document.addEventListener('DOMContentLoaded', function () {
    const uploadSection = document.getElementById('uploadSection');
    const reviewSection = document.getElementById('reviewSection');
    const processingSection = document.getElementById('processingSection');
    const dropZone = document.getElementById('dropZone');
    const fileInput = document.getElementById('fileInput');
    const startAutomationBtn = document.getElementById('startAutomationBtn');
    const discardBtn = document.getElementById('discardBtn');
    const uploadNewBtn = document.getElementById('uploadNewBtn');

    function showSection(section) {
        [uploadSection, reviewSection, processingSection].forEach(s => s.classList.add('d-none'));
        section.classList.remove('d-none');
    }

    function handleFileSelect(file) {
        if (!file) return;

        showSection(processingSection);

        // Simulate AI processing
        setTimeout(() => {
            // Mock data - in a real app, this would come from an API call
            document.getElementById('firstName').value = 'Max';
            document.getElementById('lastName').value = 'Mustermann';
            document.getElementById('street').value = 'Musterstraße 1';
            document.getElementById('zip').value = '12345';
            document.getElementById('city').value = 'Berlin';
            document.getElementById('dob').value = '1990-01-15';
            showSection(reviewSection);
        }, 2500);
    }

    // --- Event Listeners ---

    dropZone.addEventListener('click', () => fileInput.click());

    dropZone.addEventListener('dragover', (e) => {
        e.preventDefault();
        dropZone.classList.add('is-dragover');
    });

    dropZone.addEventListener('dragleave', (e) => {
        e.preventDefault();
        dropZone.classList.remove('is-dragover');
    });

    dropZone.addEventListener('drop', (e) => {
        e.preventDefault();
        dropZone.classList.remove('is-dragover');
        if (e.dataTransfer.files.length) {
            fileInput.files = e.dataTransfer.files;
            handleFileSelect(fileInput.files[0]);
        }
    });

    fileInput.addEventListener('change', () => {
        if (fileInput.files.length) {
            handleFileSelect(fileInput.files[0]);
        }
    });

    startAutomationBtn.addEventListener('click', () => {
        alert('This would start the automation process on the backend. This is just a UI mock-up for now!');
    });

    discardBtn.addEventListener('click', () => {
        if(confirm('Are you sure you want to discard the extracted data?')) {
            showSection(uploadSection);
        }
    });
    
    uploadNewBtn.addEventListener('click', () => {
        showSection(uploadSection);
    });

    // Initial state
    showSection(uploadSection);
});