// KV-Tube Main JavaScript - YouTube Clone

document.addEventListener('DOMContentLoaded', () => {
    const searchInput = document.getElementById('searchInput');
    const resultsArea = document.getElementById('resultsArea');

    if (searchInput) {
        searchInput.addEventListener('keypress', async (e) => {
            if (e.key === 'Enter') {
                e.preventDefault();
                const query = searchInput.value.trim();
                if (query) {
                    // Check if on search page already, if not redirect
                    // Since we are SPA-ish, we just call searchYouTube
                    // But if we want a dedicated search page URL, we could do:
                    // window.history.pushState({}, '', `/?q=${encodeURIComponent(query)}`);
                    searchYouTube(query);
                }
            }
        });

        // Load trending on init
        loadTrending();
    }

    // Init Theme
    initTheme();
});

// Note: Global variables like currentCategory are defined below
let currentCategory = 'general';
let currentPage = 1;
let isLoading = false;

// --- UI Helpers ---
function renderSkeleton() {
    // Generate 8 skeleton cards
    return Array(8).fill(0).map(() => `
        <div class="yt-video-card skeleton-card">
            <div class="skeleton-thumb skeleton"></div>
            <div class="skeleton-details">
                <div class="skeleton-avatar skeleton"></div>
                <div class="skeleton-text">
                    <div class="skeleton-title skeleton"></div>
                    <div class="skeleton-meta skeleton"></div>
                </div>
            </div>
        </div>
    `).join('');
}

function renderNoContent(message = 'Try searching for something else', title = 'No videos found') {
    return `
        <div class="yt-empty-state">
            <div class="yt-empty-icon"><i class="fas fa-film"></i></div>
            <div class="yt-empty-title">${title}</div>
            <div class="yt-empty-desc">${message}</div>
        </div>
    `;
}

// Search YouTube videos
async function searchYouTube(query) {
    if (isLoading) return;

    const resultsArea = document.getElementById('resultsArea');
    const loadMoreArea = document.getElementById('loadMoreArea');

    isLoading = true;
    resultsArea.innerHTML = renderSkeleton();

    try {
        const response = await fetch(`/api/search?q=${encodeURIComponent(query)}`);
        const data = await response.json();

        if (data.error) {
            resultsArea.innerHTML = `<div class="yt-loader" style="grid-column: 1/-1;"><p style="color:#f00;">Error: ${data.error}</p></div>`;
            return;
        }

        displayResults(data, false);
        if (loadMoreArea) loadMoreArea.style.display = 'none';
    } catch (error) {
        console.error('Search error:', error);
        resultsArea.innerHTML = `<div class="yt-loader" style="grid-column: 1/-1;"><p style="color:#f00;">Failed to fetch results</p></div>`;
    } finally {
        isLoading = false;
    }
}

// Switch category
async function switchCategory(category, btn) {
    if (isLoading) return;

    // Update UI (Pills)
    document.querySelectorAll('.yt-category-pill').forEach(b => b.classList.remove('active'));
    if (btn && btn.classList) btn.classList.add('active');

    // Update UI (Sidebar)
    document.querySelectorAll('.yt-sidebar-item').forEach(item => {
        item.classList.remove('active');
        if (item.getAttribute('data-category') === category) {
            item.classList.add('active');
        }
    });

    // Reset state
    currentCategory = category;
    currentPage = 1;
    window.currentPage = 1;

    const resultsArea = document.getElementById('resultsArea');
    resultsArea.innerHTML = renderSkeleton();

    // Hide pagination while loading
    const paginationArea = document.getElementById('paginationArea');
    if (paginationArea) paginationArea.style.display = 'none';

    // Load both videos and shorts with current category, sort, and region
    await loadTrending(true);

    // Also reload shorts to match category
    if (typeof loadShorts === 'function') {
        loadShorts();
    }

    // Render pagination
    if (typeof renderPagination === 'function') {
        renderPagination();
    }
}

// Load more videos
async function loadMore() {
    currentPage++;
    await loadTrending(false);
}

// Load trending videos
async function loadTrending(reset = true) {
    if (isLoading && reset) isLoading = false;

    const resultsArea = document.getElementById('resultsArea');
    const loadMoreArea = document.getElementById('loadMoreArea');
    const loadMoreBtn = document.getElementById('loadMoreBtn');

    if (!resultsArea) return; // Exit if not on home page

    isLoading = true;
    if (!reset && loadMoreBtn) {
        loadMoreBtn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Loading...';
    }

    try {
        // Get sort and region values from page (if available)
        const sortValue = window.currentSort || 'month';
        const regionValue = window.currentRegion || 'vietnam';
        const response = await fetch(`/api/trending?category=${currentCategory}&page=${currentPage}&sort=${sortValue}&region=${regionValue}`);
        const data = await response.json();

        if (data.error) {
            console.error('Trending error:', data.error);
            if (reset) {
                resultsArea.innerHTML = renderNoContent(`Error: ${data.error}`, 'Something went wrong');
            }
            return;
        }

        if (reset) resultsArea.innerHTML = '';

        if (data.length === 0) {
            if (reset) {
                resultsArea.innerHTML = renderNoContent();
            }
            const paginationArea = document.getElementById('paginationArea');
            if (paginationArea) paginationArea.style.display = 'none';
        } else {
            displayResults(data, !reset);
            const paginationArea = document.getElementById('paginationArea');
            if (paginationArea) paginationArea.style.display = 'flex';

            // Update pagination if function exists
            if (typeof renderPagination === 'function') {
                renderPagination();
            }
        }
    } catch (e) {
        console.error('Failed to load trending:', e);
        if (reset) {
            resultsArea.innerHTML = `<div class="yt-loader" style="grid-column: 1/-1;"><p style="color:#f00;">Connection error</p></div>`;
        }
    } finally {
        isLoading = false;
    }
}

// Display results with YouTube-style cards
function displayResults(videos, append = false) {
    const resultsArea = document.getElementById('resultsArea');
    if (!append) resultsArea.innerHTML = '';

    if (videos.length === 0 && !append) {
        resultsArea.innerHTML = renderNoContent();
        return;
    }

    videos.forEach(video => {
        const card = document.createElement('div');
        card.className = 'yt-video-card';
        card.innerHTML = `
            <div class="yt-thumbnail-container">
                <img class="yt-thumbnail" src="${video.thumbnail}" alt="${escapeHtml(video.title)}" loading="lazy">
                ${video.duration ? `<span class="yt-duration">${video.duration}</span>` : ''}
            </div>
            <div class="yt-video-details">
                <div class="yt-channel-avatar">
                    ${video.uploader ? video.uploader.charAt(0).toUpperCase() : 'Y'}
                </div>
                <div class="yt-video-meta">
                    <h3 class="yt-video-title">${escapeHtml(video.title)}</h3>
                    <p class="yt-channel-name">${escapeHtml(video.uploader || 'Unknown')}</p>
                    <p class="yt-video-stats">${formatViews(video.view_count)} views • ${formatDate(video.upload_date)}</p>
                </div>
            </div>
        `;
        card.addEventListener('click', () => {
            window.location.href = `/watch?v=${video.id}`;
        });
        resultsArea.appendChild(card);
    });
}

// Format view count (YouTube style)
function formatViews(views) {
    if (!views) return '0';
    const num = parseInt(views);
    if (num >= 1000000000) return (num / 1000000000).toFixed(1) + 'B';
    if (num >= 1000000) return (num / 1000000).toFixed(1) + 'M';
    if (num >= 1000) return (num / 1000).toFixed(1) + 'K';
    return num.toLocaleString();
}

// Format date (YouTube style: "2 hours ago", "3 days ago", etc.)
function formatDate(dateStr) {
    if (!dateStr) return 'Recently';

    // Handle YYYYMMDD format
    if (/^\d{8}$/.test(dateStr)) {
        const year = dateStr.substring(0, 4);
        const month = dateStr.substring(4, 6);
        const day = dateStr.substring(6, 8);
        dateStr = `${year}-${month}-${day}`;
    }

    const date = new Date(dateStr);
    if (isNaN(date.getTime())) return 'Recently';

    const now = new Date();
    const diffMs = now - date;
    const diffSec = Math.floor(diffMs / 1000);
    const diffMin = Math.floor(diffSec / 60);
    const diffHour = Math.floor(diffMin / 60);
    const diffDay = Math.floor(diffHour / 24);
    const diffWeek = Math.floor(diffDay / 7);
    const diffMonth = Math.floor(diffDay / 30);
    const diffYear = Math.floor(diffDay / 365);

    if (diffYear > 0) return `${diffYear} year${diffYear > 1 ? 's' : ''} ago`;
    if (diffMonth > 0) return `${diffMonth} month${diffMonth > 1 ? 's' : ''} ago`;
    if (diffWeek > 0) return `${diffWeek} week${diffWeek > 1 ? 's' : ''} ago`;
    if (diffDay > 0) return `${diffDay} day${diffDay > 1 ? 's' : ''} ago`;
    if (diffHour > 0) return `${diffHour} hour${diffHour > 1 ? 's' : ''} ago`;
    if (diffMin > 0) return `${diffMin} minute${diffMin > 1 ? 's' : ''} ago`;
    return 'Just now';
}

// Escape HTML to prevent XSS
function escapeHtml(text) {
    if (!text) return '';
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

// Sidebar toggle (for mobile)
function toggleSidebar() {
    const sidebar = document.getElementById('sidebar');
    const main = document.getElementById('mainContent');

    if (window.innerWidth <= 1024) {
        sidebar.classList.toggle('open');
    } else {
        sidebar.classList.toggle('collapsed');
        main.classList.toggle('sidebar-collapsed');
        localStorage.setItem('sidebarCollapsed', sidebar.classList.contains('collapsed'));
    }
}

// Close sidebar when clicking outside (mobile)
document.addEventListener('click', (e) => {
    const sidebar = document.getElementById('sidebar');
    const menuBtn = document.querySelector('.yt-menu-btn');

    if (window.innerWidth <= 1024 &&
        sidebar &&
        sidebar.classList.contains('open') &&
        !sidebar.contains(e.target) &&
        menuBtn && !menuBtn.contains(e.target)) {
        sidebar.classList.remove('open');
    }
});

// --- Theme Logic ---
function initTheme() {
    const savedTheme = localStorage.getItem('theme') || 'dark';
    document.documentElement.setAttribute('data-theme', savedTheme);

    // Update toggle if exists
    const toggle = document.getElementById('themeToggle');
    if (toggle) {
        toggle.checked = savedTheme === 'dark';
    }
}

function toggleTheme() {
    const current = document.documentElement.getAttribute('data-theme');
    const newTheme = current === 'light' ? 'dark' : 'light';

    document.documentElement.setAttribute('data-theme', newTheme);
    localStorage.setItem('theme', newTheme);
}

// --- Profile Logic ---
async function updateProfile(e) {
    if (e) e.preventDefault();

    const displayName = document.getElementById('displayName').value;
    const btn = e.target.querySelector('button');
    const originalText = btn.innerHTML;

    btn.disabled = true;
    btn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Saving...';

    try {
        const response = await fetch('/api/update_profile', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({ username: displayName })
        });

        const data = await response.json();

        if (data.success) {
            showToast('Profile updated successfully!', 'success');
            // Update UI immediately
            const avatarName = document.querySelector('.yt-avatar');
            if (avatarName) avatarName.title = displayName;
        } else {
            showToast(data.message || 'Update failed', 'error');
        }
    } catch (err) {
        showToast('Network error', 'error');
    } finally {
        btn.disabled = false;
        btn.innerHTML = originalText;
    }
}