com.phonegap.AccelListenerProxy = function() {
    this.className = "com.phonegap.AccelListener";
    this.status = -1;   // not set yet
};
com.phonegap.AccelListenerProxy.prototype.getStatus = function() {
    if (this.status == -1) {    // if not set, then request status
        this.status = PhoneGap.exec(this.className, "getStatus", []);
    }
    return this.status;
};
com.phonegap.AccelListenerProxy.prototype.onStatus = function(status) {
    console.log("AccelListener.onStatus("+status+")");
    this.status = status;
};
com.phonegap.AccelListenerProxy.prototype.getAcceleration = function() {
    var r = PhoneGap.exec(this.className, "getAcceleration", []);
    var a = new Acceleration(r.x,r.y,r.z);
    return a;
};
com.phonegap.AccelListenerProxy.prototype.start = function() {
    return PhoneGap.exec(this.className, "start", []);
};
com.phonegap.AccelListenerProxy.prototype.stop = function() {
    return PhoneGap.exec(this.className, "stop", []);
};
com.phonegap.AccelListenerProxy.prototype.setTimeout = function(timeout) {
    return PhoneGap.exec(this.className, "setTimeout", [timeout]);
};
com.phonegap.AccelListenerProxy.prototype.getTimeout = function() {
    return PhoneGap.exec(this.className, "getTimeout", []);
};
com.phonegap.AccelListener = new com.phonegap.AccelListenerProxy();

function Acceleration(x, y, z) {
  this.x = x;
  this.y = y;
  this.z = z;
  this.timestamp = new Date().getTime();
};

/**
 * This class provides access to device accelerometer data.
 * @constructor
 */
function Accelerometer() {

    /**
     * The last known acceleration.  type=Acceleration()
     */
    this.lastAcceleration = null;

    /**
     * List of accelerometer watch timers
     */
    this.timers = {};
};

Accelerometer.STOPPED = 0;
Accelerometer.STARTING = 1;
Accelerometer.RUNNING = 2;
Accelerometer.ERROR_FAILED_TO_START = 3;
Accelerometer.ERROR_MSG = ["Not running", "Starting", "", "Failed to start"];

/**
 * Asynchronously aquires the current acceleration.
 *
 * @param {Function} successCallback    The function to call when the acceleration data is available
 * @param {Function} errorCallback      The function to call when there is an error getting the acceleration data.
 * @param {AccelerationOptions} options The options for getting the accelerometer data such as timeout.
 */
Accelerometer.prototype.getCurrentAcceleration = function(successCallback, errorCallback, options) {

    // successCallback required
    if (typeof successCallback != "function") {
        console.log("Accelerometer Error: successCallback is not a function");
        return;
    }

    // errorCallback optional
    if (errorCallback && (typeof errorCallback != "function")) {
        console.log("Accelerometer Error: errorCallback is not a function");
        return;
    }

    // Get current acceleration status
    var status = com.phonegap.AccelListener.getStatus();

    // If running, then call successCallback
    if (status == Accelerometer.RUNNING) {
        try {
            var accel = com.phonegap.AccelListener.getAcceleration();
            successCallback(accel);
        } catch (e) {
            console.log("Accelerometer Error in successCallback: " + e);
        }
    }

    // If not running, then start it
    else if (status >= 0) {
        com.phonegap.AccelListener.start();

        // Wait until started
        var timer = setInterval(function() {
            var status = com.phonegap.AccelListener.getStatus();

            // If accelerometer is running
            if (status == Accelerometer.RUNNING) {
                clearInterval(timer);
                try {
                    var accel = com.phonegap.AccelListener.getAcceleration();
                    successCallback(accel);
                } catch (e) {
                    console.log("Accelerometer Error in successCallback: " + e);
                }
            }

            // If accelerometer error
            else if (status == Accelerometer.ERROR_FAILED_TO_START) {
                clearInterval(timer);
                console.log("Accelerometer Error: "+ Accelerometer.ERROR_MSG[status]);
                try {
                    if (errorCallback) {
                        errorCallback(status);
                    }
                } catch (e) {
                    console.log("Accelerometer Error in errorCallback: " + e);
                }
            }
        }, 10);
    }
};

/**
 * Asynchronously aquires the acceleration repeatedly at a given interval.
 *
 * @param {Function} successCallback    The function to call each time the acceleration data is available
 * @param {Function} errorCallback      The function to call when there is an error getting the acceleration data.
 * @param {AccelerationOptions} options The options for getting the accelerometer data such as timeout.
 * @return String                       The watch id that must be passed to #clearWatch to stop watching.
 */
Accelerometer.prototype.watchAcceleration = function(successCallback, errorCallback, options) {

    // Default interval (10 sec)
    var frequency = (options != undefined)? options.frequency : 10000;

    // successCallback required
    if (typeof successCallback != "function") {
        console.log("Accelerometer Error: successCallback is not a function");
        return;
    }

    // errorCallback optional
    if (errorCallback && (typeof errorCallback != "function")) {
        console.log("Accelerometer Error: errorCallback is not a function");
        return;
    }

    // Make sure accelerometer timeout > frequency + 10 sec
    var timeout = com.phonegap.AccelListener.getTimeout();
    if (timeout < (frequency + 10000)) {
        com.phonegap.AccelListener.setTimeout(frequency + 10000); // set to frequency + 10 sec
    }

    var id = PhoneGap.createUUID();
    com.phonegap.AccelListener.start();

    // Start watch timer
    navigator.accelerometer.timers[id] = setInterval(function() {
        var status = com.phonegap.AccelListener.getStatus();

        // If accelerometer is running
        if (status == Accelerometer.RUNNING) {
            try {
                var accel = com.phonegap.AccelListener.getAcceleration();
                successCallback(accel);
            } catch (e) {
                console.log("Accelerometer Error in successCallback: " + e);
            }
        }

        // If accelerometer had error
        else if (status == Accelerometer.ERROR_FAILED_TO_START) {
            console.log("Accelerometer Error: "+ Accelerometer.ERROR_MSG[status]);
            try {
                navigator.accelerometer.clearWatch(id);
                if (errorCallback) {
                    errorCallback(status);
                }
            } catch (e) {
                console.log("Accelerometer Error in errorCallback: " + e);
            }
        }
    }, (frequency ? frequency : 1));

    return id;
};

/**
 * Clears the specified accelerometer watch.
 *
 * @param {String} id       The id of the watch returned from #watchAcceleration.
 */
Accelerometer.prototype.clearWatch = function(id) {

    // Stop javascript timer & remove from timer list
    if (id && navigator.accelerometer.timers[id]) {
        clearInterval(navigator.accelerometer.timers[id]);
        delete navigator.accelerometer.timers[id];
    }
};

PhoneGap.addConstructor(function() {
    if (typeof navigator.accelerometer == "undefined") navigator.accelerometer = new Accelerometer();
});