(function() {
    'use strict';
    // Export functionality

    // Escape a single value for RFC-4180 CSV
    function csvCell(value) {
        const str = String(value == null ? '' : value);
        if (str.includes(',') || str.includes('"') || str.includes('\n')) {
            return '"' + str.replace(/"/g, '""') + '"';
        }
        return str;
    }

    // Convert an array of row arrays to a CSV string
    function rowsToCSV(rows) {
        return rows.map(row => row.map(csvCell).join(',')).join('\n');
    }

    // Export selected files to CSV
    function exportCSV() {
        if (window.app.selectedFiles.size === 0) {
            alert('No files selected for export.');
            return;
        }
    
        const headers = ['Tracking Number', 'Title', 'Revision', 'Status', 'Extension', 'Size', 'Size (bytes)', 'Path', 'Modified'];
        const rows = [headers];
    
        // Add data rows for selected files only
        window.app.files.forEach(file => {
            if (!window.app.selectedFiles.has(file.id)) return;
        
            rows.push([
                file.trackingNumber || '',
                file.title || '',
                file.revision || '',
                file.status || '',
                file.extension || '',
                formatFileSize(file.size),
                file.size != null ? file.size : '',
                file.path,
                file.modified ? new Date(file.modified).toLocaleString() : '—'
            ]);
        });
    
        downloadFile(rowsToCSV(rows), 'archive-export.csv', 'text/csv');
    }

    // Download selected files as ZIP
    async function downloadSelected() {
        if (window.app.selectedFiles.size === 0) {
            alert('No files selected for download.');
            return;
        }
    
        // JSZip is vendored (concat'd by build.sh), so window.JSZip is
        // already defined. Defensive check in case a future refactor
        // reorders things.
        if (typeof JSZip === 'undefined') {
            alert('JSZip library not bundled — rebuild archive with shared/vendor/jszip.min.js');
            return;
        }

        const zip = new JSZip();
        const selectedFiles = [];
    
        // Get selected file objects
        window.app.files.forEach(file => {
            if (window.app.selectedFiles.has(file.id)) {
                selectedFiles.push(file);
            }
        });
    
        // Show progress
        showProgress('Preparing ZIP file...', 0, selectedFiles.length);
    
        try {
            // Add files to ZIP
            for (let i = 0; i < selectedFiles.length; i++) {
                const file = selectedFiles[i];
                showProgress(`Adding ${file.name}...`, i + 1, selectedFiles.length);
            
                try {
                    let arrayBuffer;
                    if (file.handle) {
                        // Local mode: read via File System Access API
                        const fileData = await file.handle.getFile();
                        arrayBuffer = await fileData.arrayBuffer();
                    } else if (file.url) {
                        // HTTP mode: fetch from server
                        const resp = await fetch(file.url);
                        if (!resp.ok) throw new Error('HTTP ' + resp.status);
                        arrayBuffer = await resp.arrayBuffer();
                    } else {
                        throw new Error('No file handle or URL available');
                    }
                
                    // Create folder structure in ZIP
                    const relativePath = file.path.substring(file.path.indexOf('/') + 1); // Remove root directory
                    zip.file(relativePath, arrayBuffer);
                } catch (err) {
                    console.error(`Error adding file ${file.name}:`, err);
                }
            }
        
            showProgress('Generating ZIP...', selectedFiles.length, selectedFiles.length);
        
            // Generate ZIP
            const blob = await zip.generateAsync({ 
                type: 'blob',
                compression: 'DEFLATE',
                compressionOptions: { level: 6 }
            });
        
            // Download
            const timestamp = new Date().toISOString().replace(/[:.]/g, '-').substring(0, 19);
            downloadBlob(blob, `archive-${timestamp}.zip`);
        
            hideProgress();
        
        } catch (err) {
            hideProgress();
            console.error('Error creating ZIP:', err);
            alert('Error creating ZIP file: ' + err.message);
        }
    }

    // Show progress indicator
    function showProgress(message, current, total) {
        let progressDiv = document.getElementById('progressIndicator');
    
        if (!progressDiv) {
            progressDiv = document.createElement('div');
            progressDiv.id = 'progressIndicator';
            progressDiv.className = 'progress-indicator';
            document.body.appendChild(progressDiv);
        }
    
        const percentage = Math.round((current / total) * 100);
    
        progressDiv.innerHTML =
            '<div class="progress-indicator__message">' + window.app.modules.app.escapeHtml(message) + '</div>' +
            '<div class="progress-indicator__track">' +
                '<div class="progress-indicator__fill" style="width:' + percentage + '%"></div>' +
            '</div>' +
            '<div class="progress-indicator__label">' + current + ' / ' + total + '</div>';
    }

    // Hide progress indicator
    function hideProgress() {
        const progressDiv = document.getElementById('progressIndicator');
        if (progressDiv) {
            progressDiv.remove();
        }
    }

    // Download file utility
    function downloadFile(content, filename, mimeType) {
        const blob = new Blob([content], { type: mimeType });
        downloadBlob(blob, filename);
    }

    // Download blob utility
    function downloadBlob(blob, filename) {
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(url);
    }

    // Format file size
    function formatFileSize(bytes) {
        if (bytes === 0) return '0 B';
        const k = 1024;
        const sizes = ['B', 'KB', 'MB', 'GB'];
        const i = Math.floor(Math.log(bytes) / Math.log(k));
        return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
    }

    // Export to HTML report
    function exportHTMLReport() {
        // Group files by tracking number
        const grouped = window.app.modules.parser.groupFilesByTrackingNumber(window.app.filteredFiles);
        const sorted = window.app.modules.parser.sortGroupedFiles(grouped);
    
        const html = `
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <title>Archive Report - ${new Date().toLocaleDateString()}</title>
        <style>
            body { font-family: Arial, sans-serif; margin: 20px; }
            h1 { color: #333; }
            table { border-collapse: collapse; width: 100%; margin-top: 20px; }
            th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
            th { background-color: #f2f2f2; font-weight: bold; }
            tr:nth-child(even) { background-color: #f9f9f9; }
            .revision { font-family: monospace; }
            .status { color: #666; font-size: 0.9em; }
            @media print {
                body { margin: 0; }
                h1 { font-size: 18pt; }
                table { font-size: 10pt; }
            }
        </style>
    </head>
    <body>
        <h1>Archive Report</h1>
        <p>Generated: ${new Date().toLocaleString()}</p>
        <p>Total Files: ${window.app.filteredFiles.length}</p>
    
        <table>
            <thead>
                <tr>
                    <th>Tracking Number</th>
                    <th>Title</th>
                    <th>Revisions</th>
                </tr>
            </thead>
            <tbody>
                ${sorted.map(group => `
                    <tr>
                        <td>${window.app.modules.app.escapeHtml(group.trackingNumber)}</td>
                        <td>${window.app.modules.app.escapeHtml(group.title)}</td>
                        <td>
                            ${group.sortedRevisions.map(rev => `
                                <div>
                                    <span class="revision">${window.app.modules.app.escapeHtml(rev.revision)}</span>
                                    <span class="status">(${window.app.modules.app.escapeHtml(rev.status)})</span>
                                    ${rev.files.map(f => f.extension.toUpperCase()).join(', ')}
                                </div>
                            `).join('')}
                        </td>
                    </tr>
                `).join('')}
            </tbody>
        </table>
    </body>
    </html>`;
    
        downloadFile(html, 'archive-report.html', 'text/html');
    }

    window.app.modules.export = {
        csvCell,
        rowsToCSV,
        exportCSV,
        downloadSelected,
        showProgress,
        hideProgress,
        downloadFile,
        downloadBlob,
        formatFileSize,
        exportHTMLReport
    };

})();