// API Base URL
const API_BASE_URL = '/api';

// DOM Elements
const shareForm = document.getElementById('shareForm');
const linksContainer = document.getElementById('linksContainer');
const loadingSpinner = document.getElementById('loadingSpinner');
const successMessage = document.getElementById('successMessage');
const successText = document.getElementById('successText');

// Initialize app
document.addEventListener('DOMContentLoaded', function() {
    loadLinks();
    
    // Handle form submission
    shareForm.addEventListener('submit', handleShareSubmit);
});

// Handle share form submission
async function handleShareSubmit(e) {
    e.preventDefault();
    
    const formData = new FormData(shareForm);
    const data = {
        name: formData.get('name'),
        note: formData.get('note'),
        youtube_link: formData.get('youtube_link')
    };
    
    // Validate YouTube URL
    if (!isValidYouTubeURL(data.youtube_link)) {
        alert('กรุณากรอกลิงก์ YouTube ที่ถูกต้อง');
        return;
    }
    
    try {
        showLoading(true);
        
        const response = await fetch(`${API_BASE_URL}/posts`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(data)
        });
        
        if (!response.ok) {
            throw new Error('เกิดข้อผิดพลาดในการแชร์');
        }
        
        const result = await response.json();
        
        // Show success message
        showSuccessMessage('แชร์สำเร็จ!');
        
        // Clear form
        shareForm.reset();
        
        // Reload links
        await loadLinks();
        
    } catch (error) {
        console.error('Error sharing link:', error);
        alert('เกิดข้อผิดพลาดในการแชร์: ' + error.message);
    } finally {
        showLoading(false);
    }
}

// Load all shared links
async function loadLinks() {
    try {
        showLoading(true);
        
        const response = await fetch(`${API_BASE_URL}/posts`);
        if (!response.ok) {
            throw new Error('ไม่สามารถโหลดลิงก์ได้');
        }
        
        const links = await response.json();
        displayLinks(links);
        
    } catch (error) {
        console.error('Error loading links:', error);
        linksContainer.innerHTML = `
            <div style="text-align: center; color: #666; padding: 20px;">
                <i class="fas fa-exclamation-triangle"></i>
                <p>ไม่สามารถโหลดลิงก์ได้: ${error.message}</p>
            </div>
        `;
    } finally {
        showLoading(false);
    }
}

// Display links in the container
function displayLinks(links) {
    if (links.length === 0) {
        linksContainer.innerHTML = `
            <div style="text-align: center; color: #666; padding: 40px;">
                <i class="fab fa-youtube" style="font-size: 3rem; margin-bottom: 15px;"></i>
                <p>ยังไม่มีลิงก์ที่แชร์</p>
                <p>เป็นคนแรกที่แชร์ลิงก์ YouTube!</p>
            </div>
        `;
        return;
    }
    
    linksContainer.innerHTML = links.map(link => createLinkCard(link)).join('');
    
    // Add event listeners for like and comment buttons
    addLinkEventListeners();
}

// Create HTML for a single link card
function createLinkCard(link) {
    const videoId = extractYouTubeVideoId(link.youtube_link);
    const embedUrl = videoId ? `https://www.youtube.com/embed/${videoId}` : '';
    const timeAgo = getTimeAgo(new Date(link.created_at));
    
    return `
        <div class="link-card" data-link-id="${link.id}">
            <div class="link-header">
                <span class="user-name">
                    <i class="fas fa-user"></i> ${escapeHtml(link.name)}
                </span>
                <span class="timestamp">${timeAgo}</span>
            </div>
            
            <div class="link-note">
                ${escapeHtml(link.note)}
            </div>
            
            ${embedUrl ? `
                <div class="youtube-embed">
                    <iframe src="${embedUrl}" 
                            title="YouTube video player" 
                            frameborder="0" 
                            allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" 
                            allowfullscreen>
                    </iframe>
                </div>
            ` : `
                <div class="youtube-link">
                    <a href="${link.youtube_link}" target="_blank" rel="noopener noreferrer">
                        <i class="fab fa-youtube"></i> ดูวิดีโอใน YouTube
                    </a>
                </div>
            `}
            
            <div class="link-actions">
                <button class="action-btn like-btn" data-link-id="${link.id}">
                    <i class="fas fa-heart"></i>
                    <span class="like-count">${link.likes}</span>
                </button>
                <button class="action-btn comment-btn" data-link-id="${link.id}">
                    <i class="fas fa-comment"></i>
                    คอมเมนต์
                </button>
            </div>
            
            <div class="comments-section" id="comments-${link.id}" style="display: none;">
                <div class="comment-form">
                    <input type="text" placeholder="เขียนคอมเมนต์..." class="comment-input">
                    <button type="button" class="add-comment-btn" data-link-id="${link.id}">
                        <i class="fas fa-paper-plane"></i>
                    </button>
                </div>
                <div class="comments-list" id="comments-list-${link.id}">
                    <!-- Comments will be loaded here -->
                </div>
            </div>
        </div>
    `;
}

// Add event listeners for link interactions
function addLinkEventListeners() {
    // Like buttons
    document.querySelectorAll('.like-btn').forEach(btn => {
        btn.addEventListener('click', handleLike);
    });
    
    // Comment buttons
    document.querySelectorAll('.comment-btn').forEach(btn => {
        btn.addEventListener('click', toggleComments);
    });
    
    // Add comment buttons
    document.querySelectorAll('.add-comment-btn').forEach(btn => {
        btn.addEventListener('click', handleAddComment);
    });
    
    // Enter key for comment input
    document.querySelectorAll('.comment-input').forEach(input => {
        input.addEventListener('keypress', function(e) {
            if (e.key === 'Enter') {
                const linkId = this.closest('.comments-section').id.split('-')[1];
                const btn = document.querySelector(`.add-comment-btn[data-link-id="${linkId}"]`);
                btn.click();
            }
        });
    });
}

// Handle like button click
async function handleLike(e) {
    const linkId = e.currentTarget.dataset.linkId;
    const likeBtn = e.currentTarget;
    const likeCount = likeBtn.querySelector('.like-count');
    
    try {
        const response = await fetch(`${API_BASE_URL}/posts/${linkId}/like`, {
            method: 'POST'
        });
        
        if (!response.ok) {
            throw new Error('ไม่สามารถถูกใจได้');
        }
        
        const result = await response.json();
        likeCount.textContent = result.likes;
        
        // Add visual feedback
        likeBtn.classList.add('liked');
        setTimeout(() => likeBtn.classList.remove('liked'), 1000);
        
    } catch (error) {
        console.error('Error liking post:', error);
        alert('เกิดข้อผิดพลาดในการถูกใจ');
    }
}

// Toggle comments section
async function toggleComments(e) {
    const linkId = e.currentTarget.dataset.linkId;
    const commentsSection = document.getElementById(`comments-${linkId}`);
    
    if (commentsSection.style.display === 'none') {
        commentsSection.style.display = 'block';
        await loadComments(linkId);
    } else {
        commentsSection.style.display = 'none';
    }
}

// Load comments for a specific link
async function loadComments(linkId) {
    try {
        const response = await fetch(`${API_BASE_URL}/posts/${linkId}/comments`);
        if (!response.ok) {
            throw new Error('ไม่สามารถโหลดคอมเมนต์ได้');
        }
        
        const comments = await response.json();
        const commentsList = document.getElementById(`comments-list-${linkId}`);
        
        if (comments.length === 0) {
            commentsList.innerHTML = '<p style="text-align: center; color: #666; padding: 10px;">ยังไม่มีคอมเมนต์</p>';
        } else {
            commentsList.innerHTML = comments.map(comment => `
                <div class="comment">
                    <div class="comment-author">
                        <i class="fas fa-user"></i> ${escapeHtml(comment.name)}
                    </div>
                    <div class="comment-text">${escapeHtml(comment.comment)}</div>
                </div>
            `).join('');
        }
        
    } catch (error) {
        console.error('Error loading comments:', error);
    }
}

// Handle add comment
async function handleAddComment(e) {
    const linkId = e.currentTarget.dataset.linkId;
    const commentsSection = document.getElementById(`comments-${linkId}`);
    const commentInput = commentsSection.querySelector('.comment-input');
    const commentText = commentInput.value.trim();
    
    if (!commentText) {
        alert('กรุณาเขียนคอมเมนต์');
        return;
    }
    
    // Simple name prompt (in real app, you'd have user authentication)
    const name = prompt('กรุณากรอกชื่อของคุณ:');
    if (!name) return;
    
    try {
        const response = await fetch(`${API_BASE_URL}/posts/${linkId}/comments`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                name: name,
                comment: commentText
            })
        });
        
        if (!response.ok) {
            throw new Error('ไม่สามารถเพิ่มคอมเมนต์ได้');
        }
        
        // Clear input
        commentInput.value = '';
        
        // Reload comments
        await loadComments(linkId);
        
        showSuccessMessage('เพิ่มคอมเมนต์สำเร็จ!');
        
    } catch (error) {
        console.error('Error adding comment:', error);
        alert('เกิดข้อผิดพลาดในการเพิ่มคอมเมนต์');
    }
}

// Utility functions
function isValidYouTubeURL(url) {
    const youtubeRegex = /^(https?:\/\/)?(www\.)?(youtube\.com\/watch\?v=|youtu\.be\/|youtube\.com\/embed\/)[a-zA-Z0-9_-]{11}/;
    return youtubeRegex.test(url);
}

function extractYouTubeVideoId(url) {
    const regex = /(?:youtube\.com\/watch\?v=|youtu\.be\/|youtube\.com\/embed\/)([a-zA-Z0-9_-]{11})/;
    const match = url.match(regex);
    return match ? match[1] : null;
}

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

function getTimeAgo(date) {
    const now = new Date();
    const diffInSeconds = Math.floor((now - date) / 1000);
    
    if (diffInSeconds < 60) return 'เมื่อสักครู่';
    if (diffInSeconds < 3600) return `${Math.floor(diffInSeconds / 60)} นาทีที่แล้ว`;
    if (diffInSeconds < 86400) return `${Math.floor(diffInSeconds / 3600)} ชั่วโมงที่แล้ว`;
    return `${Math.floor(diffInSeconds / 86400)} วันที่แล้ว`;
}

function showLoading(show) {
    loadingSpinner.style.display = show ? 'block' : 'none';
}

function showSuccessMessage(message) {
    successText.textContent = message;
    successMessage.style.display = 'flex';
    setTimeout(() => {
        successMessage.style.display = 'none';
    }, 3000);
}