document.addEventListener('DOMContentLoaded', function () {
    const CHART_COLORS = {
        red: 'rgba(234, 67, 53, 0.8)',
        orange: 'rgba(249, 171, 0, 0.8)',
        green: 'rgba(52, 168, 83, 0.8)',
        blue: 'rgba(26, 115, 232, 0.8)',
    };
    const CHART_BORDERS = {
        red: 'rgb(234, 67, 53)',
        orange: 'rgb(249, 171, 0)',
        green: 'rgb(52, 168, 83)',
        blue: 'rgb(26, 115, 232)',
    };

    const chartContexts = {
        perWarehouse: document.getElementById('alertsPerWarehouseChart')?.getContext('2d'),
        overTime: document.getElementById('alertsOverTimeChart')?.getContext('2d'),
        status: document.getElementById('alertStatusChart')?.getContext('2d')
    };

    const charts = {};

    function createOrUpdateChart(ctx, type, data, options) {
        const chartId = ctx.canvas.id;
        if (charts[chartId]) {
            charts[chartId].data = data;
            charts[chartId].options = options;
            charts[chartId].update();
        } else {
            charts[chartId] = new Chart(ctx, { type, data, options });
        }
    }

    function renderAlertsTable(alerts) {
        const tableBody = document.getElementById('alerts-table-body');
        if (!tableBody) return;
        tableBody.innerHTML = ''; // Clear existing rows

        if (!alerts || alerts.length === 0) {
            tableBody.innerHTML = '<tr><td colspan="10" class="text-center text-muted">No active alerts found.</td></tr>';
            return;
        }

        alerts.forEach(alert => {
            const statusBadge = getStatusBadge(alert.status);
            const row = `
                <tr>
                    <td><span class="fw-bold">${alert.alert_id}</span></td>
                    <td>${new Date(alert.timestamp).toLocaleString()}</td>
                    <td>${alert.warehouse_name}</td>
                    <td>${alert.slot_name}</td>
                    <td>${alert.node_name}</td>
                    <td>${alert.metric_name}</td>
                    <td><span class="fw-bold text-danger">${alert.actual_value}</span></td>
                    <td>${alert.threshold_value}</td>
                    <td><span class="badge ${statusBadge}">${alert.status}</span></td>
                    <td>
                        <button class="btn btn-sm btn-outline-secondary" title="Acknowledge"><i class="bi bi-check-circle"></i></button>
                        <button class="btn btn-sm btn-outline-secondary" title="Resolve"><i class="bi bi-patch-check"></i></button>
                    </td>
                </tr>
            `;
            tableBody.insertAdjacentHTML('beforeend', row);
        });
    }
    
    function getStatusBadge(status) {
        switch (status) {
            case 'active': return 'text-bg-danger';
            case 'acknowledged': return 'text-bg-warning';
            case 'resolved': return 'text-bg-success';
            default: return 'text-bg-secondary';
        }
    }

    function renderCharts(chartData) {
        // Chart 1: Alerts per Warehouse (Bar)
        if (chartContexts.perWarehouse && chartData.per_warehouse) {
            const data = {
                labels: chartData.per_warehouse.map(d => d.name),
                datasets: [{
                    label: 'Alerts',
                    data: chartData.per_warehouse.map(d => d.alert_count),
                    backgroundColor: CHART_COLORS.blue,
                    borderColor: CHART_BORDERS.blue,
                    borderWidth: 1
                }]
            };
            const options = {
                responsive: true,
                plugins: { legend: { display: false }, title: { display: true, text: 'Alerts per Warehouse' } },
                scales: { y: { beginAtZero: true } }
            };
            createOrUpdateChart(chartContexts.perWarehouse, 'bar', data, options);
        }

        // Chart 2: Alerts over Time (Line)
        if (chartContexts.overTime && chartData.over_time) {
            const data = {
                labels: chartData.over_time.map(d => d.alert_date),
                datasets: [{
                    label: 'Alerts',
                    data: chartData.over_time.map(d => d.alert_count),
                    borderColor: CHART_COLORS.red,
                    backgroundColor: CHART_COLORS.red,
                    tension: 0.1,
                    fill: false
                }]
            };
            const options = {
                responsive: true,
                plugins: { legend: { display: false }, title: { display: true, text: 'Alerts Over Last 7 Days' } },
                scales: { y: { beginAtZero: true } }
            };
            createOrUpdateChart(chartContexts.overTime, 'line', data, options);
        }

        // Chart 3: Alert Status (Pie)
        if (chartContexts.status && chartData.status_distribution) {
            const data = {
                labels: chartData.status_distribution.map(d => d.status),
                datasets: [{
                    label: 'Alerts',
                    data: chartData.status_distribution.map(d => d.alert_count),
                    backgroundColor: [CHART_COLORS.red, CHART_COLORS.orange, CHART_COLORS.green],
                    borderColor: [CHART_BORDERS.red, CHART_BORDERS.orange, CHART_BORDERS.green],
                    borderWidth: 1
                }]
            };
            const options = {
                responsive: true,
                plugins: { 
                    legend: { position: 'top' }, 
                    title: { display: true, text: 'Alert Status Distribution' } 
                }
            };
            createOrUpdateChart(chartContexts.status, 'pie', data, options);
        }
    }

    async function fetchData() {
        const tableBody = document.getElementById('alerts-table-body');
        try {
            const response = await fetch('api/alerts-data.php');
            if (!response.ok) {
                throw new Error(`HTTP error! status: ${response.status}`);
            }
            const data = await response.json();

            if (data.success) {
                renderAlertsTable(data.alerts);
                renderCharts(data.chart_data);
            } else {
                console.error('API Error:', data.error);
                if(tableBody) tableBody.innerHTML = `<tr><td colspan="10" class="text-center text-danger">Failed to load data from API.</td></tr>`;
            }
        } catch (error) {
            console.error('Fetch Error:', error);
            if(tableBody) tableBody.innerHTML = `<tr><td colspan="10" class="text-center text-danger">Error fetching data. Check console for details.</td></tr>`;
        }
    }

    fetchData();
    // setInterval(fetchData, 30000); // Optional: Refresh every 30 seconds
});