// 天氣視覺特效(r86,Z-up):雨/雪粒子(THREE.Points 跟著鏡頭的粒子盒)、雲層
// billboard、霧濃度/夜航連動、樹隨風搖。狀態源 = adapter /api/state(考官拉
// 「暴風雨」情境,畫面就真的下雨)。效能原則:粒子+貼圖,不加幾何;共用材質。
(function () {
  var state = { wind: { speed_mps: 0, direction_deg: 0 }, weather: { rain: 0, fog: 0, snow: 0 } };
  var night = false;
  var rain = null, snow = null, clouds = [];
  var skyDay = null, skyNight = null;
  var lastT = null;

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

  // ---- 粒子盒(跟著鏡頭;count 上限,依強度用 drawRange 顯示比例) ----
  function makeParticles(count, color, size, opacity) {
    var geo = new THREE.BufferGeometry();
    var pos = new Float32Array(count * 3);
    for (var i = 0; i < count; i++) {
      pos[i * 3] = (Math.random() - 0.5) * 120;
      pos[i * 3 + 1] = (Math.random() - 0.5) * 120;
      pos[i * 3 + 2] = Math.random() * 70;
    }
    geo.addAttribute('position', new THREE.BufferAttribute(pos, 3));   // r86 是 addAttribute
    var m = new THREE.Points(geo, new THREE.PointsMaterial({
      color: color, size: size, transparent: true, opacity: opacity,
      sizeAttenuation: true, depthWrite: false }));
    m.frustumCulled = false;
    return m;
  }
  // 粒子下落 + 以鏡頭為中心 120m 盒內回繞
  function stepParticles(p, dt, fall, drift, cam) {
    var a = p.geometry.attributes.position, arr = a.array, n = arr.length / 3;
    var wr = state.wind.direction_deg * Math.PI / 180;
    var wx = -Math.sin(wr) * drift * state.wind.speed_mps;
    var wy = -Math.cos(wr) * drift * state.wind.speed_mps;
    for (var i = 0; i < n; i++) {
      arr[i * 3] += wx * dt; arr[i * 3 + 1] += wy * dt; arr[i * 3 + 2] -= fall * dt;
      var dx = arr[i * 3] - cam.x, dy = arr[i * 3 + 1] - cam.y, dz = arr[i * 3 + 2] - cam.z;
      if (dz < -25) arr[i * 3 + 2] += 70;
      if (dz > 50) arr[i * 3 + 2] -= 70;
      if (dx > 60) arr[i * 3] -= 120; else if (dx < -60) arr[i * 3] += 120;
      if (dy > 60) arr[i * 3 + 1] -= 120; else if (dy < -60) arr[i * 3 + 1] += 120;
    }
    a.needsUpdate = true;
  }

  // ---- 天空(晝/夜漸層,夜空撒星) ----
  function makeSky(nightMode) {
    var cv = document.createElement('canvas'); cv.width = 32; cv.height = 512;
    var c = cv.getContext('2d');
    var g = c.createLinearGradient(0, 0, 0, 512);
    if (nightMode) {
      g.addColorStop(0, '#040711'); g.addColorStop(0.5, '#0a1224'); g.addColorStop(1, '#141d33');
      c.fillStyle = g; c.fillRect(0, 0, 32, 512);
      c.fillStyle = '#dfe8ff';
      for (var i = 0; i < 60; i++) {
        c.globalAlpha = 0.3 + Math.random() * 0.7;
        c.fillRect(Math.random() * 32, Math.random() * 300, 1, 1);
      }
      c.globalAlpha = 1;
    } else {
      g.addColorStop(0, '#3b7fc4'); g.addColorStop(0.5, '#8fbde6'); g.addColorStop(1, '#dce9f2');
      c.fillStyle = g; c.fillRect(0, 0, 32, 512);
    }
    return new THREE.CanvasTexture(cv);
  }

  function makeClouds(sc) {
    var cv = document.createElement('canvas'); cv.width = 128; cv.height = 128;
    var c = cv.getContext('2d');
    var g = c.createRadialGradient(64, 64, 8, 64, 64, 62);
    g.addColorStop(0, 'rgba(255,255,255,.9)'); g.addColorStop(0.6, 'rgba(255,255,255,.45)');
    g.addColorStop(1, 'rgba(255,255,255,0)');
    c.fillStyle = g; c.fillRect(0, 0, 128, 128);
    var tex = new THREE.CanvasTexture(cv);
    var mat = new THREE.MeshBasicMaterial({ map: tex, transparent: true, opacity: 0.8,
      depthWrite: false, side: THREE.DoubleSide });
    var geo = new THREE.PlaneGeometry(1, 1);
    for (var i = 0; i < 8; i++) {
      var m = new THREE.Mesh(geo, mat);
      var s = 90 + Math.random() * 120;
      m.scale.set(s, s * (0.5 + Math.random() * 0.5), 1);
      m.position.set((Math.random() - 0.5) * 900, (Math.random() - 0.5) * 900, 125 + Math.random() * 60);
      sc.scene.add(m); clouds.push(m);
    }
  }

  // ---- 夜航切換(燈光/天空/霧色;窗燈路燈紅綠燈是 Basic 材質,夜裡自然發亮) ----
  window.zyNight = function (on) {
    night = on == null ? !night : !!on;
    var sc = window.scene; if (!sc || !sc.scene) return night;
    if (!skyDay) skyDay = makeSky(false);
    if (!skyNight) skyNight = makeSky(true);
    sc.scene.__zySky = night ? skyNight : skyDay;      // visual-boost 週期重套會用這張
    sc.scene.background = sc.scene.__zySky;
    var sun = sc.scene.getObjectByName('zy-sun');
    var amb = sc.scene.getObjectByName('zy-amb');
    var hemi = sc.scene.getObjectByName('zy-hemi');
    if (sun) sun.intensity = night ? 0.1 : 0.75;
    if (amb) amb.intensity = night ? 0.14 : 0.35;
    if (hemi) hemi.intensity = night ? 0.1 : 0.45;
    applyFog();
    return night;
  };
  window.zyIsNight = function () { return night; };

  // 霧:考題 fog 0..1 → 能見度;夜航霧色偏暗藍。visual-boost 重套時讀 window.zyFog。
  function applyFog() {
    var f = state.weather.fog || 0;
    window.zyFog = {
      color: night ? 0x0a1322 : 0xcfe0ee,
      near: lerp(night ? 100 : 120, 15, f),
      far: lerp(night ? 650 : 900, 90, f),
    };
    var sc = window.scene;
    if (sc && sc.scene) sc.scene.fog = new THREE.Fog(window.zyFog.color, window.zyFog.near, window.zyFog.far);
  }

  async function pollState() {
    try {
      var j = await (await fetch('/api/state')).json();
      if (j && j.wind) state.wind = j.wind;
      if (j && j.weather) state.weather = j.weather;
      applyFog();
    } catch (e) {}
  }

  function tick(t) {
    var dt = lastT == null ? 0.016 : Math.min(0.1, (t - lastT) / 1000); lastT = t;
    var sc = window.scene;
    if (sc && sc.scene && sc.camera) {
      var cam = sc.camera.position;
      if (!rain) {
        rain = makeParticles(2600, 0xa9c4da, 0.24, 0.7);
        snow = makeParticles(1600, 0xffffff, 0.28, 0.85);
        sc.scene.add(rain); sc.scene.add(snow);
        makeClouds(sc);
      }
      var rl = Math.max(0, Math.min(1, state.weather.rain || 0));
      var sl = Math.max(0, Math.min(1, state.weather.snow || 0));
      rain.geometry.setDrawRange(0, Math.floor(2600 * rl));
      snow.geometry.setDrawRange(0, Math.floor(1600 * sl));
      rain.visible = rl > 0; snow.visible = sl > 0;
      if (rl > 0) stepParticles(rain, dt, 34, 0.9, cam);
      if (sl > 0) stepParticles(snow, dt, 3.5, 1.4, cam);
      // 雲:順風漂移,離鏡頭太遠搬回附近
      var wr = state.wind.direction_deg * Math.PI / 180;
      var cwx = -Math.sin(wr) * (1 + state.wind.speed_mps * 0.4) * dt;
      var cwy = -Math.cos(wr) * (1 + state.wind.speed_mps * 0.4) * dt;
      clouds.forEach(function (cl) {
        cl.position.x += cwx; cl.position.y += cwy;
        if (Math.hypot(cl.position.x - cam.x, cl.position.y - cam.y) > 800) {
          cl.position.x = cam.x + (Math.random() - 0.5) * 700;
          cl.position.y = cam.y + (Math.random() - 0.5) * 700;
        }
      });
      stepFlocks(dt, cam, t);
      // 樹隨風搖(振幅連動風速;canopy 註冊在各 chunk userData.sway)
      if (window.zyTerrain && window.zyTerrain.groups) {
        var amp = Math.min(state.wind.speed_mps, 15) / 15 * 0.09;
        var ph = t / 1000;
        var gs = window.zyTerrain.groups();
        Object.keys(gs).forEach(function (k) {
          var sw = gs[k].userData.sway; if (!sw) return;
          for (var i = 0; i < sw.length; i++) {
            var m = sw[i];
            if (m.userData.swayBase == null) m.userData.swayBase = m.rotation.x;  // 針葉錐有 90° 基準
            m.rotation.x = m.userData.swayBase + Math.sin(ph * 1.9 + m.position.x * 0.7) * amp;
            m.rotation.y = Math.cos(ph * 1.6 + m.position.y * 0.7) * amp * 0.6;
          }
        });
      }
    }
    requestAnimationFrame(tick);
  }

  // ---- 鳥群(純視覺,無碰撞):兩群小黑鳥繞著鏡頭附近盤旋,拍翅上下擺 ----
  var flocks = [];
  function makeFlocks(sc) {
    var mat = new THREE.MeshBasicMaterial({ color: 0x23262b });
    var geo = new THREE.ConeGeometry(0.25, 1.0, 4);
    for (var f = 0; f < 2; f++) {
      var flock = { birds: [], cx: (Math.random() - 0.5) * 300, cy: (Math.random() - 0.5) * 300,
                    alt: 20 + Math.random() * 25, dir: Math.random() * Math.PI * 2,
                    speed: 8 + Math.random() * 5 };
      for (var i = 0; i < 7; i++) {
        var m = new THREE.Mesh(geo, mat);
        m.userData.off = { x: (Math.random() - 0.5) * 10, y: (Math.random() - 0.5) * 10,
                           z: (Math.random() - 0.5) * 3, ph: Math.random() * 6 };
        sc.scene.add(m); flock.birds.push(m);
      }
      flocks.push(flock);
    }
  }
  function stepFlocks(dt, cam, t) {
    flocks.forEach(function (fl) {
      fl.dir += (Math.random() - 0.5) * 0.3 * dt * 10;   // 緩慢轉向
      fl.cx += Math.cos(fl.dir) * fl.speed * dt;
      fl.cy += Math.sin(fl.dir) * fl.speed * dt;
      if (Math.hypot(fl.cx - cam.x, fl.cy - cam.y) > 500) {   // 飛遠了搬回鏡頭附近
        fl.cx = cam.x + (Math.random() - 0.5) * 250;
        fl.cy = cam.y + (Math.random() - 0.5) * 250;
      }
      fl.birds.forEach(function (b) {
        var o = b.userData.off;
        b.position.set(fl.cx + o.x, fl.cy + o.y,
                       fl.alt + o.z + Math.sin(t / 1000 * 6 + o.ph) * 0.8);   // 拍翅起伏
        b.rotation.set(Math.PI / 2, 0, -(fl.dir - Math.PI / 2));              // 錐尖朝飛行方向
      });
    });
  }

  // ---- 晝夜自動循環:10 分鐘白天 → 5 分鐘夜間 ----
  var cycleOn = false, cycleTimer = null;
  window.zyDayCycle = function (on) {
    cycleOn = on == null ? !cycleOn : !!on;
    if (cycleTimer) { clearInterval(cycleTimer); cycleTimer = null; }
    if (cycleOn) {
      cycleTimer = setInterval(function () {
        var t = (Date.now() / 1000) % 900;   // 15 分鐘一輪
        var wantNight = t > 600;             // 前 10 分鐘白天,後 5 分鐘夜間
        if (wantNight !== night) window.zyNight(wantNight);
      }, 5000);
    }
    return cycleOn;
  };

  var wait = setInterval(function () {
    if (window.scene && window.scene.scene && window.THREE) {
      clearInterval(wait);
      pollState(); setInterval(pollState, 2000);
      makeFlocks(window.scene);
      requestAnimationFrame(tick);
      console.log('[weather-fx] active');
    }
  }, 500);
})();