let cpsChart = null;

async function loadCps(hours = 24) {
    // Highlight active button
    document.querySelectorAll('.controls button').forEach(b => b.style.opacity = '0.6');
    const activeBtn = [...document.querySelectorAll('.controls button')].find(
        b => b.textContent.includes(hours <= 24 ? `${hours}h` : `${hours/24}j`) || (hours === 168 && b.textContent === '7j')
    );
    if (activeBtn) activeBtn.style.opacity = '1';

    try {
        const resp = await fetch(`${API_BASE}/api/cps/timeline?hours=${hours}`);
        if (!resp.ok) return;
        const data = await resp.json();

        if (!data.data_points || data.data_points.length === 0) {
            return;
        }

        const labels = data.data_points.map(d => d.ts);
        const cpsValues = data.data_points.map(d => d.cps);

        updateCpsChart(labels, cpsValues);
    } catch {}
}

function updateCpsChart(labels, values) {
    const ctx = document.getElementById('cps-chart').getContext('2d');

    const chartData = {
        labels: labels,
        datasets: [{
            label: 'CPS',
            data: values,
            borderColor: '#4caf50',
            backgroundColor: 'rgba(76, 175, 80, 0.1)',
            borderWidth: 1.5,
            pointRadius: 0,
            fill: true,
            tension: 0.3,
        }]
    };

    const options = {
        responsive: true,
        maintainAspectRatio: false,
        plugins: {
            legend: { labels: { color: '#e0e0e0' } },
        },
        scales: {
            x: {
                type: 'time',
                time: {
                    tooltipFormat: 'dd/MM HH:mm',
                    displayFormats: { minute: 'HH:mm', hour: 'HH:mm', day: 'dd/MM' }
                },
                title: { display: true, text: 'Temps', color: '#888' },
                ticks: { color: '#888', maxTicksLimit: 12 },
                grid: { color: '#333' },
            },
            y: {
                title: { display: true, text: 'CPS', color: '#888' },
                ticks: { color: '#888' },
                grid: { color: '#333' },
                beginAtZero: true,
            }
        }
    };

    if (cpsChart) {
        cpsChart.data = chartData;
        cpsChart.options = options;
        cpsChart.update();
    } else {
        // Chart.js needs the date adapter for time axis
        const script = document.createElement('script');
        script.src = 'https://cdn.jsdelivr.net/npm/chartjs-adapter-date-fns@3.0.0/dist/chartjs-adapter-date-fns.bundle.min.js';
        script.onload = () => {
            cpsChart = new Chart(ctx, { type: 'line', data: chartData, options });
        };
        document.head.appendChild(script);
    }
}