/* widget: Ankerwoorden */
/* =========================================================
   Anchor words — unlimited word grid around a theme
==========================================================*/
function mountAnchor(root, initState){
  const CW = 128, CH = 56, G = 10;
  /* colour cycle for connecting words: none → green → blue → red → purple → orange → yellow */
  const COLS = [null,"#3fae6a","#3b7dd8","#e0554d","#9b59b6","#f28c38","#d9a400"];
  const S = { cells:{}, pan:{x:0, y:0}, pics:{} };
  if(initState){
    const src = initState.cells || {};
    Object.keys(src).forEach(k=>{
      const v = src[k];
      /* migrate: old format stored plain strings */
      S.cells[k] = (typeof v==="string") ? {t:v, c:null} : {t:v.t||"", c:v.c||null};
    });
    S.pan = initState.pan || {x:0, y:0};
    S.pics = initState.pics || {};   /* word -> auto-fetched pictogram (or fallback emoji) */
  }
  const FALLBACK_PIC = "⚓";
  const fetching = new Set();
  /* auto-fetch a matching picture per word instead of using the anchor emoji for everything */
  function fetchPic(word){
    if(S.pics[word] !== undefined || fetching.has(word)) return;
    fetching.add(word);
    arasaacSearch(word, LANG).then(arr=>{
      S.pics[word] = (arr && arr.length) ? arasaacUrl(arr[0]._id) : FALLBACK_PIC;
    }).catch(()=>{
      S.pics[word] = FALLBACK_PIC;
    }).finally(()=>{
      fetching.delete(word);
      syncSource();
    });
  }
  root.innerHTML = `
    <div class="an">
      <div class="an-hint"></div>
      <div class="an-stage"><div class="an-layer"></div></div>
    </div>`;
  const stage = root.querySelector(".an-stage"),
        layer = root.querySelector(".an-layer"),
        hint = root.querySelector(".an-hint");
  const key = (x,y)=>x+","+y;

  /* register this grid as a word source for the language widgets */
  const reg = { el: root, name: T("wg_anchor"), words: [] };
  ANCHORS.push(reg);
  function syncSource(quiet){
    const center = S.cells["0,0"];
    reg.name = (center && center.t) ? center.t : T("wg_anchor");
    const seen = new Set();
    reg.words = [];
    Object.keys(S.cells).forEach(k=>{
      const w = (S.cells[k].t||"").trim().toLowerCase();
      if(/^[a-zà-ÿ]{2,12}$/.test(w) && !seen.has(w)){
        seen.add(w);
        if(S.pics[w] === undefined) fetchPic(w);
        reg.words.push([w, S.pics[w] || FALLBACK_PIC]);
      }
    });
    if(!quiet) document.dispatchEvent(new CustomEvent("wordschange"));
  }

  function applyPan(){ layer.style.transform = `translate(${-S.pan.x}px,${-S.pan.y}px)`; }
  function render(){
    layer.innerHTML = "";
    const w = stage.offsetWidth, h = stage.offsetHeight;
    if(w < 2) return;
    const cx = w/2, cy = h/2;
    const x0 = Math.floor((S.pan.x - cx - CW)/(CW+G)), x1 = Math.ceil((S.pan.x + w - cx + CW)/(CW+G));
    const y0 = Math.floor((S.pan.y - cy - CH)/(CH+G)), y1 = Math.ceil((S.pan.y + h - cy + CH)/(CH+G));
    for(let gx=x0; gx<=x1; gx++){
      for(let gy=y0; gy<=y1; gy++){
        const c = document.createElement("div");
        const cell = S.cells[key(gx,gy)];
        const word = cell && cell.t;
        const isRoot = gx===0 && gy===0;
        c.className = "an-cell" + (word ? " filled" : "") + (isRoot ? " root" : "");
        c.style.left = (cx + gx*(CW+G) - CW/2)+"px";
        c.style.top = (cy + gy*(CH+G) - CH/2)+"px";
        if(word){
          const span = document.createElement("span");
          span.className = "an-word";
          span.textContent = word;
          c.appendChild(span);
          /* only the theme word is styled by default; other words are plain
             until the teacher gives them a colour to show a connection */
          if(!isRoot){
            if(cell.c){
              c.style.borderColor = cell.c;
              c.style.background = cell.c + "1c";
            }
            const dot = document.createElement("button");
            dot.className = "an-dot";
            dot.style.background = cell.c || "#cdd7e4";
            dot.title = T("anchorColor");
            dot.addEventListener("pointerdown", ev=>ev.stopPropagation());
            dot.addEventListener("click", ev=>{
              ev.stopPropagation();
              cell.c = COLS[(COLS.indexOf(cell.c)+1) % COLS.length];
              render();
            });
            c.appendChild(dot);
          }
        }
        c.dataset.gx = gx; c.dataset.gy = gy;
        layer.appendChild(c);
      }
    }
    applyPan();
    hint.textContent = T("anchorHint");
  }
  /* pan by dragging, click (without moving) to type */
  let pd = null;
  stage.addEventListener("pointerdown", e=>{
    if(e.target.tagName==="INPUT") return;
    if(e.pointerType==="mouse" && e.button!==0) return;
    e.preventDefault();
    stage.setPointerCapture(e.pointerId);
    const sc = stage.getBoundingClientRect().width / stage.offsetWidth;
    pd = { x:e.clientX/sc, y:e.clientY/sc, px:S.pan.x, py:S.pan.y,
           moved:false, target:e.target.closest(".an-cell"), sc };
  });
  stage.addEventListener("pointermove", e=>{
    if(!pd) return;
    const dx = e.clientX/pd.sc - pd.x, dy = e.clientY/pd.sc - pd.y;
    if(Math.abs(dx) > 6 || Math.abs(dy) > 6) pd.moved = true;
    if(pd.moved){ S.pan.x = pd.px - dx; S.pan.y = pd.py - dy; applyPan(); }
  });
  stage.addEventListener("pointerup", ()=>{
    if(!pd) return;
    const {moved, target} = pd;
    pd = null;
    if(moved){ render(); return; }
    if(target) editCell(target);
  });
  stage.addEventListener("pointercancel", ()=>{
    const moved = pd && pd.moved;
    pd = null;
    if(moved) render();
  });
  function editCell(cell){
    if(cell.querySelector("input")) return;
    const gx = +cell.dataset.gx, gy = +cell.dataset.gy, k = key(gx,gy);
    const inp = document.createElement("input");
    inp.maxLength = 24;
    inp.value = S.cells[k] ? S.cells[k].t : "";
    if(gx===0 && gy===0) inp.placeholder = T("anchorPh");
    cell.textContent = "";
    cell.appendChild(inp);
    setTimeout(()=>{ inp.focus(); inp.select(); }, 0);
    let done = false;
    const commit = ()=>{
      if(done) return; done = true;
      const v = inp.value.trim();
      if(v) S.cells[k] = { t:v, c:(S.cells[k] && S.cells[k].c) || null };
      else delete S.cells[k];
      syncSource();
      render();
      persistWords();
    };
    inp.addEventListener("keydown", ev=>{
      ev.stopPropagation();
      if(ev.key==="Enter") commit();
      if(ev.key==="Escape"){ done = true; render(); }
    });
    inp.addEventListener("blur", commit);
    inp.addEventListener("pointerdown", ev=>ev.stopPropagation());
  }
  new ResizeObserver(render).observe(stage);
  document.addEventListener("langchange", render);
  syncSource(true);
  render();
  if(reg.words.length) document.dispatchEvent(new CustomEvent("wordschange"));
  return { getState: ()=>({ cells:S.cells, pan:S.pan, pics:S.pics }) };
}