parseTcxPoints(await fetchActivityText(item.path));
      } else if (format === "gpx" || lowerPath.endsWith(".gpx")) {
        points = parseGpxPoints(await fetchActivityText(item.path));
      }
    }

    points = simplifyPoints(points, 350);
    if (cacheKey) routeCache.set(cacheKey, points);
    return points;
  }

  function createRouteSvg(points) {
    const width = 240;
    const height = 160;
    const padding = 16;
    const lats = points.map(point => point.lat);
    const lngs = points.map(point => point.lng);
    const minLat = Math.min(...lats);
    const maxLat = Math.max(...lats);
    const minLng = Math.min(...lngs);
    const maxLng = Math.max(...lngs);
    const latRange = maxLat - minLat || 0.000001;
    const lngRange = maxLng - minLng || 0.000001;
    const usableWidth = width - padding * 2;
    const usableHeight = height - padding * 2;

    const svgPoints = points.map(point => {
      const x = padding + ((point.lng - minLng) / lngRange) * usableWidth;
      const y = padding + ((maxLat - point.lat) / latRange) * usableHeight;
      return { x, y, text: `${x.toFixed(1)},${y.toFixed(1)}` };
    });

    const pointsAttribute = svgPoints.map(point => point.text).join(" ");
    const first = svgPoints[0];
    const last = svgPoints.at(-1);

    return `
      <svg viewBox="0 0 ${width} ${height}" class="activity-route-svg" aria-hidden="true">
        <rect x="0" y="0" width="${width}" height="${height}" rx="16" class="activity-route-bg"></rect>
        <polyline points="${pointsAttribute}" class="activity-route-line-shadow"></polyline>
        <polyline points="${pointsAttribute}" class="activity-route-line"></polyline>
        <circle cx="${first.x.toFixed(1)}" cy="${first.y.toFixed(1)}" r="4.2" class="activity-route-start"></circle>
        <circle cx="${last.x.toFixed(1)}" cy="${last.y.toFixed(1)}" r="4.2" class="activity-route-end"></circle>
      </svg>`;
  }

  async function renderRouteThumb(container, item) {
    const escapeHtml = window.GalleryUtils?.escapeHtml || (value => String(value ?? ""));

    try {
      const points = await getRoutePoints(item);
      if (points.length < 2) {
        container.classList.remove("loading");
        container.classList.add("empty");
        container.innerHTML = `<div class="activity-route-placeholder"><span>${escapeHtml(item?.sport || item?.format || "Attività")}</span></div>`;
        return;
      }

      container.innerHTML = createRouteSvg(points);
      container.classList.remove("loading");
      container.classList.add("ready");
    } catch (error) {
      console.warn("[activity thumb] errore:", item?.name, error);
      container.classList.remove("loading");
      container.classList.add("empty");
      container.innerHTML = `<div class="activity-route-placeholder"><span>${escapeHtml(item?.sport || item?.format || "Attività")}</span></div>`;
    }
  }

  window.ActivityThumbs = Object.freeze({
    renderRouteThumb,
    getRoutePoints,
    parseTcxPoints,
    parseGpxPoints,
    createRouteSvg
  });

  window.renderActivityRouteThumb = renderRouteThumb;
  window.getActivityRoutePoints = getRoutePoints;
  window.parseTcxPoints = parseTcxPoints;
  window.parseGpxPoints = parseGpxPoints;
  window.createRouteSvg = createRouteSvg;
})();