const towerCount = 100; //min=1 max=150 step=1
const interspacing = 1.3; //min=.5 max=3 step=.1
const noise = .5; //min=0 max=1 step=.1
const perspective = 1.4; //min=1 max=2 step=.1
const conify = .5; //min=-1 max=1 step=.1
const border = 5; //min=0 max=50 step=1
const heightMin = 30; //min=1 max=90 step=1
const heightMax = 100; //min=2 max=150 step=1
const rMin = 5; //min=1 max=20 step=1
const rMax = 30; //min=21 max=50 step=1

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

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

const normalize2 = (a) => scale2(a, 1/len2(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];

if(border > 0) {
    const brd = 100 - border;
    ([
        [[-120, -brd], [120, -brd], [120, -120], [-120, -120]],
        [[brd, -120], [brd, 120], [120, 120], [120, -120]],
        [[-120, brd], [120, brd], [120, 120], [-120, 120]],
        [[-brd, -120], [-brd, 120], [-120, 120], [-120, -120]]
    ]).forEach((b => {
        const p = polygons.create();
        p.addPoints(...b);
        polygons.draw(turtle, p);
    }));
    
    [[-1,-1],[1,-1],[1,1],[-1,1],[-1,-1]].forEach((i, k) => k == 0? turtle.jump(scale2(i, brd)): turtle.goto(scale2(i, brd)))
}

const getRandomHeight = (hMin, hMax) => Math.min(hMin, hMax) + (Math.random() * (Math.max(hMin, hMax) - Math.min(hMin, hMax)));
const getRandomRadius = (rMin, rMax) => Math.min(rMin, rMax) + (Math.random() * (Math.max(rMin, rMax) - Math.min(rMin, rMax)));
const getRandomLocation = () => {
    return [
        (Math.random() * (200 + rMax + rMax)) - 100 - rMax,
        (Math.random() * (200 + rMax + rMax)) - 100 - rMax - heightMax]
}

const towers = [new Tower(
    getRandomLocation(),
    getRandomRadius(rMin, rMax),
    getRandomHeight(heightMin, heightMax)
)];

while(towers.length < towerCount) {//(let i = 0; i < 40; i++) {
    let candidates = Array.apply(null,{length: 10}).map(b => getRandomLocation());
    
    //calc distance to each tower for each candidate
    candidates.forEach(c => c.distances = towers.map(t => [t, dist2(c, t.pos) - (t.r + rMin)]));
    //filter candidates that are within a towers radius
    candidates = candidates.filter(c => c.distances.filter(cd => cd[1] < 0).length == 0);
    //sort remaining distances for large to small
    candidates.forEach(c => c.distances.sort((a,b) => a[1] < b[1]? -1: 1));
    //map the longest distance to the canditate
    candidates = candidates.map(c => [c[0], c[1], ...c.distances[0]]);
    //sort the candidates to find te candidate with largest distance
    candidates.sort((a,b) => a[3] < b[3]? 1: -1);

    if(candidates.length == 0) continue;

    let radius = Math.min(rMax, Math.max(rMin, candidates[0][3]));

    towers.push(new Tower(
        [candidates[0][0], candidates[0][1]],
        getRandomRadius(Math.max(radius, rMin), Math.min(radius, rMax)),
        getRandomHeight(heightMin, heightMax)
    ));
}

towers.sort((a,b) => a.pos[1] < b.pos[1]? 1: -1);

// The walk function will be called until it returns false.
function walk(i) {
    const c = heightMax - i;
    const tmpTowers = towers.filter(t => t.height >= c);
    tmpTowers.forEach(t => {
        let p = polygons.create();
        p.addPoints(...t.getPoints(heightMax - (interspacing*i)));
        p.addOutline();
        polygons.draw(turtle, p);
    });
    return  c > 0;
}

function Tower(pos, r, height) {
    class Tower {
        constructor(pos, r, h) {
            this.pos = pos;
            this.r = r;
            this.height = h;
            
            this.basePoints = [];
            let max = Math.PI * 2 * this.r | 0;
            for(let i = 0; i < max; i++) {
                this.basePoints.push([
                    Math.cos(Math.PI * 2 * (i/max)) * this.r,
                    -Math.sin(Math.PI * 2 * (i/max)) * this.r / perspective
                ]);
            }
        }
        getPoints(height) {
            const dist = [Math.random() * noise * this.r/3.5, Math.random() * noise * this.r/3.5];
            return this.basePoints
                .map(p => scale2(p, conify == 0? 1: (conify > 0? 1 - (conify * height / heightMax): (conify * height / heightMax))))
                .map(p => add2(p, dist))
//                .map(p => add2(p, [Math.random(), Math.random()]))
                .map(p => add2(add2(this.pos, [0, 100-height]), p));
        }
    }
    return new Tower(pos, r, height);
}


////////////////////////////////////////////////////////////////
// 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)}}}