/**
 * Utility Functions
 */

/**
 * Format bytes to human-readable string
 */
function formatBytes(bytes, decimals = 2) {
  if (!bytes || bytes === 0) return '0 B';
  const k = 1024;
  const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB'];
  let i = Math.floor(Math.log(Math.abs(bytes)) / Math.log(k));
  i = Math.max(0, Math.min(i, sizes.length - 1));
  const value = bytes / Math.pow(k, i);
  return value.toFixed(decimals) + ' ' + sizes[i];
}

/**
 * Format bytes per second to human-readable bandwidth
 */
function formatBandwidth(bytesPerSec, decimals = 2) {
  if (!bytesPerSec || bytesPerSec === 0) return '0 B/s';
  const k = 1024;
  const sizes = ['B/s', 'KB/s', 'MB/s', 'GB/s', 'TB/s'];
  let i = Math.floor(Math.log(Math.abs(bytesPerSec)) / Math.log(k));
  i = Math.max(0, Math.min(i, sizes.length - 1));
  const value = bytesPerSec / Math.pow(k, i);
  return value.toFixed(decimals) + ' ' + sizes[i];
}

/**
 * Format percentage
 */
function formatPercent(value, decimals = 1) {
  if (!value || isNaN(value)) return '0%';
  return value.toFixed(decimals) + '%';
}

/**
 * Format a timestamp to HH:MM
 */
function formatTime(timestamp) {
  const d = new Date(timestamp);
  return d.toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' });
}

/**
 * Format full clock
 */
function formatClock() {
  const now = new Date();
  const date = now.toLocaleDateString('zh-CN', {
    year: 'numeric',
    month: '2-digit',
    day: '2-digit'
  });
  const time = now.toLocaleTimeString('zh-CN', {
    hour: '2-digit',
    minute: '2-digit',
    second: '2-digit'
  });
  return `${date} ${time}`;
}

/**
 * Get color based on usage percentage
 */
function getUsageColor(percent) {
  if (percent < 50) return '#10b981';
  if (percent < 75) return '#f59e0b';
  return '#f43f5e';
}

/**
 * Smooth number animation
 */
function animateValue(element, start, end, duration = 600) {
  const startTime = performance.now();
  const diff = end - start;

  function update(currentTime) {
    const elapsed = currentTime - startTime;
    const progress = Math.min(elapsed / duration, 1);
    // Ease out cubic
    const eased = 1 - Math.pow(1 - progress, 3);
    const current = start + diff * eased;

    if (element.dataset.format === 'percent') {
      element.textContent = formatPercent(current);
    } else if (element.dataset.format === 'bytes') {
      element.textContent = formatBytes(current);
    } else if (element.dataset.format === 'bandwidth') {
      element.textContent = formatBandwidth(current);
    } else {
      element.textContent = Math.round(current);
    }

    if (progress < 1) {
      requestAnimationFrame(update);
    }
  }

  requestAnimationFrame(update);
}