/**
 * Auto-calculate pause based on German break rules
 * @param {number} grossHours - Total work hours
 * @returns {number} - Pause in minutes
 */
function calculateAutoPause(grossHours) {
  if (grossHours > 9) {
    return 45;
  } else if (grossHours > 6) {
    return 30;
  }
  return 0;
}

/**
 * Calculate net hours with pause and 10-hour cap
 * @param {string} startTime - Format: "HH:MM"
 * @param {string} endTime - Format: "HH:MM"
 * @param {number|null} pauseMinutes - Manual pause in minutes (null for auto-calculation)
 * @returns {object} - { grossHours, pauseMinutes, netHours }
 */
function calculateNetHours(startTime, endTime, pauseMinutes = null) {
  const [startHour, startMin] = startTime.split(':').map(Number);
  const [endHour, endMin] = endTime.split(':').map(Number);
  
  const startTotalMin = startHour * 60 + startMin;
  const endTotalMin = endHour * 60 + endMin;
  
  // Handle overnight shifts
  let diffMin = endTotalMin - startTotalMin;
  if (diffMin < 0) {
    diffMin += 24 * 60; // Add 24 hours
  }
  
  const grossHours = diffMin / 60;
  
  // Calculate required minimum pause based on gross hours
  const requiredMinPause = calculateAutoPause(grossHours);
  
  // Determine actual pause to use
  let actualPause;
  if (pauseMinutes !== null && pauseMinutes !== undefined) {
    // Manual pause provided - enforce minimum
    actualPause = Math.max(pauseMinutes, requiredMinPause);
  } else {
    // No pause provided - use required minimum
    actualPause = requiredMinPause;
  }
  
  // Calculate net hours
  const netMinutes = diffMin - actualPause;
  let netHours = netMinutes / 60;
  
  // Cap at 10 hours
  if (netHours > 10) {
    netHours = 10.0;
  }
  
  return {
    grossHours: parseFloat(grossHours.toFixed(2)),
    pauseMinutes: actualPause,
    netHours: parseFloat(netHours.toFixed(2))
  };
}

module.exports = {
  calculateAutoPause,
  calculateNetHours
};