const {
    $,
    showView,
    showFlash,
    goBack,
    clearViewStack,
    onViewLeave,
} = require("./helpers");
const { state, saveState } = require("../../shared/state");
const { decryptWithPassword } = require("../../shared/vault");
const {
    removeWalletFromState,
    broadcastActiveChanged,
} = require("../../shared/walletDelete");
const { INVISIBLE_CHARACTERS } = require("../../shared/symbolSpoof");

let deleteWalletIndex = null;
let lostPasswordIndex = null;
let ctx = null;

// The name shown for a wallet, and on the lost-password screen the string
// the user has to type back. One function so the two cannot disagree: a
// confirmation that asks for a name other than the one on screen is
// unusable. A name that shows nothing at all (only spaces, or only
// zero-width characters) is replaced by "Wallet N" for the same reason:
// there would be nothing on screen to type back.
function displayName(walletIdx) {
    const wallet = state.wallets[walletIdx];
    const name = wallet && wallet.name;
    if (name && confirmKey(name)) return name;
    return "Wallet " + (walletIdx + 1);
}

// What the typed confirmation and the wallet name are compared as. HTML
// collapses runs of whitespace when it renders the name, so a wallet named
// "My  Wallet" with two spaces DISPLAYS as "My Wallet": the user cannot
// see the second space and cannot type a string that matches the stored
// name. Characters that paint nothing, such as a zero-width space, are
// invisible the same way and are removed first. Comparing this form on
// both sides is what keeps the confirmation satisfiable, on the one screen
// whose whole purpose is unwedging a user who is already stuck. Case and
// surrounding space go the same way.
function confirmKey(name) {
    return name
        .replace(INVISIBLE_CHARACTERS, "")
        .trim()
        .replace(/\s+/g, " ")
        .toLowerCase();
}

// Drop the password from the DOM and the wallet selection from the
// closure. Registered as the view-leave handler as well as run on entry,
// so the typed password does not sit in the hidden view after the user
// navigates away by any route, including the Settings gear.
function clear() {
    deleteWalletIndex = null;
    $("delete-wallet-password").value = "";
    $("delete-wallet-flash").textContent = "";
    $("delete-wallet-flash").style.visibility = "hidden";
}

// The lost-password screen holds no secret — a wallet name is not one —
// but it is wiped on leave for the neighbouring reason: a typed
// confirmation left standing in a hidden view is one click away from
// destroying a wallet the user has since navigated off.
function clearLostPassword() {
    lostPasswordIndex = null;
    $("delete-wallet-lost-name-input").value = "";
    $("delete-wallet-lost-flash").textContent = "";
    $("delete-wallet-lost-flash").style.visibility = "hidden";
}

function show(walletIdx) {
    clear();
    deleteWalletIndex = walletIdx;
    $("delete-wallet-name").textContent = displayName(walletIdx);
    showView("delete-wallet-confirm");
}

// The two delete screens are siblings, not parent and child: nothing is
// pushed on the way here, and Back goes to show() rather than goBack().
// Both then have the same Back target — Settings, the screen that pushed
// delete-wallet-confirm — and re-entering through show() hands the confirm
// screen its wallet selection back, which a bare goBack() onto a view
// whose leave hook has already nulled that selection would not.
function showLostPassword() {
    const walletIdx = deleteWalletIndex;
    if (walletIdx === null) {
        goBack();
        return;
    }
    const name = displayName(walletIdx);
    clearLostPassword();
    $("delete-wallet-lost-name").textContent = name;
    $("delete-wallet-lost-name-echo").textContent = name;
    // showView() runs the leave hook of delete-wallet-confirm, which nulls
    // deleteWalletIndex, so this screen's own selection is recorded after
    // it and not before.
    showView("delete-wallet-lost-password");
    lostPasswordIndex = walletIdx;
}

// Remove the wallet and put the user somewhere sensible. Shared by both
// routes onto this screen, so the selection repair, the site-permission
// cleanup and the accountsChanged broadcast cannot drift apart between
// them.
async function finishDelete(walletIdx) {
    // Each route's confirm button was disabled by its own click handler
    // before the delete ran. Re-enable both here, on the one path they
    // share, so the two routes reset the same way and a second delete in
    // the same popup session finds a live button instead of a dead one.
    const passwordBtn = $("btn-delete-wallet-confirm");
    passwordBtn.disabled = false;
    passwordBtn.classList.remove("text-muted");
    const lostPasswordBtn = $("btn-delete-wallet-lost-confirm");
    lostPasswordBtn.disabled = false;
    lostPasswordBtn.classList.remove("text-muted");

    const { activeAddressChanged } = removeWalletFromState(state, walletIdx);

    deleteWalletIndex = null;
    lostPasswordIndex = null;

    if (!state.hasWallet) {
        clearViewStack();
        await saveState();
        // Save before broadcasting: the background reads the active
        // address back out of storage to build accountsChanged.
        if (activeAddressChanged) broadcastActiveChanged();
        showView("welcome");
        return;
    }

    await saveState();
    if (activeAddressChanged) broadcastActiveChanged();
    // Reset stack to [main] so Settings back goes home.
    // Use require() lazily to avoid circular dependency
    // (settings.js requires deleteWallet.js).
    clearViewStack();
    state.viewStack.push("main");
    ctx.renderWalletList();
    const settings = require("./settings");
    settings.show();
    showFlash("Wallet deleted.");
}

function init(_ctx) {
    ctx = _ctx;

    onViewLeave("delete-wallet-confirm", clear);
    onViewLeave("delete-wallet-lost-password", clearLostPassword);

    // No wipe here: goBack() routes through showView(), which runs the
    // leave hook.
    $("btn-delete-wallet-back").addEventListener("click", () => {
        goBack();
    });

    // The escape hatch, and deliberately not gated on anything a user who
    // has lost the password cannot produce. A password in front of
    // DISCARDING a secret protects nobody: an attacker at the popup who
    // wants the wallet gone can uninstall the extension, so the only
    // person such a gate stops is the owner who forgot it — and before
    // this route existed that owner could neither delete the wallet nor
    // import its recovery phrase again, because AddWallet refuses the xpub
    // as a duplicate while the wallet is still stored.
    $("btn-delete-wallet-lost-password").addEventListener("click", () => {
        showLostPassword();
    });

    $("btn-delete-wallet-lost-back").addEventListener("click", () => {
        const walletIdx = lostPasswordIndex;
        if (walletIdx === null) {
            goBack();
            return;
        }
        show(walletIdx);
    });

    $("btn-delete-wallet-lost-confirm").addEventListener("click", async () => {
        if (lostPasswordIndex === null) {
            $("delete-wallet-lost-flash").textContent =
                "No wallet selected for deletion.";
            $("delete-wallet-lost-flash").style.visibility = "visible";
            return;
        }

        // Case, surrounding spaces, repeated inner spaces and invisible
        // characters are not part of the confirmation; see confirmKey().
        // This asks whether the user knows which wallet they are on; it is
        // not a secret, and refusing "wallet 2" for "Wallet 2" would only
        // teach the user to distrust the control. An empty field is
        // refused whatever the wallet is called, so no stored name can
        // ever be confirmed by typing nothing.
        const typed = confirmKey($("delete-wallet-lost-name-input").value);
        const expected = displayName(lostPasswordIndex);
        if (typed === "" || typed !== confirmKey(expected)) {
            $("delete-wallet-lost-flash").textContent =
                "That is not the name of this wallet. Type " +
                expected +
                " to confirm.";
            $("delete-wallet-lost-flash").style.visibility = "visible";
            return;
        }

        const btn = $("btn-delete-wallet-lost-confirm");
        btn.disabled = true;
        btn.classList.add("text-muted");

        // finishDelete() re-enables the button; navigating away then runs
        // the leave hook that wipes the typed name.
        await finishDelete(lostPasswordIndex);
    });

    $("btn-delete-wallet-confirm").addEventListener("click", async () => {
        const pw = $("delete-wallet-password").value;
        if (!pw) {
            $("delete-wallet-flash").textContent =
                "Please enter your password.";
            $("delete-wallet-flash").style.visibility = "visible";
            return;
        }

        if (deleteWalletIndex === null) {
            $("delete-wallet-flash").textContent =
                "No wallet selected for deletion.";
            $("delete-wallet-flash").style.visibility = "visible";
            return;
        }

        const btn = $("btn-delete-wallet-confirm");
        btn.disabled = true;
        btn.classList.add("text-muted");

        const walletIdx = deleteWalletIndex;
        const wallet = state.wallets[walletIdx];

        // Verify password against the wallet's encrypted data
        try {
            await decryptWithPassword(wallet.encryptedSecret, pw);
        } catch {
            $("delete-wallet-flash").textContent =
                "That password is incorrect. Please try again.";
            $("delete-wallet-flash").style.visibility = "visible";
            btn.disabled = false;
            btn.classList.remove("text-muted");
            return;
        }

        await finishDelete(walletIdx);
    });
}

module.exports = { init, show };