feat: implement master key decryption for letters and add UI warning for image decryption failures

frontend/e2e/letter.spec.ts

@@ -1,6 +1,16 @@
 import { expect, test } from "@playwright/test";
+import pino from "pino";
 import { AuthHelper } from "./utils/auth";
 
+const logger = pino({
+  transport: {
+    target: "pino-pretty",
+    options: {
+      colorize: true,
+    },
+  },
+});
+
 test.describe("Letter Drafting (Real Backend)", () => {
   const password = "Password123!";
 
@@ -11,10 +21,10 @@ test.describe("Letter Drafting (Real Backend)", () => {
 
     await AuthHelper.registerAndLogin(page, email, name, password);
 
-    console.log(">> [Draft] Navigating to Editor via UI...");
+    logger.info(">> [Draft] Navigating to Editor via UI...");
     await page.getByRole("button", { name: /write something/i }).click();
 
-    console.log(`>> [Draft] Current URL after click: ${page.url()}`);
+    logger.info(`>> [Draft] Current URL after click: ${page.url()}`);
 
     // Wait for the recipient input to be present in the DOM
     const recipientInput = page.locator("#recipient");
@@ -23,15 +33,19 @@ test.describe("Letter Drafting (Real Backend)", () => {
     const recipientName = "Dear Friend";
     await recipientInput.fill(recipientName);
 
-    // Type into the Fabric.js canvas
-    console.log(">> [Draft] Typing into canvas...");
+    // Initial load: verify textarea value (populated by Fabric when focused)
     const canvasInput = page.getByLabel("Canvas text input");
-    await canvasInput.waitFor({ state: "visible" });
+    await canvasInput.waitFor({ state: "attached" });
     await canvasInput.focus();
-    await canvasInput.fill("This is a secret draft created by E2E testing.");
+    await expect(canvasInput).toHaveValue(/Take a deep breath/i);
 
-    // Store as draft
-    console.log(">> [Draft] Clicking Store...");
+    // Draft a letter
+    logger.info(">> [Draft] Typing content...");
+    await canvasInput.focus();
+    await page.keyboard.type("This is a secret draft");
+    await page.keyboard.press("Enter");
+    await page.keyboard.type("It should persist.");
+    logger.info(">> [Draft] Clicking Store...");
     await page.getByRole("button", { name: /store/i }).click();
 
     // Verify Success Modal/Alert
@@ -40,10 +54,10 @@ test.describe("Letter Drafting (Real Backend)", () => {
     // Verify URL updated with a UUID
     await expect(page).toHaveURL(/\/quill\/[0-9a-f-]{36}/);
     const savedUrl = page.url();
-    console.log(`>> [Draft] Saved URL: ${savedUrl}`);
+    logger.info(`>> [Draft] Saved URL: ${savedUrl}`);
 
     // Reload and verify persistence
-    console.log(">> [Draft] Reloading to verify persistence...");
+    logger.info(">> [Draft] Reloading to verify persistence...");
     await page.goto(savedUrl);
 
     // Wait for initial load overlay to disappear
@@ -53,7 +67,13 @@ test.describe("Letter Drafting (Real Backend)", () => {
     await expect(page.locator("#recipient")).toHaveValue(recipientName);
 
     // Check canvas content
-    await expect(canvasInput).toHaveValue(/This is a secret draft/);
+    // We wait for the content to appear in the textarea.
+    // toHaveValue will poll until it matches or timeouts.
+    await canvasInput.focus();
+    await expect(canvasInput).toHaveValue(/This is a secret draft/i, {
+      timeout: 10000,
+    });
+    await expect(canvasInput).toHaveValue(/It should persist/i);
   });
 
   test("should seal a letter and show sharing link", async ({ page }) => {
@@ -63,7 +83,7 @@ test.describe("Letter Drafting (Real Backend)", () => {
 
     await AuthHelper.registerAndLogin(page, email, name, password);
 
-    console.log(">> [Seal] Navigating to Editor via UI...");
+    logger.info(">> [Seal] Navigating to Editor via UI...");
     await page.getByRole("button", { name: /write something/i }).click();
 
     const recipientInput = page.locator("#recipient");
@@ -75,11 +95,11 @@ test.describe("Letter Drafting (Real Backend)", () => {
     await canvasInput.fill("This letter will be sealed and shared.");
 
     // Click Seal
-    console.log(">> [Seal] Clicking Seal...");
+    logger.info(">> [Seal] Clicking Seal...");
     await page.getByRole("button", { name: /seal/i }).click();
 
     // Verify "Sealed & Ready" modal
-    console.log(">> [Seal] Verifying sharing modal...");
+    logger.info(">> [Seal] Verifying sharing modal...");
     await expect(page.getByText(/sealed & ready/i)).toBeVisible();
 
     // Verify sharing link contains a hash (the key)
@@ -89,7 +109,7 @@ test.describe("Letter Drafting (Real Backend)", () => {
     expect(linkValue).toContain("/read/");
     expect(linkValue).toContain("#");
 
-    console.log(`>> [Seal] Sharing link generated: ${linkValue}`);
+    logger.info(`>> [Seal] Sharing link generated: ${linkValue}`);
 
     // Verify "Copy" button works
     await expect(page.getByRole("button", { name: /copy/i })).toBeVisible();
@@ -98,4 +118,80 @@ test.describe("Letter Drafting (Real Backend)", () => {
     await page.getByRole("button", { name: /close/i }).click();
     await expect(page.getByText(/sealed & ready/i)).toBeHidden();
   });
+
+  test("should allow author to access sealed letter from drawer without sharing key", async ({
+    page,
+  }) => {
+    const timestamp = Date.now() + Math.random();
+    const email = `drawer-${timestamp}@example.com`;
+    const name = `Drawer Author ${timestamp}`;
+    const recipientName = "Drawer Test Recipient";
+    const letterContent = "This is a sealed letter accessed via the drawer.";
+
+    await AuthHelper.registerAndLogin(page, email, name, password);
+
+    logger.info(">> [Drawer] Creating and sealing a letter...");
+    await page.getByRole("button", { name: /write something/i }).click();
+
+    const recipientInput = page.locator("#recipient");
+    await recipientInput.waitFor({ state: "visible" });
+    await recipientInput.fill(recipientName);
+
+    const canvasInput = page.getByLabel("Canvas text input");
+    await canvasInput.focus();
+    await canvasInput.fill(letterContent);
+
+    // Click Seal
+    await page.getByRole("button", { name: /seal/i }).click();
+    await expect(page.getByText(/sealed & ready/i)).toBeVisible();
+
+    // Close modal
+    await page.getByRole("button", { name: /close/i }).click();
+
+    // Navigate to Drawer - use ID or precise label
+    logger.info(">> [Drawer] Navigating to Drawer...");
+    await page.locator("button[aria-label='Open Drawer']").click();
+
+    // Open "Kept" section - search for the section with id='kept' and click its toggle button
+    logger.info(">> [Drawer] Opening Kept section...");
+    const keptSection = page.locator("#kept");
+    await keptSection.getByRole("button", { name: /kept/i }).click();
+
+    // Find the sealed letter in the drawer by recipient name and click it
+    logger.info(">> [Drawer] Clicking sealed letter in drawer...");
+    const sealedItem = page
+      .getByRole("button", { name: new RegExp(recipientName, "i") })
+      .first();
+    await sealedItem.click();
+
+    // Verify it opens the Reader without a hash
+    logger.info(">> [Drawer] Verifying Reader page...");
+    // Give it a bit more time for decryption
+    await expect(page).toHaveURL(/\/read\/[a-f0-9-]{36}$/, { timeout: 15000 }); // UUID without hash
+
+    // Check decrypted content in Reader
+    await expect(page.getByText(/decrypting/i)).toBeHidden({
+      timeout: 10000,
+    });
+    await expect(
+      page.getByText(new RegExp(`A sealed message for ${recipientName}`, "i")),
+    ).toBeVisible();
+
+    // Verify content is decrypted (using author's masterKey automatically)
+    await expect(page.getByText(/decrypting/i)).toBeHidden();
+    // In the Reader, we check if the recipient name is visible in the Reader header.
+    await expect(page.getByText(/Drawer Test Recipient/i)).toBeVisible();
+
+    // Also check if we are redirected to the Reader if we manually go to the Editor URL
+    const readerUrl = page.url();
+    const quillUrl = readerUrl.replace("/read/", "/quill/");
+    logger.info(
+      `>> [Drawer] Navigating to Editor URL (expecting redirect): ${quillUrl}`,
+    );
+    await page.goto(quillUrl);
+
+    // It should redirect back to the reader
+    await expect(page).toHaveURL(readerUrl);
+    await expect(page.getByText(/Drawer Test Recipient/i)).toBeVisible();
+  });
 });

frontend/src/components/ui/DrawerSection.tsx

@@ -24,7 +24,7 @@ export function DrawerSection({
         className={`overflow-hidden transition-all duration-1000 ease-in-out bg-neutral/10 ${
           isOpen
             ? "max-h-125 opacity-100 py-3 border-b border-base-content/5"
-            : "max-h-0 opacity-0"
+            : "max-h-0 opacity-0 pointer-events-none"
         }`}
       >
         {children}

frontend/src/pages/Drawer.tsx

@@ -11,7 +11,7 @@ import { useLetters } from "../hooks/useLetters";
 export default function Drawer() {
   const { user, logout, unlock } = useAuth();
 
-  const [openSection, setOpenSection] = useState<string | null>();
+  const [openSection, setOpenSection] = useState<string | null>(null);
   const navigate = useNavigate();
   const { drafts, kept, sent, vault, loading, isAuthRequired } = useLetters();
 

frontend/src/pages/Reader.tsx

@@ -8,8 +8,12 @@ import {
   ComposeCanvas,
 } from "../components/ui/ComposeCanvas";
 import { endpoints } from "../config/endpoints";
+import { useKeyStore } from "../store/useKeyStore";
 import { CryptoUtils } from "../utils/crypto";
-import { decryptCanvasImagesWithSharingKey } from "../utils/letterLogic";
+import {
+  decryptCanvasImages,
+  decryptCanvasImagesWithSharingKey,
+} from "../utils/letterLogic";
 
 interface LetterMetadata {
   recipient?: string;
@@ -24,13 +28,21 @@ export default function Reader() {
 
   const [isDecrypting, setIsDecrypting] = useState(true);
   const [error, setError] = useState<string | null>(null);
+  const [warning, setWarning] = useState<{
+    message: string;
+    log: string;
+  } | null>(null);
   const [metadata, setMetadata] = useState<LetterMetadata | null>(null);
   const [decryptedCanvasData, setDecryptedCanvasData] =
     useState<CanvasJSON | null>(null);
 
+  const { masterKey } = useKeyStore();
+
   useEffect(() => {
-    if (!sharingKey) {
-      setError("No sharing key provided. Please check the link.");
+    if (!(sharingKey || masterKey)) {
+      setError(
+        "No sharing key provided. Please check the link or log in if you are the author.",
+      );
       setIsDecrypting(false);
       return;
     }
@@ -38,33 +50,69 @@ export default function Reader() {
     const loadAndDecrypt = async () => {
       try {
         const response = await api.get(`${endpoints.LETTERS}${public_id}/`);
-        const { encrypted_content, encrypted_metadata, images } = response.data;
+        const { encrypted_content, encrypted_metadata, encrypted_dek, images } =
+          response.data;
 
         const cryptoUtils = new CryptoUtils();
+        const isShared = !!sharingKey;
 
-        const decryptedMetadata =
-          await cryptoUtils.decryptMetadataWithSharingKey(
-            encrypted_metadata,
-            sharingKey,
-          );
+        if (isShared && !encrypted_content) throw new Error("Content missing");
+        const isDecryptionKeyAvailable = encrypted_dek && masterKey;
+        if (!(isShared || isDecryptionKeyAvailable))
+          throw new Error("Auth required");
+
+        // Decrypt Metadata
+        const decryptedMetadata = isShared
+          ? await cryptoUtils.decryptMetadataWithSharingKey(
+              encrypted_metadata,
+              sharingKey,
+            )
+          : await cryptoUtils.decryptMetadata(
+              { encrypted_content: encrypted_metadata, encrypted_dek },
+              masterKey,
+            );
         setMetadata(decryptedMetadata as LetterMetadata);
 
-        const decryptedContent = await cryptoUtils.decryptLetterWithSharingKey(
-          encrypted_content,
-          sharingKey,
-        );
-        const json = JSON.parse(decryptedContent) as CanvasJSON;
+        // Decrypt Content
+        const decryptedContent = isShared
+          ? await cryptoUtils.decryptLetterWithSharingKey(
+              encrypted_content,
+              sharingKey,
+            )
+          : await cryptoUtils.decryptLetter(
+              { encrypted_content, encrypted_dek },
+              masterKey,
+            );
 
-        if (images && images.length > 0) {
-          await decryptCanvasImagesWithSharingKey(
-            json,
-            images,
-            sharingKey,
-            cryptoUtils,
-          );
+        const canvasData: CanvasJSON = JSON.parse(decryptedContent);
+
+        try {
+          // Decrypt Images
+          if (images?.length > 0) {
+            isShared
+              ? await decryptCanvasImagesWithSharingKey(
+                  canvasData,
+                  images,
+                  sharingKey,
+                  cryptoUtils,
+                )
+              : await decryptCanvasImages(
+                  canvasData,
+                  images,
+                  encrypted_dek,
+                  masterKey,
+                  cryptoUtils,
+                );
+          }
+        } catch (err) {
+          setWarning({
+            message:
+              "Failed to decrypt elements. Images might not render in the letter as intended.",
+            log: err,
+          });
         }
 
-        setDecryptedCanvasData(json);
+        setDecryptedCanvasData(canvasData);
       } catch (err) {
         const message = err instanceof Error ? err.message : "Unknown error";
         setError(`Failed to load letter: ${message}`);
@@ -74,7 +122,7 @@ export default function Reader() {
     };
 
     loadAndDecrypt();
-  }, [public_id, sharingKey]);
+  }, [public_id, sharingKey, masterKey]);
 
   useEffect(() => {
     if (!isDecrypting && decryptedCanvasData && canvasRef.current) {
@@ -111,6 +159,14 @@ export default function Reader() {
 
   return (
     <section className="min-h-screen w-full bg-base-200 px-4 py-8">
+      {warning && (
+        <div className="alert alert-warning">
+          <div className="flex-1">
+            <p>{warning.message}</p>
+            <p className="text-xs opacity-70">{warning.log}</p>
+          </div>
+        </div>
+      )}
       <div className="max-w-4xl mx-auto space-y-6">
         <div className="flex items-center justify-between">
           <div>