/* Shared MapLibre GL utilities — loaded by map.html.twig, dailies.html.twig, home.html.twig */
(function (global) {
  var ACCENT      = '#2A8C73';
  var ACCENT_DIM  = '#155244';
  var MAP_STYLE   = 'https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json';

  /* Build a GeoJSON LineString feature */
  function lineFeature(coords) {
    return { type: 'Feature', properties: {}, geometry: { type: 'LineString', coordinates: coords } };
  }

  /*
   * Centripetal Catmull-Rom spline (α=0.5) through waypoints → dense coords.
   * Parameterising by √chord-length prevents the large bow that uniform
   * parameterisation produces when consecutive points are very close together
   * but their neighbours are far away (e.g. two entries both in Berlin).
   */
  function catmullRomSpline(coords, steps) {
    if (coords.length < 2) return coords;
    steps = steps || 16;
    var alpha = 0.5;
    var out   = [];

    /* Phantom endpoints via reflection so the spline reaches the first and last real points */
    var ext = [
      [2*coords[0][0] - coords[1][0], 2*coords[0][1] - coords[1][1]]
    ].concat(coords).concat([
      [2*coords[coords.length-1][0] - coords[coords.length-2][0],
       2*coords[coords.length-1][1] - coords[coords.length-2][1]]
    ]);

    function segT(a, b) {
      var dx = b[0]-a[0], dy = b[1]-a[1];
      return Math.pow(Math.max(Math.sqrt(dx*dx + dy*dy), 1e-10), alpha);
    }

    for (var i = 1; i < ext.length - 2; i++) {
      var p0 = ext[i-1], p1 = ext[i], p2 = ext[i+1], p3 = ext[i+2];

      var t0 = 0;
      var t1 = t0 + segT(p0, p1);
      var t2 = t1 + segT(p1, p2);
      var t3 = t2 + segT(p2, p3);

      for (var s = 0; s < steps; s++) {
        var t = t1 + (t2 - t1) * s / steps;

        var a1x = (t1-t)/(t1-t0)*p0[0] + (t-t0)/(t1-t0)*p1[0];
        var a1y = (t1-t)/(t1-t0)*p0[1] + (t-t0)/(t1-t0)*p1[1];
        var a2x = (t2-t)/(t2-t1)*p1[0] + (t-t1)/(t2-t1)*p2[0];
        var a2y = (t2-t)/(t2-t1)*p1[1] + (t-t1)/(t2-t1)*p2[1];
        var a3x = (t3-t)/(t3-t2)*p2[0] + (t-t2)/(t3-t2)*p3[0];
        var a3y = (t3-t)/(t3-t2)*p2[1] + (t-t2)/(t3-t2)*p3[1];

        var b1x = (t2-t)/(t2-t0)*a1x + (t-t0)/(t2-t0)*a2x;
        var b1y = (t2-t)/(t2-t0)*a1y + (t-t0)/(t2-t0)*a2y;
        var b2x = (t3-t)/(t3-t1)*a2x + (t-t1)/(t3-t1)*a3x;
        var b2y = (t3-t)/(t3-t1)*a2y + (t-t1)/(t3-t1)*a3y;

        out.push([
          (t2-t)/(t2-t1)*b1x + (t-t1)/(t2-t1)*b2x,
          (t2-t)/(t2-t1)*b1y + (t-t1)/(t2-t1)*b2y
        ]);
      }
    }
    out.push(coords[coords.length - 1]);
    return out;
  }

  /*
   * Progressively draw the journey line using a requestAnimationFrame loop.
   * splineCoords: dense interpolated coords from catmullRomSpline().
   */
  function animateJourneyLine(map, splineCoords, sourceId) {
    if (splineCoords.length < 2) return;

    var segDist = [0];
    for (var i = 1; i < splineCoords.length; i++) {
      var dx = splineCoords[i][0] - splineCoords[i - 1][0];
      var dy = splineCoords[i][1] - splineCoords[i - 1][1];
      segDist.push(segDist[i - 1] + Math.sqrt(dx * dx + dy * dy));
    }
    var totalDist = segDist[segDist.length - 1];
    var DURATION  = 5000;
    var startTime = performance.now();

    function frame(now) {
      if (!map.getSource(sourceId)) return;
      var t      = Math.min((now - startTime) / DURATION, 1);
      var eased  = 1 - Math.pow(1 - t, 3);
      var target = eased * totalDist;

      var animCoords = [splineCoords[0]];
      for (var j = 1; j < splineCoords.length; j++) {
        if (segDist[j] <= target) {
          animCoords.push(splineCoords[j]);
        } else {
          var frac = (target - segDist[j - 1]) / (segDist[j] - segDist[j - 1]);
          animCoords.push([
            splineCoords[j - 1][0] + (splineCoords[j][0] - splineCoords[j - 1][0]) * frac,
            splineCoords[j - 1][1] + (splineCoords[j][1] - splineCoords[j - 1][1]) * frac
          ]);
          break;
        }
      }

      map.getSource(sourceId).setData(lineFeature(animCoords));
      if (t < 1) requestAnimationFrame(frame);
    }

    requestAnimationFrame(frame);
  }

  /*
   * Add a journey line to a loaded map — dotted, subordinate style so GPX
   * tracks read as the primary route where they exist.
   * coords: [[lng, lat], ...] raw waypoints (daily entry positions).
   */
  function addJourneyLine(map, coords, sourceId) {
    if (coords.length < 2) return;

    var splineCoords = catmullRomSpline(coords, 16);

    map.addSource(sourceId, { type: 'geojson', data: lineFeature([splineCoords[0]]) });

    map.addLayer({
      id: sourceId + '-line', type: 'line', source: sourceId,
      layout: { 'line-join': 'round', 'line-cap': 'round' },
      paint: {
        'line-color':     ACCENT,
        'line-width':     2,
        'line-opacity':   0.45,
        'line-dasharray': [0, 2.5]
      }
    });

    var reducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    if (reducedMotion) {
      map.getSource(sourceId).setData(lineFeature(splineCoords));
    } else {
      animateJourneyLine(map, splineCoords, sourceId);
    }
  }

  /*
   * Return a styled <div> element for a map marker dot.
   * isLatest: make it larger with a teal ring.
   */
  function createDotMarker(isLatest) {
    var el   = document.createElement('div');
    var size = isLatest ? 18 : 12;
    var bg   = isLatest ? ACCENT_DIM : ACCENT;
    var ring = isLatest ? ',0 0 0 4px rgba(42,140,115,0.25)' : '';
    el.style.cssText = [
      'width:' + size + 'px',
      'height:' + size + 'px',
      'background:' + bg,
      'border:2px solid #fff',
      'border-radius:50%',
      'box-shadow:0 1px 4px rgba(0,0,0,0.4)' + ring,
      'cursor:pointer'
    ].join(';');
    return el;
  }

  /*
   * Return a styled <div> element for a story marker (white diamond, teal border).
   */
  function createStoryMarker() {
    var el = document.createElement('div');
    el.style.cssText = [
      'width:10px',
      'height:10px',
      'background:#fff',
      'border:2px solid ' + ACCENT,
      'transform:rotate(45deg)',
      'box-shadow:0 1px 4px rgba(0,0,0,0.4)',
      'cursor:pointer'
    ].join(';');
    return el;
  }

  /* Haversine distance in km between two [lat, lng] points */
  function haversineKm(lat1, lng1, lat2, lng2) {
    var R    = 6371;
    var dLat = (lat2 - lat1) * Math.PI / 180;
    var dLng = (lng2 - lng1) * Math.PI / 180;
    var a    = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
               Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) *
               Math.sin(dLng / 2) * Math.sin(dLng / 2);
    return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
  }

  /* Extract [[lat, lng], ...] from a toGeoJSON output (flips GeoJSON [lng,lat] order). */
  function extractTrackpoints(geojson) {
    var points = [];
    (geojson.features || []).forEach(function (feat) {
      var coords = [];
      if (feat.geometry.type === 'LineString') {
        coords = feat.geometry.coordinates;
      } else if (feat.geometry.type === 'MultiLineString') {
        feat.geometry.coordinates.forEach(function (line) { coords = coords.concat(line); });
      }
      coords.forEach(function (c) { points.push([c[1], c[0]]); });
    });
    return points;
  }

  /* True if [markerLat, markerLng] is within thresholdKm of any point in trackpoints [[lat,lng],...]. */
  function isNearTrack(markerLat, markerLng, trackpoints, thresholdKm) {
    if (!trackpoints || trackpoints.length === 0) return false;
    var degLat = thresholdKm / 111;
    var degLng = thresholdKm / (111 * Math.cos(markerLat * Math.PI / 180));
    for (var i = 0; i < trackpoints.length; i += 10) {
      var pt = trackpoints[i];
      if (Math.abs(pt[0] - markerLat) > degLat || Math.abs(pt[1] - markerLng) > degLng) continue;
      if (haversineKm(markerLat, markerLng, pt[0], pt[1]) <= thresholdKm) return true;
    }
    var last = trackpoints[trackpoints.length - 1];
    return haversineKm(markerLat, markerLng, last[0], last[1]) <= thresholdKm;
  }

  /*
   * Build journey line segments from entries.
   *
   * entries:           [{lat, lng, force_connect?}, ...] in chronological order
   * opts.connectMode:  'on' | 'off' | 'manual' | 'intelligent_gpx' (default: 'on')
   *   'on'             → connect every consecutive pair (force_connect irrelevant)
   *   'off'            → no connectors, force_connect is also ignored
   *   'manual'         → only entries with force_connect:true draw a connector
   *   'intelligent_gpx'→ suppress connector where GPX covers both endpoints;
   *                       force_connect always overrides
   * trackpointsPerFile: [ [[lat,lng],...], ... ] — required only for intelligent_gpx
   *
   * Returns array of segments [[lng, lat], ...] in MapLibre coordinate order.
   * Segments with < 2 points are omitted.
   */
  function buildJourneySegments(entries, opts, trackpointsPerFile) {
    var mode     = (opts && opts.connectMode) || 'on';
    var segments = [];
    var current  = [];

    for (var i = 0; i < entries.length; i++) {
      var e      = entries[i];
      var lngLat = [parseFloat(e.lng), parseFloat(e.lat)];

      if (i === 0) { current.push(lngLat); continue; }

      var connect;
      if (mode === 'off') {
        connect = false;
      } else if (mode === 'on') {
        connect = true;
      } else if (mode === 'manual') {
        connect = !!e.force_connect;
      } else { /* intelligent_gpx */
        if (e.force_connect) {
          connect = true;
        } else if (!trackpointsPerFile || trackpointsPerFile.length === 0) {
          connect = true; /* no GPX present → connect all */
        } else {
          var prev = entries[i - 1];
          // Each endpoint just needs to be near SOME GPX file, not necessarily
          // the same one — a leg can legitimately span two consecutive files
          // (e.g. an unblogged intermediate stop splits one route in two).
          // Requiring one shared file used to draw a straight connector straight
          // over an already-GPX-covered path, since this trip's routes are one
          // contiguous chain recorded a day per file (…-to-X.gpx, X-to-….gpx).
          //
          // The trade: two endpoints each near a DIFFERENT track now read as
          // covered even when there is a real gap between them (a flight or a
          // train transfer), so no connector is drawn across it. That case is
          // not detectable from proximity alone — mark the entry after the gap
          // `force_connect: true` and the branch above handles it.
          var prevNear = false, currNear = false;
          for (var f = 0; f < trackpointsPerFile.length; f++) {
            if (!prevNear && isNearTrack(parseFloat(prev.lat), parseFloat(prev.lng), trackpointsPerFile[f], 10)) prevNear = true;
            if (!currNear && isNearTrack(parseFloat(e.lat),    parseFloat(e.lng),    trackpointsPerFile[f], 10)) currNear = true;
            if (prevNear && currNear) break;
          }
          connect = !(prevNear && currNear);
        }
      }

      if (connect) {
        current.push(lngLat);
      } else {
        if (current.length >= 2) segments.push(current);
        current = [lngLat];
      }
    }

    if (current.length >= 2) segments.push(current);
    return segments;
  }

  /*
   * Draw journey segments — calls addJourneyLine once per segment.
   * baseSourceId: e.g. 'journey' → sources become 'journey-0', 'journey-1', ...
   * (single segment gets plain 'journey' for backwards compatibility).
   */
  function addJourneySegments(map, segments, baseSourceId) {
    segments.forEach(function (coords, i) {
      var sid = segments.length === 1 ? baseSourceId : baseSourceId + '-' + i;
      addJourneyLine(map, coords, sid);
    });
  }

  /*
   * Fetch GPX files and render their raw tracks, then draw journey connector
   * lines between entries per opts.connectMode / force_connect.
   *
   * gpxUrls:         array of GPX file URLs to fetch (empty → no tracks, connectors only)
   * entries:         [{lat, lng, force_connect?}, ...] in chronological order
   * gpxSourcePrefix: source/layer ID prefix for raw GPX tracks (e.g. 'gpx', 'home-gpx')
   * journeySourceId: base source ID for connector segments (e.g. 'journey', 'home-journey')
   * opts:            forwarded to buildJourneySegments (opts.connectMode)
   */
  function renderGpxJourney(map, gpxUrls, entries, gpxSourcePrefix, journeySourceId, opts) {
    var needsTrackpoints = opts && opts.connectMode === 'intelligent_gpx';
    Promise.all(gpxUrls.map(function (url, idx) {
      return fetch(url)
        .then(function (r) { return r.text(); })
        .then(function (text) {
          var xml     = new DOMParser().parseFromString(text, 'text/xml');
          var geojson = toGeoJSON.gpx(xml);
          var sid     = gpxSourcePrefix + '-' + idx;
          map.addSource(sid, { type: 'geojson', data: geojson });
          map.addLayer({
            id: sid + '-line', type: 'line', source: sid,
            layout: { 'line-join': 'round', 'line-cap': 'round' },
            paint:  { 'line-color': ACCENT, 'line-width': 2, 'line-opacity': 0.7 }
          });
          return needsTrackpoints ? extractTrackpoints(geojson) : [];
        })
        .catch(function (err) { console.warn('GPX load failed:', url, err); return []; });
    })).then(function (allTrackpoints) {
      var valid    = needsTrackpoints ? allTrackpoints.filter(function (tp) { return tp.length > 0; }) : [];
      var segments = buildJourneySegments(entries, opts, valid);
      addJourneySegments(map, segments, journeySourceId);
    });
  }

  /*
   * Parse one or more GPX files and compute aggregate cycling statistics.
   * urls:     array of GPX file URL strings
   * callback: called once with { distance, eleGain, eleLoss, highest, lowest, movingTime, avgSpeed }
   *           or { error: 'no files' } if urls is empty.
   *
   * distance/eleGain/eleLoss in raw units (km / metres).
   * movingTime: "H:MM" string. avgSpeed: km/h number.
   */
  function parseGpxFiles(urls, callback) {
    var pending = urls.length;
    var fileResults = new Array(urls.length);
    if (pending === 0) { callback({ error: 'no files' }); return; }

    urls.forEach(function (url, idx) {
      fetch(url)
        .then(function (r) { return r.text(); })
        .then(function (text) {
          var xml  = new DOMParser().parseFromString(text, 'text/xml');
          var pts  = [];
          xml.querySelectorAll('trkpt').forEach(function (pt) {
            var eleEl  = pt.querySelector('ele');
            var timeEl = pt.querySelector('time');
            pts.push({
              lat:  parseFloat(pt.getAttribute('lat')),
              lon:  parseFloat(pt.getAttribute('lon')),
              ele:  eleEl  ? parseFloat(eleEl.textContent)  : NaN,
              time: timeEl ? timeEl.textContent              : null
            });
          });
          fileResults[idx] = pts;
          if (--pending === 0) computeAndCallback();
        })
        .catch(function (err) {
          console.warn('GPX load failed:', url, err);
          fileResults[idx] = [];
          if (--pending === 0) computeAndCallback();
        });
    });

    function computeAndCallback() {
      var totalDistance = 0, totalEleGain = 0, totalEleLoss = 0;
      var globalHighest = NaN, globalLowest = NaN, totalMovingTime = 0;

      fileResults.forEach(function (pts) {
        if (!pts || pts.length < 2) return;
        /* Include first point of each file in elevation range */
        if (!isNaN(pts[0].ele)) {
          if (isNaN(globalHighest) || pts[0].ele > globalHighest) globalHighest = pts[0].ele;
          if (isNaN(globalLowest)  || pts[0].ele < globalLowest)  globalLowest  = pts[0].ele;
        }
        for (var i = 1; i < pts.length; i++) {
          var p0 = pts[i - 1], p1 = pts[i];
          totalDistance += haversineKm(p0.lat, p0.lon, p1.lat, p1.lon);
          if (!isNaN(p0.ele) && !isNaN(p1.ele)) {
            var dEle = p1.ele - p0.ele;
            if (dEle > 0) totalEleGain += dEle;
            if (dEle < 0) totalEleLoss += (-dEle);
            if (isNaN(globalHighest) || p1.ele > globalHighest) globalHighest = p1.ele;
            if (isNaN(globalLowest)  || p1.ele < globalLowest)  globalLowest  = p1.ele;
          }
          if (p0.time && p1.time) {
            var dtHrs = (Date.parse(p1.time) - Date.parse(p0.time)) / 3600000;
            if (dtHrs > 0 && (haversineKm(p0.lat, p0.lon, p1.lat, p1.lon) / dtHrs) >= 1) {
              totalMovingTime += dtHrs;
            }
          }
        }
      });

      var avgSpeed  = totalMovingTime > 0 ? totalDistance / totalMovingTime : 0;
      var movHours  = Math.floor(totalMovingTime);
      var movMins   = Math.round((totalMovingTime - movHours) * 60);
      if (movMins === 60) { movHours++; movMins = 0; }

      callback({
        distance:   totalDistance,
        eleGain:    totalEleGain,
        eleLoss:    totalEleLoss,
        highest:    globalHighest,
        lowest:     globalLowest,
        movingTime: movHours + ':' + (movMins < 10 ? '0' : '') + movMins,
        avgSpeed:   avgSpeed
      });
    }
  }

  /*
   * Config-driven entry-map initialisation — the single orchestration shared by
   * the trip page and both home views. Mirrors the trip page's canonical handler:
   * compact collapsed attribution bottom-left, an on('load') marker loop with a
   * map-tip hover popup, bounds fit (jumpTo for one entry), GPX journey rendering,
   * and the fullscreen toggle.
   *
   * opts:
   *   container      string   — map div id ('trip-map', 'home-map')
   *   entries        array    — parsed map_entries [{lat,lng,slug,title,url,type?,force_connect?}, ...]
   *   cardPrefix     string?  — e.g. 'entry-'; when set and a card #prefix+slug exists,
   *                             click scrolls+flashes that card; otherwise click navigates to entry.url
   *   storyMarkers   bool     — render createStoryMarker() for entry.type === 'story' (default: dot markers)
   *   markLatest     bool     — enlarge the final non-story entry's dot (default true; pass false for
   *                             unordered sets like home highlights so no marker is singled out)
   *   fullscreen     object?  — { btnId, colSelector }; wires the fullscreen toggle + fullscreen-aware click
   *   gpx            object?  — { urls, use, autoconnect, sourcePrefix, journeyId }; forwarded to renderGpxJourney
   *   fit            object?  — { padding=60, maxZoom=11, singleZoom=10 }
   *
   * Returns the maplibregl.Map instance.
   */
  function initEntryMap(opts) {
    opts = opts || {};
    var entries    = opts.entries || [];
    var fit        = opts.fit || {};
    var padding    = fit.padding    != null ? fit.padding    : 60;
    var maxZoom    = fit.maxZoom    != null ? fit.maxZoom    : 11;
    var singleZoom = fit.singleZoom != null ? fit.singleZoom : 10;
    var markLatest = opts.markLatest !== false;

    var map = new maplibregl.Map({
      container: opts.container,
      style:     MAP_STYLE,
      center:    [20, 20],
      zoom:      2,
      attributionControl: false
    });
    map.addControl(new maplibregl.AttributionControl({ compact: true }), 'bottom-left');

    map.on('load', function () {
      if (entries.length === 0) {
        map.jumpTo({ center: [0, 20], zoom: 2 });
        return;
      }

      var bounds = new maplibregl.LngLatBounds();

      entries.forEach(function (entry, i) {
        var isLatest = markLatest && (entry.type !== 'story') && (i === entries.length - 1);
        var lngLat   = [parseFloat(entry.lng), parseFloat(entry.lat)];
        bounds.extend(lngLat);

        var el = (opts.storyMarkers && entry.type === 'story')
          ? createStoryMarker()
          : createDotMarker(isLatest);
        el.dataset.url = entry.url;

        var popup = new maplibregl.Popup({ offset: 12, closeButton: false, closeOnClick: false, className: 'map-tip-popup' })
          .setLngLat(lngLat)
          .setHTML('<span class="map-tip">' + entry.title + '</span>');
        el.addEventListener('mouseenter', function () { popup.addTo(map); });
        el.addEventListener('mouseleave', function () { popup.remove(); });
        el.addEventListener('click', function () {
          var card = opts.cardPrefix ? document.getElementById(opts.cardPrefix + entry.slug) : null;
          if (!card) { window.location.href = entry.url; return; }
          var hashId = opts.cardPrefix + entry.slug;
          function scrollAndHighlight() {
            window.location.hash = hashId;
            setTimeout(function () {
              card.classList.add('is-highlighted');
              setTimeout(function () { card.classList.remove('is-highlighted'); }, 700);
            }, 350);
          }
          if (opts.fullscreen) {
            var col  = document.querySelector(opts.fullscreen.colSelector);
            var isFs = col && col.classList.contains('is-fullscreen');
            if (isFs) {
              var fsBtn = document.getElementById(opts.fullscreen.btnId);
              if (fsBtn) fsBtn.click();
              setTimeout(scrollAndHighlight, 450);
              return;
            }
          }
          scrollAndHighlight();
        });

        new maplibregl.Marker({ element: el }).setLngLat(lngLat).addTo(map);
      });

      if (entries.length === 1) {
        map.jumpTo({ center: [parseFloat(entries[0].lng), parseFloat(entries[0].lat)], zoom: singleZoom });
      } else {
        map.fitBounds(bounds, { padding: padding, maxZoom: maxZoom });
      }

      if (opts.gpx) {
        renderGpxJourney(
          map,
          opts.gpx.use ? (opts.gpx.urls || []) : [],
          entries,
          opts.gpx.sourcePrefix,
          opts.gpx.journeyId,
          { connectMode: opts.gpx.autoconnect }
        );
      }

      /* Collapse attribution <details> which MapLibre may open on load */
      var attrib = map.getContainer().querySelector('.maplibregl-ctrl-attrib');
      if (attrib) attrib.removeAttribute('open');
    });

    setTimeout(function () { map.resize(); }, 100);

    if (opts.fullscreen) {
      var fsBtn = document.getElementById(opts.fullscreen.btnId);
      var col   = document.querySelector(opts.fullscreen.colSelector);
      if (fsBtn && col) {
        fsBtn.addEventListener('click', function () {
          var isFs = col.classList.toggle('is-fullscreen');
          fsBtn.setAttribute('aria-label', isFs ? 'Close map' : 'Expand map');
          document.body.style.overflow = isFs ? 'hidden' : '';
          setTimeout(function () { map.resize(); }, 50);
        });
      }
    }

    return map;
  }

  global.MapUtils = {
    MAP_STYLE:            MAP_STYLE,
    initEntryMap:         initEntryMap,
    ACCENT:               ACCENT,
    haversineKm:          haversineKm,
    parseGpxFiles:        parseGpxFiles,
    addJourneyLine:       addJourneyLine,
    addJourneySegments:   addJourneySegments,
    buildJourneySegments: buildJourneySegments,
    renderGpxJourney:     renderGpxJourney,
    createDotMarker:      createDotMarker,
    createStoryMarker:    createStoryMarker
  };
})(window);