/**
 * Reads the gym page DOM and returns:
 *   { attr: 'strength'|'speed'|..., current: number, gym: string }
 * or `null` if the page doesn't look like a Torn gym page.
 *
 * Torn's gym page is a React app using CSS modules with hash suffixes
 * (e.g. class="strength___iXqEf", class="propertyValue___IYxjf"). This
 * scraper targets Torn's actual structure rather than guessing at selectors.
 */
const KNOWN_ATTRS = ['strength', 'defense', 'speed', 'dexterity', 'endurance', 'intelligence'];

export function currentAttribute() {
  const li = findActiveAttributeLi();
  if (!li) return null;
  const attr = extractAttrFromLi(li);
  if (!attr) return null;
  const current = extractValueFromLi(li);
  if (current == null) return null;
  const gym = findGymName() || 'Unknown gym';
  return { attr, current, gym };
}

function findActiveAttributeLi() {
  // Priority 1: the <li> with the "success" class (just trained).
  const lis = document.querySelectorAll('ul[class*="properties"] > li[class*="success"]');
  for (const li of lis) {
    if (extractAttrFromLi(li)) return li;
  }
  // Priority 2: the <li> corresponding to the .gained message's attribute.
  const gained = document.querySelector('[class*="gained"]');
  if (gained) {
    const text = (gained.textContent || '').toLowerCase();
    for (const attr of KNOWN_ATTRS) {
      if (text.includes(attr)) {
        const li = document.querySelector('ul[class*="properties"] > li[class^="' + attr + '___"]');
        if (li) return li;
      }
    }
  }
  // Priority 3: the first <li> in the properties list.
  const all = document.querySelectorAll('ul[class*="properties"] > li');
  for (const li of all) {
    if (extractAttrFromLi(li)) return li;
  }
  return null;
}

function extractAttrFromLi(li) {
  const cls = li.className || '';
  for (const attr of KNOWN_ATTRS) {
    if (cls.split(/\s+/).some((c) => c.startsWith(attr + '___'))) return attr;
  }
  return null;
}

function extractValueFromLi(li) {
  const valueSpan = li.querySelector('[class^="propertyValue"]');
  if (!valueSpan) return null;
  return parseNumber(valueSpan.textContent);
}

function findGymName() {
  // Find the currently selected gym button. It has the "active" class.
  const activeBtn = document.querySelector('button[class*="gymButton"][class*="active"]');
  if (activeBtn) {
    const label = activeBtn.getAttribute('aria-label') || '';
    // aria-label format: "<Gym Name>. Membership cost - $X. Energy usage - N per train."
    // The gym name is everything before the first ". ".
    const dot = label.indexOf('. ');
    if (dot !== -1) return label.slice(0, dot);
    return label; // no period, return whole label as fallback
  }
  return null;
}

function parseNumber(text) {
  if (!text) return null;
  const cleaned = text.replace(/,/g, '').trim();
  if (!/^\d+(\.\d+)?$/.test(cleaned)) return null;
  const n = parseFloat(cleaned);
  return Number.isFinite(n) ? Math.floor(n) : null;
}