export class FilePreview {
    constructor(options = {}) {
        this.options = {
            containerId: options.containerId || 'filePreviewModal',
            onClose: options.onClose || (() => {}),
            ...options
        };
        this.modal = null;
        this.init();
    }

    init() {
        // Create modal if it doesn't exist
        if (!document.getElementById(this.options.containerId)) {
            const modalHtml = `
                <div class="modal fade" id="${this.options.containerId}" tabindex="-1" aria-hidden="true">
                    <div class="modal-dialog modal-lg modal-dialog-centered">
                        <div class="modal-content">
                            <div class="modal-header">
                                <h5 class="modal-title">File Preview</h5>
                                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
                            </div>
                            <div class="modal-body">
                                <div id="${this.options.containerId}Content" class="text-center">
                                    <div class="spinner-border text-primary" role="status">
                                        <span class="visually-hidden">Loading...</span>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            `;
            document.body.insertAdjacentHTML('beforeend', modalHtml);
        }

        this.modal = new bootstrap.Modal(document.getElementById(this.options.containerId));
        
        // Add event listener for modal close
        document.getElementById(this.options.containerId).addEventListener('hidden.bs.modal', () => {
            this.options.onClose();
        });
    }

    getFileIcon(filename) {
        const extension = filename.split('.').pop().toLowerCase();
        const iconMap = {
            pdf: 'fa-file-pdf',
            doc: 'fa-file-word',
            docx: 'fa-file-word',
            xls: 'fa-file-excel',
            xlsx: 'fa-file-excel',
            ppt: 'fa-file-powerpoint',
            pptx: 'fa-file-powerpoint',
            txt: 'fa-file-alt',
            jpg: 'fa-file-image',
            jpeg: 'fa-file-image',
            png: 'fa-file-image',
            gif: 'fa-file-image',
            zip: 'fa-file-archive',
            rar: 'fa-file-archive',
            mp3: 'fa-file-audio',
            mp4: 'fa-file-video'
        };
        return iconMap[extension] || 'fa-file';
    }

    async previewFile(file) {
        const contentDiv = document.getElementById('filePreviewContent');
        const extension = file.name.split('.').pop().toLowerCase();
        
        // Show loading spinner
        contentDiv.innerHTML = `
            <div class="spinner-border text-primary" role="status">
                <span class="visually-hidden">Loading...</span>
            </div>
        `;

        try {
            // Handle different file types
            if (['jpg', 'jpeg', 'png', 'gif', 'bmp', 'svg', 'webp', 'tiff'].includes(extension)) {
                // Image preview
                contentDiv.innerHTML = `
                    <img src="${file.url}" class="img-fluid" alt="${file.name}" style="max-height: 70vh;">
                `;
            } else if (['pdf'].includes(extension)) {
                // PDF preview
                contentDiv.innerHTML = `
                    <iframe src="${file.url}" width="100%" style="min-height: 600px;" frameborder="0"></iframe>
                `;
            } else if (['mp4', 'webm', 'avi', 'mov', 'wmv', 'flv', 'mkv'].includes(extension)) {
                // Video preview
                contentDiv.innerHTML = `
                    <video controls class="w-100" style="max-height: 70vh;">
                        <source src="${file.url}" type="video/${extension}">
                        Your browser does not support the video tag.
                    </video>
                `;
            } else if (['mp3', 'wav', 'ogg', 'm4a', 'flac'].includes(extension)) {
                // Audio preview
                contentDiv.innerHTML = `
                    <audio controls class="w-100">
                        <source src="${file.url}" type="audio/${extension}">
                        Your browser does not support the audio tag.
                    </audio>
                `;
            } else if (['txt', 'md', 'csv', 'py', 'js', 'html', 'css', 'json', 'xml', 'sql', 'sh', 'bat'].includes(extension)) {
                // Text/Code preview
                const response = await fetch(file.url);
                const text = await response.text();
                contentDiv.innerHTML = `
                    <pre class="bg-light p-3 rounded" style="max-height: 70vh; overflow-y: auto;">${text}</pre>
                `;
            } else if (['docx', 'doc', 'xlsx', 'xls', 'pptx', 'ppt', 'odt', 'odp', 'ods'].includes(extension)) {
                // Office document preview using Office Web Viewer
                const encodedUrl = encodeURIComponent(file.url);
                contentDiv.innerHTML = `
                    <iframe src="https://view.officeapps.live.com/op/embed.aspx?src=${encodedUrl}" 
                            width="100%" height="600px" frameborder="0"></iframe>
                `;
            } else {
                // Default preview for other file types
                contentDiv.innerHTML = `
                    <div class="text-center py-5">
                        <i class="fas ${this.getFileIcon(file.name)} fa-4x mb-3" style="color: var(--secondary-color);"></i>
                        <h5 class="mb-3">${file.name}</h5>
                        <p class="text-muted">Preview not available for this file type.</p>
                        <a href="${file.url}" class="btn btn-primary" download>
                            <i class="fas fa-download me-2"></i>Download
                        </a>
                    </div>
                `;
            }
        } catch (error) {
            console.error('Error previewing file:', error);
            contentDiv.innerHTML = `
                <div class="text-center py-5">
                    <i class="fas fa-exclamation-circle fa-4x mb-3 text-danger"></i>
                    <h5 class="mb-3">Error Loading Preview</h5>
                    <p class="text-muted">File could not be viewed. Please try downloading the file instead.</p>
                    <a href="${file.url}" class="btn btn-primary" download>
                        <i class="fas fa-download me-2"></i>Download
                    </a>
                </div>
            `;
        }

        // Show the modal
        this.modal.show();
    }

    close() {
        this.modal.hide();
    }
}