let counterLabel = document.getElementById("counter");
let count = 0;
let username = document.getElementById("username").value;

function* generate(email) {
    if(email.length <= 1) {
        yield email;
    } else {
        let head = email[0];
        let tail = email.slice(1);
        for(let item of generate(tail)) {
            yield head + item;
            yield head + '.' + item;
        }
    }
}

function updateEmails() {
    let username = document.getElementById("username").value;
    document.getElementById("emails").value = '';
    count = 0;
    let startTime = new Date();
    for(let message of generate(username)) {
        document.getElementById("emails").value += message + '@gmail.com\r\n';
        count += 1;
        counterLabel.innerText = 'Generated: ' + count;
    }
    document.getElementById("emails").value = document.getElementById("emails").value.slice(0, -1);
    let endTime = new Date();
    let timeDiff = endTime - startTime;
    console.log('Finished in ' + timeDiff + 'ms');
}
document.getElementById("username").oninput = function() {
    let newUsername = document.getElementById("username").value;
    if(username !== newUsername) {
        username = newUsername;
        if(username.length > 1) {
            setTimeout(updateEmails, 150);
        }
    }
};
document.getElementById("save").onclick = function() {
    blob = new Blob([document.getElementById('emails').value], {
        type: "text/plain;charset=utf-8",
        endings: "transparent"
    });
    FileSaver.saveAs(blob, document.getElementById('username').value + ".txt");
};