//Header file, contains global variable definitions, 
// asynchronized shader loading and utility functions

var mousedx = 0, mousedy = 0, mousedz = 0;
let seldx = 0, seldy = 0, seldz = 0;
var enableSelection = false;
var cx = 1, cy = 1, sx = 0, sy = 0;
var mouselastX, mouselastY;
var fl = 3;
let start;
var vs, fs;
var bezierMat = [-1,3,-3,1,3,-6,3,0,-3,3,0,0,1,0,0,0], 
    hermiteMat = [2,-3,0,1,-2,3,0,0,1,-2,1,0,1,-1,0,0];
var starColors = [0.9921, 0.5378,0.7109,
                    0.65, 0.56, 0.992,
                    0.992,0.7994,0.2402,
                    0.1760,0.5094,0.5378,
                    .1164, .1274, .2289,
                    .9784,.71,.4482,
                ], n_shapes = starColors.length/3;
var editor = undefined
var cos = Math.cos, sin = Math.sin, tan = Math.tan,
    acos = Math.acos, asin = Math.asin, atan = Math.atan,
    sqrt = Math.sqrt, pi = Math.PI, abs = Math.abs;
var positionsupdated = true;
var paths = [], origpath= [];
let vsfetch = new XMLHttpRequest(); 
vsfetch.open('GET', './shader.vert');
vsfetch.onloadend = function () {
    vs = vsfetch.responseText;
};
vsfetch.send();
//* LOADING FRAGMENT SHADER
let fsfetch = new XMLHttpRequest();
fsfetch.open('GET', './shader.frag');
fsfetch.onloadend = function () {
    fs = (fsfetch.responseText);
    //* START EVERYTHING AFTER FRAGMENT SHADER IS DOWNLOADED.
    if (editor != undefined)
        editor.getSession().setValue(fs);
};
fsfetch.send();
let pathFetch = new XMLHttpRequest();
pathFetch.open('GET', './paths.txt');
pathFetch.onloadend = function () {
    let text = pathFetch.responseText;
    let currX = 0, currY = 0, maxX = -1000, maxY = -1000, minX = 1000, minY = 1000;
    var currShape = [], currCurve = [];
    let i = 0;
    let postProcess = () => {
        if(currShape.length){
            let spanX = maxX - minX;
            let spanY = maxY - minY;
            let span = Math.max(spanX, spanY);
            for (var k = 0; k < currShape.length; ++k) {
                let funcs = [];
                const curve = currShape[k];
                for (let j = 0; j < curve.length; j += 2){
                    curve[j] = (curve[j] - minX) / span-spanX/(span*2);
                    curve[j + 1] = (curve[j + 1] - minY) / span - spanY/(span*2);
                    origpath.push(1,curve[j], curve[j+1],0,0,0,1);
                    if(j%6==0 && j > 5){
                        let X = [], Y = [];
                        for(let k = j - 6; k <= j+1; k += 2){
                            X.push(curve[k]);
                            Y.push(curve[k+1]);
                        }
                        
                        funcs.push([matrix_multiply(bezierMat, X), 
                                    matrix_multiply(bezierMat, Y)]);
                    }

                }
                paths.push(funcs);
            }
        }
    }
    let read_num = () =>{
        let num = 0, sign = 1, accepted = 0;
        
        while(i < text.length && (text[i] <'0' || text[i] > '9') && text[i]!='-') ++i;
        if(text[i] == '-')
        {
            sign = -1;
            ++i;
        }
        while(i < text.length&&text[i] >= '0' && text[i] <= '9'){
            let n = text[i++] - '0';
            accepted *= 10;
            accepted += n;
        }
        
        num += accepted;
        if(text[i] == '.'){
            i++;
            let multiplier = 0.1;
            accepted = 0;
            while(i < text.length&&text[i] >= '0' && text[i] <= '9'){
                let n = text[i++] - '0';
                accepted += n * multiplier;
                multiplier /= 10;
            }
            num += accepted;
        }
        return num * sign;
    } 
    let cRevs = [], c_idx = 0, prevX = 0, prevY = 0, getC = ()=>{
        return cRevs[c_idx--];
    }
    let get_next = (delta = false) => {
        if(delta){
            currX = prevX + read_num();
            currY = prevY + read_num();
        }else{
            currX = read_num();
            currY = read_num();
        }
        maxX = currX > maxX? currX:maxX;
        maxY = currY > maxY? currY:maxY;
        minX = currX < minX? currX:minX;
        minY = currY < minY? currY:minY;
        
        currCurve.push(currX);
        currCurve.push(currY);
    }
    while( i < text.length ){
        if(text[i] == 'z'){
            currCurve.length && currShape.push(currCurve);
            currCurve = [];
            ++i
        } else if (text[i] == 'N'){
            postProcess();
            currShape = [];
            maxX = -1000, maxY = -1000, minX = 1000, minY = 1000;
            ++i;
        } else if (text[i] == 'c'){

            prevX = currX;
            prevY = currY;

            for(let j = 0; j < 3; ++j){
                get_next(true);
            }
        } else if (text[i] == 'C'){
            for(let j = 0; j < 3; ++j){
                get_next();
            }
        } else if (text[i] == 'M'){
            get_next();
        }
        else ++i;
    }
};
pathFetch.send();
let matrix_inverse = src => {
    let dst = [], det = 0, cofactor = (c, r) => {
       let s = (i, j) => src[c+i & 3 | (r+j & 3) << 2];
       return (c+r & 1 ? -1 : 1) * ( (s(1,1) * (s(2,2) * s(3,3) - s(3,2) * s(2,3)))
                                   - (s(2,1) * (s(1,2) * s(3,3) - s(3,2) * s(1,3)))
                                   + (s(3,1) * (s(1,2) * s(2,3) - s(2,2) * s(1,3))) );
    }
    for (let n = 0 ; n < 16 ; n++) dst.push(cofactor(n >> 2, n & 3));
    for (let n = 0 ; n <  4 ; n++) det += src[n] * dst[n << 2];
    for (let n = 0 ; n < 16 ; n++) dst[n] /= det;
    return dst;
  }

// I HAVE IMPLEMENTED THESE FUNCTIONS FOR YOU
let matrix_identity = () => {
    return [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];
}
let matrix_translate = (x, y, z) => {
    let m = matrix_identity();
    m[12] = x;
    m[13] = y;
    m[14] = z;
    return m;
}
let matrix_perspective = (m) => {
    let ret = []
    for (let i = 0; i < 16; i ++)
        ret[i] = m[i];
    for (let i = 2; i < 15; i += 4)
    {
        ret[i] = -ret[i]; 
        ret[i+1] += ret[i]/fl;
    }
    
    return ret;
}
// YOU NEED TO PROPERLY IMPLEMENT THE FOLLOWING FIVE FUNCTIONS:
let matrix_rotateX = theta => {
    let m = matrix_identity();
    m[5] = cos(theta);
    m[6] = sin(theta);
    m[9] = -sin(theta);
    m[10] = cos(theta);
    return m;
}

let matrix_rotateY = theta => {
    let m = matrix_identity();
    m[0] = cos(theta);
    m[2] = -sin(theta);
    m[8] = sin(theta);
    m[10] = cos(theta);
    return m;
}
let matrix_rotateZ= theta => {
    let m = matrix_identity();
    m[0] = cos(theta);
    m[1] = sin(theta);
    m[4] = -sin(theta);
    m[5] = cos(theta);
    return m;
}
let matrix_scale = (x, y, z) => {
    if (y === undefined)
        y = z = x;
    let m = matrix_identity();
    m[0] = x;
    m[5] = y;
    m[10] = z;
    return m;
}
let matrix_multiply = (a, b, m = 4, n = 4) => { //dim=mn*nm=mm
    let res = [];
    if (b.length < m*n) { //mat-vec multiply (i did this for my convenience)
        for (let i = 0; i < m; ++i) {
            res[i] = 0;
            for (let j = 0; j < n; ++j)
                res[i] += b[j] * a[m * j + i];
        }
        return res;
    } //otherwise mm multiply
    for (let i = 0; i < m; ++i)
        for (let j = 0; j < m; ++j) {
            var t = 0;
            for (let k = 0; k < n; ++k)
                t += a[k * m + j] * b[i * n + k];
            res.push(t);
        }
    return res;
}
let const_multiply = (c, a) => {
    let m = [];
    for(let i = 0; i < a.length; ++ i)
        m[i] = a[i] * c;
    return m;
}
function dot(a, b){
    let m = 0;
    for(let i = 0; i < a.length; ++i)
        m += a[i] * b[i];
    return m;
}
function plus(a, b){
    let m = [];
    for(let i = 0; i < a.length; ++i)
        m[i] = a[i] + b[i];
    return m;
}
function minus(a, b){
    let m = [];
    for(let i = 0; i < a.length; ++i)
        m[i] = a[i] - b[i];
    return m;
}
function normalize(v){
    let res = [];
    sum = 0;
    for(let i = 0; i < v.length; ++ i)
        sum += v[i] * v[i];
    sum = sqrt(sum);
    for(let i = 0; i < v.length; ++ i)
        res[i] = v[i] / sum;
    return res;
}


let Matrix = function() {
    let top = 0, m = [ matrix_identity() ];
    this.identity = () => m[top] = matrix_identity();
    this.translate = (x,y,z) => m[top] = matrix_multiply(m[top], matrix_translate(x,y,z));
    this.rotateX = theta     => m[top] = matrix_multiply(m[top], matrix_rotateX(theta));
    this.rotateY = theta     => m[top] = matrix_multiply(m[top], matrix_rotateY(theta));
    this.rotateZ = theta     => m[top] = matrix_multiply(m[top], matrix_rotateZ(theta));
    this.scale   = (x,y,z)   => m[top] = matrix_multiply(m[top], matrix_scale(x,y,z));
    this.value   = ()        => m[top];
    this.save    = ()        => { m[top+1] = m[top].slice(); top++; }
    this.restore = ()        => --top;
 }
 
 let setM = (m) => {
    let mm = matrix_perspective(m);
    setUniform('Matrix4fv', 'uMatrix', false, mm);
    setUniform('Matrix4fv', 'invMatrix', false, matrix_inverse(m));
 }
 //------ CREATING MESH SHAPES
 
 // CREATE A MESH FROM A PARAMETRIC FUNCTION
 
 let createMesh = (nu, nv, f, data, oid = 0) => {
    let tmp = [];
    for (let v = 0 ; v < 1 ; v += 1/nv) {
       for (let u = 0 ; u <= 1 ; u += 1/nu) {
          tmp = tmp.concat(f(u,v,oid,data));
          tmp = tmp.concat(f(u,v+1/nv,oid,data));
       }
       tmp = tmp.concat(f(1,v,oid,data));
       tmp = tmp.concat(f(0,v+1/nv,oid,data));
    }
    return new Float32Array(tmp);
 }
 
 // GLUE TWO MESHES TOGETHER INTO A SINGLE MESH
 
 let glueMeshes = (a, b) => {
    let c = [];
    for (let i = 0 ; i < a.length ; i++)
       c.push(a[i]);                           // a
    for (let i = 0 ; i < VERTEX_SIZE ; i++)
       c.push(a[a.length - VERTEX_SIZE + i]);  // + last vertex of a
    for (let i = 0 ; i < VERTEX_SIZE ; i++)
       c.push(b[i]);                           // + first vertex of b
    for (let i = 0 ; i < b.length ; i++)
       c.push(b[i]);                           // + b
    return new Float32Array(c);
 }
 
 
 let uvToSphere = (u,v, i) => {
    let theta = 2 * Math.PI * u;
    let phi   = Math.PI * (v - .5);
    let x = Math.cos(theta) * Math.cos(phi);
    let y = Math.sin(theta) * Math.cos(phi);
    let z = Math.sin(phi);
    return [i, x,y,z].concat(normalize([x, y, z]));
 }
 
 let uvToTube = (u,v,i) => {
    let theta = 2 * Math.PI * u;
    let x = Math.cos(theta);
    let y = Math.sin(theta);
    let z = 2 * v - 1;
    return [i,x,y,z].concat(normalize([x,y,0]));
 }
 
 let uvToDisk = (u,v,i,dz) => {
    if (dz === undefined)
       dz = 0;
    let theta = 2 * Math.PI * u;
    let x = Math.cos(theta) * v;
    let y = Math.sin(theta) * v;
    let z = dz;
    return [i,x,y,z].concat([0,0,Math.sign(z)]);
 }
 let uvToTorus = (u,v,i,r) => {
    let theta = 2 * pi;
    let phi = theta * v;
    theta *= u;
    let x = 1 + r * cos(phi);
    let y = sin(theta)*x;
    x *=cos(theta);
    let z = r * sin(phi);
    let tx = -sin(theta), ty = cos(theta),tsx = sin(phi), tsy = tsx*tx, tsz = cos(phi);
    tsx*=-ty;
    return [i,x, y, z].concat(normalize([ty*tsz*0.5, -tx*tsz, tx*tsy-ty*tsx]));
 }

let createCube = (w, h, l,id) => {
    let mesh = [];
    mesh=mesh.concat([id, -w/2,-h/2,-l/2,0,-1,0]);
    mesh=mesh.concat([id, -w/2,-h/2,l/2,0,-1,0]);
    mesh=mesh.concat([id, w/2,-h/2,-l/2,0,-1,0]);
    mesh=mesh.concat([id, w/2,-h/2,l/2,0,-1,0]);

    mesh=mesh.concat([id, w/2,-h/2,l/2,0,-1,0]);
    mesh=mesh.concat([id, w/2,-h/2,l/2,0,0,1]);
    
    mesh=mesh.concat([id, w/2,-h/2,l/2,0,0,1]);
    mesh=mesh.concat([id, w/2,h/2,l/2,0,0,1]);
    mesh=mesh.concat([id, -w/2,-h/2,l/2,0,0,1]);
    mesh=mesh.concat([id, -w/2,h/2,l/2,0,0,1]);

    mesh=mesh.concat([id, -w/2,h/2,l/2,0,0,1]);
    mesh=mesh.concat([id, -w/2,h/2,l/2,-1,0,0]);
    
    mesh=mesh.concat([id, -w/2,h/2,l/2,-1,0,0]);
    mesh=mesh.concat([id, -w/2,-h/2,l/2,-1,0,0]);
    mesh=mesh.concat([id, -w/2,h/2,-l/2,-1,0,0]);
    mesh=mesh.concat([id, -w/2,-h/2,-l/2,-1,0,0]);

    mesh=mesh.concat([id, -w/2,-h/2,-l/2,-1,0,0]);
    mesh=mesh.concat([id, -w/2,-h/2,-l/2,0,0,-1]);

    mesh=mesh.concat([id, -w/2,-h/2,-l/2,0,0,-1]);
    mesh=mesh.concat([id, -w/2,h/2,-l/2,0,0,-1]);
    mesh=mesh.concat([id, w/2,-h/2,-l/2,0,0,-1]);
    mesh=mesh.concat([id, w/2,h/2,-l/2,0,0,-1]);

    mesh=mesh.concat([id, w/2,h/2,-l/2,0,0,-1]);
    mesh=mesh.concat([id, w/2,h/2,-l/2,1,0,0]);
    
    mesh=mesh.concat([id, w/2,h/2,-l/2,1,0,0]);
    mesh=mesh.concat([id, w/2,h/2,l/2,1,0,0]);
    mesh=mesh.concat([id, w/2,-h/2,-l/2,1,0,0]);
    mesh=mesh.concat([id, w/2,-h/2,l/2,1,0,0]);

    mesh=mesh.concat([id, w/2,-h/2,l/2,1,0,0]);
    mesh=mesh.concat([id, w/2,h/2,l/2,0,1,0]);

    mesh=mesh.concat([id, w/2,h/2,l/2,0,1,0]);
    mesh=mesh.concat([id, w/2,h/2,-l/2,0,1,0]);
    mesh=mesh.concat([id, -w/2,h/2,l/2,0,1,0]);
    mesh=mesh.concat([id, -w/2,h/2,-l/2,0,1,0]);
    return new Float32Array(mesh);
}
 
function updatePositions() {
    let m = matrix_rotateY(-mousedx);
    m = matrix_multiply(m, matrix_rotateX(-mousedy));
    setUniform('3f', 'V0', m[8] * (fl + mousedz), m[9] * (fl + mousedz), m[10] * (fl + mousedz));
    m = const_multiply((fl + 1 + mousedz)/(fl+1), m);
    setUniform('Matrix3fv', 'transformation', false, [m[0], m[1], m[2], m[4], m[5], m[6], m[8], m[9], m[10]]);
    positionsupdated = false;
}
function hitTest(pos){
    if(!enableSelection)
        return -1; 
    let m = matrix_rotateY(-mousedx);
    m = matrix_multiply(m, matrix_rotateX(-mousedy));
    let V = [m[8] * (fl + mousedz), m[9] * (fl + mousedz), m[10] * (fl + mousedz)];
    m = const_multiply((fl + 1 + mousedz)/(fl+1), m);
    let trPos = matrix_multiply([m[0], m[1], m[2], m[4], m[5], m[6], m[8], m[9], m[10]], pos, 3,3);
 
    let W=normalize(minus(trPos, V));
    let tMin=10000.;
    let iMin = -1;
    for(let i=0;i<cns;i++){
    let Vp=minus(V, matrix_multiply(SphTr[i], Sph[i]));
    let B=dot(W,Vp);
    let C=dot(Vp,Vp)-Sph[i][4]*Sph[i][4];
    let D=B*B-C;
    if(D>0.){
       let t=-B-sqrt(D);
       if(t > 0.0 && t < tMin){
          tMin = t; // This is an optimization, we don't have to do lighting/tex
          iMin = i; // for objects that are occuluded, which is expensive!
       }
       }
    }
    return iMin;
 }