{% extends "base.html" %}
{% block title %}{{ 'brand'|t(lang) }}{% endblock %}
{% block nav %}
<nav class="navbar">
    <a href="/" class="nav-brand">{{ 'brand'|t(lang) }}</a>
    <div class="nav-links">
        <div class="lang-switcher" id="langSwitcher">
            <button type="button" class="lang-globe" onclick="document.getElementById('langDropdown').classList.toggle('show')">🌐</button>
            <div class="lang-dropdown" id="langDropdown">
                {% for code, name in available_languages.items() %}
                <a href="/?lang={{ code }}" class="lang-option {% if lang == code %}active{% endif %}">{{ name }}</a>
                {% endfor %}
            </div>
        </div>
        <a href="/login" class="btn btn-sm" style="margin-left:.5rem">{{ 'index.go_login'|t(lang) }}</a>
        <a href="/register" class="btn btn-primary btn-sm">{{ 'index.go_register'|t(lang) }}</a>
    </div>
</nav>
{% endblock %}
{% block content %}
<div class="section-header">
    <h1>📮 {{ 'index.title'|t(lang) }}</h1>
    <p style="color:var(--text-muted);margin-top:.25rem">{{ 'index.subtitle'|t(lang) }}</p>
</div>

{% set visible = [] %}
{% for pc in postcards %}
    {% if pc.image_front %}
        {% if visible.append(pc) %}{% endif %}
    {% endif %}
{% endfor %}

{% if visible|length > 0 or has_more %}
<div class="showcase-grid" id="showcase-grid">
    {% for pc in visible %}
    <div class="showcase-card" data-front="{{ pc.image_front }}" onclick="openLightbox(this)">
        <img src="{{ pc.image_front }}" alt="" class="showcase-card-img" loading="lazy">
        <div class="showcase-card-body">
            <div class="showcase-card-meta">
                {% if pc.country_to_from and pc.country_to %}<span>{{ pc.country_to_from|flag }} {{ pc.country_to_from }} → {{ pc.country_to|flag }} {{ pc.country_to }}</span>
                {% elif pc.country_to %}<span>{{ pc.country_to|flag }} {{ pc.country_to }}</span>
                {% endif %}
            </div>
        </div>
    </div>
    {% endfor %}
</div>
<div id="scroll-sentinel" style="height:1px"></div>
<div id="scroll-loading" style="text-align:center;padding:1rem;color:var(--text-muted);display:none">⏳</div>
{% else %}
<div class="empty-state">
    <p>{{ 'index.empty'|t(lang) }}</p>
</div>
{% endif %}

<!-- Lightbox -->
<div id="lightbox" class="lightbox" onclick="closeLightbox()" style="display:none">
    <div class="lightbox-content" onclick="event.stopPropagation()">
        <button class="lightbox-close" onclick="closeLightbox()">&times;</button>
        <button class="lightbox-prev" onclick="navLightbox(-1)">&#8249;</button>
        <button class="lightbox-next" onclick="navLightbox(1)">&#8250;</button>
        <img id="lightbox-img" src="" alt="">
        <div id="lightbox-caption" class="lightbox-caption"></div>
    </div>
</div>

<script>
/* ---- Infinite Scroll ---- */
var _page = 1;
var _hasMore = {{ 'true' if has_more else 'false' }};
var _loading = false;

function _appendCard(c) {
    var grid = document.getElementById('showcase-grid');
    if (!grid) return;
    var div = document.createElement('div');
    div.className = 'showcase-card';
    div.setAttribute('data-front', c.image_front);
    div.onclick = function() { openLightbox(div); };
    var countryHtml = '';
    if (c.country_from && c.country_to) countryHtml = '<span>' + _flag(c.country_from) + ' ' + c.country_from + ' → ' + _flag(c.country_to) + ' ' + c.country_to + '</span>';
    else if (c.country_to) countryHtml = '<span>' + _flag(c.country_to) + ' ' + c.country_to + '</span>';
    div.innerHTML = '<img src="' + c.image_front + '" alt="" class="showcase-card-img" loading="lazy">' +
        '<div class="showcase-card-body"><div class="showcase-card-meta">' + countryHtml + '</div></div>';
    grid.appendChild(div);
}

function _flag(code) {
    if (!code || code.length !== 2) return code || '';
    return String.fromCodePoint(0x1F1E6 + code.charCodeAt(0) - 65) + String.fromCodePoint(0x1F1E6 + code.charCodeAt(1) - 65);
}

function _loadMore() {
    if (_loading || !_hasMore) return;
    _loading = true;
    document.getElementById('scroll-loading').style.display = '';
    fetch('/api/public/cards?page=' + (_page + 1) + '&limit=20')
        .then(function(r) { return r.json(); })
        .then(function(data) {
            _loading = false;
            document.getElementById('scroll-loading').style.display = 'none';
            _page = data.page;
            _hasMore = data.has_more;
            data.cards.forEach(_appendCard);
            if (!_hasMore) {
                var s = document.getElementById('scroll-sentinel');
                if (s) s.remove();
            }
        })
        .catch(function() { _loading = false; });
}

var _observer = new IntersectionObserver(function(entries) {
    if (entries[0].isIntersecting) _loadMore();
}, {rootMargin: '400px'});
var _sentinel = document.getElementById('scroll-sentinel');
if (_sentinel) _observer.observe(_sentinel);

/* ---- Lightbox ---- */
var lightboxItems = [];
var lightboxIdx = 0;

function buildLightboxItems() {
    lightboxItems = [];
    document.querySelectorAll('#showcase-grid .showcase-card[data-front]').forEach(function(card) {
        lightboxItems.push({src: card.getAttribute('data-front')});
    });
}

function openLightbox(el) {
    buildLightboxItems();
    var src = el.getAttribute('data-front');
    if (!src) return;
    for (var i = 0; i < lightboxItems.length; i++) {
        if (lightboxItems[i].src === src) { lightboxIdx = i; break; }
    }
    showLightboxItem();
    document.getElementById('lightbox').style.display = 'flex';
    document.body.style.overflow = 'hidden';
}

function showLightboxItem() {
    if (!lightboxItems.length) return;
    var item = lightboxItems[lightboxIdx];
    document.getElementById('lightbox-img').src = item.src;
    document.getElementById('lightbox-caption').textContent = (lightboxIdx+1) + '/' + lightboxItems.length;
}

function closeLightbox(e) {
    if (e) e.stopPropagation();
    document.getElementById('lightbox').style.display = 'none';
    document.body.style.overflow = '';
}

function navLightbox(dir, e) {
    if (e) e.stopPropagation();
    if (!lightboxItems.length) return;
    lightboxIdx = (lightboxIdx + dir + lightboxItems.length) % lightboxItems.length;
    showLightboxItem();
}

document.addEventListener('keydown', function(e) {
    var lb = document.getElementById('lightbox');
    if (!lb || lb.style.display === 'none') return;
    if (e.key === 'Escape') closeLightbox();
    else if (e.key === 'ArrowLeft') navLightbox(-1);
    else if (e.key === 'ArrowRight') navLightbox(1);
});
</script>
{% endblock %}