content.js

// Regex for time + timezone patterns
const timeRegex = /(\d{1,2}:\d{2}|\d{1,2}\s*([ap]m?\.?)?)\s+[\(\[]?(UTC|GMT|PST|PDT|EST|EDT|ET|CST|CDT|CT|MST|MDT|MT|PT|CET|CEST|JST|IST)[\)\]]?/gi;

// Track processed nodes
const processedNodes = new WeakSet();

// Timezone offset mappings
const timezoneMap = {
  'PST': -8, 'PDT': -7, 'PT': -8,
  'EST': -5, 'EDT': -4, 'ET': -5,
  'CST': -6, 'CDT': -5, 'CT': -6,
  'MST': -7, 'MDT': -6, 'MT': -7,
  'CET': 1, 'CEST': 2, 'JST': 9, 'IST': 5.5
};

// Convert timezone string to local time
function convertToLocalTime(match) {
  try {
    // Try direct parsing first
    let date = new Date(Date.parse(match));
    if (!isNaN(date)) {
      return date.toLocaleString(undefined, { timeZoneName: "short" });
    }

    // Manual parsing
    const cleanMatch = match.trim().toUpperCase();
    let timeStr, timezoneAbbr;
    
    // Extract time and timezone
    const cleanedMatch = cleanMatch.replace(/[\(\)\[\]]/g, '');
    const parts = cleanedMatch.split(/\s+/);
    
    if (parts.length >= 2) {
      timeStr = parts[0];
      timezoneAbbr = parts[parts.length - 1];
      
      // Normalize time format
      if (timeStr.includes(':')) {
        timeStr = timeStr.replace(/(\d{1,2}:\d{2})\s*([ap]m?\.?)?/i, (match, time, ampm) => {
          if (ampm) {
            const normalized = ampm.toLowerCase().replace(/\./g, '').replace(/^([ap])m?$/, '$1m').toUpperCase();
            return `${time} ${normalized}`;
          }
          return time;
        });
      } else {
        timeStr = timeStr.replace(/(\d{1,2})\s*([ap]m?\.?)?/i, (match, hour, ampm) => {
          if (ampm) {
            const normalized = ampm.toLowerCase().replace(/\./g, '').replace(/^([ap])m?$/, '$1m').toUpperCase();
            return `${hour}:00 ${normalized}`;
          }
          return `${hour}:00`;
        });
      }
      
      // Convert timezone to local time
      if (timezoneAbbr === 'UTC' || timezoneAbbr === 'GMT') {
        const now = new Date();
        const timeOnly = new Date(`${now.toDateString()} ${timeStr}`);
        if (!isNaN(timeOnly)) {
          const utcTime = new Date(timeOnly.getTime() - timeOnly.getTimezoneOffset() * 60000);
          return utcTime.toLocaleString(undefined, { timeZoneName: "short" });
        }
      }
      
      if (timezoneMap[timezoneAbbr]) {
        const offsetHours = timezoneMap[timezoneAbbr];
        const now = new Date();
        const timeOnly = new Date(`${now.toDateString()} ${timeStr}`);
        if (!isNaN(timeOnly)) {
          const utcTime = new Date(timeOnly.getTime() - (offsetHours * 60 * 60 * 1000) - (timeOnly.getTimezoneOffset() * 60000));
          return utcTime.toLocaleString(undefined, { timeZoneName: "short" });
        }
      }
    }

    return null;
  } catch {
    return null;
  }
}

// Process text nodes
function processTextNode(node) {
  const parent = node.parentNode;
  if (!parent || processedNodes.has(node)) return;

  const text = node.textContent;
  const matches = text.match(timeRegex);
  if (!matches) return;

  let lastIndex = 0;
  const fragment = document.createDocumentFragment();

  matches.forEach(match => {
    const index = text.indexOf(match, lastIndex);
    if (index > lastIndex) {
      fragment.appendChild(document.createTextNode(text.slice(lastIndex, index)));
    }

    const local = convertToLocalTime(match);
    if (local) {
      const span = document.createElement("span");
      span.textContent = match;
      // Show time only, no date
      const timeOnly = local.split(',')[1]?.trim() || local.split(' ').slice(-3).join(' ');
      span.title = timeOnly;
      span.style.borderBottom = "1px dotted gray";
      fragment.appendChild(span);
    } else {
      fragment.appendChild(document.createTextNode(match));
    }

    lastIndex = index + match.length;
  });

  if (lastIndex < text.length) {
    fragment.appendChild(document.createTextNode(text.slice(lastIndex)));
  }

  parent.replaceChild(fragment, node);
  processedNodes.add(node);
}

// DOM walker
function walk(node) {
  if (node.nodeType === Node.TEXT_NODE) {
    processTextNode(node);
  } else if (node.nodeType === Node.ELEMENT_NODE &&
             !["SCRIPT","STYLE","TEXTAREA","IFRAME","INPUT","SELECT","CODE","PRE"].includes(node.tagName)) {
    Array.from(node.childNodes).forEach(walk);
  }
}

// Initial scan
window.addEventListener("load", () => walk(document.body));

// Watch for dynamic content
let observerTimeout;
const observer = new MutationObserver(mutations => {
  clearTimeout(observerTimeout);
  observerTimeout = setTimeout(() => {
    mutations.forEach(m => {
      m.addedNodes.forEach(node => {
        if (node.nodeType === Node.ELEMENT_NODE || node.nodeType === Node.TEXT_NODE) {
          walk(node);
        }
      });
    });
  }, 100);
});

// Start observer
if (document.body) {
  observer.observe(document.body, { childList: true, subtree: true });
}