(function () {
  "use strict";

  function getCellText(row, index) {
    var cell = row.children[index];
    return cell ? cell.textContent.trim() : "";
  }

  function isEmptyValue(text) {
    return text === "" || text === "—";
  }

  function isPureNumber(text) {
    return /^-?\d+(\.\d+)?$/.test(text);
  }

  function columnIsNumeric(rows, index) {
    var sawValue = false;
    for (var i = 0; i < rows.length; i++) {
      var text = getCellText(rows[i], index);
      if (isEmptyValue(text)) continue;
      sawValue = true;
      if (!isPureNumber(text)) return false;
    }
    return sawValue;
  }

  function compareRows(a, b, index, numeric, dir) {
    var textA = getCellText(a, index);
    var textB = getCellText(b, index);
    var emptyA = isEmptyValue(textA);
    var emptyB = isEmptyValue(textB);
    if (emptyA && emptyB) return 0;
    if (emptyA) return 1;
    if (emptyB) return -1;

    var result = numeric
      ? parseFloat(textA) - parseFloat(textB)
      : textA.localeCompare(textB, undefined, { numeric: true, sensitivity: "base" });
    return dir === "desc" ? -result : result;
  }

  function sortTable(table, th) {
    var thead = table.tHead;
    var tbody = table.tBodies[0];
    if (!thead || !tbody) return;

    var headerRow = thead.rows[0];
    var index = Array.prototype.indexOf.call(headerRow.children, th);
    if (index === -1) return;

    var rows = Array.prototype.slice.call(tbody.rows);
    if (rows.length < 2) return;

    var nextDir = th.getAttribute("data-sort-dir") === "asc" ? "desc" : "asc";
    Array.prototype.forEach.call(headerRow.children, function (cell) {
      cell.removeAttribute("data-sort-dir");
      cell.removeAttribute("aria-sort");
    });
    th.setAttribute("data-sort-dir", nextDir);
    th.setAttribute("aria-sort", nextDir === "asc" ? "ascending" : "descending");

    var numeric = columnIsNumeric(rows, index);
    rows.sort(function (a, b) {
      return compareRows(a, b, index, numeric, nextDir);
    });
    rows.forEach(function (row) {
      tbody.appendChild(row);
    });
  }

  document.addEventListener("click", function (event) {
    var th = event.target.closest("table.sortable thead th");
    if (!th || th.hasAttribute("data-sort-off") || th.textContent.trim() === "") return;
    sortTable(th.closest("table"), th);
  });
})();