/* widgets: Rekenen (+ - x : %) */
/* =========================================================
   Math practice engine — add / sub / mul / div / percentages
==========================================================*/
function mountMath(root, initState, mode, opts){
  const ROUND = 10;
  const onProgress = opts && opts.onProgress;
  const S = { level:1, snd:true, amode:"blocks", q:null, tries:0, done:0, good:0, input:"", busy:false };
  if(initState){
    S.level = initState.level||1;
    S.snd = initState.snd!==false;
    S.amode = initState.amode||"blocks";
  }
  const play = f=>{ if(S.snd) f(); };
  const rnd = n => Math.floor(Math.random()*n);

  root.innerHTML = `
    <div class="mt blocks">
      <div class="mt-top">
        <button class="lg-snd"></button>
        <button class="lg-mode"></button>
        <div class="lg-levels">
          <button data-l="1"></button><button data-l="2"></button><button data-l="3"></button>
        </div>
        <div class="mt-score"></div>
      </div>
      <div class="mt-card">
        <div class="mt-q"></div>
        <div class="mt-a"></div>
        <div class="mt-slots"></div>
        <div class="mt-fb"></div>
        <div class="mt-done">
          <div class="dg">🌟</div><div class="dt"></div><div class="ds"></div>
          <button class="mt-again"></button>
        </div>
      </div>
      <div class="lg-tray mt-tray"></div>
      <div class="mt-pad"></div>
    </div>`;

  const el = s => root.querySelector(s);
  const mtEl = el(".mt"), qEl = el(".mt-q"), aEl = el(".mt-a"), fbEl = el(".mt-fb"),
        scoreEl = el(".mt-score"), doneEl = el(".mt-done"),
        sndBtn = el(".lg-snd"), modeBtn = el(".lg-mode"),
        padEl = el(".mt-pad"), slotsEl = el(".mt-slots"), trayEl = el(".mt-tray");

  /* ---- digit blocks with dot patterns (like the letter blocks) ---- */
  function makeDigitBlock(d){
    const b = document.createElement("div");
    b.className = "blok sm";
    b.dataset.digit = d;
    b.innerHTML = `<div class="bl">${d}</div>`;
    const dg = dotGrid(d); dg.classList.add("blok-dots");
    b.appendChild(dg);
    attachDigitDrag(b);
    return b;
  }
  "0123456789".split("").forEach(d=>trayEl.appendChild(makeDigitBlock(d)));

  function makeDigitSlot(d){
    const s = document.createElement("div");
    s.className = "slot sm";
    s.dataset.digit = d;
    s.innerHTML = `<div class="ghost"></div>`;
    const dg = dotGrid(d); dg.classList.add("slot-dots");
    s.appendChild(dg);
    s.addEventListener("click", ()=>{
      const placed = s.querySelector(".blok");
      if(placed && Date.now() - (+placed.dataset.placedAt||0) > 400){
        placed.remove();
        s.classList.remove("filled");
      }
    });
    return s;
  }
  function attachDigitDrag(block){
    block.addEventListener("pointerdown", e=>{
      if(e.pointerType==="mouse" && e.button!==0) return;
      if(S.busy || doneEl.classList.contains("show")) return;
      e.preventDefault();
      try{ block.releasePointerCapture(e.pointerId); }catch(_){}
      const clone = block.cloneNode(true);
      clone.id = "dragClone";
      document.body.appendChild(clone);
      const moveTo = ev=>{ const zf = VZ(); clone.style.left = (ev.clientX/zf)+"px"; clone.style.top = (ev.clientY/zf)+"px"; };
      moveTo(e);
      let hovered = null;
      const hit = ev=>{
        const pad = 8;
        let found = null;
        slotsEl.querySelectorAll(".slot:not(.filled)").forEach(s=>{
          const r = s.getBoundingClientRect();
          if(ev.clientX>=r.left-pad && ev.clientX<=r.right+pad &&
             ev.clientY>=r.top-pad && ev.clientY<=r.bottom+pad) found = s;
        });
        return found;
      };
      const move = ev=>{
        moveTo(ev);
        const s = hit(ev);
        if(hovered && hovered!==s) hovered.classList.remove("droptarget");
        hovered = s;
        if(hovered) hovered.classList.add("droptarget");
      };
      const up = ev=>{
        document.removeEventListener("pointermove",move);
        document.removeEventListener("pointerup",up);
        document.removeEventListener("pointercancel",cancel);
        clone.remove();
        if(hovered) hovered.classList.remove("droptarget");
        const target = hit(ev);
        if(target){
          if(target.dataset.digit === block.dataset.digit){
            const copy = block.cloneNode(true);
            copy.classList.add("in-slot");
            copy.dataset.placedAt = Date.now();
            target.appendChild(copy);
            target.classList.add("filled");
            play(sndGood);
            if(!slotsEl.querySelector(".slot:not(.filled)")) blocksSolved();
          }else{
            target.classList.add("shake");
            setTimeout(()=>target.classList.remove("shake"), 400);
            play(sndBad);
          }
        }
      };
      const cancel = ()=>{
        document.removeEventListener("pointermove",move);
        document.removeEventListener("pointerup",up);
        document.removeEventListener("pointercancel",cancel);
        clone.remove();
        if(hovered) hovered.classList.remove("droptarget");
      };
      document.addEventListener("pointermove",move);
      document.addEventListener("pointerup",up);
      document.addEventListener("pointercancel",cancel);
    });
  }
  function blocksSolved(){
    S.busy = true;
    S.good++;
    fbEl.textContent = T("mGood");
    play(sndWin);
    confetti(el(".mt-card"));
    setTimeout(next, 1000);
  }

  function gen(){
    const L = S.level;
    let a, b, ans, txt;
    if(mode==="add"){
      const max = L===1 ? 10 : L===2 ? 20 : 100;
      a = rnd(max+1); b = rnd(max-a+1); ans = a+b;
      txt = `${a} + ${b} =`;
    }else if(mode==="sub"){
      const max = L===1 ? 10 : L===2 ? 20 : 100;
      a = rnd(max+1); b = rnd(a+1); ans = a-b;
      txt = `${a} − ${b} =`;
    }else if(mode==="mul"){
      const tmax = L===1 ? 5 : L===2 ? 10 : 12;
      a = 1+rnd(tmax); b = 1+rnd(L===3 ? 12 : 10); ans = a*b;
      txt = `${a} × ${b} =`;
    }else if(mode==="div"){
      const tmax = L===1 ? 5 : L===2 ? 10 : 12;
      const t = 1+rnd(tmax), q = 1+rnd(L===3 ? 12 : 10);
      a = t*q; ans = q;
      txt = `${a} ${S.lang==="nl" || LANG==="nl" ? ":" : "÷"} ${t} =`;
    }else{ /* pct */
      const sets = L===1 ? [10,50,100] : L===2 ? [10,20,25,50,75,100] : [5,10,20,25,30,40,50,60,70,75,80,90];
      const p = sets[rnd(sets.length)];
      const step = {5:20,10:10,20:5,25:4,30:10,40:5,50:2,60:5,70:10,75:4,80:5,90:10,100:1}[p];
      const base = step*(1+rnd(12));
      ans = p*base/100;
      txt = `${p}% ${T("mOf")} ${base} =`;
    }
    return { txt, ans };
  }

  function newQuestion(){
    let q = gen();
    if(S.q && q.txt===S.q.txt) q = gen();  /* avoid the same sum twice in a row */
    S.q = q; S.tries = 0; S.input = ""; S.busy = false;
    qEl.textContent = q.txt;
    aEl.textContent = "";
    aEl.classList.remove("ok");
    fbEl.textContent = ""; fbEl.classList.remove("ans");
    slotsEl.innerHTML = "";
    if(S.amode==="blocks"){
      String(q.ans).split("").forEach(d=>slotsEl.appendChild(makeDigitSlot(d)));
    }
    updateScore();
  }
  function updateScore(){
    scoreEl.textContent = `${S.good} ${T("mGoed")} · ${Math.min(S.done+1,ROUND)}/${ROUND}`;
  }
  function endRound(){
    doneEl.querySelector(".dt").textContent = T("mDoneT");
    doneEl.querySelector(".ds").textContent = `${S.good}/${ROUND} ${T("mGoed")}`;
    doneEl.querySelector(".dg").textContent = S.good>=8 ? "🌟" : S.good>=5 ? "👍" : "💪";
    doneEl.classList.add("show");
    if(S.good>=8) play(sndWin);
    if(onProgress) onProgress({ attempts: ROUND, correct: S.good, stars: 0 });
  }
  function next(){
    S.done++;
    if(S.done >= ROUND){ endRound(); }
    else newQuestion();
  }
  function check(){
    if(S.busy || S.input==="") return;
    if(+S.input === S.q.ans){
      S.busy = true;
      S.good++;
      aEl.classList.add("ok");
      fbEl.textContent = T("mGood");
      play(sndGood);
      confetti(el(".mt-card"));
      setTimeout(next, 900);
    }else{
      S.tries++;
      aEl.classList.add("shake");
      setTimeout(()=>aEl.classList.remove("shake"), 400);
      play(sndBad);
      S.input = ""; aEl.textContent = "";
      if(S.tries >= 3){
        S.busy = true;
        fbEl.textContent = `${T("mAnsWas")} ${S.q.ans}`;
        fbEl.classList.add("ans");
        setTimeout(next, 1800);
      }
    }
  }

  ["7","8","9","⌫","4","5","6","0","1","2","3","✓"].forEach(k=>{
    const b = document.createElement("button");
    b.textContent = k;
    if(k==="✓") b.className = "ok";
    b.addEventListener("click", ()=>{
      if(doneEl.classList.contains("show")) return;
      if(k==="⌫"){ if(!S.busy){ S.input = S.input.slice(0,-1); aEl.textContent = S.input; } }
      else if(k==="✓") check();
      else if(!S.busy && S.input.length<4){ S.input += k; aEl.textContent = S.input; }
    });
    padEl.appendChild(b);
  });

  el(".mt-again").addEventListener("click", ()=>{
    S.done = 0; S.good = 0;
    doneEl.classList.remove("show");
    newQuestion();
  });
  root.querySelectorAll(".lg-levels button").forEach(b=>{
    b.addEventListener("click", ()=>{
      S.level = +b.dataset.l;
      S.done = 0; S.good = 0;
      doneEl.classList.remove("show");
      labels(); newQuestion();
    });
  });
  sndBtn.addEventListener("click", ()=>{
    S.snd = !S.snd;
    sndBtn.textContent = S.snd ? "🔔" : "🔕";
    sndBtn.classList.toggle("off", !S.snd);
  });
  modeBtn.addEventListener("click", ()=>{
    S.amode = S.amode==="blocks" ? "type" : "blocks";
    labels(); newQuestion();
  });

  function labels(){
    root.querySelectorAll(".lg-levels button").forEach(b=>{
      b.textContent = T("lvl"+b.dataset.l);
      b.classList.toggle("active", +b.dataset.l===S.level);
    });
    sndBtn.textContent = S.snd ? "🔔" : "🔕";
    sndBtn.classList.toggle("off", !S.snd);
    sndBtn.title = T("sndWidget");
    modeBtn.textContent = S.amode==="blocks" ? "🧱" : "⌨️";
    modeBtn.title = T("amode");
    mtEl.classList.toggle("blocks", S.amode==="blocks");
    el(".mt-again").textContent = T("mAgain");
    updateScore();
  }
  document.addEventListener("langchange", ()=>{ labels(); newQuestion(); });

  labels();
  newQuestion();
  return {
    getState: ()=>({ level:S.level, snd:S.snd, amode:S.amode }),
    setState: st=>{ if(st){ S.level=st.level||1; S.snd=st.snd!==false; S.amode=st.amode||"blocks"; labels(); newQuestion(); } }
  };
}