(function() {

    var mnemonic = new Mnemonic("english");
    var bip32RootKey = null;
    var bip32ExtendedKey = null;
    var network = Bitcoin.networks.bitcoin;
    var addressRowTemplate = $("#address-row-template");

    var phraseChangeTimeoutEvent = null;

    var DOM = {};
    DOM.phrase = $(".phrase");
    DOM.generate = $(".generate");
    DOM.rootKey = $(".root-key");
    DOM.extendedPrivKey = $(".extended-priv-key");
    DOM.extendedPubKey = $(".extended-pub-key");
    DOM.bip32path = $("#bip32-path");
    DOM.bip44path = $("#bip44-path");
    DOM.bip44purpose = $("#bip44 .purpose");
    DOM.bip44coin = $("#bip44 .coin");
    DOM.bip44account = $("#bip44 .account");
    DOM.bip44change = $("#bip44 .change");
    DOM.strength = $(".strength");
    DOM.addresses = $(".addresses");
    DOM.rowsToAdd = $(".rows-to-add");
    DOM.more = $(".more");
    DOM.feedback = $(".feedback");
    DOM.tab = $(".derivation-type a");
    DOM.indexToggle = $(".index-toggle");
    DOM.addressToggle = $(".address-toggle");
    DOM.privateKeyToggle = $(".private-key-toggle");

    var derivationPath = DOM.bip44path.val();

    function init() {
        // Events
        DOM.phrase.on("keyup", delayedPhraseChanged);
        DOM.generate.on("click", generateClicked);
        DOM.more.on("click", showMore);
        DOM.bip32path.on("keyup", bip32Changed);
        DOM.bip44purpose.on("keyup", bip44Changed);
        DOM.bip44coin.on("keyup", bip44Changed);
        DOM.bip44account.on("keyup", bip44Changed);
        DOM.bip44change.on("keyup", bip44Changed);
        DOM.tab.on("click", tabClicked);
        DOM.indexToggle.on("click", toggleIndexes);
        DOM.addressToggle.on("click", toggleAddresses);
        DOM.privateKeyToggle.on("click", togglePrivateKeys);
        disableForms();
        hidePending();
        hideValidationError();
    }

    // Event handlers

    function delayedPhraseChanged() {
        hideValidationError();
        showPending();
        if (phraseChangeTimeoutEvent != null) {
            clearTimeout(phraseChangeTimeoutEvent);
        }
        phraseChangeTimeoutEvent = setTimeout(phraseChanged, 400);
    }

    function phraseChanged() {
        showPending();
        hideValidationError();
        // Get the mnemonic phrase
        var phrase = DOM.phrase.val();
        var errorText = findPhraseErrors(phrase);
        if (errorText) {
            showValidationError(errorText);
            return;
        }
        // Get the derivation path
        var errorText = findDerivationPathErrors();
        if (errorText) {
            showValidationError(errorText);
            return;
        }
        // Calculate and display
        calcBip32Seed(phrase, derivationPath);
        displayBip32Info();
        hidePending();
    }

    function generateClicked() {
        clearDisplay();
        showPending();
        setTimeout(function() {
            var phrase = generateRandomPhrase();
            if (!phrase) {
                return;
            }
            phraseChanged();
        }, 50);
    }

    function tabClicked(e) {
        var activePath = $(e.target.getAttribute("href") + " .path");
        derivationPath = activePath.val();
        derivationChanged();
    }

    function derivationChanged() {
        delayedPhraseChanged();
    }

    function bip32Changed() {
        derivationPath = DOM.bip32path.val();
        derivationChanged();
    }

    function bip44Changed() {
        setBip44DerivationPath();
        derivationPath = DOM.bip44path.val();
        derivationChanged();
    }

    function toggleIndexes() {
        $("td.index span").toggleClass("invisible");
    }

    function toggleAddresses() {
        $("td.address span").toggleClass("invisible");
    }

    function togglePrivateKeys() {
        $("td.privkey span").toggleClass("invisible");
    }

    // Private methods

    function generateRandomPhrase() {
        if (!hasStrongRandom()) {
            var errorText = "This browser does not support strong randomness";
            showValidationError(errorText);
            return;
        }
        var numWords = parseInt(DOM.strength.val());
        // Check strength is an integer
        if (isNaN(numWords)) {
            DOM.strength.val("12");
            numWords = 12;
        }
        // Check strength is a multiple of 32, if not round it down
        if (numWords % 3 != 0) {
            numWords = Math.floor(numWords / 3) * 3;
            DOM.strength.val(numWords);
        }
        // Check strength is at least 32
        if (numWords == 0) {
            numWords = 3;
            DOM.strength.val(numWords);
        }
        var strength = numWords / 3 * 32;
        var words = mnemonic.generate(strength);
        DOM.phrase.val(words);
        return words;
    }

    function calcBip32Seed(phrase, path) {
        var seed = mnemonic.toSeed(phrase);
        var seedHash = Bitcoin.crypto.sha256(seed).toString("hex");
        bip32RootKey = Bitcoin.HDNode.fromSeedHex(seedHash, network);
        bip32ExtendedKey = bip32RootKey;
        // Derive the key from the path
        var pathBits = path.split("/");
        for (var i=0; i<pathBits.length; i++) {
            var bit = pathBits[i];
            var index = parseInt(bit);
            if (isNaN(index)) {
                continue;
            }
            var hardened = bit[bit.length-1] == "'";
            if (hardened) {
                bip32ExtendedKey = bip32ExtendedKey.deriveHardened(index);
            }
            else {
                bip32ExtendedKey = bip32ExtendedKey.derive(index);
            }
        }
    }

    function showValidationError(errorText) {
        DOM.feedback
            .text(errorText)
            .show();
    }

    function hideValidationError() {
        DOM.feedback
            .text("")
            .hide();
    }

    function findPhraseErrors(phrase) {
        // TODO make this right
        // Preprocess the words
        var parts = phrase.split(" ");
        var proper = [];
        for (var i=0; i<parts.length; i++) {
            var part = parts[i];
            if (part.length > 0) {
                // TODO check that lowercasing is always valid to do
                proper.push(part.toLowerCase());
            }
        }
        // TODO some levenstein on the words
        var properPhrase = proper.join(' ');
        // Check the words are valid
        var isValid = mnemonic.check(properPhrase);
        if (!isValid) {
            return "Invalid mnemonic";
        }
        return false;
    }

    function findDerivationPathErrors(path) {
        // TODO
        return false;
    }

    function displayBip32Info() {
        // Display the key
        var rootKey = bip32RootKey.toBase58();
        DOM.rootKey.val(rootKey);
        var extendedPrivKey = bip32ExtendedKey.toBase58();
        DOM.extendedPrivKey.val(extendedPrivKey);
        var extendedPubKey = bip32ExtendedKey.toBase58(false);
        DOM.extendedPubKey.val(extendedPubKey);
        // Display the addresses and privkeys
        clearAddressesList();
        displayAddresses(0, 20);
    }

    function displayAddresses(start, total) {
        for (var i=0; i<total; i++) {
            var index = i+ start;
            var key = bip32ExtendedKey.derive(index);
            var address = key.getAddress().toString();
            var privkey = key.privKey.toWIF();
            addAddressToList(index, address, privkey);
        }
    }

    function showMore() {
        var start = DOM.addresses.children().length;
        var rowsToAdd = parseInt(DOM.rowsToAdd.val());
        if (isNaN(rowsToAdd)) {
            rowsToAdd = 20;
            DOM.rowsToAdd.val("20");
        }
        if (rowsToAdd > 200) {
            var msg = "Generating " + rowsToAdd + " rows could take a while. ";
            msg += "Do you want to continue?";
            if (!confirm(msg)) {
                return;
            }
        }
        showPending();
        setTimeout(function() {
        displayAddresses(start, rowsToAdd);
        hidePending();
        }, 50);
    }

    function clearDisplay() {
        clearAddressesList();
        clearKey();
        hideValidationError();
    }

    function clearAddressesList() {
        DOM.addresses.empty();
    }

    function clearKey() {
        DOM.rootKey.val("");
        DOM.extendedPrivKey.val("");
        DOM.extendedPubKey.val("");
    }

    function addAddressToList(index, address, privkey) {
        var row = $(addressRowTemplate.html());
        row.find(".index span").text(index);
        row.find(".address span").text(address);
        row.find(".privkey span").text(privkey);
        DOM.addresses.append(row);
    }

    function hasStrongRandom() {
        return 'crypto' in window && window['crypto'] !== null;
    }

    function disableForms() {
        $("form").on("submit", function(e) {
            e.preventDefault();
        });
    }

    function setBip44DerivationPath() {
        var purpose = parseIntNoNaN(DOM.bip44purpose.val(), 44);
        var coin = parseIntNoNaN(DOM.bip44coin.val(), 0);
        var account = parseIntNoNaN(DOM.bip44account.val(), 0);
        var change = parseIntNoNaN(DOM.bip44change.val(), 0);
        var path = "m/";
        path += purpose + "'/";
        path += coin + "'/";
        path += account + "'/";
        path += change;
        DOM.bip44path.val(path);
    }

    function parseIntNoNaN(val, defaultVal) {
        var v = parseInt(val);
        if (isNaN(v)) {
            return defaultVal;
        }
        return v;
    }

    function showPending() {
        DOM.feedback
            .text("Calculating...")
            .show();
    }

    function hidePending() {
        DOM.feedback
            .text("")
            .hide();
    }

    init();

})();