/**
 * Unified date formatting utilities for consistent date display across the application
 */

/**
 * Format date string to display format (DD/MM/YYYY HH:mm or DD/MM/YYYY)
 * Handles multiple input formats: ISO, DD-MM-YYYY, YYYY-MM-DD, DD/MM/YYYY
 */
export const formatDate = (dateString: string | null | undefined): string => {
  if (!dateString) return "-";
  
  try {
    let date: Date;
    
    // Check if it's an ISO date string (e.g., "2025-06-09T22:58:47.731Z")
    if (dateString.includes('T') || dateString.includes('Z')) {
      date = new Date(dateString);
    }
    // Handle DD-MM-YYYY format
    else if (dateString.match(/^\d{1,2}-\d{1,2}-\d{4}$/)) {
      const [day, month, year] = dateString.split("-");
      date = new Date(parseInt(year), parseInt(month) - 1, parseInt(day));
    }
    // Handle DD/MM/YYYY format
    else if (dateString.match(/^\d{1,2}\/\d{1,2}\/\d{4}$/)) {
      const [day, month, year] = dateString.split("/");
      date = new Date(parseInt(year), parseInt(month) - 1, parseInt(day));
    }
    // Handle YYYY-MM-DD format
    else if (dateString.match(/^\d{4}-\d{1,2}-\d{1,2}$/)) {
      date = new Date(dateString);
    }
    // Fallback to direct parsing
    else {
      date = new Date(dateString);
    }
    
    // Check if date is valid
    if (isNaN(date.getTime())) {
      console.warn("Invalid date format:", dateString);
      return dateString;
    }
    
    // Format date in DD/MM/YYYY HH:mm format
    const day = date.getDate().toString().padStart(2, '0');
    const month = (date.getMonth() + 1).toString().padStart(2, '0');
    const year = date.getFullYear();
    const hours = date.getHours().toString().padStart(2, '0');
    const minutes = date.getMinutes().toString().padStart(2, '0');
    
    // Include time if it's not midnight
    if (hours !== '00' || minutes !== '00') {
      return `${day}/${month}/${year} ${hours}:${minutes}`;
    }
    
    return `${day}/${month}/${year}`;
  } catch (error) {
    console.error('Date formatting error:', error, dateString);
    return dateString;
  }
};

/**
 * Get relative time description (e.g., "2 days ago", "Yesterday", "Today")
 */
export const getRelativeTime = (dateString: string | null | undefined): string => {
  if (!dateString) return '';
  
  try {
    let date: Date;
    
    // Handle DD-MM-YYYY format
    if (dateString.includes('-') && dateString.match(/^\d{1,2}-\d{1,2}-\d{4}$/)) {
      const parts = dateString.split('-');
      if (parts.length === 3) {
        const [day, month, year] = parts;
        date = new Date(parseInt(year), parseInt(month) - 1, parseInt(day));
      } else {
        date = new Date(dateString);
      }
    } else {
      date = new Date(dateString);
    }
    
    if (isNaN(date.getTime())) return '';
    
    const now = new Date();
    const diffTime = Math.abs(now.getTime() - date.getTime());
    const diffDays = Math.floor(diffTime / (1000 * 60 * 60 * 24));
    
    if (diffDays === 0) return 'Today';
    if (diffDays === 1) return 'Yesterday';
    if (diffDays < 7) return `${diffDays} days ago`;
    if (diffDays < 30) return `${Math.floor(diffDays / 7)} weeks ago`;
    if (diffDays < 365) return `${Math.floor(diffDays / 30)} months ago`;
    return `${Math.floor(diffDays / 365)} years ago`;
  } catch (error) {
    console.error('Relative time calculation error:', error, dateString);
    return '';
  }
};

/**
 * Format date for display in US locale (Month DD, YYYY)
 */
export const formatDateUS = (dateString: string | null | undefined): string => {
  if (!dateString) return "-";
  
  try {
    let date: Date;
    
    // Handle DD-MM-YYYY format
    if (dateString.includes('-') && dateString.match(/^\d{1,2}-\d{1,2}-\d{4}$/)) {
      const parts = dateString.split('-');
      if (parts.length === 3) {
        const [day, month, year] = parts;
        date = new Date(parseInt(year), parseInt(month) - 1, parseInt(day));
      } else {
        date = new Date(dateString);
      }
    } else {
      date = new Date(dateString);
    }
    
    if (isNaN(date.getTime())) {
      console.warn("Invalid date format:", dateString);
      return "-";
    }
    
    return date.toLocaleDateString("en-US", {
      year: "numeric",
      month: "short", 
      day: "numeric",
    });
  } catch (error) {
    console.error("Error formatting date:", dateString, error);
    return "-";
  }
};