// app/static/js/overdue_analysis.js
document.addEventListener('DOMContentLoaded', function() {
    let overdueRangeChart = null;
    let overdueStatusChart = null;

    // 初始加载
    loadOverdueStatistics();

    function loadOverdueStatistics() {
        // 调用API获取数据
        fetch('/statistics/api/overdue-statistics')
            .then(response => response.json())
            .then(data => {
                updateOverdueCards(data);
                updateOverdueRangeChart(data.overdue_ranges);
                updateOverdueStatusChart(data);
            })
            .catch(error => {
                console.error('加载逾期统计数据失败:', error);
            });
    }

    function updateOverdueCards(data) {
        document.getElementById('total-borrows').querySelector('.card-value').textContent = data.total_borrows;
        document.getElementById('current-overdue').querySelector('.card-value').textContent = data.current_overdue;
        document.getElementById('returned-overdue').querySelector('.card-value').textContent = data.returned_overdue;
        document.getElementById('overdue-rate').querySelector('.card-value').textContent = data.overdue_rate + '%';
    }

    function updateOverdueRangeChart(rangeData) {
        // 销毁旧图表
        if (overdueRangeChart) {
            overdueRangeChart.destroy();
        }

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

        // 准备图表数据
        const labels = rangeData.map(item => item.range);
        const counts = rangeData.map(item => item.count);

        // 创建图表
        const ctx = document.getElementById('overdue-range-chart').getContext('2d');
        overdueRangeChart = new Chart(ctx, {
            type: 'bar',
            data: {
                labels: labels,
                datasets: [{
                    label: '逾期数量',
                    data: counts,
                    backgroundColor: [
                        'rgba(255, 206, 86, 0.7)',
                        'rgba(255, 159, 64, 0.7)',
                        'rgba(255, 99, 132, 0.7)',
                        'rgba(255, 0, 0, 0.7)'
                    ],
                    borderWidth: 1
                }]
            },
            options: {
                responsive: true,
                maintainAspectRatio: false,
                scales: {
                    y: {
                        beginAtZero: true,
                        title: {
                            display: true,
                            text: '数量'
                        }
                    }
                },
                plugins: {
                    title: {
                        display: true,
                        text: '逾期时长分布'
                    }
                }
            }
        });
    }

    function updateOverdueStatusChart(data) {
        // 销毁旧图表
        if (overdueStatusChart) {
            overdueStatusChart.destroy();
        }

        // 准备图表数据
        const statusLabels = ['当前逾期', '历史逾期', '正常'];
        const statusData = [
            data.current_overdue,
            data.returned_overdue,
            data.total_borrows - data.current_overdue - data.returned_overdue
        ];

        // 创建图表
        const ctx = document.getElementById('overdue-status-chart').getContext('2d');
        overdueStatusChart = new Chart(ctx, {
            type: 'pie',
            data: {
                labels: statusLabels,
                datasets: [{
                    data: statusData,
                    backgroundColor: [
                        'rgba(255, 99, 132, 0.7)',
                        'rgba(255, 206, 86, 0.7)',
                        'rgba(75, 192, 192, 0.7)'
                    ],
                    borderWidth: 1
                }]
            },
            options: {
                responsive: true,
                maintainAspectRatio: false,
                plugins: {
                    title: {
                        display: true,
                        text: '借阅状态分布'
                    }
                }
            }
        });
    }
});