document.addEventListener('DOMContentLoaded', function() {
    // Expense data
    const expenses = [
        { id: 1, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'July 9, 2020', cost: 12176.60, renewalDate: 'July 9, 2020' },
        { id: 2, software: 'Plaxis', invoiceDate: 'September 1, 2020', cost: 5361.00, renewalDate: 'September 1, 2020' },
        { id: 3, software: 'Tekla', invoiceDate: 'December 1, 2020', cost: 13503.40, renewalDate: 'December 1, 2020' },
        { id: 4, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'July 9, 2021', cost: 11877.00, renewalDate: 'July 9, 2021' },
        { id: 5, software: 'Plaxis', invoiceDate: 'September 1, 2021', cost: 5391.00, renewalDate: 'September 1, 2021' },
        { id: 6, software: 'Tekla', invoiceDate: 'December 1, 2021', cost: 6868.60, renewalDate: 'December 1, 2021' },
        { id: 7, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'August 10, 2022', cost: 13482.00, renewalDate: 'August 10, 2022' },
        { id: 8, software: 'Plaxis', invoiceDate: 'September 5, 2022', cost: 5796.00, renewalDate: 'September 5, 2022' },
        { id: 9, software: 'Tekla', invoiceDate: 'October 18, 2022', cost: 7130.37, renewalDate: 'December 1, 2022' },
        { id: 10, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'July 4, 2023', cost: 11664.00, renewalDate: 'July 4, 2023' },
        { id: 11, software: 'Plaxis', invoiceDate: 'September 21, 2023', cost: 6201.00, renewalDate: 'September 5, 2023' },
        { id: 12, software: 'Tekla', invoiceDate: 'October 18, 2023', cost: 7792.20, renewalDate: 'December 1, 2023' },
        { id: 13, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'July 4, 2024', cost: 11336.00, renewalDate: 'July 4, 2024' },
        { id: 14, software: 'Plaxis', invoiceDate: 'September 18, 2024', cost: 7003.40, renewalDate: '18/9/2024' },
        { id: 15, software: 'Tekla', invoiceDate: 'October 10, 2024', cost: 8316.00, renewalDate: '10/10/2024' },
        { id: 16, software: 'CSI [Etabs, SAFE, SAP2000]', invoiceDate: 'May 22, 2025', cost: 11336.00, renewalDate: 'May 22, 2025' },
        { id: 17, software: 'Unreal Engine', invoiceDate: '6-Sept-24', cost: 2727.18, renewalDate: '6-Sept-24' },
        { id: 18, software: 'Plaxis', invoiceDate: 'September 18, 2025', cost: 7752.84, renewalDate: '18/9/2025' }
    ];

    // Populate table
    const tableBody = document.getElementById('expenseTable');
    expenses.forEach(expense => {
        const row = document.createElement('tr');
        row.className = 'hover:bg-gray-50 fade-in';
        row.innerHTML = `
            <td class="px-6 py-4 whitespace-nowrap text-sm font-medium text-gray-900">${expense.id}</td>
            <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-500">${expense.software}</td>
            <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-500">${expense.invoiceDate}</td>
            <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-500">${expense.cost.toLocaleString('en-SG', {style: 'currency', currency: 'SGD'})}</td>
            <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-500">${expense.renewalDate}</td>
        `;
        tableBody.appendChild(row);
    });

    // Prepare data for charts
    const years = ['2020', '2021', '2022', '2023', '2024', '2025'];
    const annualCosts = years.map(year => {
        return expenses
            .filter(expense => expense.renewalDate.includes(year))
            .reduce((sum, expense) => sum + expense.cost, 0);
    });

    const softwareNames = [...new Set(expenses.map(expense => expense.software))];
    const softwareCosts = softwareNames.map(software => {
        return expenses
            .filter(expense => expense.software === software)
            .reduce((sum, expense) => sum + expense.cost, 0);
    });

    // Create charts
    createAnnualChart(years, annualCosts);
    createSoftwareChart(softwareNames, softwareCosts);
});

function createAnnualChart(years, costs) {
    const ctx = document.getElementById('annualChart').getContext('2d');
    new Chart(ctx, {
        type: 'bar',
        data: {
            labels: years,
            datasets: [{
                label: 'Annual Software Costs (SGD)',
                data: costs,
                backgroundColor: '#3B82F6',
                borderColor: '#2563EB',
                borderWidth: 1
            }]
        },
        options: {
            responsive: true,
            plugins: {
                legend: {
                    position: 'top',
                },
                tooltip: {
                    callbacks: {
                        label: function(context) {
                            return context.parsed.y.toLocaleString('en-SG', {style: 'currency', currency: 'SGD'});
                        }
                    }
                }
            },
            scales: {
                y: {
                    beginAtZero: true,
                    ticks: {
                        callback: function(value) {
                            return value.toLocaleString('en-SG', {style: 'currency', currency: 'SGD'});
                        }
                    }
                }
            }
        }
    });
}

function createSoftwareChart(softwareNames, costs) {
    const ctx = document.getElementById('softwareChart').getContext('2d');
    new Chart(ctx, {
        type: 'pie',
        data: {
            labels: softwareNames,
            datasets: [{
                data: costs,
                backgroundColor: [
                    '#3B82F6',
                    '#10B981',
                    '#F59E0B',
                    '#EF4444',
                    '#8B5CF6'
                ],
                borderWidth: 1
            }]
        },
        options: {
            responsive: true,
            plugins: {
                legend: {
                    position: 'right',
                },
                tooltip: {
                    callbacks: {
                        label: function(context) {
                            const label = context.label || '';
                            const value = context.raw || 0;
                            const total = context.dataset.data.reduce((a, b) => a + b, 0);
                            const percentage = Math.round((value / total) * 100);
                            return `${label}: ${value.toLocaleString('en-SG', {style: 'currency', currency: 'SGD'})} (${percentage}%)`;
                        }
                    }
                }
            }
        }
    });
}