/** Tiny DOM helpers (no framework). */

/**
 * el("button.cls#id", {onclick, ...attrs}, [children|string])
 * Tag is optional (defaults to div); `.class` and `#id` tokens may appear in
 * any order and any count after it (e.g. "section.view#view-compose").
 */
export function el(spec, attrs = {}, children = []) {
    const tagMatch = spec.match(/^[a-z][a-z0-9]*/i);
    const tag = tagMatch ? tagMatch[0] : "div";
    const node = document.createElement(tag);
    const rest = spec.slice(tagMatch ? tagMatch[0].length : 0);
    const idMatch = rest.match(/#([\w-]+)/);
    if (idMatch) node.id = idMatch[1];
    const classes = [...rest.matchAll(/\.([\w-]+)/g)].map((x) => x[1]);
    if (classes.length) node.className = classes.join(" ");
    for (const [k, v] of Object.entries(attrs)) {
        if (v == null || v === false) continue;
        if (k.startsWith("on") && typeof v === "function") {
            node.addEventListener(k.slice(2).toLowerCase(), v);
        } else if (k === "class") {
            node.className = node.className ? `${node.className} ${v}` : v;
        } else if (k === "html") {
            node.innerHTML = v;
        } else if (k in node && k !== "list") {
            try { node[k] = v; } catch { node.setAttribute(k, v); }
        } else {
            node.setAttribute(k, v);
        }
    }
    const kids = Array.isArray(children) ? children : [children];
    for (const c of kids) {
        if (c == null || c === false) continue;
        node.append(c.nodeType ? c : document.createTextNode(String(c)));
    }
    return node;
}

export function clear(node) {
    while (node.firstChild) node.removeChild(node.firstChild);
    return node;
}

/** Render a morse pattern string ('.-') as styled dot/dash chips. */
export function morsePattern(pattern) {
    const wrap = el("span.pattern");
    for (const ch of pattern) {
        wrap.append(el(`span.${ch === "." ? "dot" : "dash"}`));
    }
    return wrap;
}