const border = 10; //min=0 max=100 step=5
const grid = 11; //min=2 max=50 step=1
const missing = 1; //min=0 max=2 step=1 (No, Yes, Random)
const hatch = 1; //min=0 max=1 step=1 (No, Yes)
const minHatch = .25; //min=0 max=1.5 step=.05
const maxHatch = .7; //min=.25 max=1.5 step=.05

const turtle = new Turtle();
const polygons = new Polygons();

let size = (100 - border) * 2 / grid;
const t = (p) => [p[0] - 100 + border, p[1] - 100 + border];

let effectiveGrid = grid + 1;

let hatchMap = [];
if(missing == 1) {
    hatchMap['10-10'] = null;
} else if(missing == 2) {
    hatchMap[(Math.random() * grid | 0) + '-' + (Math.random() * grid | 0)] = null;
}

function walk(i) {
    let col = i % effectiveGrid;
    let row = i / effectiveGrid | 0;
    if(row % 2 == 0) {
        if(col == effectiveGrid - 1) {
            return true;
        }
    } else {
        if(row == (effectiveGrid * 2) - 1) {
            return true;
        }
    }
    //if(row > effectiveGrid * 2 - 1) return false;
    turtle.seth(row % 2 == 0? 0: 90);
    turtle.jump(t([col * size, (row - (row % 2 == 0? 0: 1))/2 * size]));
    
    let type = 0;
    if(row == 0) {
        type = 1;
    } else if(row == effectiveGrid * 2 - 2) {
        type = 3;
    } else if(col == 0 && row % 2 == 1) {
        type = 4;
    } else if(col == effectiveGrid - 1) {
        type = 2;
    }
    
    let hatchRow = Math.floor(row / 2);
    let hatchCol = col;
    
    let hatchOne = null;
    let hatchTwo = null;
    if(row % 2 == 0) {
        if(row > 0) {
            hatchTwo = hatchCol + '-' + (hatchRow - 1);
        }
        if(row < effectiveGrid * 2 - 2) {
            hatchOne = hatchCol + '-' + hatchRow;
        }
    } else {
        if(col > 0) {
            hatchOne = (hatchCol - 1) + '-' + hatchRow;
        }
        if(col < effectiveGrid - 1) {
            hatchTwo = hatchCol + '-' + hatchRow;
        }
    }
    const color = () => [Math.PI * 2 * Math.random(), minHatch + ((maxHatch - minHatch) * Math.random())];
    if(hatchOne != null) {
        if(!(hatchOne in hatchMap)) {
            hatchMap[hatchOne] = color();
        }
    }
    if(hatchTwo != null) {
        if(!(hatchTwo in hatchMap)) {
            hatchMap[hatchTwo] = color();
        }
    }
    
    if(missing == 0 || (hatchMap[hatchOne] != null || hatchMap[hatchTwo] != null)) {
        drawTile(size, type, Math.random() < .5, hatchOne == null? null: hatchMap[hatchOne], hatchTwo == null? null: hatchMap[hatchTwo]);  
    }
    return i < (effectiveGrid**2 * 2) - effectiveGrid - 2;
}

function pCircle(p, turtle, r, ext) {
    let steps = 60;
    let radStep = ext / steps;//1 / (Math.PI * 2 * Math.abs(r));
    let stepLength = ((ext/turtle._fullCircle) * (2 * Math.PI * r)) / steps;    

    for(let i = 0; i < steps; i++) {
        turtle.right(radStep* (r < 0? -1: 1));
        turtle.forward(stepLength* (r < 0? -1: 1));
        p.addPoints(turtle.pos());
    }
}

function drawTile(size, type, leftright, hOne, hTwo) {
    leftright = leftright? 1: -1;
    
    let h = turtle.h();
    let pos = turtle.pos();

    let p = polygons.create();
    
    p.addPoints(turtle.pos());
    switch(type) {
        case 0:
            let ratio = size/156.06448009586634;
            turtle.left(10*leftright);
            turtle.forward(60 * ratio);
            p.addPoints(turtle.pos());
            pCircle(p, turtle, 10 * ratio*leftright, 155);
            pCircle(p, turtle, -20 * ratio*leftright, 290);
            pCircle(p, turtle, 10 * ratio*leftright, 155);
            turtle.forward(60 * ratio);
            p.addPoints(turtle.pos());
            turtle.left(10*leftright);
            break;
        case 1:
        case 2:
        case 3:
        case 4:
            turtle.forward(size);
            p.addPoints(turtle.pos());
            break;
            
    }
    turtle.jump(pos);
    turtle.seth(h); 
    turtle.up();
    turtle.forward(size)
    p.addPoints(turtle.pos());
    
    turtle.right(turtle._fullCircle * 3 / 8);
    turtle.forward(Math.sqrt(size**2 / 2));
    p.addPoints(turtle.pos());
    turtle.right(turtle._fullCircle / 4);
    turtle.forward(Math.sqrt(size**2 / 2));
    turtle.down();
    if(hOne != null && hatch == 1) {//type < 3) {
        p.addHatching(...hOne);//1.2, .8);
    }
    polygons.draw(turtle, p);
    turtle.jump(pos);
    turtle.seth(h); 


    p = polygons.create();
    turtle.up();
    turtle.left(turtle._fullCircle / 8);
    for(let i = 0; i < 4; i++) {
        p.addPoints(turtle.pos());
        turtle.forward(Math.sqrt(size**2 / 2))
        turtle.right(turtle._fullCircle / 4);
    }
    turtle.right(turtle._fullCircle / 8);
    turtle.down();
    if(hTwo != null && hatch == 1) {//type == 0 || 2 < type) {
        p.addHatching(...hTwo);//.7, .5);
    }
    polygons.draw(turtle, p);
    turtle.jump(pos);
    turtle.seth(h); 
}


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