feat: add xprv wallet import support

Add the ability to import an existing HD wallet using an extended
private key (xprv) instead of a mnemonic phrase.

- New 'xprv' wallet type with full HD derivation and address scanning
- New importXprv view with password encryption
- Updated getSignerForAddress to handle xprv wallet type
- Added xprv link to the add-wallet view
- Allow adding derived addresses for xprv wallets

Closes #20

src/popup/views/addWallet.js

@@ -124,6 +124,11 @@ function init(ctx) {
         "click",
         ctx.showImportKeyView,
     );
+
+    $("btn-add-wallet-import-xprv").addEventListener(
+        "click",
+        ctx.showImportXprvView,
+    );
 }
 
 module.exports = { init, show };

src/popup/views/home.js

@@ -239,7 +239,7 @@ function render(ctx) {
         html += `<div>`;
         html += `<div class="flex justify-between items-center bg-section py-1 px-2" style="margin:0 -0.5rem">`;
         html += `<span class="font-bold cursor-pointer wallet-name underline decoration-dashed" data-wallet="${wi}">${wallet.name}</span>`;
-        if (wallet.type === "hd") {
+        if (wallet.type === "hd" || wallet.type === "xprv") {
             html += `<button class="btn-add-address border border-border px-1 hover:bg-fg hover:text-bg cursor-pointer text-xs" data-wallet="${wi}" title="Add another address to this wallet">+</button>`;
         }
         html += `</div>`;

src/popup/views/importXprv.js

@@ -0,0 +1,106 @@
+const { $, showView, showFlash } = require("./helpers");
+const { hdWalletFromXprv, isValidXprv } = require("../../shared/wallet");
+const { encryptWithPassword } = require("../../shared/vault");
+const { state, saveState } = require("../../shared/state");
+const { scanForAddresses } = require("../../shared/balances");
+
+function show() {
+    $("import-xprv-key").value = "";
+    $("import-xprv-password").value = "";
+    $("import-xprv-password-confirm").value = "";
+    showView("import-xprv");
+}
+
+function init(ctx) {
+    $("btn-import-xprv-confirm").addEventListener("click", async () => {
+        const xprv = $("import-xprv-key").value.trim();
+        if (!xprv) {
+            showFlash("Please enter your extended private key.");
+            return;
+        }
+        if (!isValidXprv(xprv)) {
+            showFlash("Invalid extended private key.");
+            return;
+        }
+        let result;
+        try {
+            result = hdWalletFromXprv(xprv);
+        } catch (e) {
+            showFlash("Invalid extended private key.");
+            return;
+        }
+        const { xpub, firstAddress } = result;
+        const duplicate = state.wallets.find(
+            (w) =>
+                (w.type === "hd" || w.type === "xprv") &&
+                w.addresses[0] &&
+                w.addresses[0].address.toLowerCase() ===
+                    firstAddress.toLowerCase(),
+        );
+        if (duplicate) {
+            showFlash("This key is already added (" + duplicate.name + ").");
+            return;
+        }
+        const pw = $("import-xprv-password").value;
+        const pw2 = $("import-xprv-password-confirm").value;
+        if (!pw) {
+            showFlash("Please choose a password.");
+            return;
+        }
+        if (pw.length < 12) {
+            showFlash("Password must be at least 12 characters.");
+            return;
+        }
+        if (pw !== pw2) {
+            showFlash("Passwords do not match.");
+            return;
+        }
+        const encrypted = await encryptWithPassword(xprv, pw);
+        const walletNum = state.wallets.length + 1;
+        const wallet = {
+            type: "xprv",
+            name: "Wallet " + walletNum,
+            xpub: xpub,
+            encryptedSecret: encrypted,
+            nextIndex: 1,
+            addresses: [
+                { address: firstAddress, balance: "0.0000", tokenBalances: [] },
+            ],
+        };
+        state.wallets.push(wallet);
+        state.hasWallet = true;
+        await saveState();
+        ctx.renderWalletList();
+        showView("main");
+
+        // Scan for used HD addresses beyond index 0.
+        showFlash("Scanning for addresses...", 30000);
+        const scan = await scanForAddresses(xpub, state.rpcUrl);
+        if (scan.addresses.length > 1) {
+            wallet.addresses = scan.addresses.map((a) => ({
+                address: a.address,
+                balance: "0.0000",
+                tokenBalances: [],
+            }));
+            wallet.nextIndex = scan.nextIndex;
+            await saveState();
+            ctx.renderWalletList();
+            showFlash("Found " + scan.addresses.length + " addresses.");
+        } else {
+            showFlash("Ready.", 1000);
+        }
+
+        ctx.doRefreshAndRender();
+    });
+
+    $("btn-import-xprv-back").addEventListener("click", () => {
+        if (!state.hasWallet) {
+            showView("welcome");
+        } else {
+            ctx.renderWalletList();
+            showView("main");
+        }
+    });
+}
+
+module.exports = { init, show };