/**
 * Audit Log Service
 * Provides audit logging functionality for tracking system changes
 */

export interface AuditLogEntry {
  action: string;
  entityType: string;
  entityId: string;
  userId?: string;
  tenantId: string;
  changes?: Record<string, any>;
  previousValues?: Record<string, any>;
  metadata?: Record<string, any>;
  timestamp?: string;
  ipAddress?: string;
  userAgent?: string;
}

export class AuditLogService {
  /**
   * Log an audit event
   */
  async log(entry: AuditLogEntry): Promise<void> {
    const auditEntry = {
      ...entry,
      timestamp: entry.timestamp || new Date().toISOString(),
      id: crypto.randomUUID()
    };

    // TODO: Implement actual audit log storage
    // This could write to database, file system, or external logging service
    console.log('Audit Log:', auditEntry);
  }

  /**
   * Log a create operation
   */
  async logCreate(
    entityType: string,
    entityId: string,
    data: Record<string, any>,
    userId?: string,
    tenantId?: string
  ): Promise<void> {
    await this.log({
      action: `${entityType}_created`,
      entityType,
      entityId,
      userId,
      tenantId: tenantId!,
      changes: data
    });
  }

  /**
   * Log an update operation
   */
  async logUpdate(
    entityType: string,
    entityId: string,
    changes: Record<string, any>,
    previousValues: Record<string, any>,
    userId?: string,
    tenantId?: string
  ): Promise<void> {
    await this.log({
      action: `${entityType}_updated`,
      entityType,
      entityId,
      userId,
      tenantId: tenantId!,
      changes,
      previousValues
    });
  }

  /**
   * Log a delete operation
   */
  async logDelete(
    entityType: string,
    entityId: string,
    previousValues: Record<string, any>,
    userId?: string,
    tenantId?: string
  ): Promise<void> {
    await this.log({
      action: `${entityType}_deleted`,
      entityType,
      entityId,
      userId,
      tenantId: tenantId!,
      previousValues
    });
  }

  /**
   * Log a custom action
   */
  async logAction(
    action: string,
    entityType: string,
    entityId: string,
    metadata?: Record<string, any>,
    userId?: string,
    tenantId?: string
  ): Promise<void> {
    await this.log({
      action,
      entityType,
      entityId,
      userId,
      tenantId: tenantId!,
      metadata
    });
  }

  /**
   * Retrieve audit logs for an entity
   */
  async getAuditLogs(
    entityType: string,
    entityId: string,
    tenantId: string,
    limit: number = 50
  ): Promise<AuditLogEntry[]> {
    // TODO: Implement actual audit log retrieval
    console.warn(`AuditLogService.getAuditLogs not implemented for ${entityType}:${entityId}`);
    return [];
  }

  /**
   * Retrieve audit logs for a user
   */
  async getUserAuditLogs(
    userId: string,
    tenantId: string,
    limit: number = 50
  ): Promise<AuditLogEntry[]> {
    // TODO: Implement actual user audit log retrieval
    console.warn(`AuditLogService.getUserAuditLogs not implemented for user:${userId}`);
    return [];
  }
}