export class AccountMessageComponent implements OnInit, OnDestroy {
  // Data Properties
  messages: AccountMessage[] = [];
  filteredMessages: AccountMessage[] = [];
  selectedMessages: AccountMessage[] = [];
  currentUser: User | null = null;
  loading: boolean = false;
  error: string | null = null;
  
  // Filter and Search Properties
  searchTerm: string = '';
  statusFilter: string = 'all';
  dateFilter: DateRange | null = null;
  userFilter: string = '';
  
  // Pagination Properties
  currentPage: number = 1;
  itemsPerPage: number = 10;
  totalItems: number = 0;
  
  // Sorting Properties
  sortField: string = 'createdAt';
  sortDirection: 'asc' | 'desc' = 'desc';
  
  // UI State Properties
  showComposeModal: boolean = false;
  showFilters: boolean = false;
  selectedMessage: AccountMessage | null = null;
  isEditing: boolean = false;
  
  // Form Properties
  messageForm: FormGroup;
  composeForm: FormGroup;
}

/**
 * Component initialization
 */
ngOnInit(): void

/**
 * Component cleanup
 */
ngOnDestroy(): void

/**
 * After view initialization
 */
ngAfterViewInit(): void

/**
 * Load account messages for current user
 */
loadAccountMessages(): void

/**
 * Load messages with pagination
 * @param page - Page number to load
 * @param pageSize - Number of items per page
 */
loadMessagesWithPagination(page: number, pageSize: number): void

/**
 * Load user account information
 */
loadUserAccount(): void

/**
 * Refresh message list
 */
refreshMessages(): void

/**
 * Load message by ID
 * @param messageId - ID of the message to load
 */
loadMessageById(messageId: string): void

/**
 * Create new account message
 * @param messageData - Message data to create
 */
createMessage(messageData: CreateMessageRequest): void

/**
 * Update existing message
 * @param messageId - ID of message to update
 * @param messageData - Updated message data
 */
updateMessage(messageId: string, messageData: UpdateMessageRequest): void

/**
 * Delete message
 * @param messageId - ID of message to delete
 */
deleteMessage(messageId: string): void

/**
 * Mark message as read
 * @param messageId - ID of message to mark as read
 */
markAsRead(messageId: string): void

/**
 * Mark message as unread
 * @param messageId - ID of message to mark as unread
 */
markAsUnread(messageId: string): void

/**
 * Archive message
 * @param messageId - ID of message to archive
 */
archiveMessage(messageId: string): void

/**
 * Restore archived message
 * @param messageId - ID of message to restore
 */
restoreMessage(messageId: string): void

/**
 * Select all messages
 */
selectAllMessages(): void

/**
 * Clear all selections
 */
clearSelection(): void

/**
 * Toggle message selection
 * @param message - Message to toggle selection
 */
toggleMessageSelection(message: AccountMessage): void

/**
 * Delete selected messages
 */
deleteSelectedMessages(): void

/**
 * Mark selected messages as read
 */
markSelectedAsRead(): void

/**
 * Archive selected messages
 */
archiveSelectedMessages(): void

/**
 * Search messages by term
 * @param searchTerm - Term to search for
 */
searchMessages(searchTerm: string): void

/**
 * Filter messages by status
 * @param status - Status to filter by
 */
filterByStatus(status: string): void

/**
 * Filter messages by user
 * @param userId - User ID to filter by
 */
filterByUser(userId: string): void

/**
 * Filter messages by date range
 * @param dateRange - Date range to filter by
 */
filterByDateRange(dateRange: DateRange): void

/**
 * Apply all filters to messages
 */
applyFilters(): void

/**
 * Clear all filters
 */
clearFilters(): void

/**
 * Reset search and filters
 */
resetFilters(): void

/**
 * Sort messages by field
 * @param field - Field to sort by
 */
sortBy(field: string): void

/**
 * Toggle sort direction
 */
toggleSortDirection(): void

/**
 * Apply current sorting to messages
 */
applySorting(): void

/**
 * Go to specific page
 * @param page - Page number to navigate to
 */
goToPage(page: number): void

/**
 * Go to next page
 */
nextPage(): void

/**
 * Go to previous page
 */
previousPage(): void

/**
 * Change items per page
 * @param itemsPerPage - Number of items per page
 */
changeItemsPerPage(itemsPerPage: number): void

/**
 * Calculate total pages
 */
getTotalPages(): number

/**
 * Open message composition modal
 */
openComposeModal(): void

/**
 * Close message composition modal
 */
closeComposeModal(): void

/**
 * Toggle filters panel
 */
toggleFilters(): void

/**
 * Select message for viewing/editing
 * @param message - Message to select
 */
selectMessage(message: AccountMessage): void

/**
 * Open message details
 * @param message - Message to view details
 */
openMessageDetails(message: AccountMessage): void

/**
 * Close message details
 */
closeMessageDetails(): void

/**
 * Toggle edit mode
 */
toggleEditMode(): void

/**
 * Initialize message form
 */
initializeMessageForm(): void

/**
 * Initialize compose form
 */
initializeComposeForm(): void

/**
 * Submit message form
 */
submitMessageForm(): void

/**
 * Submit compose form
 */
submitComposeForm(): void

/**
 * Validate message form
 */
validateMessageForm(): boolean

/**
 * Reset message form
 */
resetMessageForm(): void

/**
 * Reset compose form
 */
resetComposeForm(): void

/**
 * Format message date
 * @param date - Date to format
 */
formatMessageDate(date: Date): string

/**
 * Get message status color
 * @param status - Message status
 */
getStatusColor(status: string): string

/**
 * Get message priority icon
 * @param priority - Message priority
 */
getPriorityIcon(priority: string): string

/**
 * Check if user can edit message
 * @param message - Message to check permissions for
 */
canEditMessage(message: AccountMessage): boolean

/**
 * Check if user can delete message
 * @param message - Message to check permissions for
 */
canDeleteMessage(message: AccountMessage): boolean

/**
 * Export messages to CSV
 */
exportToCSV(): void

/**
 * Print messages
 */
printMessages(): void

/**
 * Handle API errors
 * @param error - Error object
 */
handleError(error: any): void

/**
 * Show error message
 * @param message - Error message to display
 */
showError(message: string): void

/**
 * Show success message
 * @param message - Success message to display
 */
showSuccess(message: string): void

/**
 * Clear error state
 */
clearError(): void

export class AccountMessageService {
  // Private properties
  private readonly apiUrl = 'api/account-messages';
  private messagesSubject = new BehaviorSubject<AccountMessage[]>([]);
  private loadingSubject = new BehaviorSubject<boolean>(false);
  private errorSubject = new BehaviorSubject<string | null>(null);
  
  // Public observables
  public messages$ = this.messagesSubject.asObservable();
  public loading$ = this.loadingSubject.asObservable();
  public error$ = this.errorSubject.asObservable();
}

/**
 * Get all account messages
 * @param accountId - Account ID to get messages for
 */
getAccountMessages(accountId: string): Observable<AccountMessage[]>

/**
 * Get account messages with pagination
 * @param accountId - Account ID
 * @param page - Page number
 * @param pageSize - Items per page
 * @param filters - Filter options
 */
getAccountMessagesWithPagination(
  accountId: string, 
  page: number, 
  pageSize: number, 
  filters?: MessageFilters
): Observable<PaginatedResponse<AccountMessage>>

/**
 * Get message by ID
 * @param messageId - Message ID
 */
getMessageById(messageId: string): Observable<AccountMessage>

/**
 * Create new account message
 * @param messageData - Message data to create
 */
createAccountMessage(messageData: CreateMessageRequest): Observable<AccountMessage>

/**
 * Update account message
 * @param messageId - Message ID to update
 * @param messageData - Updated message data
 */
updateAccountMessage(messageId: string, messageData: UpdateMessageRequest): Observable<AccountMessage>

/**
 * Delete account message
 * @param messageId - Message ID to delete
 */
deleteAccountMessage(messageId: string): Observable<void>

/**
 * Bulk delete messages
 * @param messageIds - Array of message IDs to delete
 */
bulkDeleteMessages(messageIds: string[]): Observable<void>

/**
 * Mark message as read
 * @param messageId - Message ID
 */
markAsRead(messageId: string): Observable<void>

/**
 * Mark message as unread
 * @param messageId - Message ID
 */
markAsUnread(messageId: string): Observable<void>

/**
 * Mark multiple messages as read
 * @param messageIds - Array of message IDs
 */
markMultipleAsRead(messageIds: string[]): Observable<void>

/**
 * Update message status
 * @param messageId - Message ID
 * @param status - New status
 */
updateMessageStatus(messageId: string, status: MessageStatus): Observable<void>

/**
 * Archive message
 * @param messageId - Message ID
 */
archiveMessage(messageId: string): Observable<void>

/**
 * Restore archived message
 * @param messageId - Message ID
 */
restoreMessage(messageId: string): Observable<void>

/**
 * Search messages by term
 * @param accountId - Account ID
 * @param searchTerm - Search term
 */
searchMessages(accountId: string, searchTerm: string): Observable<AccountMessage[]>

/**
 * Filter messages by criteria
 * @param accountId - Account ID
 * @param filters - Filter criteria
 */
filterMessages(accountId: string, filters: MessageFilters): Observable<AccountMessage[]>

/**
 * Get messages by status
 * @param accountId - Account ID
 * @param status - Message status
 */
getMessagesByStatus(accountId: string, status: MessageStatus): Observable<AccountMessage[]>

/**
 * Get messages by date range
 * @param accountId - Account ID
 * @param startDate - Start date
 * @param endDate - End date
 */
getMessagesByDateRange(accountId: string, startDate: Date, endDate: Date): Observable<AccountMessage[]>

/**
 * Get messages for specific user
 * @param userId - User ID
 */
getMessagesForUser(userId: string): Observable<AccountMessage[]>

/**
 * Validate user permissions for message operations
 * @param userId - User ID
 * @param operation - Operation type
 */
validateUserPermissions(userId: string, operation: string): Observable<boolean>

/**
 * Get user account information
 * @param userId - User ID
 */
getUserAccount(userId: string): Observable<User>

/**
 * Check if user can access message
 * @param userId - User ID
 * @param messageId - Message ID
 */
canUserAccessMessage(userId: string, messageId: string): Observable<boolean>

/**
 * Get message statistics for account
 * @param accountId - Account ID
 */
getMessageStatistics(accountId: string): Observable<MessageStatistics>

/**
 * Get unread message count
 * @param accountId - Account ID
 */
getUnreadMessageCount(accountId: string): Observable<number>

/**
 * Get message activity summary
 * @param accountId - Account ID
 * @param period - Time period
 */
getMessageActivity(accountId: string, period: TimePeriod): Observable<MessageActivity[]>

/**
 * Clear message cache
 */
clearCache(): void

/**
 * Refresh cached messages
 * @param accountId - Account ID
 */
refreshCache(accountId: string): void

/**
 * Update cached message
 * @param message - Updated message
 */
updateCachedMessage(message: AccountMessage): void

/**
 * Remove message from cache
 * @param messageId - Message ID
 */
removeCachedMessage(messageId: string): void

/**
 * Handle HTTP errors
 * @param error - HTTP error response
 */
private handleError(error: HttpErrorResponse): Observable<never>

/**
 * Log error message
 * @param error - Error object
 */
private logError(error: any): void

/**
 * Retry failed operations
 * @param operation - Failed operation
 */
private retryOperation<T>(operation: Observable<T>): Observable<T>

/**
 * Format message for API
 * @param message - Message object
 */
private formatMessageForApi(message: AccountMessage): any

/**
 * Parse API response to message object
 * @param response - API response
 */
private parseApiResponse(response: any): AccountMessage

/**
 * Validate message data
 * @param messageData - Message data to validate
 */
validateMessageData(messageData: CreateMessageRequest | UpdateMessageRequest): boolean

/**
 * Generate message ID
 */
private generateMessageId(): string

/**
 * Sort messages by criteria
 * @param messages - Messages to sort
 * @param sortField - Field to sort by
 * @param sortDirection - Sort direction
 */
sortMessages(messages: AccountMessage[], sortField: string, sortDirection: 'asc' | 'desc'): AccountMessage[]

interface AccountMessage {
  id: string;
  accountId: string;
  userId: string;
  subject: string;
  content: string;
  status: MessageStatus;
  priority: MessagePriority;
  category: MessageCategory;
  isRead: boolean;
  isArchived: boolean;
  createdAt: Date;
  updatedAt: Date;
  readAt?: Date;
  archivedAt?: Date;
  metadata?: MessageMetadata;
}

interface CreateMessageRequest {
  accountId: string;
  userId: string;
  subject: string;
  content: string;
  priority?: MessagePriority;
  category?: MessageCategory;
  metadata?: MessageMetadata;
}

interface UpdateMessageRequest {
  subject?: string;
  content?: string;
  priority?: MessagePriority;
  category?: MessageCategory;
  metadata?: MessageMetadata;
}

interface MessageFilters {
  status?: MessageStatus;
  priority?: MessagePriority;
  category?: MessageCategory;
  searchTerm?: string;
  dateRange?: DateRange;
  isRead?: boolean;
  isArchived?: boolean;
}

interface MessageStatistics {
  total: number;
  unread: number;
  read: number;
  archived: number;
  byStatus: Record<MessageStatus, number>;
  byPriority: Record<MessagePriority, number>;
}

enum MessageStatus {
  ACTIVE = 'active',
  PENDING = 'pending',
  PROCESSED = 'processed',
  FAILED = 'failed'
}

enum MessagePriority {
  LOW = 'low',
  NORMAL = 'normal',
  HIGH = 'high',
  URGENT = 'urgent'
}

enum MessageCategory {
  SYSTEM = 'system',
  BILLING = 'billing',
  SUPPORT = 'support',
  MARKETING = 'marketing',
  SECURITY = 'security'
}