import * as lsys from "@thi.ng/lsys";
import * as g from "@thi.ng/geom";
import * as fs from "fs";

// example L-Systems shown above

const examples = [
    { rules: { s: "[f++f++f]", f: "f+f--f+f" }, delta: Math.PI / 3, iter: 5 },
    { rules: { s: "[f-f-f-f-f-f-f-f]", f: "f---f+f+f+f+f+f+f---f" }, delta: Math.PI / 4, iter: 6 },
    { rules: { s: "[x]", x: "-yf+xfx+fy-", y: "+xf-yfy-fx+" }, delta: Math.PI / 2, iter: 7 },
    { rules: { s: "[a]", a: "a-b--b+a++aa+b-", b: "+a-bb--b-a++a+b" }, delta: Math.PI / 3, iter: 5 }
];

const impl = lsys.TURTLE_IMPL_2D;

examples.forEach(({ rules, delta, iter }, i) =>
    fs.writeFileSync(
        `lsys-ex${i}.svg`,
        g.asSvg(
            g.svgDoc(
                { stroke: "#00f", "stroke-width": 0.25, width: 600, height: 600 },
                ...lsys.interpret(
                    // create turtle instance with customized delta (rot angle)
                    lsys.turtle2d({ delta }),
                    // customize implementation to process syms "a" & "b" as "f"
                    { ...impl, a: impl.f, b: impl.f },
                    // recursively expand start rule "s"
                    lsys.expand(rules, "s", iter)
                    //convert result paths to polylines for SVG export
                ).paths.map(g.polyline)
            )
        )
    )
);