/**
GDevelop - Skeleton Object Extension
Copyright (c) 2017-2018 Franco Maciel (francomaciel10@gmail.com)
This project is released under the MIT License.
*/

 /**
 * @memberof gdjs.sk
 */
gdjs.sk = gdjs.sk || {
    // Some useful constants
    SLOT_UNDEFINED: -1,
    SLOT_IMAGE: 0,
    SLOT_MESH: 1,
    SLOT_POLYGON: 2,
    SLOT_ARMATURE: 3,
    EASING_CONST: 0,
    EASING_LINEAR: 1,
    EASING_CURVE: 2,
    EVENT_STOP: 0,
    EVENT_PLAY: 1,
    EVENT_PLAYSINGLE: 2
};


/**
 * The Matrix holds the basic transformation data in a matrix form.
 *
 * @memberof gdjs.sk
 * @class Matrix
 */
gdjs.sk.Matrix = function(a=1, b=0, tx=0, c=0, d=1, ty=0){
    this.a = a; this.b = b; this.tx = tx;
    this.c = c; this.d = d; this.ty = ty;
    this.u = 0; this.v = 0; this.w  = 1;
};

gdjs.sk.Matrix.prototype.translation = function(x, y){
    this.tx = x;
    this.ty = y;
    return this;
};

gdjs.sk.Matrix.prototype.rotation = function(angle){
    this.a = Math.cos(angle); this.b = -Math.sin(angle);
    this.c = Math.sin(angle); this.d =  Math.cos(angle);
    return this;
};

gdjs.sk.Matrix.prototype.scale = function(sx, sy){
    this.a = sx;
    this.d = sy;
    return this;
};

gdjs.sk.Matrix.prototype.clone = function(){
    return new gdjs.sk.Matrix(this.a, this.b, this.tx,
                              this.c, this.d, this.ty,
                              this.u, this.v, this.w );
};

gdjs.sk.Matrix.prototype.mul = function(m){
    return new gdjs.sk.Matrix(this.a*m.a + this.b*m.c,
                              this.a*m.b + this.b*m.d,
                              this.a*m.tx + this.b*m.ty + this.tx,
                              this.c*m.a + this.d*m.c,
                              this.c*m.b + this.d*m.d,
                              this.c*m.tx + this.d*m.ty + this.ty);
};

gdjs.sk.Matrix.prototype.mulVec = function(v){
    return [this.a*v[0] + this.b*v[1] + this.tx,
            this.c*v[0] + this.d*v[1] + this.ty];
};

gdjs.sk.Matrix.prototype.invert = function(){
    var det_inv = 1.0 / (this.a*this.d - this.b*this.c);
    var a = this.a;
    var tx = this.tx;

    this.tx = (this.b*this.ty - this.d*tx)*det_inv;
    this.ty = (this.c*tx - this.a*this.ty)*det_inv;
    this.a = this.d*det_inv;
    this.b =-this.b*det_inv;
    this.c =-this.c*det_inv;
    this.d = a*det_inv;
    
    return this;
};

gdjs.sk.Matrix.prototype.inverse = function(){
    var det_inv = 1.0 / (this.a*this.d - this.b*this.c);
    return new gdjs.sk.Matrix( this.d*det_inv,
                              -this.b*det_inv,
                              (this.b*this.ty - this.d*this.tx)*det_inv,
                              -this.c*det_inv,
                               this.a*det_inv,
                              (this.c*this.tx - this.a*this.ty)*det_inv);
};

gdjs.sk.Matrix.prototype.str = function(){
    return "|" + this.a.toFixed(2) + ", " + this.b.toFixed(2) + ", " + this.tx.toFixed(2) + "|\n" +
           "|" + this.c.toFixed(2) + ", " + this.d.toFixed(2) + ", " + this.ty.toFixed(2) + "|\n" +
           "|" + this.u.toFixed(2) + ", " + this.v.toFixed(2) + ", " + this.w.toFixed(2) + "|\n";
};



/**
 * The Transform is the basic class for transformable objects as bones, slots and armatures.
 *
 * @memberof gdjs.sk
 * @class Transform
 */
gdjs.sk.Transform = function(x=0, y=0, rot=0, sx=1, sy=1){
    this.parent = null;
    this.children = [];
    this.x = x;
    this.y = y;
    this.rot = rot * Math.PI / 180.0;
    this.sx = sx;
    this.sy = sy;
    this.matrix = new gdjs.sk.Matrix();
    this.worldMatrix = new gdjs.sk.Matrix();
    this._updateMatrix = true;
    this._updateWorldMatrix = false;
    this.inheritTranslation = true;
    this.inheritRotation = true;
    this.inheritScale = true;
};

gdjs.sk.Transform.prototype.addChild = function(child){
    this.children.push(child);
    child.reparent(this);
};

gdjs.sk.Transform.prototype.reparent = function(parent){
    if(this.parent){
        this.parent.removeChild(this);
    }
    this.parent = parent;
    this._updateWorldMatrix = true;
};

gdjs.sk.Transform.prototype.removeChild = function(child){
    var index = this.children.indexOf(child);
    if(index > -1){
        this.children.splice(index, 1);
    }
};

gdjs.sk.Transform.prototype.getX = function(){
    return this.x;
};

gdjs.sk.Transform.prototype.setX = function(x){
    if(this.x !== x){
        this.x = x;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.getGlobalX = function(){
    this.updateParentsTransform();
    return this.worldMatrix.tx;
};

gdjs.sk.Transform.prototype.setGlobalX = function(x){
    var globalY = this.getGlobalY(); // Also updates parent transforms
    var localPos = this.parent.worldMatrix.inverse().mulVec([x, globalY, 1.0]);
    this.x = localPos[0];
    this.y = localPos[1];
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.getY = function(){
    return this.y;
};

gdjs.sk.Transform.prototype.setY = function(y){
    if(this.y !== y){
        this.y = y;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.getGlobalY = function(){
    this.updateParentsTransform();
    return this.worldMatrix.ty;
};

gdjs.sk.Transform.prototype.setGlobalY = function(y){
    var globalX = this.getGlobalX(); // Also updates parent transforms
    var localPos = this.parent.worldMatrix.inverse().mulVec([globalX, y, 1.0]);
    this.x = localPos[0];
    this.y = localPos[1];
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.setPos = function(x, y){
    if(this.x !== x || this.y !== y){
        this.x = x;
        this.y = y;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.getRot = function(){
    return this.rot * 180.0 / Math.PI;
};

gdjs.sk.Transform.prototype.setRot = function(angle){
    angle *= Math.PI / 180.0;
    if(this.rot !== angle){
        this.rot = angle;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.getGlobalRot = function(){
    this.updateParentsTransform();
    var sx = Math.sqrt(this.worldMatrix.a * this.worldMatrix.a +
                       this.worldMatrix.c * this.worldMatrix.c );
    var sy = Math.sqrt(this.worldMatrix.b * this.worldMatrix.b +
                       this.worldMatrix.d * this.worldMatrix.d );
    return Math.atan2(-this.worldMatrix.b/sy, this.worldMatrix.a/sx) * 180.0 / Math.PI;
};

gdjs.sk.Transform.prototype.setGlobalRot = function(rot){
    var parentGlobalRot = this.parent ? this.parent.getGlobalRot() : 0;
    this.rot = (rot - parentGlobalRot)*Math.PI/180.0;
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.getSx = function(){
    return this.sx;
};

gdjs.sk.Transform.prototype.getSy = function(){
    return this.sy;
};

gdjs.sk.Transform.prototype.setSx = function(sx){
    if(this.sx !== sx){
        this.sx = sx;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.setSy = function(sy){
    if(this.sy !== sy){
        this.sy = sy;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.setScale = function(sx, sy){
    if(this.sx !== sx || this.sy !== sy){
        this.sx = sx;
        this.sy = sy;
        this._updateMatrix = true;
    }
};

gdjs.sk.Transform.prototype.move = function(x, y){
    this.x += x;
    this.y += y;
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.rotate = function(angle){
    this.rot += angle * Math.PI / 180.0;
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.scale = function(sx, sy){
    this.sx *= sx;
    this.sy *= sy;
    this._updateMatrix = true;
};

gdjs.sk.Transform.prototype.update = function(){
    this.updateTransform();

    for(var i=0; i<this.children.length; i++){
        this.children[i].update();
    }
};

gdjs.sk.Transform.prototype.updateTransform = function(){
    var sin_rot, cos_rot;
    if(this._updateMatrix || this._updateWorldMatrix){
        sin_rot = Math.sin(this.rot);
        cos_rot = Math.cos(this.rot);
    }

    if(this._updateMatrix){
        this.matrix = new gdjs.sk.Matrix(this.sx*cos_rot,-this.sy*sin_rot, this.x,
                                         this.sx*sin_rot, this.sy*cos_rot, this.y,
                                                       0,               0,      1);
    }
    if(this._updateMatrix || this._updateWorldMatrix){
        if(!this.parent){
            this.worldMatrix = this.matrix.clone();
        }
        else{
            this.worldMatrix = this.parent.worldMatrix.mul(this.matrix);

            if(!this.inheritRotation || !this.inheritScale){
                if(this.inheritScale){ // Non iherited rotation
                    var worldSx = Math.sqrt(this.worldMatrix.a*this.worldMatrix.a +
                                            this.worldMatrix.c*this.worldMatrix.c);
                    var worldSy = Math.sqrt(this.worldMatrix.b*this.worldMatrix.b +
                                            this.worldMatrix.d*this.worldMatrix.d);
                    this.worldMatrix.a =  worldSx*cos_rot;
                    this.worldMatrix.b = -worldSy*sin_rot;
                    this.worldMatrix.c =  worldSx*sin_rot;
                    this.worldMatrix.d =  worldSy*cos_rot;
                }
                else if(this.inheritRotation){ // Non inherited scale
                    var worldSx = Math.sqrt(this.worldMatrix.a*this.worldMatrix.a +
                                            this.worldMatrix.c*this.worldMatrix.c);
                    var worldSy = Math.sqrt(this.worldMatrix.b*this.worldMatrix.b +
                                            this.worldMatrix.d*this.worldMatrix.d);
                    this.worldMatrix.a *= this.sx / worldSx;
                    this.worldMatrix.b *= this.sy / worldSy;
                    this.worldMatrix.c *= this.sx / worldSx;
                    this.worldMatrix.d *= this.sy / worldSy;
                }
                else{ // Non inherited rotation nor scale
                    this.worldMatrix.a =  this.sx*cos_rot;
                    this.worldMatrix.b = -this.sy*sin_rot;
                    this.worldMatrix.c =  this.sx*sin_rot;
                    this.worldMatrix.d =  this.sy*cos_rot;
                }
            }

            if(!this.inheritTranslation){
                this.worldMatrix.tx = this.x;
                this.worldMatrix.ty = this.y;
            }

        }

        for(var i=0; i<this.children.length; i++){
            this.children[i]._updateWorldMatrix = true;
        }
    }

    this._updateMatrix = false;
    this._updateWorldMatrix = false;
};

gdjs.sk.Transform.prototype.updateParentsTransform = function(){
    if(this.parent){
        this.parent.updateParentsTransform();
    }
    this.updateTransform();
};

gdjs.sk.Transform.prototype.transformPolygon = function(vertices){
    this.updateParentsTransform();

    var worldPoly = new gdjs.Polygon();
    for(var i=0; i<vertices.length; i++){
        worldPoly.vertices.push(this.worldMatrix.mulVec(vertices[i]));
    }
    return worldPoly;
};

gdjs.sk.Transform._statics = {
    transform: {
        x: 0,
        y: 0,
        sx: 1,
        sy: 1,
        skx: 0,
        sky: 0,
        rot: 0
    }
};

gdjs.sk.Transform.decomposeMatrix = function(matrix){
    var transform = gdjs.sk.Transform._statics.transform;

    transform.x = matrix.tx
    transform.y = matrix.ty;
    var sx = Math.sqrt(matrix.a*matrix.a + matrix.c*matrix.c);
    var sy = Math.sqrt(matrix.b*matrix.b + matrix.d*matrix.d);
    transform.sx = sx;
    transform.sy = sy;
    transform.skx = -Math.atan2(matrix.d, matrix.b) + Math.PI/2.0;
    transform.sky =  Math.atan2(matrix.c, matrix.a);
    transform.rot = Math.atan2(-matrix.b/sy, matrix.a/sx);

    return transform;
};