document.addEventListener('DOMContentLoaded', () => {
    // ... (theme switcher and other existing code) ...

    const apiRequest = async (url, options = {}) => {
        // ... (same as before) ...
    };

    const loadDashboardStats = async () => {
        // ... (same as before) ...
    };

    // ... (contact form code) ...

    // Deal Management
    const dealModal = document.getElementById('dealModal') ? new bootstrap.Modal(document.getElementById('dealModal')) : null;
    const dealForm = document.getElementById('dealForm');
    const modalTitle = document.getElementById('dealModalLabel');
    let dataTable = null;

    const fetchDealsAndInitTable = async (filters = {}) => {
        try {
            const queryParams = new URLSearchParams({ action: 'get_deals', ...filters }).toString();
            const result = await apiRequest(`api.php?${queryParams}`);

            if (result && result.success) {
                if (dataTable) {
                    dataTable.destroy();
                }
                dataTable = new DataTable('#deals-table', {
                    data: result.deals,
                    columns: [
                        { data: 'name' },
                        { data: 'vendor' },
                        { data: 'category' },
                        { data: 'purchase_date' },
                        { 
                            data: 'price',
                            render: (data, type, row) => `${row.currency} ${data}`
                        },
                        { 
                            data: 'rating',
                            render: (data, type, row) => `<div class="text-nowrap">${Array(5).fill(0).map((_, i) => `<i class="bi bi-star-fill ${i < data ? 'text-warning' : 'text-secondary'}"></i>`).join('')}</div>`
                        },
                        {
                            data: 'website',
                            render: (data, type, row) => `<a href="${data}" target="_blank" class="btn btn-sm btn-outline-primary">Visit</a>`
                        },
                        {
                            data: 'files',
                            render: (data, type, row) => {
                                if (!data) return '';
                                const files = data.split(',').map(f => {
                                    const [id, name] = f.split(':');
                                    return `<div class="file-chip"><a href="uploads/${name}" target="_blank">${name}</a><button class="btn-close btn-close-sm delete-file-btn" data-file-id="${id}"></button></div>`;
                                });
                                return files.join('');
                            }
                        },
                        {
                            data: 'id',
                            render: (data, type, row) => 
                                `<button class="btn btn-sm btn-outline-secondary edit-deal-btn" data-id="${data}">Edit</button>
                                 <button class="btn btn-sm btn-outline-danger delete-deal-btn" data-id="${data}">Delete</button>`,
                            orderable: false
                        }
                    ],
                    responsive: true,
                });
            } else if(result) {
                console.error('Failed to fetch deals:', result.error);
            }
        } catch (error) {
            console.error('Error fetching deals:', error);
        }
    };

    const deleteDeal = async (id) => {
        // ... (same as before) ...
    };

    const deleteDealFile = async (fileId) => {
        if (!confirm('Are you sure you want to delete this file?')) return;
        try {
            const result = await apiRequest('api.php?action=delete_deal_file', {
                method: 'POST',
                body: { id: fileId }
            });
            if (result && result.success) {
                fetchDealsAndInitTable(); // Refresh table
            } else {
                alert('Error deleting file.');
            }
        } catch (error) {
            alert('An error occurred while deleting the file.');
        }
    };

    const editDeal = (dealId) => {
        const dealData = dataTable.rows().data().toArray().find(d => d.id == dealId);
        if (dealData) {
            modalTitle.textContent = 'Edit Deal';
            // Clear previous data and files
            dealForm.reset();
            document.getElementById('deal-files-list').innerHTML = '';

            // Populate form
            Object.keys(dealData).forEach(key => {
                const input = dealForm.querySelector(`[name="${key}"]`);
                if (input) {
                    if (key === 'purchaseDate') {
                        input.value = dealData.purchase_date;
                    } else {
                        input.value = dealData[key];
                    }
                }
            });
            // Add hidden ID field
            let idInput = dealForm.querySelector('[name="id"]');
            if (!idInput) {
                idInput = document.createElement('input');
                idInput.type = 'hidden';
                idInput.name = 'id';
                dealForm.appendChild(idInput);
            }
            idInput.value = dealData.id;

            // Display existing files
            if (dealData.files) {
                const filesList = document.getElementById('deal-files-list');
                dealData.files.split(',').forEach(f => {
                    const [id, name] = f.split(':');
                    const fileEl = document.createElement('div');
                    fileEl.className = 'file-chip';
                    fileEl.innerHTML = `<span>${name}</span><button type="button" class="btn-close btn-close-sm delete-file-btn" data-file-id="${id}"></button>`;
                    filesList.appendChild(fileEl);
                });
            }

            dealModal.show();
        }
    };

    // ... (loadCategoryFilter, loadTagsFilter) ...

    if (dealForm) {
        dealForm.addEventListener('submit', async (e) => {
            e.preventDefault();
            
            const formData = new FormData(dealForm);
            const dealId = formData.get('id');
            const action = dealId ? 'update_deal' : 'add_deal';
            
            // Add action to formData
            formData.append('action', action);

            try {
                const response = await fetch(`api.php?action=${action}`, {
                    method: 'POST',
                    body: formData // FormData object
                    // No 'Content-Type' header; browser sets it automatically
                });

                const result = await response.json();

                if (result.success) {
                    dealModal.hide();
                    fetchDealsAndInitTable(); // Refresh table
                    loadDashboardStats(); // Refresh stats
                    loadCategoryChart();
                } else {
                    alert(`Error: ${result.error || 'Unknown error'}`);
                }
            } catch (error) {
                console.error('Form submission error:', error);
                alert('An error occurred while submitting the form.');
            }
        });
    }

    // ... (addDealBtn handler) ...

    if (dealsTable) {
        dealsTable.addEventListener('click', (e) => {
            if (e.target.classList.contains('delete-deal-btn')) {
                deleteDeal(e.target.dataset.id);
            } else if (e.target.classList.contains('edit-deal-btn')) {
                editDeal(e.target.dataset.id);
            } else if (e.target.classList.contains('delete-file-btn')) {
                deleteDealFile(e.target.dataset.fileId);
            }
        });
        
        // ... (filters and initial load) ...
    }

    // ... (loadCategoryChart) ...
});