'use strict';
/* ============================================================
   TOWER DEFENSE — 100 WAVES
   Place towers, evolve them through 4 stages, survive 100 waves.
   ============================================================ */
const cv = document.getElementById('td100game');
const ctx = cv.getContext('2d');

// ---------- Layout ----------
const W = 960, HUD_H = 64, COLS = 20, ROWS = 12, CELL = 48;
const GRID_Y = HUD_H, GRID_H = ROWS * CELL;      // 576
const SHOP_Y = GRID_Y + GRID_H;                 // 640
const H = SHOP_Y + 120;                         // 760

// ---------- Path (cell coords) ----------
const WAY_CELLS = [[-1,2],[3,2],[3,5],[8,5],[8,9],[14,9],[14,4],[21,4]];
const waypoints = WAY_CELLS.map(([c,r]) => ({ x:(c+0.5)*CELL, y:GRID_Y+(r+0.5)*CELL }));
const blocked = new Set();
(function buildBlocked(){
  for(let s=0;s<WAY_CELLS.length-1;s++){
    const [c1,r1]=WAY_CELLS[s], [c2,r2]=WAY_CELLS[s+1];
    const steps=Math.ceil(Math.hypot(c2-c1,r2-r1)*4);
    for(let i=0;i<=steps;i++){
      const c=Math.round(c1+(c2-c1)*i/steps), r=Math.round(r1+(r2-r1)*i/steps);
      if(c>=0&&c<COLS&&r>=0&&r<ROWS) blocked.add(c+','+r);
    }
  }
})();

// ---------- Tower definitions (4 evolution stages each) ----------
const EVO_ROMAN=['I','II','III','IV'];
const TOWER_DEFS = {
  gun:   { name:'Gunner', cost:50,  color:'#38e1ff', desc:'Rapid fire',
    evo:[ {dmg:6,  rate:3.0, range:2.5, cost:0},
          {dmg:11, rate:3.8, range:2.7, cost:70},
          {dmg:20, rate:4.8, range:3.0, cost:150},
          {dmg:36, rate:6.0, range:3.3, cost:280} ] },
  cannon:{ name:'Cannon', cost:110, color:'#ff9f43', desc:'Splash damage',
    evo:[ {dmg:26, rate:0.70, range:2.6, splash:1.0, cost:0},
          {dmg:48, rate:0.75, range:2.8, splash:1.2, cost:130},
          {dmg:90, rate:0.85, range:3.0, splash:1.4, cost:260},
          {dmg:170,rate:1.00, range:3.3, splash:1.7, cost:520} ] },
  laser: { name:'Laser',  cost:160, color:'#ff4d6d', desc:'Melting beam',
    evo:[ {dps:45,  range:2.8, cost:0},
          {dps:95,  range:3.0, cost:190},
          {dps:200, range:3.2, cost:380},
          {dps:420, range:3.5, cost:760} ] },
  frost: { name:'Frost',  cost:120, color:'#8ef6ff', desc:'Slows enemies',
    evo:[ {dmg:6,  rate:1.0, range:2.4, slow:0.35, cost:0},
          {dmg:14, rate:1.0, range:2.6, slow:0.45, cost:150},
          {dmg:30, rate:1.0, range:2.8, slow:0.55, cost:300},
          {dmg:65, rate:1.0, range:3.1, slow:0.65, cost:600} ] },
  sniper:{ name:'Sniper', cost:200, color:'#c084fc', desc:'Long range',
    evo:[ {dmg:65,  rate:0.60, range:4.5, cost:0},
          {dmg:135, rate:0.65, range:5.0, cost:250},
          {dmg:280, rate:0.75, range:5.6, cost:500},
          {dmg:600, rate:0.85, range:6.2, cost:1000} ] },
};
const SHOP_ORDER = ['gun','cannon','laser','frost','sniper'];

// ---------- Game state ----------
let state='menu';           // menu | play | victory | defeat
let wave=1, gold=300, lives=20, score=0;
let towers=[], enemies=[], projectiles=[], queue=[];
let tracers=[], sparks=[], explosions=[], pulses=[], texts=[];
let waveActive=false, spawnT=0, spawnInterval=0.8;
let speed=1, paused=false, time=0;
let shopSel=null, towerSel=null, hoverCell=null;
let leakFlash=0, shakeT=0, shakeMsg='';
const SAVE_KEY='td100_save_v1';

// ---------- Audio (tiny synth, no assets) ----------
let AC=null, muted=false;
const lastSfx={};
function sfx(kind){
  if(muted) return;
  const now=performance.now();
  if(lastSfx[kind] && now-lastSfx[kind]<60) return;
  lastSfx[kind]=now;
  try{
    AC = AC || new (window.AudioContext||window.webkitAudioContext)();
    if(AC.state==='suspended') AC.resume();
    const o=AC.createOscillator(), g=AC.createGain();
    const P={ gun:[880,0.05,'square',0.018], sniper:[220,0.18,'sawtooth',0.03],
      cannon:[120,0.25,'sine',0.06], frost:[1200,0.2,'sine',0.025],
      kill:[520,0.09,'triangle',0.035], place:[660,0.08,'square',0.03],
      evolve:[440,0.3,'square',0.035], leak:[140,0.4,'sawtooth',0.06],
      coin:[1320,0.07,'sine',0.03], start:[330,0.25,'square',0.04] }[kind]||[440,0.1,'square',0.03];
    o.type=P[2]; o.frequency.setValueAtTime(P[0],AC.currentTime);
    if(kind==='kill'||kind==='leak') o.frequency.exponentialRampToValueAtTime(80,AC.currentTime+P[1]);
    if(kind==='evolve') o.frequency.exponentialRampToValueAtTime(880,AC.currentTime+P[1]);
    g.gain.setValueAtTime(P[3],AC.currentTime);
    g.gain.exponentialRampToValueAtTime(0.0001,AC.currentTime+P[1]);
    o.connect(g); g.connect(AC.destination);
    o.start(); o.stop(AC.currentTime+P[1]+0.02);
  }catch(e){}
}

// ---------- Save / load ----------
function saveGame(){
  if(state!=='play'||waveActive) return;
  try{
    localStorage.setItem(SAVE_KEY, JSON.stringify({
      wave, gold, lives, score,
      towers: towers.map(t=>({type:t.type,evo:t.evo,gx:t.gx,gy:t.gy,invested:t.invested}))
    }));
  }catch(e){}
}
function loadGame(){
  try{
    const s=JSON.parse(localStorage.getItem(SAVE_KEY));
    if(!s||!s.wave||s.wave>100) return false;
    wave=s.wave; gold=s.gold; lives=s.lives; score=s.score||0; towers=[];
    for(const st of (s.towers||[])){
      towers.push({ type:st.type, evo:st.evo, gx:st.gx, gy:st.gy,
        x:(st.gx+0.5)*CELL, y:GRID_Y+(st.gy+0.5)*CELL,
        cd:0, angle:-Math.PI/2, invested:st.invested, beam:null, pulse:null, target:null });
    }
    return true;
  }catch(e){ return false; }
}
function hasSave(){
  try{ const s=JSON.parse(localStorage.getItem(SAVE_KEY)); return !!(s&&s.wave&&s.wave<=100); }
  catch(e){ return false; }
}
function clearSave(){ try{ localStorage.removeItem(SAVE_KEY); }catch(e){} }

// ---------- Helpers ----------
function towerStats(t){ return TOWER_DEFS[t.type].evo[t.evo]; }
function fmt(n){ return Math.floor(n).toLocaleString('en-US'); }
function rr(x,y,w,h,r){
  ctx.beginPath();
  ctx.moveTo(x+r,y); ctx.arcTo(x+w,y,x+w,y+h,r); ctx.arcTo(x+w,y+h,x,y+h,r);
  ctx.arcTo(x,y+h,x,y,r); ctx.arcTo(x,y,x+w,y,r); ctx.closePath();
}
function addText(x,y,text,color,size){
  texts.push({x,y,text,color:color||'#ffe27a',size:size||15,ttl:1.1});
}
function cellCenter(gx,gy){ return { x:(gx+0.5)*CELL, y:GRID_Y+(gy+0.5)*CELL }; }
function towerAt(gx,gy){ return towers.find(t=>t.gx===gx&&t.gy===gy); }

// ================= WAVE GENERATION =================
function waveSpec(n){
  const isBoss = (n%10===0), isFast = (n%5===0 && !isBoss);
  const count = isBoss ? Math.min(4+Math.floor(n/10),10) : Math.min(8+n, 40);
  const hp    = Math.round(22*Math.pow(1.084,n) + 5*n);
  const speed = Math.min(52 + n*1.0, 145);
  const size  = Math.min(9 + n*0.18, 27);
  const reward= 5 + n;
  return { n, isBoss, count, hp, speed, size, reward,
           interval: Math.max(0.22, 0.9 - n*0.006) };
}
function startWave(){
  if(state!=='play'||waveActive||wave>100) return;
  const s = waveSpec(wave);
  queue = [];
  if(s.isBoss){
    // escorts first, then the boss
    for(let i=0;i<Math.min(6+s.n/10,12);i++)
      queue.push({hp:s.hp*0.5, maxHp:s.hp*0.5, speed:s.speed*1.1, size:s.size*0.8, reward:Math.ceil(s.reward*0.6), boss:false, fast:false});
    queue.push({hp:s.hp*10, maxHp:s.hp*10, speed:s.speed*0.65, size:s.size*1.7, reward:s.reward*15, boss:true, fast:false});
    for(let i=0;i<Math.min(6+s.n/10,12);i++)
      queue.push({hp:s.hp*0.5, maxHp:s.hp*0.5, speed:s.speed*1.1, size:s.size*0.8, reward:Math.ceil(s.reward*0.6), boss:false, fast:false});
  } else {
    for(let i=0;i<s.count;i++){
      const fast = s.n%5===0 && i%3===0;
      queue.push({ hp: fast? s.hp*0.6 : s.hp, maxHp: fast? s.hp*0.6 : s.hp,
        speed: fast? s.speed*1.6 : s.speed, size: fast? s.size*0.75 : s.size,
        reward: s.reward, boss:false, fast });
    }
  }
  spawnInterval = s.interval;
  spawnT = 0.3;
  waveActive = true;
  towerSel = null; shopSel = null;
  sfx('start');
  addText(W/2, GRID_Y+120, s.isBoss? '⚠ BOSS WAVE '+wave+' ⚠' : 'WAVE '+wave, '#ffd166', 34);
}
function spawnEnemy(q){
  enemies.push({ x:waypoints[0].x, y:waypoints[0].y, wp:1, dist:0,
    hp:q.hp, maxHp:q.maxHp, baseSpeed:q.speed, size:q.size,
    reward:q.reward, boss:q.boss, fast:q.fast,
    slowUntil:0, slowAmt:0, wob:Math.random()*6.28, dead:false });
}
function killEnemy(e){
  if(e.dead) return;
  e.dead = true;
  gold += e.reward; score += e.reward*10 + wave*5;
  explosions.push({x:e.x,y:e.y,r:e.size*0.6,max:e.size*2.4,ttl:0.3,t:0});
  addText(e.x, e.y-14, '+$'+e.reward, '#ffe27a', e.boss?20:14);
  sfx(e.boss?'evolve':'kill');
}

// ================= ACTIONS =================
function tryPlace(gx,gy){
  const def = TOWER_DEFS[shopSel];
  if(!def) return;
  if(gx<0||gx>=COLS||gy<0||gy>=ROWS) return;
  if(blocked.has(gx+','+gy)||towerAt(gx,gy)){ deny('Blocked'); return; }
  if(gold<def.cost){ deny('Not enough gold'); return; }
  gold -= def.cost;
  const c = cellCenter(gx,gy);
  towers.push({ type:shopSel, evo:0, gx, gy, x:c.x, y:c.y,
    cd:0, angle:-Math.PI/2, invested:def.cost, beam:null, pulse:null, target:null });
  sfx('place');
  sparks.push({x:c.x,y:c.y,ttl:0.25,r:22});
  if(!waveActive) saveGame();
}
function tryEvolve(){
  const t = towerSel; if(!t) return;
  if(t.evo>=3) return;
  const cost = TOWER_DEFS[t.type].evo[t.evo+1].cost;
  if(gold<cost){ deny('Not enough gold'); return; }
  gold -= cost; t.invested += cost; t.evo++;
  sfx('evolve');
  pulses.push({x:t.x,y:t.y,r:8,max:70,ttl:0.5,t:0,color:TOWER_DEFS[t.type].color});
  addText(t.x, t.y-30, 'EVOLVED '+EVO_ROMAN[t.evo], '#7CFC9A', 16);
  if(!waveActive) saveGame();
}
function trySell(){
  const t = towerSel; if(!t) return;
  gold += Math.floor(t.invested*0.7);
  addText(t.x, t.y-20, '+$'+Math.floor(t.invested*0.7), '#ffe27a', 15);
  towers = towers.filter(x=>x!==t);
  towerSel = null;
  sfx('coin');
  if(!waveActive) saveGame();
}
function deny(msg){
  shakeT=0.35; shakeMsg=msg; sfx('leak');
}
function gameOver(){
  state='defeat'; waveActive=false; clearSave(); sfx('leak');
}
function victory(){
  state='victory'; waveActive=false; clearSave(); sfx('evolve');
}
function newGame(){
  wave=1; gold=300; lives=20; score=0;
  towers=[]; enemies=[]; projectiles=[]; queue=[];
  tracers=[]; sparks=[]; explosions=[]; pulses=[]; texts=[];
  waveActive=false; speed=1; paused=false; time=0;
  shopSel=null; towerSel=null; leakFlash=0;
  clearSave(); state='play';
}

// ================= UPDATE =================
function update(dt){
  if(state!=='play'||paused) return;
  const sdt = Math.min(dt,0.05)*speed;
  time += sdt;
  if(leakFlash>0) leakFlash-=sdt;

  // spawning
  if(waveActive && queue.length){
    spawnT -= sdt;
    while(spawnT<=0 && queue.length){ spawnEnemy(queue.shift()); spawnT += spawnInterval; }
  }

  // enemies move
  for(let i=enemies.length-1;i>=0;i--){
    const e=enemies[i];
    if(e.dead) continue;
    const slowed = time < e.slowUntil;
    const sp = e.baseSpeed * (slowed ? (1-e.slowAmt) : 1);
    let rem = sp*sdt;
    while(rem>0 && e.wp<waypoints.length){
      const t=waypoints[e.wp], dx=t.x-e.x, dy=t.y-e.y, d=Math.hypot(dx,dy)||0.001;
      if(d<=rem){ e.x=t.x; e.y=t.y; e.dist+=d; rem-=d; e.wp++; }
      else { e.x+=dx/d*rem; e.y+=dy/d*rem; e.dist+=rem; rem=0; }
    }
    e.wob += sdt*6;
    if(e.wp>=waypoints.length){
      e.dead=true;
      const dmg = e.boss?5:1;
      lives -= dmg;
      addText(W-90, GRID_Y+50, '-'+dmg+' ❤', '#ff5d5d', 22);
      leakFlash=0.4; sfx('leak');
      if(lives<=0){ lives=0; gameOver(); return; }
    }
  }

  // towers fire
  for(const t of towers){
    t.cd -= sdt;
    const st = towerStats(t), def = TOWER_DEFS[t.type];
    const R = st.range*CELL;
    let best=null, bd=-1;
    for(const e of enemies){
      if(e.dead) continue;
      if(Math.hypot(e.x-t.x,e.y-t.y) <= R + e.size*0.4 && e.dist>bd){ bd=e.dist; best=e; }
    }
    t.target = best;
    if(best) t.angle = Math.atan2(best.y-t.y, best.x-t.x);
    if(!best){ t.beam=null; continue; }

    if(t.type==='laser'){
      best.hp -= st.dps*sdt;
      t.beam = {x:best.x, y:best.y, ttl:0.12};
      if(best.hp<=0) killEnemy(best);
    } else if(t.type==='frost'){
      if(t.cd<=0){
        t.cd = 1/st.rate;
        pulses.push({x:t.x,y:t.y,r:10,max:R,ttl:0.4,t:0,color:def.color});
        sfx('frost');
        for(const e of enemies){
          if(e.dead) continue;
          if(Math.hypot(e.x-t.x,e.y-t.y)<=R){
            e.hp -= st.dmg;
            if(time>=e.slowUntil || st.slow>e.slowAmt){ e.slowUntil=time+1.6; e.slowAmt=st.slow; }
            if(e.hp<=0) killEnemy(e);
          }
        }
      }
    } else if(t.cd<=0){
      t.cd = 1/st.rate;
      if(t.type==='cannon'){
        const d = Math.hypot(best.x-t.x,best.y-t.y);
        projectiles.push({x:t.x,y:t.y,tx:best.x,ty:best.y,t:0,
          dur:Math.max(0.12,d/480),dmg:st.dmg,splash:st.splash*CELL});
        sfx('cannon');
      } else {
        best.hp -= st.dmg;
        tracers.push({x1:t.x,y1:t.y,x2:best.x,y2:best.y,ttl:0.09,color:def.color,big:t.type==='sniper'});
        sparks.push({x:best.x,y:best.y,ttl:0.14,r:t.type==='sniper'?11:6});
        sfx(t.type);
        if(best.hp<=0) killEnemy(best);
      }
    }
  }

  // projectiles
  for(let i=projectiles.length-1;i>=0;i--){
    const p=projectiles[i];
    p.t += sdt;
    const k = Math.min(1, p.t/p.dur);
    p.x += (p.tx-p.x)*Math.min(1,sdt*14);
    p.y += (p.ty-p.y)*Math.min(1,sdt*14);
    if(k>=1){
      projectiles.splice(i,1);
      explosions.push({x:p.tx,y:p.ty,r:8,max:p.splash,ttl:0.32,t:0});
      for(const e of enemies){
        if(e.dead) continue;
        if(Math.hypot(e.x-p.tx,e.y-p.ty)<=p.splash){ e.hp-=p.dmg; if(e.hp<=0) killEnemy(e); }
      }
    }
  }

  // sweep dead
  if(enemies.some(e=>e.dead)) enemies = enemies.filter(e=>!e.dead);

  // effects decay
  for(const a of [tracers,sparks,explosions,pulses]) for(let i=a.length-1;i>=0;i--){ a[i].ttl-=sdt; if(a[i].ttl<=0) a.splice(i,1); }
  for(let i=texts.length-1;i>=0;i--){ const x=texts[i]; x.ttl-=sdt; x.y-=34*sdt; if(x.ttl<=0) texts.splice(i,1); }
  for(const t of towers){ if(t.beam){ t.beam.ttl-=sdt; if(t.beam.ttl<=0) t.beam=null; } }
  if(shakeT>0) shakeT-=sdt;

  // wave complete?
  if(waveActive && !queue.length && !enemies.length){
    waveActive=false;
    const bonus = 25 + wave*3;
    gold += bonus; score += 100 + wave*10;
    addText(W/2, GRID_Y+170, 'WAVE '+wave+' CLEAR  +$'+bonus, '#7CFC9A', 24);
    sfx('coin');
    wave++;
    if(wave>100){ victory(); }
    else saveGame();
  }
}

// ================= LAYOUT (shared by draw + clicks) =================
const UI = {
  mute:   {x:W-96, y:12, w:40, h:40},
  restart:{x:W-52, y:12, w:40, h:40},
  cards:  SHOP_ORDER.map((t,i)=>({x:12+i*160, y:SHOP_Y+12, w:150, h:96, type:t})),
  start:  {x:824, y:SHOP_Y+8,  w:124, h:54},
  speed:  {x:824, y:SHOP_Y+68, w:60,  h:44},
  pause:  {x:890, y:SHOP_Y+68, w:58,  h:44},
  evolve: {x:560, y:SHOP_Y+16, w:170, h:46},
  sell:   {x:740, y:SHOP_Y+16, w:100, h:46},
  pclose: {x:850, y:SHOP_Y+16, w:46,  h:46},
  menuStart:   {x:W/2-150, y:470, w:300, h:60},
  menuContinue:{x:W/2-150, y:545, w:300, h:54},
  again:  {x:W/2-150, y:500, w:300, h:60},
};
function inRect(x,y,r){ return x>=r.x&&x<=r.x+r.w&&y>=r.y&&y<=r.y+r.h; }

// ================= RENDER =================
function render(){
  ctx.save();
  if(shakeT>0) ctx.translate((Math.random()-0.5)*8*shakeT*3,(Math.random()-0.5)*8*shakeT*3);
  drawBG(); drawGrid(); drawPath(); drawPortals();
  drawPlacementGhost();
  for(const t of towers) drawTower(t);
  for(const e of enemies) drawEnemy(e);
  drawProjectiles(); drawEffects(); drawTexts();
  drawHUD(); drawBottom();
  if(leakFlash>0){ ctx.fillStyle=`rgba(255,40,40,${leakFlash*0.5})`; ctx.fillRect(0,0,W,H); }
  if(shakeT>0&&shakeMsg){ ctx.fillStyle='#ff8a8a'; ctx.font='bold 18px sans-serif';
    ctx.textAlign='center'; ctx.fillText(shakeMsg, W/2, GRID_Y+40); }
  if(state==='menu') drawMenu();
  if(state==='victory') drawEnd(true);
  if(state==='defeat') drawEnd(false);
  ctx.restore();
}
function drawBG(){
  const g=ctx.createLinearGradient(0,0,0,H);
  g.addColorStop(0,'#070c1e'); g.addColorStop(0.6,'#0a1330'); g.addColorStop(1,'#060a1a');
  ctx.fillStyle=g; ctx.fillRect(0,0,W,H);
  ctx.fillStyle='rgba(255,255,255,0.05)';
  for(let i=0;i<70;i++){
    const x=(i*137.5)%W, y=(i*89.3)%(GRID_Y+GRID_H);
    ctx.fillRect(x,y,2,2);
  }
}
function drawGrid(){
  ctx.strokeStyle='rgba(120,160,255,0.06)'; ctx.lineWidth=1;
  ctx.beginPath();
  for(let c=0;c<=COLS;c++){ ctx.moveTo(c*CELL,GRID_Y); ctx.lineTo(c*CELL,GRID_Y+GRID_H); }
  for(let r=0;r<=ROWS;r++){ ctx.moveTo(0,GRID_Y+r*CELL); ctx.lineTo(W,GRID_Y+r*CELL); }
  ctx.stroke();
}
function strokePath(){
  ctx.beginPath();
  ctx.moveTo(waypoints[0].x,waypoints[0].y);
  for(let i=1;i<waypoints.length;i++) ctx.lineTo(waypoints[i].x,waypoints[i].y);
  ctx.stroke();
}
function drawPath(){
  ctx.lineJoin='round'; ctx.lineCap='round';
  ctx.strokeStyle='rgba(56,225,255,0.08)'; ctx.lineWidth=CELL*0.92; strokePath();
  ctx.strokeStyle='#131c3a'; ctx.lineWidth=CELL*0.74; strokePath();
  ctx.strokeStyle='rgba(56,225,255,0.28)'; ctx.lineWidth=3;
  ctx.setLineDash([16,20]); strokePath(); ctx.setLineDash([]);
}
function drawPortals(){
  const sy=waypoints[0].y, ey=waypoints[waypoints.length-1].y;
  // entry (cyan)
  const g1=ctx.createRadialGradient(16,sy,2,16,sy,30);
  g1.addColorStop(0,'rgba(56,225,255,0.9)'); g1.addColorStop(1,'rgba(56,225,255,0)');
  ctx.fillStyle=g1; ctx.beginPath(); ctx.arc(16,sy,30,0,7); ctx.fill();
  ctx.strokeStyle='#38e1ff'; ctx.lineWidth=3;
  for(let k=0;k<2;k++){ ctx.beginPath();
    ctx.arc(16,sy,14+k*8,time*2+k*1.5,time*2+k*1.5+4.2); ctx.stroke(); }
  // exit base (red)
  const g2=ctx.createRadialGradient(W-16,ey,2,W-16,ey,34);
  g2.addColorStop(0,'rgba(255,70,70,0.9)'); g2.addColorStop(1,'rgba(255,70,70,0)');
  ctx.fillStyle=g2; ctx.beginPath(); ctx.arc(W-16,ey,34,0,7); ctx.fill();
  ctx.fillStyle='#ff5252';
  ctx.beginPath(); ctx.arc(W-16,ey,10+Math.sin(time*5)*2,0,7); ctx.fill();
  ctx.strokeStyle='rgba(255,82,82,0.7)'; ctx.lineWidth=2;
  ctx.beginPath(); ctx.arc(W-16,ey,20,-time*1.5,-time*1.5+3.6); ctx.stroke();
}
function drawPlacementGhost(){
  if(!shopSel||!hoverCell||state!=='play') return;
  const {gx,gy}=hoverCell;
  if(gx<0||gx>=COLS||gy<0||gy>=ROWS) return;
  const c=cellCenter(gx,gy), def=TOWER_DEFS[shopSel], st=def.evo[0];
  const ok=!blocked.has(gx+','+gy)&&!towerAt(gx,gy)&&gold>=def.cost;
  ctx.globalAlpha=0.35;
  ctx.fillStyle=ok?def.color:'#ff5252';
  ctx.beginPath(); ctx.arc(c.x,c.y,st.range*CELL,0,7); ctx.fill();
  ctx.globalAlpha=0.8;
  ctx.fillStyle=def.color;
  ctx.beginPath(); ctx.arc(c.x,c.y,16,0,7); ctx.fill();
  ctx.globalAlpha=1;
  if(!ok){ ctx.strokeStyle='#ff5252'; ctx.lineWidth=4;
    ctx.beginPath(); ctx.moveTo(c.x-12,c.y-12); ctx.lineTo(c.x+12,c.y+12);
    ctx.moveTo(c.x+12,c.y-12); ctx.lineTo(c.x-12,c.y+12); ctx.stroke(); }
}
function drawTower(t){
  const def=TOWER_DEFS[t.type], st=towerStats(t);
  // selection / placement range
  if(towerSel===t){
    ctx.fillStyle='rgba(255,255,255,0.10)';
    ctx.beginPath(); ctx.arc(t.x,t.y,st.range*CELL,0,7); ctx.fill();
    ctx.strokeStyle='#fff'; ctx.lineWidth=2; ctx.setLineDash([8,6]);
    ctx.beginPath(); ctx.arc(t.x,t.y,st.range*CELL,0,7); ctx.stroke(); ctx.setLineDash([]);
  }
  // shadow + base
  ctx.fillStyle='rgba(0,0,0,0.35)';
  ctx.beginPath(); ctx.ellipse(t.x,t.y+16,20,8,0,0,7); ctx.fill();
  ctx.fillStyle='#1a2447'; rr(t.x-20,t.y-20,40,40,10); ctx.fill();
  ctx.strokeStyle=def.color; ctx.lineWidth=2.5; rr(t.x-20,t.y-20,40,40,10); ctx.stroke();
  // glyph
  ctx.save(); ctx.translate(t.x,t.y);
  const evoScale=1+t.evo*0.12;
  ctx.scale(evoScale,evoScale);
  ctx.fillStyle=def.color; ctx.strokeStyle=def.color;
  if(t.type==='gun'||t.type==='cannon'||t.type==='sniper'){
    ctx.rotate(t.angle);
    ctx.lineWidth=t.type==='cannon'?9:5;
    ctx.beginPath(); ctx.moveTo(0,0); ctx.lineTo(t.type==='sniper'?26:20,0); ctx.stroke();
    ctx.beginPath(); ctx.arc(0,0,t.type==='cannon'?11:9,0,7); ctx.fill();
    ctx.fillStyle='#0a1330'; ctx.beginPath(); ctx.arc(0,0,4,0,7); ctx.fill();
  } else if(t.type==='laser'){
    ctx.rotate(time*1.5);
    ctx.beginPath();
    for(let i=0;i<4;i++){ const a=i*Math.PI/2;
      ctx.moveTo(Math.cos(a)*4,Math.sin(a)*4); ctx.lineTo(Math.cos(a)*15,Math.sin(a)*15); }
    ctx.lineWidth=5; ctx.stroke();
    ctx.fillStyle='#fff'; ctx.beginPath(); ctx.arc(0,0,4,0,7); ctx.fill();
  } else { // frost
    ctx.lineWidth=3.5;
    for(let i=0;i<3;i++){ ctx.rotate(Math.PI/3);
      ctx.beginPath(); ctx.moveTo(-12,0); ctx.lineTo(12,0); ctx.stroke();
      ctx.beginPath(); ctx.moveTo(7,-5); ctx.lineTo(12,0); ctx.lineTo(7,5); ctx.stroke(); }
  }
  ctx.restore();
  // evolution pips
  for(let i=0;i<4;i++){
    ctx.fillStyle=i<=t.evo?def.color:'rgba(255,255,255,0.18)';
    ctx.beginPath(); ctx.arc(t.x-15+i*10,t.y+26,3.4,0,7); ctx.fill();
  }
  if(t.beam){
    const fl=0.75+Math.random()*0.25;
    const g=ctx.createLinearGradient(t.x,t.y,t.beam.x,t.beam.y);
    g.addColorStop(0,'rgba(255,255,255,0.95)'); g.addColorStop(1,def.color);
    ctx.strokeStyle=g; ctx.lineWidth=(5+t.evo*2)*fl;
    ctx.beginPath(); ctx.moveTo(t.x,t.y); ctx.lineTo(t.beam.x,t.beam.y); ctx.stroke();
    ctx.fillStyle='rgba(255,120,140,0.8)';
    ctx.beginPath(); ctx.arc(t.beam.x,t.beam.y,6+t.evo*2,0,7); ctx.fill();
  }
}
function drawEnemy(e){
  const hue = e.boss? 278 : Math.max(0, 128 - wave*1.22);
  const wob = Math.sin(e.wob)*e.size*0.08;
  const r = e.size + wob;
  if(e.boss){ // spikes
    ctx.fillStyle=`hsl(${hue},70%,30%)`;
    ctx.beginPath();
    for(let i=0;i<10;i++){ const a=i*Math.PI/5+time*0.8;
      const x1=e.x+Math.cos(a)*r*0.9, y1=e.y+Math.sin(a)*r*0.9;
      const x2=e.x+Math.cos(a+0.31)*r*1.5, y2=e.y+Math.sin(a+0.31)*r*1.5;
      ctx.moveTo(e.x,e.y); ctx.lineTo(x1,y1); ctx.lineTo(x2,y2); }
    ctx.fill();
  }
  const g=ctx.createRadialGradient(e.x-r*0.3,e.y-r*0.3,r*0.2,e.x,e.y,r);
  g.addColorStop(0,`hsl(${hue},95%,${e.boss?60:68}%)`);
  g.addColorStop(1,`hsl(${hue},85%,${e.boss?32:38}%)`);
  ctx.fillStyle=g;
  ctx.beginPath(); ctx.arc(e.x,e.y,r,0,7); ctx.fill();
  if(time<e.slowUntil){ ctx.strokeStyle='rgba(140,240,255,0.9)'; ctx.lineWidth=3;
    ctx.beginPath(); ctx.arc(e.x,e.y,r+3,0,7); ctx.stroke(); }
  // eyes look toward travel direction
  const wp=waypoints[Math.min(e.wp,waypoints.length-1)];
  const dx=wp.x-e.x, dy=wp.y-e.y, d=Math.hypot(dx,dy)||1;
  const ex=dx/d*r*0.3, ey=dy/d*r*0.3;
  ctx.fillStyle='#fff';
  ctx.beginPath(); ctx.arc(e.x-ex*0.5-r*0.28,e.y+ey*0.5-r*0.18,r*0.24,0,7); ctx.fill();
  ctx.beginPath(); ctx.arc(e.x-ex*0.5+r*0.28,e.y+ey*0.5-r*0.18,r*0.24,0,7); ctx.fill();
  ctx.fillStyle='#111';
  ctx.beginPath(); ctx.arc(e.x-ex*0.5-r*0.28+ex*0.4,e.y+ey*0.5-r*0.18+ey*0.4,r*0.11,0,7); ctx.fill();
  ctx.beginPath(); ctx.arc(e.x-ex*0.5+r*0.28+ex*0.4,e.y+ey*0.5-r*0.18+ey*0.4,r*0.11,0,7); ctx.fill();
  // hp bar
  if(e.hp<e.maxHp){
    const w=Math.max(30,e.size*2.2), p=Math.max(0,e.hp/e.maxHp);
    ctx.fillStyle='rgba(0,0,0,0.55)'; ctx.fillRect(e.x-w/2,e.y-r-12,w,6);
    ctx.fillStyle=p>0.5?'#5dff7a':p>0.25?'#ffd166':'#ff5252';
    ctx.fillRect(e.x-w/2,e.y-r-12,w*p,6);
  }
}
function drawProjectiles(){
  for(const p of projectiles){
    ctx.fillStyle='#ffb347';
    ctx.beginPath(); ctx.arc(p.x,p.y,6,0,7); ctx.fill();
    ctx.fillStyle='rgba(255,180,70,0.35)';
    ctx.beginPath(); ctx.arc(p.x,p.y,11,0,7); ctx.fill();
  }
}
function drawEffects(){
  for(const t of tracers){
    ctx.globalAlpha=Math.max(0,t.ttl/0.09);
    ctx.strokeStyle=t.color; ctx.lineWidth=t.big?4:2.5;
    ctx.beginPath(); ctx.moveTo(t.x1,t.y1); ctx.lineTo(t.x2,t.y2); ctx.stroke();
  }
  ctx.globalAlpha=1;
  for(const s of sparks){
    ctx.globalAlpha=Math.max(0,s.ttl/0.15);
    ctx.fillStyle='#fff7c4';
    ctx.beginPath(); ctx.arc(s.x,s.y,s.r*(s.ttl/0.15),0,7); ctx.fill();
  }
  ctx.globalAlpha=1;
  for(const x of explosions){
    const k=1-x.ttl/0.32, r=x.r+(x.max-x.r)*k;
    ctx.globalAlpha=Math.max(0,1-k);
    ctx.strokeStyle='#ffb347'; ctx.lineWidth=5;
    ctx.beginPath(); ctx.arc(x.x,x.y,r,0,7); ctx.stroke();
    ctx.fillStyle='rgba(255,200,100,0.5)';
    ctx.beginPath(); ctx.arc(x.x,x.y,r*0.6,0,7); ctx.fill();
  }
  ctx.globalAlpha=1;
  for(const p of pulses){
    const k=1-p.ttl/0.5, r=8+(p.max-8)*k;
    ctx.globalAlpha=Math.max(0,1-k)*0.9;
    ctx.strokeStyle=p.color; ctx.lineWidth=4;
    ctx.beginPath(); ctx.arc(p.x,p.y,r,0,7); ctx.stroke();
  }
  ctx.globalAlpha=1;
}
function drawTexts(){
  ctx.textAlign='center';
  for(const t of texts){
    ctx.globalAlpha=Math.min(1,t.ttl*2);
    ctx.font=`bold ${t.size}px sans-serif`;
    ctx.strokeStyle='rgba(0,0,0,0.7)'; ctx.lineWidth=3;
    ctx.strokeText(t.text,t.x,t.y);
    ctx.fillStyle=t.color; ctx.fillText(t.text,t.x,t.y);
  }
  ctx.globalAlpha=1;
}
function drawHUD(){
  ctx.fillStyle='rgba(4,8,20,0.85)'; ctx.fillRect(0,0,W,HUD_H);
  ctx.strokeStyle='rgba(56,225,255,0.25)'; ctx.lineWidth=1;
  ctx.beginPath(); ctx.moveTo(0,HUD_H); ctx.lineTo(W,HUD_H); ctx.stroke();
  ctx.textAlign='left'; ctx.fillStyle='#fff'; ctx.font='bold 20px sans-serif';
  ctx.fillText(`WAVE ${Math.min(wave,100)}/100`, 16, 30);
  ctx.font='bold 19px sans-serif'; ctx.fillStyle='#ffe27a';
  ctx.fillText(`💰 ${fmt(gold)}`, 16, 54);
  ctx.fillStyle = lives<=5 ? '#ff5d5d' : '#ff8a8a';
  ctx.fillText(`❤ ${lives}`, 150, 54);
  ctx.fillStyle='#9fb3ff'; ctx.font='16px sans-serif';
  ctx.fillText(`SCORE ${fmt(score)}`, 230, 54);
  if(waveActive){
    const left=queue.length+enemies.length;
    ctx.fillStyle='#ffd166'; ctx.font='bold 17px sans-serif'; ctx.textAlign='center';
    ctx.fillText(`👾 ${left} left`, W/2, 40); ctx.textAlign='left';
  } else if(state==='play'&&wave<=100){
    ctx.fillStyle='#7CFC9A'; ctx.font='bold 17px sans-serif'; ctx.textAlign='center';
    ctx.fillText('Ready — start the wave when you are', W/2, 40); ctx.textAlign='left';
  }
  ctx.fillStyle='rgba(160,180,220,0.5)'; ctx.font='11px sans-serif'; ctx.textAlign='right';
  ctx.fillText('WIKIBUSINESS ARCADE', W-110, 56); ctx.textAlign='left';
  // buttons
  hudBtn(UI.mute, muted?'🔇':'🔊');
  hudBtn(UI.restart, '⟳');
}
function hudBtn(r,icon){
  ctx.fillStyle='rgba(56,225,255,0.10)'; rr(r.x,r.y,r.w,r.h,8); ctx.fill();
  ctx.strokeStyle='rgba(56,225,255,0.4)'; ctx.lineWidth=1.5; rr(r.x,r.y,r.w,r.h,8); ctx.stroke();
  ctx.fillStyle='#cfe9ff'; ctx.font='20px sans-serif'; ctx.textAlign='center';
  ctx.fillText(icon, r.x+r.w/2, r.y+27); ctx.textAlign='left';
}
function drawBottom(){
  ctx.fillStyle='rgba(4,8,20,0.92)'; ctx.fillRect(0,SHOP_Y,W,H-SHOP_Y);
  ctx.strokeStyle='rgba(56,225,255,0.25)';
  ctx.beginPath(); ctx.moveTo(0,SHOP_Y); ctx.lineTo(W,SHOP_Y); ctx.stroke();
  if(towerSel) drawTowerPanel(); else drawShop();
}
function drawShop(){
  ctx.fillStyle='#9fb3ff'; ctx.font='bold 13px sans-serif'; ctx.textAlign='left';
  ctx.fillText('BUILD  (tap a tower, then tap the map)', 16, SHOP_Y+10);
  for(const c of UI.cards){
    const def=TOWER_DEFS[c.type], afford=gold>=def.cost, sel=shopSel===c.type;
    ctx.fillStyle=sel?'rgba(56,225,255,0.16)':'rgba(20,30,60,0.9)';
    rr(c.x,c.y,c.w,c.h,10); ctx.fill();
    ctx.strokeStyle=sel?def.color:(afford?'rgba(120,160,255,0.35)':'rgba(120,120,140,0.2)');
    ctx.lineWidth=sel?3:1.5; rr(c.x,c.y,c.w,c.h,10); ctx.stroke();
    ctx.fillStyle=def.color; rr(c.x,c.y,c.w,6,3); ctx.fill();
    ctx.globalAlpha=afford?1:0.45;
    ctx.fillStyle='#fff'; ctx.font='bold 16px sans-serif';
    ctx.fillText(def.name, c.x+12, c.y+30);
    ctx.fillStyle='#ffe27a'; ctx.font='bold 15px sans-serif';
    ctx.fillText('$'+def.cost, c.x+12, c.y+52);
    ctx.fillStyle='#9fb3ff'; ctx.font='12px sans-serif';
    ctx.fillText(def.desc, c.x+12, c.y+70);
    ctx.fillStyle='rgba(200,220,255,0.55)'; ctx.font='bold 12px sans-serif';
    ctx.fillText('['+(SHOP_ORDER.indexOf(c.type)+1)+']', c.x+c.w-30, c.y+30);
    ctx.globalAlpha=1;
  }
  // start / speed / pause
  const s=UI.start;
  ctx.fillStyle=waveActive?'rgba(90,90,110,0.5)':'rgba(60,220,120,0.25)';
  rr(s.x,s.y,s.w,s.h,10); ctx.fill();
  ctx.strokeStyle=waveActive?'#666':'#4be08a'; ctx.lineWidth=2; rr(s.x,s.y,s.w,s.h,10); ctx.stroke();
  ctx.fillStyle=waveActive?'#999':'#c9ffd9'; ctx.font='bold 16px sans-serif'; ctx.textAlign='center';
  ctx.fillText(waveActive?'FIGHTING…':'▶ START', s.x+s.w/2, s.y+23);
  ctx.font='bold 13px sans-serif';
  ctx.fillText(waveActive?'wave '+wave:'wave '+Math.min(wave,100), s.x+s.w/2, s.y+42);
  ctx.textAlign='left';
  bigBtn(UI.speed, speed+'×');
  bigBtn(UI.pause, paused?'▶':'⏸');
}
function bigBtn(r,label){
  ctx.fillStyle='rgba(56,225,255,0.10)'; rr(r.x,r.y,r.w,r.h,10); ctx.fill();
  ctx.strokeStyle='rgba(56,225,255,0.4)'; ctx.lineWidth=1.5; rr(r.x,r.y,r.w,r.h,10); ctx.stroke();
  ctx.fillStyle='#cfe9ff'; ctx.font='bold 18px sans-serif'; ctx.textAlign='center';
  ctx.fillText(label, r.x+r.w/2, r.y+29); ctx.textAlign='left';
}
function statLine(type,st){
  if(type==='laser') return `DPS ${st.dps}   •   RANGE ${st.range.toFixed(1)}`;
  if(type==='frost') return `DMG ${st.dmg}   •   SLOW ${Math.round(st.slow*100)}%   •   RANGE ${st.range.toFixed(1)}`;
  const s=`DMG ${st.dmg}   •   ${st.rate}/s   •   RANGE ${st.range.toFixed(1)}`;
  return type==='cannon'? s+`   •   SPLASH ${st.splash.toFixed(1)}` : s;
}
function drawTowerPanel(){
  const t=towerSel, def=TOWER_DEFS[t.type], st=towerStats(t);
  ctx.fillStyle='rgba(20,30,60,0.95)'; rr(8,SHOP_Y+6,W-16,108,10); ctx.fill();
  ctx.strokeStyle=def.color; ctx.lineWidth=2; rr(8,SHOP_Y+6,W-16,108,10); ctx.stroke();
  ctx.fillStyle='#fff'; ctx.font='bold 19px sans-serif';
  ctx.fillText(`${def.name}  —  Evolution ${EVO_ROMAN[t.evo]}`, 28, SHOP_Y+36);
  ctx.fillStyle='#9fb3ff'; ctx.font='14px sans-serif';
  ctx.fillText(statLine(t.type,st), 28, SHOP_Y+60);
  ctx.fillStyle='rgba(200,220,255,0.6)'; ctx.font='12px sans-serif';
  if(t.evo<3){
    const nx=def.evo[t.evo+1];
    ctx.fillText('Next ('+EVO_ROMAN[t.evo+1]+'): '+statLine(t.type,nx), 28, SHOP_Y+84);
  } else ctx.fillText('MAX evolution reached — a true monster.', 28, SHOP_Y+84);
  // evolve
  const e=UI.evolve;
  const canEvo=t.evo<3, cost=canEvo?def.evo[t.evo+1].cost:0, afford=gold>=cost;
  ctx.fillStyle=!canEvo?'rgba(90,90,110,0.5)':(afford?'rgba(60,220,120,0.25)':'rgba(120,60,60,0.25)');
  rr(e.x,e.y,e.w,e.h,10); ctx.fill();
  ctx.strokeStyle=!canEvo?'#666':(afford?'#4be08a':'#a05050'); ctx.lineWidth=2; rr(e.x,e.y,e.w,e.h,10); ctx.stroke();
  ctx.fillStyle=!canEvo?'#999':(afford?'#c9ffd9':'#ffb0b0');
  ctx.font='bold 16px sans-serif'; ctx.textAlign='center';
  ctx.fillText(canEvo?`⬆ EVOLVE $${cost}`:'MAX', e.x+e.w/2, e.y+29);
  // sell
  const sl=UI.sell, val=Math.floor(t.invested*0.7);
  ctx.fillStyle='rgba(255,180,80,0.18)'; rr(sl.x,sl.y,sl.w,sl.h,10); ctx.fill();
  ctx.strokeStyle='#ffb050'; ctx.lineWidth=2; rr(sl.x,sl.y,sl.w,sl.h,10); ctx.stroke();
  ctx.fillStyle='#ffe0b0'; ctx.fillText(`SELL +$${val}`, sl.x+sl.w/2, sl.y+29);
  // close
  const c=UI.pclose;
  ctx.fillStyle='rgba(120,140,180,0.15)'; rr(c.x,c.y,c.w,c.h,10); ctx.fill();
  ctx.strokeStyle='#8fa0c0'; ctx.lineWidth=2; rr(c.x,c.y,c.w,c.h,10); ctx.stroke();
  ctx.fillStyle='#dfe8ff'; ctx.fillText('✕', c.x+c.w/2, c.y+29);
  ctx.textAlign='left';
}
function drawMenu(){
  ctx.fillStyle='rgba(2,4,12,0.82)'; ctx.fillRect(0,0,W,H);
  ctx.textAlign='center';
  ctx.fillStyle='#38e1ff'; ctx.font='bold 58px sans-serif';
  ctx.fillText('TOWER DEFENSE', W/2, 150);
  ctx.fillStyle='#ffd166'; ctx.font='bold 30px sans-serif';
  ctx.fillText('100 WAVES', W/2, 195);
  ctx.fillStyle='#cfe0ff'; ctx.font='17px sans-serif';
  const lines=[
    'Enemies march from the portal (left) to your base (right).',
    'Tap a tower below, then tap the map to build it.',
    'Tap a placed tower to EVOLVE it (4 stages) or sell it.',
    'Kills earn gold. Leaked enemies cost ❤ — bosses cost 5.',
    'Every 10th wave: a BOSS. Survive all 100 waves to win.',
  ];
  lines.forEach((l,i)=>ctx.fillText(l, W/2, 260+i*30));
  ctx.fillStyle='#9fb3ff'; ctx.font='14px sans-serif';
  ctx.fillText('Keys: 1-5 build • Space start wave • F speed • P pause', W/2, 440);
  menuBtn(UI.menuStart,'▶  START NEW GAME','#4be08a');
  if(hasSave()) menuBtn(UI.menuContinue,'↻  CONTINUE — WAVE '+JSON.parse(localStorage.getItem(SAVE_KEY)).wave,'#38e1ff');
  ctx.textAlign='left';
}
function menuBtn(r,label,color){
  ctx.fillStyle='rgba(10,16,36,0.95)'; rr(r.x,r.y,r.w,r.h,12); ctx.fill();
  ctx.strokeStyle=color; ctx.lineWidth=3; rr(r.x,r.y,r.w,r.h,12); ctx.stroke();
  ctx.fillStyle=color; ctx.font='bold 21px sans-serif'; ctx.textAlign='center';
  ctx.fillText(label, r.x+r.w/2, r.y+37); ctx.textAlign='left';
}
function drawEnd(win){
  ctx.fillStyle='rgba(2,4,12,0.85)'; ctx.fillRect(0,0,W,H);
  ctx.textAlign='center';
  ctx.fillStyle=win?'#7CFC9A':'#ff5d5d'; ctx.font='bold 54px sans-serif';
  ctx.fillText(win?'🏆 VICTORY!':'💀 BASE OVERRUN', W/2, 220);
  ctx.fillStyle='#cfe0ff'; ctx.font='20px sans-serif';
  ctx.fillText(win?'You survived all 100 waves. Legendary commander.':
                   `You fell on wave ${Math.min(wave,100)}. The blobs send their regards.`, W/2, 280);
  ctx.fillStyle='#ffe27a'; ctx.font='bold 22px sans-serif';
  ctx.fillText(`SCORE ${fmt(score)}   •   TOWERS ${towers.length}`, W/2, 330);
  ctx.fillStyle='#9fb3ff'; ctx.font='16px sans-serif';
  ctx.fillText(win?'Your max-evolution army held the line. Play again?':'Evolve more, slow them down, try again.', W/2, 370);
  menuBtn(UI.again, win?'↻  PLAY AGAIN':'↻  TRY AGAIN', win?'#7CFC9A':'#ff8a8a');
  ctx.textAlign='left';
}

// ================= INPUT =================
function canvasPos(ev){
  const r=cv.getBoundingClientRect();
  const cx=(ev.touches&&ev.touches[0]?ev.touches[0].clientX:ev.clientX);
  const cy=(ev.touches&&ev.touches[0]?ev.touches[0].clientY:ev.clientY);
  return { x:(cx-r.left)*W/r.width, y:(cy-r.top)*H/r.height };
}
cv.addEventListener('pointerdown', ev=>{
  ev.preventDefault();
  try{ AC=AC||new (window.AudioContext||window.webkitAudioContext)(); if(AC.state==='suspended')AC.resume(); }catch(e){}
  const p=canvasPos(ev);
  handleTap(p.x,p.y);
});
cv.addEventListener('pointermove', ev=>{
  const p=canvasPos(ev);
  if(p.y>=GRID_Y&&p.y<GRID_Y+GRID_H)
    hoverCell={gx:Math.floor(p.x/CELL),gy:Math.floor((p.y-GRID_Y)/CELL)};
  else hoverCell=null;
});
cv.addEventListener('contextmenu', ev=>ev.preventDefault());
function handleTap(x,y){
  if(state==='menu'){
    if(inRect(x,y,UI.menuStart)){ newGame(); return; }
    if(hasSave()&&inRect(x,y,UI.menuContinue)){ if(loadGame()){ state='play'; } return; }
    return;
  }
  if(state==='victory'||state==='defeat'){
    if(inRect(x,y,UI.again)){ state='menu'; }
    return;
  }
  // HUD
  if(inRect(x,y,UI.mute)){ muted=!muted; return; }
  if(inRect(x,y,UI.restart)){ saveGame(); state='menu'; return; }
  // bottom area
  if(y>=SHOP_Y){
    if(towerSel){
      if(inRect(x,y,UI.evolve)){ tryEvolve(); return; }
      if(inRect(x,y,UI.sell)){ trySell(); return; }
      if(inRect(x,y,UI.pclose)){ towerSel=null; return; }
      return;
    }
    for(const c of UI.cards){
      if(inRect(x,y,c)){ shopSel=(shopSel===c.type?null:c.type); towerSel=null; sfx('coin'); return; }
    }
    if(inRect(x,y,UI.start)){ startWave(); return; }
    if(inRect(x,y,UI.speed)){ speed=speed>=3?1:speed+1; return; }
    if(inRect(x,y,UI.pause)){ paused=!paused; return; }
    return;
  }
  // grid
  if(y>=GRID_Y&&y<GRID_Y+GRID_H){
    const gx=Math.floor(x/CELL), gy=Math.floor((y-GRID_Y)/CELL);
    if(shopSel){ tryPlace(gx,gy); return; }
    const t=towerAt(gx,gy);
    towerSel=t||null;
    if(t) sfx('coin');
  } else { shopSel=null; towerSel=null; }
}
window.addEventListener('keydown', ev=>{
  if(state!=='play') return;
  const k=ev.key.toLowerCase();
  const idx=['1','2','3','4','5'].indexOf(k);
  if(idx>=0){ shopSel=(shopSel===SHOP_ORDER[idx]?null:SHOP_ORDER[idx]); towerSel=null; }
  else if(k==='escape'){ shopSel=null; towerSel=null; }
  else if(k===' '){ ev.preventDefault(); startWave(); }
  else if(k==='f'){ speed=speed>=3?1:speed+1; }
  else if(k==='p'){ paused=!paused; }
  else if(k==='m'){ muted=!muted; }
});
window.addEventListener('pagehide', saveGame);

// ================= MAIN LOOP =================
let lastT=performance.now();
function loop(now){
  const dt=(now-lastT)/1000; lastT=now;
  update(dt);
  render();
  requestAnimationFrame(loop);
}
render();
requestAnimationFrame(loop);