/**
* barnsley-fern-functional.js
*
*/

import "./lib/dfhi.js";
import * as JXG from "jsxgraph" ;
import {exportBoard} from "./lib/dfhi-plot";

let board = undefined;
function initBoard () {
    return JXG.JSXGraph.initBoard('plotter', {
        boundingbox: [-6, 12, 6, -1],
        axis: false,
        keepAspectRatio:true
    });
}

window.init = function() {
    board = initBoard();
    document.getElementById("export")
        .addEventListener("click", (event) => exportBoard(board));
};


window.main = function(...argv) {
    if (board) {
        JXG.JSXGraph.freeBoard(board);
        board = undefined;
        board = initBoard();
    }
    let n = Number.parseInt(argv[0], 10);
    prePlot();
    barnsley(n, appendPointToBoard);
    postPlot();
};


function prePlot() {
    board.suspendUpdate();
}

function postPlot() {
    board.unsuspendUpdate();
    board.dehighlightAll();
}


function appendPointToBoard(point) {
    const pointOption = {withLabel:false, fixed:true, size:0.001, fillColor:"#00aa00", strokeWidth:0};
    board.create('point', point, pointOption );
}

function barnsley(n, plotFn) {
    const m = [
        [ 0    ,  0    , 0     , 0.16 , 0.500   , 0    , 0.01],
        [ 0.85 ,  0.04 , -0.04 , 0.85 , 0.075   , 1.60 , 0.85],
        [ 0.20 , -0.26 , 0.23  , 0.22 , 0.400   , 1.60 , 0.07],
        [-0.15 ,  0.28 , 0.26  , 0.24 , 0.575   , 0.44 , 0.07]
    ];
    const p = [ m[0][6], m[0][6] + m[1][6], m[0][6] + m[1][6] + m[2][6] ];
    let x = 0, y = 0;
    for(let i = 0; i < n; ++i) {
        const r = Math.random();
        let f = 0;
        if (r < p[0]) {
            f = 0;
        }else if (r < p[1]) {
            f = 1;
        }else if (r < p[2]) {
            f = 2;
        } else {
            f = 3;
        }
        let nX = (m[f][0] * x) + (m[f][1] * y) + m[f][4];
        y =  (m[f][2] * x) + (m[f][3] * y) + m[f][5];
        x = nX;
        plotFn([x, y]);
    }
}