const paletteSize = 50; //min=2 max=100 step=1
const n = 500; //min=1 max=2000 step=1
const minThickness = 5; //min=1 max=100 step=1
const maxThickness = 15; //min=1 max=100 step=1
const minEdges = 3; //min=3 max=40 step=1
const maxEdges = 8; //min=3 max=40 step=1
const minScale = 2; //min=1 max=50 step=1
const maxScale = 15; //min=1 max=50 step=1
const voidPointX = 0; //min=-150 max=150 step=1
const voidPointY = 0; //min=-150 max=150 step=1
const lightPointX = 100; //min=-150 max=150 step=1
const lightPointY = -50; //min=-150 max=150 step=1
const voidSizeImpact = .43; //min=-1 max=1 step=.01
const lightSizeImpact = .23; //min=-1 max=1 step=.01
const depthSizeImpact = .27; //min=-1 max=1 step=.01
const border = 15; //min=0 max=100 step=1

// You can find the Turtle API reference here: https://turtletoy.net/syntax
Canvas.setpenopacity(1/paletteSize);

// Global code will be evaluated once.
const bales = Bales(paletteSize, true);

const canvasSize = 200;
const voidPoint = [voidPointX, voidPointY];
const lightSource = [lightPointX, lightPointY]; //todo: implement light source (shading of sides)

const maxiThickness = Math.max(maxThickness, minThickness);
const maxiEdges = Math.max(maxEdges, minEdges);
const maxiScale = Math.max(maxScale, minScale);

const normalize2 = (a) => scale2(a, 1/length2(a));
const length2 = (a) => Math.sqrt(lengthSquared2(a));
const lengthSquared2 = (a) => dot2(a,a);
const rotationMatrix2 = (radians) => [Math.cos(radians), -Math.sin(radians), Math.sin(radians), Math.cos(radians)];
const transform2 = (matrix, a) => [matrix[0]*a[0]+matrix[2]*a[1], matrix[1]*a[0]+matrix[3]*a[1]];
const scale2 = (a, scalar) => [a[0]*scalar,a[1]*scalar];
const add2 = (a,b) => [a[0]+b[0],a[1]+b[1]];
const sub2 = (a,b) => [a[0]-b[0],a[1]-b[1]];
const dist2 = (a,b) => Math.hypot(...sub2(a,b));
const lerp2 = (a,b,t) => [a[0]*(1-t)+b[0]*t,a[1]*(1-t)+b[1]*t];
const dot2 = (a,b) => a[0]*b[0]+a[1]*b[1];
const average2 = (...pts) => scale2(pts.reduce((p, c) => add2(p, c), [0,0]), 1/pts.length);

// Global code will be evaluated once.
const turtle = new Turtle();
const polygons = new Polygons();
const outlinePolygons = new Polygons();
const halfCanvasSize = canvasSize / 2;

const locationBuffer = [];

// The walk function will be called until it returns false.
function walk(i) {
    const polygon = (minEdges + Math.random() * (maxiEdges - minEdges + 1)) | 0
    
    const limits = [[halfCanvasSize, halfCanvasSize], [-halfCanvasSize, halfCanvasSize], [-halfCanvasSize, -halfCanvasSize],  [halfCanvasSize, -halfCanvasSize]];
    const maxDistanceToLight = limits.map(i => lengthSquared2(i, lightSource))
        .reduce((p, c) => c > p? p: c);
    const maxDistanceToVoid = limits.map(i => lengthSquared2(i, voidPoint))
        .reduce((p, c) => c > p? p: c);
    
    const locations = Array.from({length: 10}).map(i => [Math.random() * (canvasSize - border*2) - (halfCanvasSize - border), Math.random() * (canvasSize - border*2) - (halfCanvasSize - border)]);
    if(i == 10) {
        const distances = locations
            .map(l => [l, locationBuffer
                            .reduce((p,bl) => {
                                const d = lengthSquared2(sub2(bl, l));
                                return p < d? p: d
                            }, Number.MAX_VALUE)
                      ])
            .reduce((p, c) => p[1] < c[1]? c: p, [null, -1]);
    }
    const location = locations[0];
    locationBuffer.push(location);

    const z = n - i;
    const thickness = Math.random() * (maxiThickness-minThickness) + minThickness;
    const rot = rotationMatrix2(Math.random() * Math.PI * 2);
    const scale = (minScale + (maxiScale-minScale))
        * (
            (1 - depthSizeImpact) +
            (depthSizeImpact * (z/n))
        )
        * (
            (1 - lightSizeImpact) +
            (lightSizeImpact * (lengthSquared2(sub2(location, lightSource))/maxDistanceToLight))
        )
        * (
            (1 - voidSizeImpact) + 
            (voidSizeImpact * (lengthSquared2(sub2(location, voidPoint)) / maxDistanceToVoid))
        );

    const baseHex = Array.from({length: polygon}).map((i, k) => [
        Math.sin(k * 2 * Math.PI / polygon),
        Math.cos(k * 2 * Math.PI / polygon)
    ]);
    
    const hex = baseHex
        .map(i => transform2(rot, i))
        .map(p => scale2(p, scale))
        .map(i => add2(i, location));
    
    const shadow = hex
        .map(i => lerp2(i, voidPoint, thickness/maxiThickness * z/n * .1));
    
    const p = polygons.create();
    const pp = outlinePolygons.create();
    p.addPoints(...hex);
    pp.addPoints(...hex);
    p.addHatching(1, .15);
    pp.addOutline();
    polygons.draw(bales[Math.max(1, paletteSize - 3)], p);
    outlinePolygons.draw(bales[(paletteSize * .6) | 0], pp);
    
    const sides = hex.map((i, k) => [hex[k], hex[(k+1)%hex.length], shadow[(k+1)%hex.length], shadow[k]]);
    const sidesAvg = sides.map(i => [i, average2(...i)]);
    sidesAvg.sort((a, b) => lengthSquared2(sub2(a[1], voidPoint)) < lengthSquared2(sub2(b[1], voidPoint))? -1: 1);
    sidesAvg.forEach(i => {
        const b = polygons.create();
        const bb = outlinePolygons.create();
        b.addPoints(...i[0]);
        bb.addPoints(...i[0]);
        
        const dot = (dot2(normalize2(sub2(i[1], location)), normalize2(sub2(lightSource, i[1]))) + 1) / 2;
        b.addHatching(1, .15);
        //bb.addOutline();
        polygons.draw(bales[((dot * paletteSize * .7) + (paletteSize * .15)) | 0], b);
        outlinePolygons.draw(bales[0], bb);
    });
    return i + 1 < n;
}

////////////////////////////////////////////////////////////////
// Polygon Clipping utility code - Created by Reinder Nijhoff 2019
// (Polygon binning by Lionel Lemarie 2021)
// https://turtletoy.net/turtle/a5befa1f8d
////////////////////////////////////////////////////////////////
function Polygons(){const t=[],s=25,e=Array.from({length:s**2},t=>[]),n=class{constructor(){this.cp=[],this.dp=[],this.aabb=[]}addPoints(...t){let s=1e5,e=-1e5,n=1e5,h=-1e5;(this.cp=[...this.cp,...t]).forEach(t=>{s=Math.min(s,t[0]),e=Math.max(e,t[0]),n=Math.min(n,t[1]),h=Math.max(h,t[1])}),this.aabb=[s,n,e,h]}addSegments(...t){t.forEach(t=>this.dp.push(t))}addOutline(){for(let t=0,s=this.cp.length;t<s;t++)this.dp.push(this.cp[t],this.cp[(t+1)%s])}draw(t){for(let s=0,e=this.dp.length;s<e;s+=2)t.jump(this.dp[s]),t.goto(this.dp[s+1])}addHatching(t,s){const e=new n;e.cp.push([-1e5,-1e5],[1e5,-1e5],[1e5,1e5],[-1e5,1e5]);const h=Math.sin(t)*s,o=Math.cos(t)*s,a=200*Math.sin(t),i=200*Math.cos(t);for(let t=.5;t<150/s;t++)e.dp.push([h*t+i,o*t-a],[h*t-i,o*t+a]),e.dp.push([-h*t+i,-o*t-a],[-h*t-i,-o*t+a]);e.boolean(this,!1),this.dp=[...this.dp,...e.dp]}inside(t){let s=0;for(let e=0,n=this.cp.length;e<n;e++)this.segment_intersect(t,[.1,-1e3],this.cp[e],this.cp[(e+1)%n])&&s++;return 1&s}boolean(t,s=!0){const e=[];for(let n=0,h=this.dp.length;n<h;n+=2){const h=this.dp[n],o=this.dp[n+1],a=[];for(let s=0,e=t.cp.length;s<e;s++){const n=this.segment_intersect(h,o,t.cp[s],t.cp[(s+1)%e]);!1!==n&&a.push(n)}if(0===a.length)s===!t.inside(h)&&e.push(h,o);else{a.push(h,o);const n=o[0]-h[0],i=o[1]-h[1];a.sort((t,s)=>(t[0]-h[0])*n+(t[1]-h[1])*i-(s[0]-h[0])*n-(s[1]-h[1])*i);for(let n=0;n<a.length-1;n++)(a[n][0]-a[n+1][0])**2+(a[n][1]-a[n+1][1])**2>=.001&&s===!t.inside([(a[n][0]+a[n+1][0])/2,(a[n][1]+a[n+1][1])/2])&&e.push(a[n],a[n+1])}}return(this.dp=e).length>0}segment_intersect(t,s,e,n){const h=(n[1]-e[1])*(s[0]-t[0])-(n[0]-e[0])*(s[1]-t[1]);if(0===h)return!1;const o=((n[0]-e[0])*(t[1]-e[1])-(n[1]-e[1])*(t[0]-e[0]))/h,a=((s[0]-t[0])*(t[1]-e[1])-(s[1]-t[1])*(t[0]-e[0]))/h;return o>=0&&o<=1&&a>=0&&a<=1&&[t[0]+o*(s[0]-t[0]),t[1]+o*(s[1]-t[1])]}};return{list:()=>t,create:()=>new n,draw:(n,h,o=!0)=>{reducedPolygonList=function(n){const h={},o=200/s;for(var a=0;a<s;a++){const c=a*o-100,r=[0,c,200,c+o];if(!(n[3]<r[1]||n[1]>r[3]))for(var i=0;i<s;i++){const c=i*o-100;r[0]=c,r[2]=c+o,n[0]>r[2]||n[2]<r[0]||e[i+a*s].forEach(s=>{const e=t[s];n[3]<e.aabb[1]||n[1]>e.aabb[3]||n[0]>e.aabb[2]||n[2]<e.aabb[0]||(h[s]=1)})}}return Array.from(Object.keys(h),s=>t[s])}(h.aabb);for(let t=0;t<reducedPolygonList.length&&h.boolean(reducedPolygonList[t]);t++);h.draw(n),o&&function(n){t.push(n);const h=t.length-1,o=200/s;e.forEach((t,e)=>{const a=e%s*o-100,i=(e/s|0)*o-100,c=[a,i,a+o,i+o];c[3]<n.aabb[1]||c[1]>n.aabb[3]||c[0]>n.aabb[2]||c[2]<n.aabb[0]||t.push(h)})}(h)}}}


////////////////////////////////////////////////////////////////
// Bale utility code - Created by Jurgen Westerhof 2022
// https://turtletoy.net/turtle/7269af8a23
// Abusing the opacity, usage:
//      Canvas.setpenopacity(1/baleSize);
//      const bales = Array.apply(null,{length: baleSize}).map(b => new Bale(baleSize--);
// Then use bales[x] wherever you would use a turtle object to 'draw'
// in 'color' x (i.e Polygon hatching with a bale object and .15 interspacing)
////////////////////////////////////////////////////////////////
function Bale(n) {
    class Bale {
        constructor(n) { this.turtles = Array.apply(null,{length: n}).map(i => new Turtle()); }
        
        back(e)         { this.turtles.map(t => t.back(e)); return this; }
        backward(e)     { this.turtles.map(t => t.backward(e)); return this; }
        bk(e)           { this.turtles.map(t => t.bk(e)); return this; }
        fd(e)           { this.turtles.map(t => t.fd(e)); return this; }
        forward(e)      { this.turtles.map(t => t.forward(e)); return this; }

        left(e)         { this.turtles.map(t => t.left(e)); return this; }
        lt(e)           { this.turtles.map(t => t.lt(e)); return this; }
        right(e)        { this.turtles.map(t => t.right(e)); return this; }
        rt(e)           { this.turtles.map(t => t.rt(e)); return this; }

        seth(e)         { this.turtles.map(t => t.seth(e)); return this; }
        setheading(e)   { this.turtles.map(t => t.setheading(e)); return this; }

        setx(e)         { this.turtles.map(t => t.setx(e)); return this; }
        sety(e)         { this.turtles.map(t => t.sety(e)); return this; }

        setpos(x, y)        { this.turtles.map(t => t.setpos(x, y)); return this; }
        setposition(x, y)   { this.turtles.map(t => t.setposition(x, y)); return this; }

        toradians(e)    { this.turtles.map(t => t.toradians(e)); return this; }
        degrees(e)      { this.turtles.map(t => t.degrees(e)); return this; }

        goto(x, y)      { this.turtles.map(t => t.goto(x, y)); return this; }
        jmp(x, y)       { this.turtles.map(t => t.jmp(x, y)); return this; }
        jump(x, y)      { this.turtles.map(t => t.jump(x, y)); return this; }

        circle(radius, extent, steps) { this.turtles.map(t => t.circle(radius, extent, steps)); return this; }

        clone()         { let b = new Bale(this.turtle.length); this.turtles.map((t, k) => b.turtles[k] = t.clone()); return b; }

        h()             { return this.turtles[0].h(); }
        heading()       { return this.turtles[0].heading(); }
        
        home()          { this.turtles.map(t => t.home()); return this; }
        
        isdown()        { return this.turtles[0].isdown(); }

        pos()           { return this.turtles[0].pos(); }
        position()      { return this.turtles[0].position(); }

        pd()            { this.turtles.map(t => t.pd()); return this; }
        pendown()       { this.turtles.map(t => t.pendown()); return this; }
        penup()         { this.turtles.map(t => t.penup()); return this; }
        pu()            { this.turtles.map(t => t.pu()); return this; }
        down()          { this.turtles.map(t => t.down()); return this; }
        up()            { this.turtles.map(t => t.up()); return this; }

        radians()       { this.turtles.map(t => t.radians()); return this; }

        x()             { return this.turtles[0].x(); }
        xcor()          { return this.turtles[0].xcor(); }
        y()             { return this.turtles[0].y(); }
        ycor()          { return this.turtles[0].ycor(); }
    }
    return new Bale(n);
}
function Bales(count, includeWhite = false) {
    if(count == 1) return [new Bale(1)];
    const getExponent = (base, target) => Math.log(target) / Math.log(base);
    const baleSize = count - (includeWhite?1:0);
    const n = Array.apply(null,{length: baleSize}).map((v,k) => Math.round(getExponent(1 - 1/count, 1 - (count - k == count?.99:(baleSize - k)/baleSize))));
    if(includeWhite) n.push(0);
    return n.map(i => new Bale(i));
}