var alphaChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

function generateRandomKey(length) {
    s = "";
    for (var i = 0; i < length; i++) {
        var r = Math.floor(Math.random() * 26);
        s += alphaChars[r];
    }
    return s;
}

function formatTime() {
    var a_p = "";
    var d = new Date();
    var curr_hour = d.getHours();
    if (curr_hour < 12)
    {
        a_p = "AM";
    }
    else
    {
        a_p = "PM";
    }
    if (curr_hour == 0)
    {
        curr_hour = 12;
    }
    if (curr_hour > 12)
    {
        curr_hour = curr_hour - 12;
    }

    if (curr_hour.length == 1)
        curr_hour = "0" + curr_hour;

    var curr_min = d.getMinutes();

    curr_min = curr_min + "";

    if (curr_min.length == 1)
    {
        curr_min = "0" + curr_min;
    }
    return curr_hour + ":" + curr_min + " " + a_p;
}

Key = generateRandomKey(10);
Timestamp = 0;
Counter = 0;
ClientMap = {};

function showError(err) {
    var msg = formatTime() + "  " + err;
    console.error(msg);
    $('#msgs').append($('<div>').css('color', 'red').text(msg));
};


function handleMessages(msgs, oldTime, newTime) {
    $.map(msgs, function(m) {
        var split = m.content.split("-");
        if (split.length != 2) {
            showError("Bad message " + m.content);
            return;
        }
        var client = split[0];
        var i = parseInt(split[1]);
        console.warn(client + " " + i);
        
        if (client in ClientMap) {
            var p = ClientMap[client];
            if (i - p != 1) {
                showError("[" + Key + "] Error for client " + client
                          + "! Expected " + (p+1) + ", got " + i
                          + "  (" + oldTime + " -> " + newTime + ")"
                         );
            }
        }
        ClientMap[client] = i;
    });
}

function refresh() {
    var onSuccess = function(json) {
        try {
            handleMessages(json.messages, Timestamp, json.timestamp);
            Timestamp = json.timestamp;
        } catch(e) {
            console.error(e);
            $('#msgs').append($('<div>').css('color', 'red').text(e));
        }
        setTimeout(refresh, 1000);
    };
    var onError = function(resp, textStatus, errorThrown) {
        console.error($.trim(resp.responseText));
        setTimeout(refresh, 1000);
    };

    $.ajax({
        type: 'GET',
        timeout: 5000,
        url: '/refresh',
        data: { 'room': 'test', 'since': Timestamp },
        cache: false,
        dataType: 'json',
        success: onSuccess,
        error: onError
    });
}

function postMessageWrapper() {
    var delay = Math.ceil(1000 + Math.random() * 3000);
    setTimeout(postMessage, delay);
}

function postMessage() {
    var content = Key + "-" + Counter;
    Counter++;
    var onError = function(resp, textStatus, errorThrown) {
        showError("Error posting " + content + ": " + resp.responseText);
        postMessageWrapper();
    };

    $.ajax({
        type: 'POST',
        timeout: 5000,
        url: '/msg',
        data: { 'room': 'test', 'content': content },
        cache: false,
        dataType: 'json',
        success: postMessageWrapper,
        error: onError
    });
}

function initClient() {
    showError("Initializing client " + Key);
    refresh();
    postMessageWrapper();
};