/**
 * Utilities for managing anonymous list IDs in localStorage
 * This helps track lists created before user registration for migration
 * 
 * Requirements: 10.2, 10.5 - Migration path for existing anonymous lists
 */

const STORAGE_KEY = 'anonymousListIds'

/**
 * Add a list ID to the anonymous lists tracking
 */
export function trackAnonymousList(listId: string): void {
  if (typeof window === 'undefined') return

  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    const listIds: string[] = stored ? JSON.parse(stored) : []
    
    if (!listIds.includes(listId)) {
      listIds.push(listId)
      localStorage.setItem(STORAGE_KEY, JSON.stringify(listIds))
    }
  } catch (error) {
    console.error('Error tracking anonymous list:', error)
  }
}

/**
 * Remove a list ID from anonymous lists tracking
 */
export function untrackAnonymousList(listId: string): void {
  if (typeof window === 'undefined') return

  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    if (!stored) return

    const listIds: string[] = JSON.parse(stored)
    const filtered = listIds.filter(id => id !== listId)
    
    if (filtered.length > 0) {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(filtered))
    } else {
      localStorage.removeItem(STORAGE_KEY)
    }
  } catch (error) {
    console.error('Error untracking anonymous list:', error)
  }
}

/**
 * Get all tracked anonymous list IDs
 */
export function getAnonymousListIds(): string[] {
  if (typeof window === 'undefined') return []

  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    return stored ? JSON.parse(stored) : []
  } catch (error) {
    console.error('Error getting anonymous list IDs:', error)
    return []
  }
}

/**
 * Clear all tracked anonymous list IDs
 */
export function clearAnonymousLists(): void {
  if (typeof window === 'undefined') return

  try {
    localStorage.removeItem(STORAGE_KEY)
  } catch (error) {
    console.error('Error clearing anonymous lists:', error)
  }
}

/**
 * Check if there are any tracked anonymous lists
 */
export function hasAnonymousLists(): boolean {
  return getAnonymousListIds().length > 0
}