(function() {

    // mnemonics is populated as required by getLanguage
    var mnemonics = { "english": new Mnemonic("english") };
    var mnemonic = mnemonics["english"];
    var seed = null
    var bip32RootKey = null;
    var bip32ExtendedKey = null;
    var network = bitcoin.networks.bitcoin;
    var addressRowTemplate = $("#address-row-template");

    var showIndex = true;
    var showAddress = true;
    var showPrivKey = true;

    var phraseChangeTimeoutEvent = null;
    var rootKeyChangedTimeoutEvent = null;

    var DOM = {};
    DOM.network = $(".network");
    DOM.phraseNetwork = $("#network-phrase");
    DOM.phrase = $(".phrase");
    DOM.passphrase = $(".passphrase");
    DOM.generate = $(".generate");
    DOM.seed = $(".seed");
    DOM.rootKey = $(".root-key");
    DOM.extendedPrivKey = $(".extended-priv-key");
    DOM.extendedPubKey = $(".extended-pub-key");
    DOM.bip32tab = $("#bip32-tab");
    DOM.bip44tab = $("#bip44-tab");
    DOM.bip32panel = $("#bip32");
    DOM.bip44panel = $("#bip44");
    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.hardenedAddresses = $(".hardened-addresses");
    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");
    DOM.languages = $(".languages a");

    function init() {
        // Events
        DOM.network.on("change", networkChanged);
        DOM.phrase.on("input", delayedPhraseChanged);
        DOM.passphrase.on("input", delayedPhraseChanged);
        DOM.generate.on("click", generateClicked);
        DOM.more.on("click", showMore);
        DOM.rootKey.on("input", delayedRootKeyChanged);
        DOM.bip32path.on("input", calcForDerivationPath);
        DOM.bip44purpose.on("input", calcForDerivationPath);
        DOM.bip44coin.on("input", calcForDerivationPath);
        DOM.bip44account.on("input", calcForDerivationPath);
        DOM.bip44change.on("input", calcForDerivationPath);
        DOM.tab.on("shown.bs.tab", calcForDerivationPath);
        DOM.hardenedAddresses.on("change", calcForDerivationPath);
        DOM.indexToggle.on("click", toggleIndexes);
        DOM.addressToggle.on("click", toggleAddresses);
        DOM.privateKeyToggle.on("click", togglePrivateKeys);
        DOM.languages.on("click", languageChanged);
        disableForms();
        hidePending();
        hideValidationError();
        populateNetworkSelect();
    }

    // Event handlers

    function networkChanged(e) {
        var networkIndex = e.target.value;
        networks[networkIndex].onSelect();
        if (seed != null) {
            phraseChanged();
        }
        else {
            rootKeyChanged();
        }
    }

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

    function phraseChanged() {
        showPending();
        hideValidationError();
        setMnemonicLanguage();
        // Get the mnemonic phrase
        var phrase = DOM.phrase.val();
        var errorText = findPhraseErrors(phrase);
        if (errorText) {
            showValidationError(errorText);
            return;
        }
        // Calculate and display
        var passphrase = DOM.passphrase.val();
        calcBip32RootKeyFromSeed(phrase, passphrase);
        calcForDerivationPath();
        hidePending();
    }

    function delayedRootKeyChanged() {
        // Warn if there is an existing mnemonic or passphrase.
        if (DOM.phrase.val().length > 0 || DOM.passphrase.val().length > 0) {
            if (!confirm("This will clear existing mnemonic and passphrase")) {
                DOM.rootKey.val(bip32RootKey);
                return
            }
        }
        hideValidationError();
        showPending();
        // Clear existing mnemonic and passphrase
        DOM.phrase.val("");
        DOM.passphrase.val("");
        seed = null;
        if (rootKeyChangedTimeoutEvent != null) {
            clearTimeout(rootKeyChangedTimeoutEvent);
        }
        rootKeyChangedTimeoutEvent = setTimeout(rootKeyChanged, 400);
    }

    function rootKeyChanged() {
        showPending();
        hideValidationError();
        // Validate the root key TODO
        var rootKeyBase58 = DOM.rootKey.val();
        var errorText = validateRootKey(rootKeyBase58);
        if (errorText) {
            showValidationError(errorText);
            return;
        }
        // Calculate and display
        calcBip32RootKeyFromBase58(rootKeyBase58);
        calcForDerivationPath();
        hidePending();
    }

    function calcForDerivationPath() {
        showPending();
        hideValidationError();
        // Get the derivation path
        var derivationPath = getDerivationPath();
        var errorText = findDerivationPathErrors(derivationPath);
        if (errorText) {
            showValidationError(errorText);
            return;
        }
        calcBip32ExtendedKey(derivationPath);
        displayBip32Info();
        hidePending();
    }

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

    function languageChanged() {
        setTimeout(function() {
            setMnemonicLanguage();
            if (DOM.phrase.val().length > 0) {
                var newPhrase = convertPhraseToNewLanguage();
                DOM.phrase.val(newPhrase);
                phraseChanged();
            }
            else {
                DOM.generate.trigger("click");
            }
        }, 50);
    }

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

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

    function togglePrivateKeys() {
        showPrivKey = !showPrivKey;
        $("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());
        var strength = numWords / 3 * 32;
        var words = mnemonic.generate(strength);
        DOM.phrase.val(words);
        return words;
    }

    function calcBip32RootKeyFromSeed(phrase, passphrase) {
        seed = mnemonic.toSeed(phrase, passphrase);
        bip32RootKey = bitcoin.HDNode.fromSeedHex(seed, network);
    }

    function calcBip32RootKeyFromBase58(rootKeyBase58) {
        bip32RootKey = bitcoin.HDNode.fromBase58(rootKeyBase58, network);
    }

    function calcBip32ExtendedKey(path) {
        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
        phrase = mnemonic.normalizeString(phrase);
        var words = phraseToWordArray(phrase);
        // Check each word
        for (var i=0; i<words.length; i++) {
            var word = words[i];
            var language = getLanguage();
            if (WORDLISTS[language].indexOf(word) == -1) {
                console.log("Finding closest match to " + word);
                var nearestWord = findNearestWord(word);
                return word + " not in wordlist, did you mean " + nearestWord + "?";
            }
        }
        // Check the words are valid
        var properPhrase = wordArrayToPhrase(words);
        var isValid = mnemonic.check(properPhrase);
        if (!isValid) {
            return "Invalid mnemonic";
        }
        return false;
    }

    function validateRootKey(rootKeyBase58) {
        try {
            bitcoin.HDNode.fromBase58(rootKeyBase58);
        }
        catch (e) {
            return "Invalid root key";
        }
        return "";
    }

    function getDerivationPath() {
        if (DOM.bip44tab.hasClass("active")) {
            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);
            var derivationPath = DOM.bip44path.val();
            console.log("Using derivation path from BIP44 tab: " + derivationPath);
            return derivationPath;
        }
        else if (DOM.bip32tab.hasClass("active")) {
            var derivationPath = DOM.bip32path.val();
            console.log("Using derivation path from BIP32 tab: " + derivationPath);
            return derivationPath;
        }
        else {
            console.log("Unknown derivation path");
        }
    }

    function findDerivationPathErrors(path) {
        // TODO is not perfect but is better than nothing
        // Inspired by
        // https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#test-vectors
        // and
        // https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#extended-keys
        var maxDepth = 255; // TODO verify this!!
        var maxIndexValue = Math.pow(2, 31); // TODO verify this!!
        if (path[0] != "m") {
            return "First character must be 'm'";
        }
        if (path.length > 1) {
            if (path[1] != "/") {
                return "Separator must be '/'";
            }
            var indexes = path.split("/");
            if (indexes.length > maxDepth) {
                return "Derivation depth is " + indexes.length + ", must be less than " + maxDepth;
            }
            for (var depth = 1; depth<indexes.length; depth++) {
                var index = indexes[depth];
                var invalidChars = index.replace(/^[0-9]+'?$/g, "")
                if (invalidChars.length > 0) {
                    return "Invalid characters " + invalidChars + " found at depth " + depth;
                }
                var indexValue = parseInt(index.replace("'", ""));
                if (isNaN(depth)) {
                    return "Invalid number at depth " + depth;
                }
                if (indexValue > maxIndexValue) {
                    return "Value of " + indexValue + " at depth " + depth + " must be less than " + maxIndexValue;
                }
            }
        }
        return false;
    }

    function displayBip32Info() {
        // Display the key
        DOM.seed.val(seed);
        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;
            new TableRow(index);
        }
    }

    function TableRow(index) {

        var useHardenedAddresses = DOM.hardenedAddresses.prop("checked");

        function init() {
            calculateValues();
        }

        function calculateValues() {
            setTimeout(function() {
                var key = "";
                if (useHardenedAddresses) {
                    key = bip32ExtendedKey.deriveHardened(index);
                }
                else {
                    key = bip32ExtendedKey.derive(index);
                }
                var address = key.getAddress().toString();
                var privkey = key.privKey.toWIF(network);
                var indexText = getDerivationPath() + "/" + index;
                if (useHardenedAddresses) {
                    indexText = indexText + "'";
                }
                addAddressToList(indexText, address, privkey);
            }, 50)
        }

        init();

    }

    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;
            }
        }
        displayAddresses(start, rowsToAdd);
    }

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

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

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

    function addAddressToList(indexText, address, privkey) {
        var row = $(addressRowTemplate.html());
        // Elements
        var indexCell = row.find(".index span");
        var addressCell = row.find(".address span");
        var privkeyCell = row.find(".privkey span");
        // Content
        indexCell.text(indexText);
        addressCell.text(address);
        privkeyCell.text(privkey);
        // Visibility
        if (!showIndex) {
            indexCell.addClass("invisible");
        }
        if (!showAddress) {
            addressCell.addClass("invisible");
        }
        if (!showPrivKey) {
            privkeyCell.addClass("invisible");
        }
        DOM.addresses.append(row);
    }

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

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

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

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

    function findNearestWord(word) {
        var language = getLanguage();
        var words = WORDLISTS[language];
        var minDistance = 99;
        var closestWord = words[0];
        for (var i=0; i<words.length; i++) {
            var comparedTo = words[i];
            var distance = Levenshtein.get(word, comparedTo);
            if (distance < minDistance) {
                closestWord = comparedTo;
                minDistance = distance;
            }
        }
        return closestWord;
    }

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

    function populateNetworkSelect() {
        for (var i=0; i<networks.length; i++) {
            var network = networks[i];
            var option = $("<option>");
            option.attr("value", i);
            option.text(network.name);
            DOM.phraseNetwork.append(option);
        }
    }

    function getLanguage() {
        var defaultLanguage = "english";
        // Try to get from existing phrase
        var language = getLanguageFromPhrase();
        // Try to get from url if not from phrase
        if (language.length == 0) {
            language = getLanguageFromUrl();
        }
        // Default to English if no other option
        if (language.length == 0) {
            language = defaultLanguage;
        }
        return language;
    }

    function getLanguageFromPhrase(phrase) {
        // Check if how many words from existing phrase match a language.
        var language = "";
        if (!phrase) {
            phrase = DOM.phrase.val();
        }
        if (phrase.length > 0) {
            var words = phraseToWordArray(phrase);
            var languageMatches = {};
            for (l in WORDLISTS) {
                // Track how many words match in this language
                languageMatches[l] = 0;
                for (var i=0; i<words.length; i++) {
                    var wordInLanguage = WORDLISTS[l].indexOf(words[i]) > -1;
                    if (wordInLanguage) {
                        languageMatches[l]++;
                    }
                }
                // Find languages with most word matches.
                // This is made difficult due to commonalities between Chinese
                // simplified vs traditional.
                var mostMatches = 0;
                var mostMatchedLanguages = [];
                for (var l in languageMatches) {
                    var numMatches = languageMatches[l];
                    if (numMatches > mostMatches) {
                        mostMatches = numMatches;
                        mostMatchedLanguages = [l];
                    }
                    else if (numMatches == mostMatches) {
                        mostMatchedLanguages.push(l);
                    }
                }
            }
            if (mostMatchedLanguages.length > 0) {
                // Use first language and warn if multiple detected
                language = mostMatchedLanguages[0];
                if (mostMatchedLanguages.length > 1) {
                    console.warn("Multiple possible languages");
                    console.warn(mostMatchedLanguages);
                }
            }
        }
        return language;
    }

    function getLanguageFromUrl() {
        return window.location.hash.substring(1);
    }

    function setMnemonicLanguage() {
        var language = getLanguage();
        // Load the bip39 mnemonic generator for this language if required
        if (!(language in mnemonics)) {
            mnemonics[language] = new Mnemonic(language);
        }
        mnemonic = mnemonics[language];
    }

    function convertPhraseToNewLanguage() {
        var oldLanguage = getLanguageFromPhrase();
        var newLanguage = getLanguageFromUrl();
        var oldPhrase = DOM.phrase.val();
        var oldWords = phraseToWordArray(oldPhrase);
        var newWords = [];
        for (var i=0; i<oldWords.length; i++) {
            var oldWord = oldWords[i];
            var index = WORDLISTS[oldLanguage].indexOf(oldWord);
            var newWord = WORDLISTS[newLanguage][index];
            newWords.push(newWord);
        }
        newPhrase = wordArrayToPhrase(newWords);
        return newPhrase;
    }

    // TODO look at jsbip39 - mnemonic.splitWords
    function phraseToWordArray(phrase) {
        var words = phrase.split(/\s/g);
        var noBlanks = [];
        for (var i=0; i<words.length; i++) {
            var word = words[i];
            if (word.length > 0) {
                noBlanks.push(word);
            }
        }
        return noBlanks;
    }

    // TODO look at jsbip39 - mnemonic.joinWords
    function wordArrayToPhrase(words) {
        var phrase = words.join(" ");
        var language = getLanguageFromPhrase(phrase);
        if (language == "japanese") {
            phrase = words.join("\u3000");
        }
        return phrase;
    }

    var networks = [
        {
            name: "Bitcoin",
            onSelect: function() {
                network = bitcoin.networks.bitcoin;
                DOM.bip44coin.val(0);
            },
        },
        {
            name: "Bitcoin Testnet",
            onSelect: function() {
                network = bitcoin.networks.testnet;
                DOM.bip44coin.val(1);
            },
        },
        {
            name: "Litecoin",
            onSelect: function() {
                network = bitcoin.networks.litecoin;
                DOM.bip44coin.val(2);
            },
        },
        {
            name: "Dogecoin",
            onSelect: function() {
                network = bitcoin.networks.dogecoin;
                DOM.bip44coin.val(3);
            },
        },
        {
            name: "ShadowCash",
            onSelect: function() {
                network = bitcoin.networks.shadow;
                DOM.bip44coin.val(35);
            },
        },
        {
            name: "ShadowCash Testnet",
            onSelect: function() {
                network = bitcoin.networks.shadowtn;
                DOM.bip44coin.val(1);
            },
        },
        {
            name: "Viacoin",
            onSelect: function() {
                network = bitcoin.networks.viacoin;
                DOM.bip44coin.val(14);
            },
        },
        {
            name: "Viacoin Testnet",
            onSelect: function() {
                network = bitcoin.networks.viacointestnet;
                DOM.bip44coin.val(1);
            },
        },
        {
            name: "Jumbucks",
            onSelect: function() {
                network = bitcoin.networks.jumbucks;
                DOM.bip44coin.val(26);
            },
        },
        {
            name: "CLAM",
            onSelect: function() {
                network = bitcoin.networks.clam;
                DOM.bip44coin.val(23);
            },
        },
        {
            name: "DASH",
            onSelect: function() {
                network = bitcoin.networks.dash;
                DOM.bip44coin.val(5);
            },
        },
        {
            name: "Namecoin",
            onSelect: function() {
                network = bitcoin.networks.namecoin;
                DOM.bip44coin.val(7);
            },
        },
        {
            name: "Peercoin",
            onSelect: function() {
                network = bitcoin.networks.peercoin;
                DOM.bip44coin.val(6);
            },
        },
    ]

    init();

})();