// Dashboard JavaScript functionality
document.addEventListener('DOMContentLoaded', function() {
    // Initialize user trend chart if canvas exists
    const chartCanvas = document.getElementById('userTrendChart');
    if (chartCanvas) {
        initUserTrendChart();
    }
    
    // Auto refresh dashboard data every 5 minutes
    setInterval(function() {
        refreshDashboardStats();
    }, 300000); // 5 minutes
});

function initUserTrendChart() {
    const ctx = document.getElementById('userTrendChart').getContext('2d');
    
    // Get data from template variables (these will be rendered by Jinja2)
    const labels = window.userTrendLabels || [];
    const data = window.userTrendData || [];
    
    const userTrendChart = new Chart(ctx, {
        type: 'line',
        data: {
            labels: labels,
            datasets: [{
                label: '注册用户数',
                data: data,
                borderColor: 'rgb(102, 126, 234)',
                backgroundColor: 'rgba(102, 126, 234, 0.1)',
                tension: 0.4,
                fill: true
            }]
        },
        options: {
            responsive: true,
            maintainAspectRatio: false,
            plugins: {
                legend: {
                    display: false
                }
            },
            scales: {
                y: {
                    beginAtZero: true,
                    ticks: {
                        stepSize: 1
                    }
                }
            }
        }
    });
}

function refreshDashboardStats() {
    // This function could be used to refresh dashboard statistics via AJAX
    // For now, it's a placeholder for future implementation
    console.log('Refreshing dashboard stats...');
}

// Utility function to format numbers
function formatNumber(num) {
    if (num >= 1000000) {
        return (num / 1000000).toFixed(1) + 'M';
    } else if (num >= 1000) {
        return (num / 1000).toFixed(1) + 'K';
    }
    return num.toString();
}

// Function to update stats cards (for future AJAX updates)
function updateStatsCard(cardSelector, value) {
    const card = document.querySelector(cardSelector);
    if (card) {
        const valueElement = card.querySelector('h3');
        if (valueElement) {
            valueElement.textContent = formatNumber(value);
        }
    }
}