class PaperCard extends HTMLElement {
    constructor() {
        super();
        this.attachShadow({ mode: 'open' });
    }

    connectedCallback() {
        this.render();
    }

    render() {
        const title = this.getAttribute('title') || '';
        const authors = this.getAttribute('authors') || '';
        const abstract = this.getAttribute('abstract') || '';
        const year = this.getAttribute('year') || '';
        const venue = this.getAttribute('venue') || '';
        const citations = this.getAttribute('citations') || '0';
        const references = this.getAttribute('references') || '0';
        const categories = this.getAttribute('categories') || '';
        const keywords = this.getAttribute('keywords') || '';
        const pdfUrl = this.getAttribute('pdf-url') || '';
        const url = this.getAttribute('url') || '';

        const categoryTags = categories ? categories.split(',').filter(cat => cat).map(cat => this.getCategoryTag(cat)).join('') : '';
        const keywordTags = keywords ? keywords.split(',').filter(kw => kw).map(kw => `<span class="keyword-tag">${this.escapeHtml(kw)}</span>`).join('') : '';

        this.shadowRoot.innerHTML = `
            <style>
                * {
                    box-sizing: border-box;
                }
                :host {
                    display: block;
                    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
                }
                .paper-card {
                    background: var(--dark-surface, #1f2937);
                    border-radius: 12px;
                    padding: 1.5rem;
                    height: 100%;
                    border: 1px solid var(--dark-border, #374151);
                    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
                    display: flex;
                    flex-direction: column;
                    position: relative;
                    overflow: hidden;
                }
                .paper-card:hover {
                    transform: translateY(-8px);
                    box-shadow: 0 20px 40px rgba(245, 158, 11, 0.15);
                    border-color: var(--amber-primary, #f59e0b);
                }
                .paper-card::before {
                    content: '';
                    position: absolute;
                    top: 0;
                    left: 0;
                    right: 0;
                    height: 3px;
                    background: linear-gradient(to right, var(--amber-primary, #f59e0b), var(--yellow-primary, #eab308));
                    opacity: 0;
                    transition: opacity 0.3s ease;
                }
                .paper-card:hover::before {
                    opacity: 1;
                }
                .paper-header {
                    margin-bottom: 1rem;
                }
                .paper-title {
                    font-size: 1.125rem;
                    font-weight: 700;
                    color: var(--amber-primary, #f59e0b);
                    line-height: 1.4;
                    margin: 0 0 0.5rem 0;
                }
.paper-meta {
                    display: flex;
                    flex-wrap: wrap;
                    gap: 0.75rem;
                    font-size: 0.875rem;
                    color: #9ca3af;
                    margin-bottom: 0.75rem;
                }
                .meta-item {
                    display: flex;
                    align-items: center;
                    gap: 0.25rem;
                }
                .paper-authors {
                    color: #d1d5db;
                    font-size: 0.875rem;
                    margin-bottom: 0.75rem;
                }
                .paper-abstract {
                    color: #9ca3af;
                    font-size: 0.875rem;
                    line-height: 1.5;
                    margin-bottom: 1rem;
                    flex-grow: 1;
                }
.paper-tags {
                    display: flex;
                    flex-wrap: wrap;
                    gap: 0.5rem;
                    margin-bottom: 1.25rem;
                }
                .category-tag {
                    padding: 0.25rem 0.75rem;
                    border-radius: 9999px;
                    font-size: 0.75rem;
                    font-weight: 600;
                    text-transform: uppercase;
                    letter-spacing: 0.05em;
                }
                .keyword-tag {
                    padding: 0.125rem 0.5rem;
                    border-radius: 0.375rem;
                    font-size: 0.75rem;
                    background: rgba(245, 158, 11, 0.1);
                    color: var(--amber-primary, #f59e0b);
                    border: 1px solid rgba(245, 158, 11, 0.2);
                }
                .paper-actions {
                    display: flex;
                    gap: 0.5rem;
                    margin-top: auto;
                }
                .btn {
                    padding: 0.5rem 1rem;
                    border-radius: 0.5rem;
                    font-size: 0.875rem;
                    font-weight: 600;
                    text-decoration: none;
                    border: none;
                    cursor: pointer;
                    display: inline-flex;
                    align-items: center;
                    justify-content: center;
                    gap: 0.5rem;
                    transition: all 0.2s ease;
                    flex: 1;
                }
                .btn-primary {
                    background: var(--amber-primary, #f59e0b);
                    color: #111827;
                }
                .btn-primary:hover {
                    background: var(--amber-secondary, #fbbf24);
                    transform: scale(1.03);
                }
                .btn-secondary {
                    background: transparent;
                    color: var(--amber-primary, #f59e0b);
                    border: 1px solid var(--amber-primary, #f59e0b);
                }
                .btn-secondary:hover {
                    background: var(--amber-primary, #f59e0b);
                    color: #111827;
                    transform: scale(1.03);
                }
                .btn:disabled {
                    opacity: 0.5;
                    cursor: not-allowed;
                    transform: none !important;
                }
                .citation-badge {
                    position: absolute;
                    top: 0.75rem;
                    right: 0.75rem;
                    background: rgba(234, 179, 8, 0.9);
                    color: #111827;
                    padding: 0.25rem 0.5rem;
                    border-radius: 0.375rem;
                    font-size: 0.75rem;
                    font-weight: 700;
                    display: flex;
                    align-items: center;
                    gap: 0.25rem;
                }
                /* Category specific styles */
                .tag-ml {
                    background: rgba(245, 158, 11, 0.15);
                    color: #f59e0b;
                    border: 1px solid rgba(245, 158, 11, 0.3);
                }
                .tag-cv {
                    background: rgba(234, 179, 8, 0.15);
                    color: #eab308;
                    border: 1px solid rgba(234, 179, 8, 0.3);
                }
                .tag-nlp {
                    background: rgba(251, 191, 36, 0.15);
                    color: #fbbf24;
                    border: 1px solid rgba(251, 191, 36, 0.3);
                }
                .tag-robotics {
                    background: rgba(253, 224, 71, 0.15);
                    color: #fde047;
                    border: 1px solid rgba(253, 224, 71, 0.3);
                }
                .tag-ds {
                    background: rgba(245, 158, 11, 0.1);
                    color: #f59e0b;
                    border: 1px solid rgba(245, 158, 11, 0.2);
                }
                .feather {
                    width: 16px;
                    height: 16px;
                }
                @media (max-width: 640px) {
                    .paper-card {
                        padding: 1.25rem;
                    }
                    .paper-title {
                        font-size: 1rem;
                    }
                    .paper-meta {
                        flex-direction: column;
                        gap: 0.25rem;
                    }
                    .paper-actions {
                        flex-direction: column;
                    }
                }
</style>
            <div class="paper-card">
                ${citations > 0 ? `
                    <div class="citation-badge">
                        <svg class="feather" data-feather="trending-up" style="width: 12px; height: 12px;"></svg>
                        ${citations}
                    </div>
                ` : ''}
                
                <div class="paper-header">
                    <h3 class="paper-title">${this.escapeHtml(title)}</h3>
                    <div class="paper-meta">
                        <div class="meta-item">
                            <svg class="feather" data-feather="calendar"></svg>
                            ${year}
                        </div>
                        <div class="meta-item">
                            <svg class="feather" data-feather="map-pin"></svg>
                            ${this.escapeHtml(venue)}
                        </div>
                        <div class="meta-item">
                            <svg class="feather" data-feather="file-text"></svg>
                            ${references} refs
                        </div>
                    </div>
                    <div class="paper-authors">
                        ${this.escapeHtml(authors)}
                    </div>
                </div>
                
                <div class="paper-abstract">
                    ${this.escapeHtml(abstract)}
                </div>
<div class="paper-tags">
                    ${categoryTags}
                </div>
                
                <div class="paper-tags">
                    ${keywordTags}
                </div>
                
                <div class="paper-actions">
                    ${pdfUrl ? `
                        <a href="${pdfUrl}" target="_blank" rel="noopener noreferrer" class="btn btn-primary">
                            <svg class="feather" data-feather="download"></svg>
                            PDF
                        </a>
                    ` : `
                        <button class="btn btn-primary" disabled>
                            <svg class="feather" data-feather="download"></svg>
                            PDF
                        </button>
                    `}
                    <a href="${url}" target="_blank" rel="noopener noreferrer" class="btn btn-secondary">
                        <svg class="feather" data-feather="external-link"></svg>
                        View
                    </a>
                </div>
            </div>
        `;
        
        // Initialize feather icons in shadow DOM
        if (window.feather) {
            window.feather.replace({ 
                'stroke-width': 1.5,
                'width': 16,
                'height': 16
            });
        }
    }

    getCategoryTag(category) {
        const categoryMap = {
            'machine-learning': { name: 'ML', class: 'tag-ml' },
            'computer-vision': { name: 'CV', class: 'tag-cv' },
            'nlp': { name: 'NLP', class: 'tag-nlp' },
            'robotics': { name: 'Robotics', class: 'tag-robotics' },
            'data-science': { name: 'Data Science', class: 'tag-ds' },
            'artificial-intelligence': { name: 'AI', class: 'tag-ml' }
        };
        
        const categoryInfo = categoryMap[category.toLowerCase()] || { name: category.toUpperCase(), class: 'tag-ds' };
        return `<span class="category-tag ${categoryInfo.class}">${categoryInfo.name}</span>`;
    }

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

customElements.define('paper-card', PaperCard);