(function () {
        if (typeof Chart !== 'undefined' && Chart?.register) {
        try {
            Chart.register();
        } catch (e) {
            console.warn('Błąd rejestracji pluginów Chart.js:', e);
        }
    } else {
        console.warn('Chart.js nie jest dostępny. Upewnij się, że <script src="...chart.js"> jest załadowany przed tym skryptem.');
    }
    // --- funkcje pomocnicze twojego oryginalnego modułu (trimData, loadExcelChart) ---
    function trimData(labels, ...series) {
        let lastIndex = -1;
        series.forEach(arr => {
            const idx = arr.map((v, i) => v !== null ? i : -1).reduce((a, b) => Math.max(a, b), -1);
            if (idx > lastIndex) lastIndex = idx;
        });
        if (lastIndex >= 0) {
            labels.splice(lastIndex + 1);
            series.forEach(arr => arr.splice(lastIndex + 1));
        }
    }

    async function loadExcelChart(config) {
        try {
            if (!config || !config.plik) {
                console.error("Brak cfg.plik");
                return;
            }

            const response = await fetch(config.plik);
            if (!response.ok) {
                throw new Error(`Błąd pobierania pliku: ${response.status} ${response.statusText}`);
            }

            const arrayBuffer = await response.arrayBuffer();
            let workbook;
            try {
                workbook = XLSX.read(new Uint8Array(arrayBuffer), { type: 'array' });
            } catch (err) {
                throw new Error("Błąd parsowania pliku XLSX — sprawdź format lub nazwę arkusza.");
            }

            const sheetName = workbook.SheetNames[config.sheetIndex];
            if (!sheetName) {
                throw new Error(`Arkusz nr ${config.sheetIndex} nie istnieje.`);
            }

            const sheet = workbook.Sheets[sheetName];
            const data = XLSX.utils.sheet_to_json(sheet, { header: 1, defval: "" });

            if (!data || data.length < (config.dataStartRow ?? 2)) {
                console.warn("⚠️ Brak danych do wyświetlenia.");
                return;
            }

            if (config.titleId) {
                const el = document.getElementById(config.titleId);
                if (el) el.textContent =
                    (data[0]?.[0] ?? "Brak danych").split(" ").slice(2).join(" ");
            }
            if (config.subtitleId) {
                const el2 = document.getElementById(config.subtitleId);
                if (el2) el2.textContent = data[1]?.[0] ?? "";
            }

            let labels = [];
            let datasets = [];

            if (config.useMonth) {
                labels = data.slice(config.dataStartRow).map(row => {
                    const month = row?.[0]?.toString() ?? "";
                    const year = row?.[1]?.toString() ?? "";
                    return { month, year, label: `${year} ${month}` };
                });

                datasets = config.series.map(series => ({
                    label: series.label,
                    data: data.slice(config.dataStartRow).map(row =>
                        row[series.col] === "" ? null : Number(row[series.col])
                    ),
                    borderColor: series.borderColor,
                    backgroundColor: series.backgroundColor,
                    pointStyle: 'line',
                    fill: false,
                    borderWidth: series.borderWidth ?? 4,
                    pointRadius: 0,
                    tension: 0.1
                }));

                trimData(labels, ...datasets.map(ds => ds.data));
                labels = labels.map(l => l.label);
            } else {
                labels = (data[config.labelsRow] || []).slice(1).map(x => x?.toString() || "");

                datasets = config.series.map(series => ({
                    label: series.label,
                    data: (data[series.row] || []).slice(1).map(x =>
                        x === "" ? null : Number(x)
                    ),
                    borderColor: series.borderColor,
                    backgroundColor: series.backgroundColor,
                    pointStyle: 'line',
                    fill: false,
                    borderWidth: series.borderWidth ?? 4,
                    pointRadius: 0,
                    tension: 0.1
                }));

                trimData(labels, ...datasets.map(ds => ds.data));
            }

            const container = document.getElementById(`charts-${config.chartId}`);
            if (!container) {
                console.error(`Nie znaleziono elementu charts-${config.chartId}`);
                return;
            }

            const canvas = document.createElement("canvas");
            canvas.id = config.chartId;
            container.appendChild(canvas);

            new Chart(canvas, {
                type: "line",
                data: { labels, datasets },
                options: {
                    responsive: true,
                    interaction: { mode: 'index', intersect: false },
                    layout: { padding: { bottom: 20 } },
                    plugins: {
                        datalabels: {
                            display: false
                        },
                        legend: config.showLegend ? {
                            position: "bottom",
                            labels: {
                                usePointStyle: true, pointStyle: 'line', padding: 20,
                                font: { size: 14 }, color: "#000", boxWidth: 20, boxHeight: 11
                            }
                        } : { display: false },
                        tooltip: {
                            enabled: false,
                            external: ctx => {
                                try { window.customTooltip(ctx, config.fractionDigits ?? 0); }
                                catch (e) { console.error("Tooltip error:", e); }
                            }
                        }
                    },
                    scales: {
                        x: {
                            border: { display: false },
                            grid: { drawOnChartArea: false },
                            ticks: {
                                font: { size: 13 },
                                color: "#000",
                                maxRotation: config.useMonth ? 90 : 0,
                                minRotation: config.useMonth ? 90 : 0,
                                align: config.useMonth ? "start" : "center"
                            }
                        },
                        y: {
                            border: { display: false },
                            grid: { color: "rgba(0,0,0,0.15)", drawBorder: false, drawTicks: false },
                            beginAtZero: false,
                            grace: '3%',
                            ticks: {
                                callback: v => v.toString().replace(/\s/g, ''),
                                font: { size: 13 },
                                padding: 10,
                                color: "#000"
                            }
                        }
                    }
                },
                plugins: [verticalLinePlugin]
            });

        } catch (error) {
            console.error(`Błąd w loadExcelChart(${config.chartId}):`, error);
        }
    }

    window.loadExcelChart = loadExcelChart;

    window.addEventListener("load", function () {
        try {
            if (typeof plik === 'undefined') {
                console.warn('Zmienna "plik" nie jest zdefiniowana w global scope — upewnij się że wskazuje na URL XLSX.');
                return;
            }
            loadExcelChart({
                plik,
                sheetIndex: 17,
                chartId: "Ludnosc2",
                titleId: "tytul-Ludnosc2",
                subtitleId: "podtytul-Ludnosc2",
                useMonth: true,
                dataStartRow: 2,
                series: [{ label: "Ludność", col: 2, borderColor: "rgba(82, 35, 152, 1)", backgroundColor: "rgba(82, 35, 152, 0.6)" }],
                fractionDigits: 0,
                showLegend: false
            });
            loadExcelChart({
                plik,
                sheetIndex: 16,
                chartId: "Ludnosc",
                titleId: "tytul-Ludnosc",
                subtitleId: null,
                useMonth: false,
                labelsRow: 1,
                series: [
                    { label: "Urodzenia żywe", row: 2, borderColor: "rgba(82, 35, 152, 1)", backgroundColor: "rgba(82, 35, 152, 0.6)" },
                    { label: "Zgony", row: 3, borderColor: "rgba(192, 176, 212, 1)", backgroundColor: "rgba(192, 176, 212, 0.6)", borderWidth: 4 }
                ],
                fractionDigits: 0,
                showLegend: true
            });
        } catch (e) { console.error(e); }
    });

})(); // koniec IIFE