(function() {
    var LOOKAT_MIX_ALPHA = 0.05;
    var lookAtPoint = undefined;
    var lookingAtAvatarID = undefined;
    var lookingAvatarJointIndex = undefined;
    var getNormalizedLookAtPoint = function(worldLookAtPoint) {
        return Vec3.sum(MyAvatar.getHeadPosition(), Vec3.normalize(Vec3.subtract(worldLookAtPoint, MyAvatar.getHeadPosition())));
    }
    var interpolatedLookAt = getNormalizedLookAtPoint(MyAvatar.getHeadLookAt());
    var mousePressEvent = function(event) {
        if (!event.isLeftButton) return;
        var pickRay = Camera.computePickRay(event.x, event.y);
        var intersection = AvatarManager.findRayIntersection({origin: pickRay.origin, direction: pickRay.direction}, [], [MyAvatar.sessionUUID], false);
        lookingAtAvatarID = intersection.intersects ? intersection.avatarID : undefined;
        if (!lookingAtAvatarID) {
            intersection = Entities.findRayIntersection({origin: pickRay.origin, direction: pickRay.direction}, true);
            lookAtPoint = intersection.intersection;
        } else {
            var avatar = AvatarList.getAvatar(lookingAtAvatarID);
            console.log("Looking at avatar: " + avatar.displayName);
            lookingAvatarJointIndex = intersection.jointIndex;
        }
    }
    var avatarWeights = {};
    var avatarsLoudness = 0.0;
    var avatarTalking = false;
    var isInterpolatingBack = false;
    function updateAvatarWeights() {
        var nearbyAvatars = AvatarManager.getAvatarsInRange(MyAvatar.position, 10.0);
        for (var n = 0; n < nearbyAvatars.length; n++) {
            if (nearbyAvatars[n] === MyAvatar.sessionUUID) {
                continue;
            }
            var avatar = AvatarManager.getAvatar(nearbyAvatars[n]);
            var distance = Vec3.distance(MyAvatar.position, avatar.position);
            var loudnessAttenuation = (1.0 / distance) - 0.1;
            var loudness = loudnessAttenuation * avatar.audioLoudness;
            var TALKING_TAU = 0.01;
            if (avatarWeights[avatar.sessionUUID] === undefined) {
                avatarWeights[avatar.sessionUUID] = {"loudness": loudness , "position": avatar.position};
            } else {
                avatarWeights[avatar.sessionUUID].loudness = avatarWeights[avatar.sessionUUID].loudness + TALKING_TAU * (loudness - avatarWeights[avatar.sessionUUID].loudness);
                avatarWeights[avatar.sessionUUID].position = avatar.position;
            }
        }
        var avatarIDs = Object.keys(avatarWeights);
        avatarsLoudness = 0.0;
        for (var n = 0; n < avatarIDs.length; n++) {
            if (nearbyAvatars.indexOf(avatarIDs[n]) == -1) {
                delete avatarWeights[avatarIDs[n]];
            } else {
                avatarsLoudness += avatarWeights[avatarIDs[n]].loudness;
            }
        }
        avatarTalking = avatarsLoudness > 5.0;
    }
    function getTalkingPoint() {
        var avatarIDs = Object.keys(avatarWeights);
        var weightedLookAtPoint = Vec3.ZERO;
        if (avatarIDs.length == 0 || avatarsLoudness == 0.0) return undefined;
        for (var n = 0; n < avatarIDs.length; n++) {
            if (avatarWeights[avatarIDs[n]] != undefined) {
                var relativePos = Vec3.subtract(avatarWeights[avatarIDs[n]].position, MyAvatar.position);
                weightedLookAtPoint = Vec3.sum(weightedLookAtPoint, Vec3.multiply(relativePos, avatarWeights[avatarIDs[n]].loudness / avatarsLoudness));          
            }            
        }
        var relativeMed = Vec3.multiply(weightedLookAtPoint, 1.0/avatarIDs.length);
        return Vec3.sum(relativeMed, MyAvatar.position);
    }
    Script.update.connect(function() {
        updateAvatarWeights();
        lookAtPoint = Vec3.sum(getTalkingPoint(), {x: 0.0, y: 0.6, z: 0.0});
        /*
        if (lookAtPoint || lookingAtAvatarID) {
            if (lookingAtAvatarID && !avatarTalking) {
                lookAtPoint = AvatarList.getAvatar(lookingAtAvatarID).getJointPosition(lookingAvatarJointIndex);
            }
            var normalizedLookAt = getNormalizedLookAtPoint(lookAtPoint);
            interpolatedLookAt = Vec3.mix(interpolatedLookAt, normalizedLookAt, LOOKAT_MIX_ALPHA);
            MyAvatar.setHeadLookAt(interpolatedLookAt);
        }
        */
        
        if (avatarTalking && lookAtPoint) {
            console.log(avatarsLoudness);
            var normalizedLookAt = getNormalizedLookAtPoint(lookAtPoint);
            interpolatedLookAt = Vec3.mix(interpolatedLookAt, normalizedLookAt, LOOKAT_MIX_ALPHA);
            MyAvatar.setHeadLookAt(interpolatedLookAt);
            isInterpolatingBack = true;
        } else if (isInterpolatingBack) {
            var normalizedLookAt = getNormalizedLookAtPoint(MyAvatar.getHeadLookAt());
            interpolatedLookAt = Vec3.mix(interpolatedLookAt, normalizedLookAt, LOOKAT_MIX_ALPHA);
            if (Vec3.distance(interpolatedLookAt, normalizedLookAt) < 0.01) {
                isInterpolatingBack = false;
            }
            MyAvatar.setHeadLookAt(interpolatedLookAt);
        } else {
            interpolatedLookAt = MyAvatar.getHeadLookAt();
        }
        

    });
    
    Controller.mousePressEvent.connect(mousePressEvent);
})();