// chart.js
let ctx = null;

export function drawChart(canvas, history) {
    if (!canvas || !history?.length) return;

    const ctx = canvas.getContext("2d");

    const rect = canvas.getBoundingClientRect();
    canvas.width = rect.width;
    canvas.height = rect.height;

    const w = canvas.width;
    const h = canvas.height;

    ctx.clearRect(0, 0, w, h);

    const stepX = w / 1000;
    const scaleY = h / 63;

    ctx.strokeStyle = "#00ff88";
    ctx.beginPath();

    for (let i = 0; i < history.length; i++) {
        const x = i * stepX;
        const y = h - history[i].value * scaleY; // 👈 FIX

        if (i === 0) ctx.moveTo(x, y);
        else ctx.lineTo(x, y);
    }

    ctx.stroke();
}