wip

packages/domain/value-objects/SessionLifetime.ts

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+/**
+ * SessionLifetime Value Object
+ * 
+ * Represents the lifetime of an authentication session with expiry tracking.
+ * Handles validation of session expiry dates with a configurable buffer window.
+ */
+export class SessionLifetime {
+  private readonly expiry: Date | null;
+  private readonly bufferMinutes: number;
+
+  constructor(expiry: Date | null, bufferMinutes: number = 5) {
+    if (expiry !== null) {
+      if (isNaN(expiry.getTime())) {
+        throw new Error('Invalid expiry date provided');
+      }
+      
+      // Allow dates within buffer window to support checking expiry of recently expired sessions
+      const bufferMs = bufferMinutes * 60 * 1000;
+      const expiryWithBuffer = expiry.getTime() + bufferMs;
+      if (expiryWithBuffer < Date.now()) {
+        throw new Error('Expiry date cannot be in the past');
+      }
+    }
+
+    this.expiry = expiry;
+    this.bufferMinutes = bufferMinutes;
+  }
+
+  /**
+   * Check if the session is expired.
+   * Considers the buffer time - sessions within the buffer window are treated as expired.
+   * 
+   * @returns true if expired or expiring soon (within buffer), false otherwise
+   */
+  isExpired(): boolean {
+    if (this.expiry === null) {
+      return false;
+    }
+
+    const bufferMs = this.bufferMinutes * 60 * 1000;
+    const expiryWithBuffer = this.expiry.getTime() - bufferMs;
+    return Date.now() >= expiryWithBuffer;
+  }
+
+  /**
+   * Check if the session is expiring soon (within buffer window).
+   * 
+   * @returns true if expiring within buffer window, false otherwise
+   */
+  isExpiringSoon(): boolean {
+    if (this.expiry === null) {
+      return false;
+    }
+
+    const bufferMs = this.bufferMinutes * 60 * 1000;
+    const now = Date.now();
+    const expiryTime = this.expiry.getTime();
+    const expiryWithBuffer = expiryTime - bufferMs;
+
+    return now >= expiryWithBuffer && now < expiryTime;
+  }
+
+  /**
+   * Get the expiry date.
+   * 
+   * @returns The expiry date or null if no expiration
+   */
+  getExpiry(): Date | null {
+    return this.expiry;
+  }
+
+  /**
+   * Get remaining time until expiry in milliseconds.
+   * 
+   * @returns Milliseconds until expiry, or Infinity if no expiration
+   */
+  getRemainingTime(): number {
+    if (this.expiry === null) {
+      return Infinity;
+    }
+
+    const remaining = this.expiry.getTime() - Date.now();
+    return Math.max(0, remaining);
+  }
+}