// Forked from "Hilbert curve" by 4rknova
// https://turtletoy.net/turtle/5da041b968

// Using base L-System implementation from reinder
// Global code will be evaluated once.
Canvas.setpenopacity(1);
const turtle = new Turtle();
let offset = -95 //min=-100,max=0, step=1
turtle.penup();
turtle.goto(offset,offset);
turtle.pendown();

let distance = 1.5; //min=1, max=5, step=0.1
let innerations = 7 //min=1, max=7, step=1
let angle = 90;


// l-system
function createLSystem(numIters, axiom) {
    let s = axiom;
    for (let i=0; i<numIters; i++) {
        s = processString(s);
    }
    return s;
}

function processString(oldStr) {
    let newstr = "";
    for (let i=0; i<oldStr.length; i++) {
        newstr += applyRules(oldStr[i]);
    }
    return newstr;
}

function applyRules(ch) {
    switch (ch) {
        case "A": return "+BF-AFA-FB+";
        case "B": return "-AF+BFB+FA-";
        default: return ch;
    }
}

let data = [];
const saveP = (x, y, a) => data.push({x, y, a});
const loadP = () => data.pop();

turtle.setheading(90);
const inst = createLSystem(innerations, "A"); // number of iterations and axiom

// The walk function will be called until it returns false.
function walk(i) {
    const cmd = inst[i];

    switch (cmd) {
        case "F":   turtle.forward(distance);
                    break;
        case "-":   turtle.right(angle);
                    break;
        case "+":   turtle.left(angle);
                    break;
        default:
    }
      
    return i < inst.length - 1;
}