// ============ povui.js — on-ride first-person camera ============
import { sampleTrack } from '../game/coaster.js';
import { sfx } from '../core/audio.js';

let povRAF = null;

export function stopPOV() {
  const ov = document.getElementById('pov-overlay');
  if (ov) ov.remove();
  if (povRAF) { cancelAnimationFrame(povRAF); povRAF = null; }
}

export function startPOV(ride) {
  if (!ride?.track?.length && !ride.def) return;
  // custom coasters use track; prebuilt rides get a synthesized scenic track
  let track = ride.track;
  if (!track || !track.length) {
    track = synthTrackFor(ride);
    ride.cycleDur = ride.def.rideTime;
  }
  stopPOV();
  sfx.whoosh();
  const ov = document.createElement('div');
  ov.id = 'pov-overlay';
  ov.innerHTML = `
    <canvas id="pov-canvas"></canvas>
    <div id="pov-hud">
      <span>🎢 <b>${ride.name}</b></span>
      <span>💨 <span id="pov-speed">0</span> km/h</span>
      <span>⚡ ${ride.excite.toFixed ? ride.excite.toFixed(1) : ride.excite}</span>
      <span id="pov-time"></span>
    </div>
    <button id="pov-exit" class="btn danger">✕ Exit Ride</button>`;
  document.body.appendChild(ov);
  const cvs = document.getElementById('pov-canvas');
  const ctx = cvs.getContext('2d');
  document.getElementById('pov-exit').addEventListener('click', stopPOV);

  let prog = 0, lastT = performance.now();
  const dur = Math.max(8, ride.cycleDur);
  const maxSpeed = ride.stats?.maxSpeed || Math.round((ride.def?.excite || 4) * 12);
  const isNight = () => { const st = window.__getState?.(); return st ? (st.time.hour >= 20 || st.time.hour < 6) : false; };

  function resize() { cvs.width = innerWidth; cvs.height = innerHeight; }
  resize();
  window.addEventListener('resize', resize);

  function frame(now) {
    const dt = Math.min(0.05, (now - lastT) / 1000);
    lastT = now;
    prog += dt / dur;
    const s = sampleTrack(track, prog % 0.9999);
    drawFrame(ctx, cvs.width, cvs.height, s, prog, maxSpeed, isNight(), track, prog);
    const sp = document.getElementById('pov-speed');
    if (sp) sp.textContent = Math.round(maxSpeed * (0.55 + Math.abs(s.slope ?? 0) * 0.18));
    const tm = document.getElementById('pov-time');
    if (tm) tm.textContent = `⏱ ${Math.round((prog % 1) * 100)}%`;
    if (!document.getElementById('pov-overlay')) return;   // exited
    povRAF = requestAnimationFrame(frame);
  }
  povRAF = requestAnimationFrame(frame);
}

function synthTrackFor(ride) {
  // simple oval circuit with a hill
  const pts = [];
  const w = ride.w || 3, h = ride.h || 3;
  const cx = ride.x + w / 2, cy = ride.y + h / 2;
  const N = 28;
  for (let i = 0; i < N; i++) {
    const a = i / N * Math.PI * 2;
    pts.push({
      x: cx + Math.cos(a) * (w / 2 + 1.5),
      y: cy + Math.sin(a) * (h / 2 + 1.5),
      z: Math.round(Math.abs(Math.sin(a * 2)) * 3),
      type: 'straight', dir: Math.floor(a / (Math.PI / 2)) % 4,
      lift: false,
    });
  }
  return pts;
}

function drawFrame(ctx, W, H, s, prog, maxSpeed, night, track, rawProg) {
  // sky
  const g = ctx.createLinearGradient(0, 0, 0, H);
  if (night) { g.addColorStop(0, '#0a0e2a'); g.addColorStop(1, '#232a55'); }
  else { g.addColorStop(0, '#69aef0'); g.addColorStop(1, '#cfe6f7'); }
  ctx.fillStyle = g;
  ctx.fillRect(0, 0, W, H);

  // loop rotation flips world
  const loopRot = s.loop ? (prog % 0.9999 > 0.45 && prog % 0.9999 < 0.62 ? Math.PI : 0) : 0;

  const slopeTilt = clampN((s.slope ?? 0) * -26, -160, 160);
  const steerShift = Math.sin(rawProg * Math.PI * 8) * 40;

  ctx.save();
  ctx.translate(W / 2 + steerShift, H / 2 + slopeTilt * 0.4);
  ctx.rotate(loopRot);

  // ground
  const horizonY = 60 + slopeTilt;
  const gg = ctx.createLinearGradient(0, horizonY, 0, H * 2);
  gg.addColorStop(0, '#7fb069'); gg.addColorStop(1, '#3d6b35');
  ctx.fillStyle = gg;
  ctx.fillRect(-W, horizonY, W * 2, H * 2);
  // water strip far away
  ctx.fillStyle = night ? '#16204d' : '#3a7cc9';
  ctx.fillRect(-W, horizonY - 14, W * 2, 10);

  // scrolling ground stripes (speed feel)
  const speedF = 0.5 + maxSpeed / 60;
  const scroll = (rawProg * 900 * speedF) % 120;
  ctx.strokeStyle = 'rgba(255,255,255,.10)';
  ctx.lineWidth = 3;
  for (let i = -3; i < 22; i++) {
    const y = horizonY + ((i * 120 - scroll) ** 1.35) / 40;
    if (y > H * 1.6) break;
    ctx.beginPath();
    ctx.moveTo(-W, y);
    ctx.lineTo(W, y);
    ctx.stroke();
  }

  // track rails ahead (perspective V)
  ctx.strokeStyle = '#ffd166';
  ctx.lineWidth = 6;
  ctx.beginPath();
  ctx.moveTo(-70, H * 0.75); ctx.quadraticCurveTo(-30, horizonY + 140, -16, horizonY + 34);
  ctx.stroke();
  ctx.beginPath();
  ctx.moveTo(70, H * 0.75); ctx.quadraticCurveTo(30, horizonY + 140, 16, horizonY + 34);
  ctx.stroke();

  // passing posts
  const postScroll = (rawProg * 40) % 3;
  ctx.fillStyle = 'rgba(60,64,80,.85)';
  for (let i = 0; i < 6; i++) {
    const k = i - postScroll;
    if (k < -1) continue;
    const px = (k - 2) * 260;
    const ph = 90 + (i % 3) * 30;
    ctx.fillRect(px, horizonY + 60, 10, ph + 200);
  }
  // trees silhouettes occasionally
  for (let i = 0; i < 4; i++) {
    const k = i - ((rawProg * 17) % 1) * 1;
    const tx = ((i * 397 + Math.floor(rawProg * 17) * 131) % (W * 2)) - W / 2;
    ctx.fillStyle = night ? '#101530' : '#2e6b34';
    ctx.beginPath();
    ctx.arc(tx, horizonY + 46, 34, 0, Math.PI * 2);
    ctx.fill();
  }
  ctx.restore();

  // wind speed lines at high speed
  if (maxSpeed > 45) {
    ctx.strokeStyle = 'rgba(255,255,255,.25)';
    for (let i = 0; i < 8; i++) {
      const y = Math.random() * H;
      const x = Math.random() * W;
      ctx.lineWidth = Math.random() * 2;
      ctx.beginPath(); ctx.moveTo(x, y); ctx.lineTo(x + 60 + Math.random() * 90, y + (Math.random() - .5) * 10); ctx.stroke();
    }
  }
  // vignette
  const vg = ctx.createRadialGradient(W / 2, H / 2, H * 0.35, W / 2, H / 2, H);
  vg.addColorStop(0, 'rgba(0,0,0,0)');
  vg.addColorStop(1, 'rgba(0,0,10,.42)');
  ctx.fillStyle = vg;
  ctx.fillRect(0, 0, W, H);

  // coaster car front
  ctx.fillStyle = '#e05b5b';
  ctx.beginPath();
  ctx.moveTo(W / 2 - 130, H + 40);
  ctx.quadraticCurveTo(W / 2, H - 150, W / 2 + 130, H + 40);
  ctx.closePath();
  ctx.fill();
}
function clampN(v, a, b) { return v < a ? a : v > b ? b : v; }