import { api } from '../api.js';

class FilePreview extends HTMLElement {
    constructor() {
        super();
        this.file = null;
        this.handleEscape = this.handleEscape.bind(this);
    }

    connectedCallback() {
        this.render();
        this.setupEventListeners();
    }

    setupEventListeners() {
        const closeBtn = this.querySelector('.close-preview');
        const modal = this.querySelector('.preview-modal');
        const downloadBtn = this.querySelector('.download-btn');
        const shareBtn = this.querySelector('.share-btn');

        closeBtn.addEventListener('click', () => this.close());
        modal.addEventListener('click', (e) => {
            if (e.target === modal) this.close();
        });

        downloadBtn.addEventListener('click', () => this.downloadFile());
        shareBtn.addEventListener('click', () => this.shareFile());
    }

    handleEscape(e) {
        if (e.key === 'Escape' && this.style.display === 'block') {
            this.close();
        }
    }

    async show(file) {
        this.file = file;
        this.style.display = 'block';
        document.addEventListener('keydown', this.handleEscape);
        this.renderPreview();
    }

    close() {
        this.style.display = 'none';
        this.file = null;
        document.removeEventListener('keydown', this.handleEscape);
    }

    async renderPreview() {
        const previewContent = this.querySelector('.preview-content');
        const fileName = this.querySelector('.preview-file-name');
        const fileInfo = this.querySelector('.preview-file-info');

        fileName.textContent = this.file.name;
        fileInfo.textContent = `${this.formatFileSize(this.file.size)} • ${new Date(this.file.created_at).toLocaleDateString()}`;

        if (this.file.mime_type.startsWith('image/')) {
            previewContent.innerHTML = `<img alt="${this.file.name}">`;
            this.loadAuthenticatedMedia(previewContent.querySelector('img'));
        } else if (this.file.mime_type.startsWith('video/')) {
            previewContent.innerHTML = `
                <video controls>
                    Your browser does not support the video tag.
                </video>
            `;
            this.loadAuthenticatedMedia(previewContent.querySelector('video'));
        } else if (this.file.mime_type.startsWith('audio/')) {
            previewContent.innerHTML = `
                <audio controls>
                    Your browser does not support the audio tag.
                </audio>
            `;
            this.loadAuthenticatedMedia(previewContent.querySelector('audio'));
        } else if (this.file.mime_type === 'application/pdf') {
            previewContent.innerHTML = `<iframe type="application/pdf"></iframe>`;
            this.loadAuthenticatedMedia(previewContent.querySelector('iframe'));
        } else if (this.file.mime_type.startsWith('text/')) {
            this.loadTextPreview(previewContent);
        } else {
            previewContent.innerHTML = `
                <div class="no-preview">
                    <p>Preview not available for this file type</p>
                    <button class="btn btn-primary" onclick="this.getRootNode().host.downloadFile()">Download File</button>
                </div>
            `;
        }
    }

    async loadAuthenticatedMedia(element) {
        try {
            const blob = await api.downloadFile(this.file.id);
            const url = URL.createObjectURL(blob);
            element.src = url;
        } catch (error) {
            console.error('Failed to load media:', error);
            element.parentElement.innerHTML = '<p>Failed to load preview</p>';
        }
    }

    async loadTextPreview(container) {
        try {
            const blob = await api.downloadFile(this.file.id);
            const text = await blob.text();
            container.innerHTML = `<pre>${this.escapeHtml(text)}</pre>`;
        } catch (error) {
            container.innerHTML = '<p>Failed to load preview</p>';
        }
    }

    async downloadFile() {
        try {
            const blob = await api.downloadFile(this.file.id);
            const url = window.URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = this.file.name;
            document.body.appendChild(a);
            a.click();
            window.URL.revokeObjectURL(url);
            document.body.removeChild(a);
        } catch (error) {
            console.error('Failed to download file:', error);
        }
    }

    shareFile() {
        this.dispatchEvent(new CustomEvent('share-file', {
            detail: { file: this.file },
            bubbles: true
        }));
    }

    formatFileSize(bytes) {
        const units = ['B', 'KB', 'MB', 'GB'];
        let size = bytes;
        let unitIndex = 0;
        while (size >= 1024 && unitIndex < units.length - 1) {
            size /= 1024;
            unitIndex++;
        }
        return `${size.toFixed(1)} ${units[unitIndex]}`;
    }

    escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }

    render() {
        this.innerHTML = `
            <div class="preview-modal">
                <div class="preview-container">
                    <div class="preview-header">
                        <div class="preview-info">
                            <h3 class="preview-file-name"></h3>
                            <p class="preview-file-info"></p>
                        </div>
                        <div class="preview-actions">
                            <button class="btn btn-icon download-btn" title="Download">⬇</button>
                            <button class="btn btn-icon share-btn" title="Share">🔗</button>
                            <button class="btn btn-icon close-preview" title="Close">✕</button>
                        </div>
                    </div>
                    <div class="preview-content"></div>
                </div>
            </div>
        `;
        this.style.display = 'none';
    }
}

customElements.define('file-preview', FilePreview);
export { FilePreview };