feat: warn when sending to address with zero tx history (#82)

On the confirm-tx screen, asynchronously check the recipient address
via Blockscout API. If the address has never sent or received any
transactions, display a prominent red warning banner.

Closes #82

src/popup/index.html

@@ -581,11 +581,23 @@
                     id="confirm-errors"
                     class="mb-2 border border-border border-dashed p-2 hidden"
                 ></div>
+                <div class="mb-2">
+                    <label class="block mb-1 text-xs">Password</label>
+                    <input
+                        type="password"
+                        id="confirm-tx-password"
+                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
+                    />
+                </div>
+                <div
+                    id="confirm-tx-password-error"
+                    class="text-xs mb-2 min-h-[1.25rem]"
+                ></div>
                 <button
                     id="btn-confirm-send"
                     class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
                 >
-                    Send
+                    Sign &amp; Send
                 </button>
             </div>
 
@@ -664,42 +676,6 @@
                 </button>
             </div>
 
-            <!-- ============ PASSWORD MODAL ============ -->
-            <div
-                id="password-modal"
-                class="hidden fixed inset-0 bg-bg flex items-center justify-center z-50"
-            >
-                <div class="border border-border p-4 bg-bg w-80">
-                    <h2 class="font-bold mb-2">Enter Password</h2>
-                    <p class="text-xs text-muted mb-2">
-                        Your password is needed to authorize this transaction.
-                    </p>
-                    <input
-                        type="password"
-                        id="modal-password"
-                        class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg mb-2"
-                    />
-                    <div
-                        id="modal-password-error"
-                        class="text-xs mb-2 border border-border border-dashed p-1 hidden"
-                    ></div>
-                    <div class="flex gap-2">
-                        <button
-                            id="btn-modal-confirm"
-                            class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
-                        >
-                            Confirm
-                        </button>
-                        <button
-                            id="btn-modal-cancel"
-                            class="border border-border px-2 py-1 hover:bg-fg hover:text-bg cursor-pointer"
-                        >
-                            Cancel
-                        </button>
-                    </div>
-                </div>
-            </div>
-
             <!-- ============ RECEIVE ============ -->
             <div id="view-receive" class="view hidden">
                 <button
@@ -1139,7 +1115,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="approve-tx-error" class="text-xs hidden mb-2"></div>
+                <div
+                    id="approve-tx-error"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                ></div>
                 <div class="flex justify-between">
                     <button
                         id="btn-approve-tx"
@@ -1202,7 +1181,10 @@
                         class="border border-border p-1 w-full font-mono text-sm bg-bg text-fg"
                     />
                 </div>
-                <div id="approve-sign-error" class="text-xs hidden mb-2"></div>
+                <div
+                    id="approve-sign-error"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                ></div>
                 <div class="flex justify-between">
                     <button
                         id="btn-approve-sign"

src/popup/index.js

@@ -74,6 +74,7 @@ const RESTORABLE_VIEWS = new Set([
     "receive",
     "settings",
     "settings-addtoken",
+    "confirm-tx",
     "transaction",
     "success-tx",
     "error-tx",
@@ -127,6 +128,13 @@ function restoreView() {
         case "settings-addtoken":
             settingsAddToken.show();
             break;
+        case "confirm-tx":
+            if (state.viewData && state.viewData.pendingTx) {
+                confirmTx.restore();
+            } else {
+                fallbackView();
+            }
+            break;
         case "transaction":
             if (state.viewData && state.viewData.tx) {
                 transactionDetail.render();

src/popup/views/approval.js

@@ -4,6 +4,8 @@ const {
     addressTitle,
     escapeHtml,
     showView,
+    showError,
+    hideError,
 } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
 const { formatEther, formatUnits, Interface, toUtf8String } = require("ethers");
@@ -170,6 +172,8 @@ function showTxApproval(details) {
     // If this is an ERC-20 call, try to extract the real recipient and amount
     const decoded = decodeCalldata(details.txParams.data, toAddr || "");
     if (decoded && decoded.details) {
+        let decodedTokenAddr = null;
+        let decodedTokenSymbol = null;
         for (const d of decoded.details) {
             if (d.label === "Recipient" && d.address) {
                 pendingTxDetails.to = d.address;
@@ -177,10 +181,20 @@ function showTxApproval(details) {
             if (d.label === "Amount") {
                 pendingTxDetails.amount = d.rawValue || d.value;
             }
+            if (d.label === "Token In" && d.isToken && d.address) {
+                const t = TOKEN_BY_ADDRESS.get(d.address.toLowerCase());
+                if (t) {
+                    decodedTokenAddr = d.address;
+                    decodedTokenSymbol = t.symbol;
+                }
+            }
         }
         if (token) {
             pendingTxDetails.token = toAddr;
             pendingTxDetails.tokenSymbol = token.symbol;
+        } else if (decodedTokenAddr) {
+            pendingTxDetails.token = decodedTokenAddr;
+            pendingTxDetails.tokenSymbol = decodedTokenSymbol;
         }
     }
 
@@ -254,6 +268,9 @@ function showTxApproval(details) {
         $("approve-tx-data-section").classList.add("hidden");
     }
 
+    $("approve-tx-password").value = "";
+    $("approve-tx-error").classList.add("hidden");
+
     showView("approve-tx");
 }
 
@@ -342,7 +359,7 @@ function showSignApproval(details) {
     }
 
     $("approve-sign-password").value = "";
-    $("approve-sign-error").classList.add("hidden");
+    hideError("approve-sign-error");
     $("btn-approve-sign").disabled = false;
     $("btn-approve-sign").classList.remove("text-muted");
 
@@ -407,11 +424,10 @@ function init(ctx) {
     $("btn-approve-tx").addEventListener("click", () => {
         const password = $("approve-tx-password").value;
         if (!password) {
-            $("approve-tx-error").textContent = "Please enter your password.";
-            $("approve-tx-error").classList.remove("hidden");
+            showError("approve-tx-error", "Please enter your password.");
             return;
         }
-        $("approve-tx-error").classList.add("hidden");
+        hideError("approve-tx-error");
         $("btn-approve-tx").disabled = true;
         $("btn-approve-tx").classList.add("text-muted");
 
@@ -447,11 +463,10 @@ function init(ctx) {
     $("btn-approve-sign").addEventListener("click", () => {
         const password = $("approve-sign-password").value;
         if (!password) {
-            $("approve-sign-error").textContent = "Please enter your password.";
-            $("approve-sign-error").classList.remove("hidden");
+            showError("approve-sign-error", "Please enter your password.");
             return;
         }
-        $("approve-sign-error").classList.add("hidden");
+        hideError("approve-sign-error");
         $("btn-approve-sign").disabled = true;
         $("btn-approve-sign").classList.add("text-muted");
 
@@ -469,8 +484,7 @@ function init(ctx) {
                 } else {
                     const msg =
                         (response && response.error) || "Signing failed.";
-                    $("approve-sign-error").textContent = msg;
-                    $("approve-sign-error").classList.remove("hidden");
+                    showError("approve-sign-error", msg);
                     $("btn-approve-sign").disabled = false;
                     $("btn-approve-sign").classList.remove("text-muted");
                 }

src/popup/views/confirmTx.js

@@ -1,6 +1,6 @@
-// Transaction confirmation view + password modal.
-// Shows transaction details, warnings, errors. On proceed, opens
-// password modal, decrypts secret, signs and broadcasts.
+// Transaction confirmation view with inline password.
+// Shows transaction details, warnings, errors. On Sign & Send,
+// reads inline password, decrypts secret, signs and broadcasts.
 
 const {
     parseEther,
@@ -25,6 +25,7 @@ const { decryptWithPassword } = require("../../shared/vault");
 const { formatUsd, getPrice } = require("../../shared/prices");
 const { getProvider } = require("../../shared/balances");
 const { isScamAddress } = require("../../shared/scamlist");
+const { hasTransactionHistory } = require("../../shared/transactions");
 const { ERC20_ABI } = require("../../shared/constants");
 const { log } = require("../../shared/log");
 const makeBlockie = require("ethereum-blockies-base64");
@@ -39,6 +40,13 @@ const EXT_ICON =
 
 let pendingTx = null;
 
+function restore() {
+    const d = state.viewData;
+    if (d && d.pendingTx) {
+        show(d.pendingTx);
+    }
+}
+
 function etherscanTokenLink(address) {
     return `https://etherscan.io/token/${address}`;
 }
@@ -226,12 +234,18 @@ function show(txInfo) {
         sendBtn.classList.remove("text-muted");
     }
 
+    // Reset password field and error
+    $("confirm-tx-password").value = "";
+    hideError("confirm-tx-password-error");
+
     // Gas estimate — show placeholder then fetch async
     $("confirm-fee").classList.remove("hidden");
     $("confirm-fee-amount").textContent = "Estimating...";
+    state.viewData = { pendingTx: txInfo };
     showView("confirm-tx");
 
     estimateGas(txInfo);
+    checkRecipientHistory(txInfo);
 }
 
 async function estimateGas(txInfo) {
@@ -274,39 +288,45 @@ async function estimateGas(txInfo) {
     }
 }
 
-function showPasswordModal() {
-    $("modal-password").value = "";
-    hideError("modal-password-error");
-    $("password-modal").classList.remove("hidden");
-}
-
-function hidePasswordModal() {
-    $("password-modal").classList.add("hidden");
+async function checkRecipientHistory(txInfo) {
+    try {
+        const hasHistory = await hasTransactionHistory(
+            txInfo.to,
+            state.blockscoutUrl,
+        );
+        if (hasHistory === false) {
+            const warningsEl = $("confirm-warnings");
+            const warningDiv = document.createElement("div");
+            warningDiv.className =
+                "border border-dashed p-2 mb-1 text-xs font-bold";
+            warningDiv.style.color = "#dc2626";
+            warningDiv.style.borderColor = "#dc2626";
+            warningDiv.textContent =
+                "WARNING: This address has ZERO transaction history on-chain. " +
+                "It has never sent or received any transactions. " +
+                "Double-check the address before sending.";
+            warningsEl.appendChild(warningDiv);
+            warningsEl.classList.remove("hidden");
+        }
+    } catch (e) {
+        log.errorf("recipient history check failed:", e.message);
+    }
 }
 
 function init(ctx) {
-    $("btn-confirm-send").addEventListener("click", () => {
-        showPasswordModal();
-    });
-
-    $("btn-confirm-back").addEventListener("click", () => {
-        showView("send");
-    });
-
-    $("btn-modal-cancel").addEventListener("click", () => {
-        hidePasswordModal();
-    });
-
-    $("btn-modal-confirm").addEventListener("click", async () => {
-        const password = $("modal-password").value;
+    $("btn-confirm-send").addEventListener("click", async () => {
+        const password = $("confirm-tx-password").value;
         if (!password) {
-            showError("modal-password-error", "Please enter your password.");
+            showError(
+                "confirm-tx-password-error",
+                "Please enter your password.",
+            );
             return;
         }
 
         const wallet = state.wallets[state.selectedWallet];
         let decryptedSecret;
-        hideError("modal-password-error");
+        hideError("confirm-tx-password-error");
 
         try {
             decryptedSecret = await decryptWithPassword(
@@ -314,11 +334,12 @@ function init(ctx) {
                 password,
             );
         } catch (e) {
-            showError("modal-password-error", "Wrong password.");
+            showError("confirm-tx-password-error", "Wrong password.");
             return;
         }
 
-        hidePasswordModal();
+        $("btn-confirm-send").disabled = true;
+        $("btn-confirm-send").classList.add("text-muted");
 
         let tx;
         try {
@@ -355,8 +376,15 @@ function init(ctx) {
             decryptedSecret = null;
             const hash = tx ? tx.hash : null;
             txStatus.showError(pendingTx, hash, e.shortMessage || e.message);
+        } finally {
+            $("btn-confirm-send").disabled = false;
+            $("btn-confirm-send").classList.remove("text-muted");
         }
     });
+
+    $("btn-confirm-back").addEventListener("click", () => {
+        showView("send");
+    });
 }
 
-module.exports = { init, show };
+module.exports = { init, show, restore };

src/popup/views/txStatus.js

@@ -43,10 +43,11 @@ function toAddressHtml(address) {
     if (title) {
         return (
             `<div class="flex items-center font-bold">${dot}${escapeHtml(title)}</div>` +
-            `<div class="break-all">${escapeHtml(address)}${extLink}</div>`
+            `<div class="break-all underline decoration-dashed cursor-pointer" data-copy="${escapeHtml(address)}">${escapeHtml(address)}</div>` +
+            extLink
         );
     }
-    return `<div class="flex items-center">${dot}<span class="break-all">${escapeHtml(address)}</span>${extLink}</div>`;
+    return `<div class="flex items-center">${dot}<span class="break-all underline decoration-dashed cursor-pointer" data-copy="${escapeHtml(address)}">${escapeHtml(address)}</span>${extLink}</div>`;
 }
 
 function txHashHtml(hash) {
@@ -139,7 +140,7 @@ function etherscanTokenLink(address) {
 
 function decodedDetailsHtml(decoded) {
     if (!decoded || !decoded.details) return "";
-    let html = "";
+    let html = `<div class="border border-border border-dashed p-2 mb-3">`;
     if (decoded.name) {
         html += `<div class="mb-2"><div class="text-xs text-muted mb-1">Action</div>`;
         html += `<div class="font-bold">${escapeHtml(decoded.name)}</div></div>`;
@@ -164,20 +165,36 @@ function decodedDetailsHtml(decoded) {
         }
         html += `</div>`;
     }
+    html += `</div>`;
     return html;
 }
 
 function renderSuccess() {
     const d = state.viewData;
     if (!d || !d.hash) return;
-    $("success-tx-summary").textContent = d.amount + " " + d.symbol;
-    $("success-tx-to").innerHTML = toAddressHtml(d.to);
+
+    const hasDecoded = d.decoded && d.decoded.details;
+
+    // When decoded details are present, the Amount and To are already
+    // shown inside the decoded well — hide the top-level duplicates.
+    const summarySection = $("success-tx-summary").parentElement;
+    const toSection = $("success-tx-to").parentElement;
+    if (hasDecoded) {
+        summarySection.classList.add("hidden");
+        toSection.classList.add("hidden");
+    } else {
+        summarySection.classList.remove("hidden");
+        toSection.classList.remove("hidden");
+        $("success-tx-summary").textContent = d.amount + " " + d.symbol;
+        $("success-tx-to").innerHTML = toAddressHtml(d.to);
+    }
+
     $("success-tx-block").textContent = String(d.blockNumber);
     $("success-tx-hash").innerHTML = txHashHtml(d.hash);
 
     // Show decoded calldata details if present
     const decodedEl = $("success-tx-decoded");
-    if (decodedEl && d.decoded) {
+    if (decodedEl && hasDecoded) {
         decodedEl.innerHTML = decodedDetailsHtml(d.decoded);
         decodedEl.classList.remove("hidden");
     } else if (decodedEl) {

src/shared/transactions.js

@@ -251,4 +251,36 @@ function filterTransactions(txs, filters = {}) {
     return { transactions: filtered, newFraudContracts: newFraud };
 }
 
-module.exports = { fetchRecentTransactions, filterTransactions };
+async function hasTransactionHistory(address, blockscoutUrl) {
+    try {
+        const resp = await debugFetch(blockscoutUrl + "/addresses/" + address);
+        if (!resp.ok) {
+            // If Blockscout returns 404, the address has never been seen on-chain.
+            if (resp.status === 404) return false;
+            log.errorf(
+                "blockscout address check:",
+                resp.status,
+                resp.statusText,
+            );
+            return null; // unknown
+        }
+        const data = await resp.json();
+        // Blockscout v2 address endpoint returns tx counts.
+        // An address with no history may still exist (e.g. received ETH once
+        // but shows 0 outgoing). We check both transactions_count and
+        // token_transfers_count to be thorough.
+        const txCount =
+            (parseInt(data.transactions_count, 10) || 0) +
+            (parseInt(data.token_transfers_count, 10) || 0);
+        return txCount > 0;
+    } catch (e) {
+        log.errorf("hasTransactionHistory error:", e.message);
+        return null; // unknown, don't block the user
+    }
+}
+
+module.exports = {
+    fetchRecentTransactions,
+    filterTransactions,
+    hasTransactionHistory,
+};

src/shared/uniswap.js

@@ -445,12 +445,18 @@ function decode(data, toAddress) {
             const maxUint160 = BigInt(
                 "0xffffffffffffffffffffffffffffffffffffffff",
             );
-            const amountStr =
-                inputAmount >= maxUint160
-                    ? "Unlimited"
-                    : formatAmount(inputAmount, inInfo.decimals) +
-                      (inSymbol ? " " + inSymbol : "");
-            details.push({ label: "Amount", value: amountStr });
+            const isUnlimited = inputAmount >= maxUint160;
+            const amountRaw = isUnlimited
+                ? "Unlimited"
+                : formatAmount(inputAmount, inInfo.decimals);
+            const amountStr = isUnlimited
+                ? "Unlimited"
+                : amountRaw + (inSymbol ? " " + inSymbol : "");
+            details.push({
+                label: "Amount",
+                value: amountStr,
+                rawValue: amountRaw,
+            });
         }
 
         if (outSymbol) {