MattiSG/Watai

/**A helper to ease CLI animation.
* Most of this code is extracted from TJ Holowaychuk’s Mocha.
*
*@namespace
*/
var CLIanimator = {};


/** Presents the given information to the user.
*@param    {String}    prefix            A symbol to prepend to the message.
*@param    {String}    type            The type of information to present (i.e. "debug", "info", "warn"…).
*@param    {String}    message            The actual content to present to the user.
*@param    {String}    [messageType]    The type of the actual content, for different colouration.
*@param    {Stream}    [out]            The stream to which the content should be written. Defaults to process.stdout.
*/
CLIanimator.log = function log(prefix, type, message, messageType, out) {
    out = out || process.stdout;

    stop();
    out.write(makeLine(prefix, typeToColorCode[type], message + '\n', typeToColorCode[messageType]));
};

/** Erases the current line.
*/
CLIanimator.clear = function clear() {
    process.stdout.write('\r');
};

/** Hides the cursor.
*/
CLIanimator.hideCursor = function hideCursor() {
    process.stdout.write('\033[?25l');
};

/** Shows the cursor.
*/
CLIanimator.showCursor = function showCursor() {
    process.stdout.write('\033[?25h');
};

/** Does a spinner animation with the given message.
*/
CLIanimator.spin = function spin(message) {
    stop();
    play(makeFrames(message));
};

/** Creates a coloured line out of the given pieces.
*@return    String
*@private
*/
function makeLine(prefix, colorCode, message, messageColorCode) {
    messageColorCode = messageColorCode || 0;
    return '\r\033[' + colorCode + 'm' + prefix + ' \033[' + messageColorCode + 'm ' + message + '\033[0m';
}

/** Generates a series of line “frames” to be played with a spinner animation.
*@return    Array<String>
*@private
*/
function makeFrames(msg) {
    return [
        makeLine('◜', 96, msg, 90),
        makeLine('◠', 96, msg, 90),
        makeLine('◝', 96, msg, 90),
        makeLine('◞', 96, msg, 90),
        makeLine('◡', 96, msg, 90),
        makeLine('◟', 96, msg, 90)
    ];
}

/** Maps types to the corresponding ANSI color code.
*@type    {Object.<String, Number>}
*@private
*/
var typeToColorCode = {
    debug    : 34,
    cyan    : 36,
    purple    : 35,
    info    : 32,
    error    : 31,
    warn    : 31,
    yellow    : 33,
    grey    : 90,
    gray    : 90
};

/** Plays the given array of strings.
*@private
*@author    TJ Holowaychuk    (Mocha)
*/

function play(frames, interval) {
    CLIanimator.hideCursor();

    var len = frames.length,
        interval = interval || 100,
        i = 0;

    play.timer = setInterval(function() {
        var str = frames[i++ % len];
        process.stdout.write('\r' + str);
    }, interval);
}

/**Stop play()ing.
*@private
*@author    TJ Holowaychuk    (Mocha)
*/
function stop() {
    clearInterval(play.timer);
    CLIanimator.showCursor();
}

/*
* Ensure we don't mess the user's prompt up.
*/

process.on('SIGINT', function() {
    CLIanimator.showCursor();
    process.stdout.write('\n');
    process.exit();
});

process.addListener('uncaughtException', function(e) {
    CLIanimator.showCursor();    // ensure the prompt is always restored, even if the process crashes
    throw e;
});

module.exports = CLIanimator;    // CommonJS export