(function($) {
    const canvas = document.getElementById('ntPriceChart');
    if (!canvas) return;

    const product_id = canvas.dataset.productId;

    $.post(ntPriceHistory.ajaxurl, {
        action: 'nt_update_price_history',
        product_id: product_id
    }, function(response) {
        if (!response.success) {
            console.error('Chyba v odpovědi serveru:', response);
            return;
        }

        let data = response.data;
        if (!data || data.length === 0) {
            console.warn('Žádná data k zobrazení:', data);
            return;
        }

        // Kontrola formátu dat
        console.log('Přijatá data:', data);

        let dataPoints = data.map(point => {
            let date = new Date(point.x);
            if (isNaN(date)) {
                if (point.x.match(/^\d{2}\.\d{2}\.\d{4}$/)) {
                    const [day, month, year] = point.x.split('.');
                    date = new Date(`${year}-${month}-${day}`);
                }
            }
            return { x: date.toISOString().split('T')[0], y: point.y };
        });

        const prices = dataPoints.map(p => p.y);
        const minPrice = Math.min(...prices);
        const maxPrice = Math.max(...prices);

        // Handle single data point case
        if (dataPoints.length === 1) {
            const singlePrice = dataPoints[0].y;
            const today = new Date();
            const thirtyDaysAgo = new Date(today.getTime() - 30 * 24 * 60 * 60 * 1000);
            const fifteenDaysAgo = new Date(today.getTime() - 15 * 24 * 60 * 60 * 1000);

            dataPoints = [
                { x: thirtyDaysAgo.toISOString().split('T')[0], y: singlePrice },
                { x: fifteenDaysAgo.toISOString().split('T')[0], y: singlePrice },
                { x: today.toISOString().split('T')[0], y: singlePrice }
            ];
        }

        const ctx = canvas.getContext('2d');
        new Chart(ctx, {
            type: 'line',
            data: {
                datasets: [{
                    label: 'Historie ceny (30 dní)',
                    data: dataPoints,
                    borderColor: '#0094DE',
                    backgroundColor: function(context) {
                        const gradient = context.chart.ctx.createLinearGradient(0, 0, 0, 300);
                        gradient.addColorStop(0, 'rgba(0,148,222,0.3)');
                        gradient.addColorStop(1, 'rgba(0,148,222,0)');
                        return gradient;
                    },
                    fill: true,
                    tension: dataPoints.length === 1 ? 0 : 0.3,
                    pointRadius: dataPoints.length === 1 ? [0, 4, 0] : 4,
                    pointHoverRadius: dataPoints.length === 1 ? [0, 6, 0] : 6,
                    pointBackgroundColor: dataPoints.map(p => {
                        if (p.y === minPrice) return 'green';
                        if (p.y === maxPrice) return 'red';
                        return '#0094DE';
                    })
                }]
            },
            options: {
                parsing: { xAxisKey: 'x', yAxisKey: 'y' },
                plugins: {
                    tooltip: {
                        enabled: true,
                        backgroundColor: '#0094DE',
                        titleColor: '#fff',
                        bodyColor: '#fff',
                        callbacks: {
                            title: function(context) {
                                const index = context[0].dataIndex;
                                const originalDate = dataPoints[index].x; // Použijeme původní datum z dataPoints
                                console.log('Tooltip original date:', originalDate); // Ladění
                                const date = new Date(originalDate);
                                if (isNaN(date)) {
                                    console.error('Neplatné datum v tooltipu:', originalDate);
                                    return 'Datum: Neplatné';
                                }
                                const day = String(date.getDate()).padStart(2, '0');
                                const month = String(date.getMonth() + 1).padStart(2, '0');
                                const year = date.getFullYear();
                                return `Datum: ${day}.${month}.${year}`;
                            },
                            label: function(context) {
                                return 'Cena: ' + context.formattedValue + ' Kč';
                            }
                        }
                    },
                    legend: { display: false }
                },
                scales: {
                    x: {
                        display: true,
                        title: { display: true, text: 'Datum' },
                        ticks: { autoSkip: true, maxTicksLimit: 10 },
                        grid: { color: 'rgba(0,0,0,0.05)' },
                        type: 'time',
                        time: {
                            unit: 'day',
                            displayFormats: { day: 'dd.MM.yyyy' }
                        },
                        min: new Date(new Date().getTime() - 30 * 24 * 60 * 60 * 1000).toISOString().split('T')[0],
                        max: new Date().toISOString().split('T')[0]
                    },
                    y: {
                        display: true,
                        title: { display: true, text: 'Cena (Kč)' },
                        beginAtZero: false,
                        grid: { color: 'rgba(0,0,0,0.05)' }
                    }
                }
            }
        });
    });
})(jQuery);