AutistMask/src/popup/views/send.js

// Send view: collect To, Amount, Token. Then go to confirmation.

const {
    $,
    showFlash,
    addressTitle,
    displaySymbol,
    escapeHtml,
    nativeCurrency,
    renderAddressHtml,
    attachCopyHandlers,
    goBack,
    tokenSourcesByChainId,
} = require("./helpers");
const { state, currentAddress, currentNetwork } = require("../../shared/state");
let ctx;
const { getProvider } = require("../../shared/balances");
const { resolveTokenDecimals } = require("../../shared/approvalAmount");
const { resolveSymbol } = require("../../shared/tokenList");
const { isLowHolderCount } = require("../../shared/holders");
const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
const {
    truncateAmountNeverZero,
    isBelowOneMillionth,
} = require("../../shared/amountDisplay");
const {
    feeReserveWei,
    isValidAmount,
    maxEthAmount,
    maxTokenAmount,
} = require("../../shared/txValidation");
const { log } = require("../../shared/log");
const { getAddress, parseEther } = require("ethers");

const ZERO_ADDRESS = "0x0000000000000000000000000000000000000000";

// Whether the amount field holds what Max filled in. The confirmation screen
// re-derives a max ETH amount from its own fee estimate; typing in the field
// makes it an ordinary amount again.
let amountIsMax = false;

// Counts the times the Send screen has opened, so a Max fee estimate started
// before it was last opened fills nothing in.
let sendScreenOpenings = 0;

/**
 * Validate a destination address string.
 * Returns { valid: true } or { valid: false, error: "..." }.
 */
function validateToAddress(value) {
    const v = value.trim();
    if (!v) return { valid: false, error: "" };

    // ENS names: contains a dot and doesn't start with 0x
    if (v.includes(".") && !v.startsWith("0x")) {
        // Basic ENS format check: at least one label before and after dot
        if (/^[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+$/.test(v)) {
            return { valid: true };
        }
        return {
            valid: false,
            error: "Please enter a valid ENS name.",
        };
    }

    // Must look like an Ethereum address
    if (!/^0x[0-9a-fA-F]{40}$/.test(v)) {
        return {
            valid: false,
            error: "Please enter a valid Ethereum address.",
        };
    }

    // Reject zero address
    if (v.toLowerCase() === ZERO_ADDRESS) {
        return {
            valid: false,
            error: "Sending to the zero address is not allowed.",
        };
    }

    // EIP-55 checksum validation: all-lowercase is ok, otherwise must match checksum
    if (v !== v.toLowerCase()) {
        try {
            const checksummed = getAddress(v);
            if (checksummed !== v) {
                return {
                    valid: false,
                    error: "Address checksum is invalid. Check the address.",
                };
            }
        } catch {
            return {
                valid: false,
                error: "Address checksum is invalid. Check the address.",
            };
        }
    }

    // Warn if sending to own address
    const addr = currentAddress();
    if (addr && v.toLowerCase() === addr.address.toLowerCase()) {
        // Allow but will warn — we return valid with a warning
        return {
            valid: true,
            warning: "This is your own address. Are you sure?",
        };
    }

    return { valid: true };
}

function updateToValidation() {
    const input = $("send-to");
    const errorEl = $("send-to-error");
    const btn = $("btn-send-review");
    const value = input.value.trim();

    if (!value) {
        errorEl.textContent = "";
        btn.disabled = true;
        btn.classList.add("opacity-50");
        return;
    }

    const result = validateToAddress(value);
    if (!result.valid) {
        errorEl.textContent = result.error;
        errorEl.style.color = "#cc0000";
        btn.disabled = true;
        btn.classList.add("opacity-50");
    } else if (result.warning) {
        errorEl.textContent = result.warning;
        errorEl.style.color = "#b8860b";
        btn.disabled = false;
        btn.classList.remove("opacity-50");
    } else {
        errorEl.textContent = "";
        btn.disabled = false;
        btn.classList.remove("opacity-50");
    }
}

function renderSendTokenSelect(addr) {
    // Only Blockscout reports the tokens the user has not tracked.
    $("send-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
    const sel = $("send-token");
    sel.innerHTML = `<option value="ETH">${escapeHtml(nativeCurrency())}</option>`;
    const fraudSet = new Set(
        (state.fraudContracts || []).map((a) => a.toLowerCase()),
    );
    for (const t of addr.tokenBalances || []) {
        // A holding below 0.000001 is left out, as the balance lists leave it
        // out. Its token's own screen can still send it: there
        // state.selectedToken picks the token, not this list.
        if (isBelowOneMillionth(t.balance)) continue;
        if (isSpoofedSymbol(t.symbol, t.address, currentNetwork().chainId)) {
            continue;
        }
        if (fraudSet.has(t.address.toLowerCase())) continue;
        // An unknown holder count does not withhold a token the user holds:
        // only a count the explorer actually reported as below the threshold
        // does.  Otherwise a missing field makes a real asset unspendable.
        if (state.hideLowHolderTokens && isLowHolderCount(t.holders)) continue;
        const opt = document.createElement("option");
        opt.value = t.address;
        opt.textContent = displaySymbol(t.symbol);
        sel.appendChild(opt);
    }
}

// The token balance the Send screen states, and the scale it hands the
// confirmation screen, which reads the balance itself from the network it is
// drawn for.
//
// The scale is resolved the same way balances.js resolved the scale it
// DISPLAYED this token's balance at: bundled list, then the user's tracked
// tokens, then the explorer. The stored tokenBalances[].decimals is the
// explorer's own answer alone, so reading it raw carries a null forward for a
// token the wallet does know the scale of — and displayedDecimals() then throws
// inside estimateGas(), which the confirmation screen reports as an unestimable
// fee. Unsendable, over a scale that was never in doubt
// (https://git.eeqj.de/sneak/AutistMask/issues/349). Still null when nothing
// knows: no fallback.
//
// Resolved WITH `wallets`, which balances.js does not pass: that adds
// explorerDecimals()'s cross-address check, so a contract two addresses report
// different scales for answers null rather than picking one. That check has to
// apply here, because this scale encodes the transfer — it is carried forward
// so the transfer is encoded with the number the user read rather than with
// whatever the contract answers at signing time (see
// src/shared/transferAmount.js). balances.js is formatting one explorer row at
// fetch time and cannot consult a state it is in the middle of replacing. As on
// the approval screens, tokenSourcesByChainId() gives the wallets only while
// "Use Blockscout" is on.
//
// The two resolutions can therefore differ, and where they do, the stored
// `balance` is a quantity computed at a scale this screen has just declined to
// stand behind, so it is withdrawn: unknown scale means unknown balance. It is
// null rather than "0": this screen states it as unknown, as the confirmation
// screen does, and Max fills nothing in for it. Only a stored quantity is
// withdrawn: the "0" for a token that has no row at all is an absence of
// holdings, which is true at every scale. A token with no row whose tracked
// record carries `balanceNotFetched` gets null instead, because no refresh has
// read its balance.
function tokenBalanceAndDecimals(addr, token) {
    const tb = (addr.tokenBalances || []).find(
        (t) => t.address.toLowerCase() === token.toLowerCase(),
    );
    const tokenDecimals = resolveTokenDecimals(token, tokenSourcesByChainId());
    if (!tb) {
        const tracked = state.trackedTokens.find(
            (t) => t.address.toLowerCase() === token.toLowerCase(),
        );
        const notRead = tracked && tracked.balanceNotFetched;
        return { tokenBalance: notRead ? null : "0", tokenDecimals };
    }
    if (tokenDecimals === null) return { tokenBalance: null, tokenDecimals };
    return { tokenBalance: tb.balance ?? null, tokenDecimals };
}

function updateSendBalance() {
    const addr = currentAddress();
    if (!addr) return;
    const title = addressTitle(addr.address, state.wallets);
    $("send-from").innerHTML = renderAddressHtml(addr.address, {
        title,
        ensName: addr.ensName,
    });
    attachCopyHandlers($("send-from"));
    const token = state.selectedToken || $("send-token").value;
    if (token === "ETH") {
        $("send-balance").textContent =
            "Current balance: " +
            truncateAmountNeverZero(addr.balance || "0") +
            " " +
            nativeCurrency();
    } else {
        const symbol = resolveSymbol(
            token,
            addr.tokenBalances,
            state.trackedTokens,
            currentNetwork().chainId,
        );
        // A null balance is a holding whose scale is unknown. Saying a figure
        // for it would be a claim about the amount, so it reads as the
        // confirmation screen's balance line reads it; the send itself is
        // refused later by transferAmountUnits() for the same missing scale.
        const bal = tokenBalanceAndDecimals(addr, token).tokenBalance;
        $("send-balance").textContent =
            bal == null
                ? "Current balance: unknown (" + symbol + ")"
                : "Current balance: " +
                  truncateAmountNeverZero(bal) +
                  " " +
                  symbol;
    }
}

// Fill the amount field with the most the selected holding can send: a
// token's whole balance (cut to 18 decimal places), or for ETH the exact
// balance minus the fee reserve the confirmation screen checks against, never
// the rounded balance the screen shows. Where there is nothing to fill in, a
// flash message says why.
async function fillMaxAmount() {
    const addr = currentAddress();
    if (!addr) return;
    const token = state.selectedToken || $("send-token").value;

    if (token !== "ETH") {
        const { tokenBalance: bal, tokenDecimals } = tokenBalanceAndDecimals(
            addr,
            token,
        );
        if (bal == null) {
            showFlash("This token's balance is unknown.");
            return;
        }
        const amount = maxTokenAmount(bal);
        // The balance is stored at the token's own decimal places and cut to
        // 18 above, so the only balance this refuses is zero.
        if (!isValidAmount(amount, tokenDecimals)) {
            showFlash("This token's balance is zero.");
            return;
        }
        $("send-amount").value = amount;
        amountIsMax = true;
        return;
    }

    // The fee is estimated for this recipient, as the confirmation screen
    // estimates it: sending to a contract can cost more gas.
    const to = $("send-to").value.trim();
    if (!validateToAddress(to).valid) {
        showFlash("Please enter a recipient address first.");
        return;
    }
    const typed = $("send-amount").value;
    const opening = sendScreenOpenings;
    let feeWei = null;
    try {
        const provider = getProvider(state.rpcUrl, state.networkId);
        const [feeData, gasLimit] = await Promise.all([
            provider.getFeeData(),
            provider.estimateGas({
                from: addr.address,
                to,
                value: parseEther(addr.balance || "0"),
            }),
        ]);
        feeWei = feeReserveWei(gasLimit, feeData);
    } catch (e) {
        // Cancelled by the popup closing, not failed: see pageClosed in
        // src/popup/index.js.
        if (ctx.pageClosed.aborted) return;
        log.errorf(
            "max amount fee estimate failed:",
            e.shortMessage || e.message,
        );
    }
    // While the estimate was in flight the user left the screen (and perhaps
    // opened it again), typed an amount, or changed the address, the holding
    // or the recipient: what they did wins.
    if (
        state.currentView !== "send" ||
        sendScreenOpenings !== opening ||
        currentAddress()?.address !== addr.address ||
        (state.selectedToken || $("send-token").value) !== token ||
        $("send-to").value.trim() !== to ||
        $("send-amount").value !== typed
    ) {
        return;
    }

    if (feeWei === null) {
        showFlash("The network fee could not be estimated.");
        return;
    }
    const amount = maxEthAmount(addr.balance, feeWei);
    if (amount === null) {
        showFlash("Your balance does not cover the network fee.");
        return;
    }
    $("send-amount").value = amount;
    amountIsMax = true;
}

function init(_ctx) {
    ctx = _ctx;
    $("send-token").addEventListener("change", () => {
        // A filled-in maximum is the maximum of the holding it was filled in
        // for.
        if (amountIsMax) {
            $("send-amount").value = "";
            amountIsMax = false;
        }
        updateSendBalance();
    });

    $("btn-send-max").addEventListener("click", fillMaxAmount);
    $("send-amount").addEventListener("input", () => {
        amountIsMax = false;
    });

    // Initial state: disable review button until address is entered
    $("btn-send-review").disabled = true;
    $("btn-send-review").classList.add("opacity-50");

    // Validate address on input
    $("send-to").addEventListener("input", updateToValidation);

    $("btn-send-review").addEventListener("click", async () => {
        const to = $("send-to").value.trim();
        const amount = $("send-amount").value.trim();
        if (!to) {
            showFlash("Please enter a recipient address.");
            return;
        }

        // Re-validate before proceeding
        const validation = validateToAddress(to);
        if (!validation.valid) {
            showFlash(
                validation.error || "Please enter a valid Ethereum address.",
            );
            return;
        }

        const token = state.selectedToken || $("send-token").value;
        const addr = currentAddress();

        let tokenSymbol = null;
        let tokenDecimals = null;
        if (token !== "ETH") {
            tokenSymbol = resolveSymbol(
                token,
                addr.tokenBalances,
                state.trackedTokens,
                currentNetwork().chainId,
            );
            ({ tokenDecimals } = tokenBalanceAndDecimals(addr, token));
        }

        // The confirmation screen's own amount check, so it is never shown
        // an amount it would refuse.
        if (!isValidAmount(amount, tokenDecimals)) {
            showFlash("Please enter a valid amount.");
            return;
        }

        // Resolve ENS if needed
        let resolvedTo = to;
        let ensName = null;
        if (to.includes(".") && !to.startsWith("0x")) {
            try {
                const provider = getProvider(state.rpcUrl, state.networkId);
                const resolved = await provider.resolveName(to);
                // getProvider() does not look up a name resolved off-chain,
                // so such a name comes back with no address too. The message
                // covers both, in the one line the flash area shows.
                if (!resolved) {
                    showFlash("That ENS name has no on-chain address.");
                    return;
                }
                resolvedTo = resolved;
                ensName = to;
            } catch {
                showFlash("Failed to resolve ENS name.");
                return;
            }
        }

        ctx.showConfirmTx({
            from: addr.address,
            to: resolvedTo,
            ensName: ensName,
            amount: amount,
            token: token,
            tokenSymbol: tokenSymbol,
            tokenDecimals: tokenDecimals,
            max: amountIsMax,
        });
    });

    $("btn-send-back").addEventListener("click", () => {
        $("send-token-dropdown").classList.remove("hidden");
        $("send-token-static").classList.add("hidden");
        goBack();
    });
}

// Called each time the Send screen opens, with its fields cleared.
function resetSendValidation() {
    sendScreenOpenings++;
    amountIsMax = false;
    const errorEl = $("send-to-error");
    const btn = $("btn-send-review");
    if (errorEl) errorEl.textContent = "";
    if (btn) {
        btn.disabled = true;
        btn.classList.add("opacity-50");
    }
}

module.exports = {
    init,
    updateSendBalance,
    renderSendTokenSelect,
    resetSendValidation,
};