export const $ = (sel, root = document) => root.querySelector(sel);
export const $$ = (sel, root = document) =>
  Array.from(root.querySelectorAll(sel));

export function el(tag, attrs = {}, children = []) {
  const node = document.createElement(tag);
  Object.entries(attrs).forEach(([k, v]) => {
    if (k === "class") node.className = v;
    else if (k.startsWith("on") && typeof v === "function")
      node.addEventListener(k.slice(2), v);
    else if (v !== undefined && v !== null) node.setAttribute(k, v);
  });
  for (const ch of Array.isArray(children) ? children : [children]) {
    if (typeof ch === "string") node.appendChild(document.createTextNode(ch));
    else if (ch) node.appendChild(ch);
  }
  return node;
}

export function formToJSON(form) {
  const data = {};
  const coerceNumberIfNeeded = (key, value) => {
    const field = form.elements.namedItem(key);
    let isNumber = false;
    let integerOnly = false;

    const inspect = (el) => {
      if (!el) return;
      if (el.getAttribute && el.getAttribute("data-type") === "number") {
        isNumber = true;
      }
      if (el.getAttribute && el.getAttribute("data-integer") === "true") {
        isNumber = true;
        integerOnly = true;
      }
      if (el.tagName === "INPUT") {
        const type = (el.type || "").toLowerCase();
        if (type === "number") {
          isNumber = true;
          const step = el.step;
          if (
            step &&
            (step === "1" || (!step.includes(".") && step !== "any"))
          ) {
            integerOnly = true;
          }
        }
      }
    };

    if (
      field &&
      typeof RadioNodeList !== "undefined" &&
      field instanceof RadioNodeList
    ) {
      inspect(field[0]);
    } else {
      inspect(field);
    }

    if (isNumber) {
      if (value === "" || value === null) return null;
      const n = Number(value);
      if (Number.isNaN(n)) return null;
      return integerOnly ? Math.trunc(n) : n;
    }
    return value;
  };

  new FormData(form).forEach((v, k) => {
    const val = coerceNumberIfNeeded(k, v);
    if (data[k] !== undefined) {
      if (!Array.isArray(data[k])) data[k] = [data[k]];
      data[k].push(val);
    } else data[k] = val;
  });
  return data;
}

export function saveSession(session) {
  localStorage.setItem("srab.session", JSON.stringify(session));
}
export function loadSession() {
  try {
    return JSON.parse(localStorage.getItem("srab.session")) || null;
  } catch {
    return null;
  }
}
export function clearSession() {
  localStorage.removeItem("srab.session");
}

export function setTopUser(text) {
  $("#top-user").textContent = text || "";
}
export function setLogoutVisible(vis) {
  $("#btn-logout").hidden = !vis;
}

export function setAvg(text) {
  const n = $("#top-avg");
  n.textContent = text || "";
  n.className = "avg badge ok";
}

export function fmtDateInput(d = new Date()) {
  const yyyy = d.getFullYear();
  const mm = String(d.getMonth() + 1).padStart(2, "0");
  const dd = String(d.getDate()).padStart(2, "0");
  return `${yyyy}-${mm}-${dd}`;
}