var gui = require('gui');
var gfx = gui.gfx;

var sp = 8;

// data
const datapoints = [
    { x: 0, v: 0 },
    { x: 1, v: 100 },
    { x: 2, v: -39 },
    { x: 3, v: -24 },
    { x: 4, v: 24 },
    { x: 5, v: -12 },
    { x: 6, v: 100 }
];

// create window (initial size; drawing will use current window client area)
let gadgets = [];
let win = gui.createWindow({
    title: "Summary Chart",
    width: 400,
    height: 200,
    left: 30,
    top: 30,
    gadgets: gadgets
});

// Compute cumulative series and min/max (include 0 to ensure Y=0 is visible)
let cumulative = [];
let cur = 0;
cumulative.push({ x: datapoints[0].x, y: 0 }); // start at 0
let lowest = 0;
let highest = 0;

for (let i = 0; i < datapoints.length; ++i) {
    cur += datapoints[i].v;
    cumulative.push({ x: datapoints[i].x, y: cur });
    if (cur < lowest) lowest = cur;
    if (cur > highest) highest = cur;
}
if (0 < lowest) lowest = 0;
if (0 > highest) highest = 0;

// Draw function using current window size
function drawChart() {
    const totalW = Math.max(10, 400 - sp * 3);
    const totalH = Math.max(10, 200 - sp * 3);
    const left = sp;
    const top = sp;
    const right = left + totalW;
    const bottom = top + totalH;

    // X and Y ranges
    const minX = cumulative[0].x;
    const maxX = cumulative[cumulative.length - 1].x;
    const xRange = (maxX === minX) ? 1 : (maxX - minX);
    let yRange = highest - lowest;
    if (yRange === 0) yRange = 1;

    // mapping functions
    const mapX = x => left + ((x - minX) / xRange) * totalW;
    const mapY = y => bottom - ((y - lowest) / yRange) * totalH; // invert Y

    // draw Y=0 axis
    const y0 = mapY(0);
    gfx.setColor(win, 1);
    gfx.drawLine(win, left, y0, right, y0);

    gfx.setColor(win, 4);
    // draw polyline
    let last = cumulative[0];
    for (let i = 1; i < cumulative.length; ++i) {
        let p = cumulative[i];
        gfx.drawLine(win, mapX(last.x), mapY(last.y), mapX(p.x), mapY(p.y));
        last = p;
    }
}

// initial draw
drawChart();

    while (true) {
            var evt = gui.waitEvent(win);
            if (!evt) continue;
    
            if (evt.type === 'close') {
                gui.closeWindow(win);
                break;
            }
    }

    console.log("close");