/**
 * 밍글 스튜디오 블로그 목록 페이지
 * blog/index.json에서 글 목록을 불러와 렌더링
 */
(function() {
    'use strict';

    var grid = document.getElementById('blogGrid');
    var filtersWrap = document.getElementById('blogFilters');
    var loadingEl = document.getElementById('blogLoading');
    if (!grid) return;

    var lang = document.documentElement.lang || 'ko';
    var langPrefix = { ko: '', en: '/en', ja: '/ja', zh: '/zh' };
    var prefix = langPrefix[lang] || '';

    var readMore = { ko: '자세히 보기', en: 'Read more', ja: '続きを読む', zh: '阅读更多' };
    var emptyText = { ko: '아직 작성된 글이 없습니다.', en: 'No posts yet.', ja: 'まだ記事がありません。', zh: '暂无文章。' };
    var allText = { ko: '전체', en: 'All', ja: 'すべて', zh: '全部' };

    var allPosts = [];
    var currentFilter = 'all';

    function init() {
        fetch('/devlog/index.json?t=' + Date.now())
            .then(function(res) { return res.json(); })
            .then(function(posts) {
                allPosts = posts;
                if (loadingEl) loadingEl.style.display = 'none';
                buildFilters();
                renderPosts();
            })
            .catch(function() {
                if (loadingEl) loadingEl.style.display = 'none';
                grid.innerHTML = '<div class="blog-empty"><i class="fas fa-pen-fancy"></i><p>' + emptyText[lang] + '</p></div>';
            });
    }

    function buildFilters() {
        if (!filtersWrap || allPosts.length === 0) return;

        var categories = {};
        allPosts.forEach(function(p) {
            var cat = (p.categories && p.categories[lang]) || (p.categories && p.categories.ko) || p.category || '';
            if (cat) categories[cat] = true;
        });

        var cats = Object.keys(categories).sort();
        if (cats.length < 2) { filtersWrap.style.display = 'none'; return; }

        var html = '<button class="blog-filter-btn active" data-cat="all">' + allText[lang] + '</button>';
        cats.forEach(function(c) {
            html += '<button class="blog-filter-btn" data-cat="' + c + '">' + c + '</button>';
        });
        filtersWrap.innerHTML = html;

        filtersWrap.addEventListener('click', function(e) {
            var btn = e.target.closest('.blog-filter-btn');
            if (!btn) return;
            filtersWrap.querySelectorAll('.blog-filter-btn').forEach(function(b) { b.classList.remove('active'); });
            btn.classList.add('active');
            currentFilter = btn.getAttribute('data-cat');
            renderPosts();
        });
    }

    function getCategory(post) {
        return (post.categories && post.categories[lang]) || (post.categories && post.categories.ko) || post.category || '';
    }

    function renderPosts() {
        var filtered = currentFilter === 'all' ? allPosts : allPosts.filter(function(p) { return getCategory(p) === currentFilter; });

        if (filtered.length === 0) {
            grid.innerHTML = '<div class="blog-empty"><i class="fas fa-pen-fancy"></i><p>' + emptyText[lang] + '</p></div>';
            return;
        }

        var html = '';
        filtered.forEach(function(post) {
            var title = (post.titles && post.titles[lang]) || (post.titles && post.titles.ko) || post.slug;
            var desc = (post.descriptions && post.descriptions[lang]) || (post.descriptions && post.descriptions.ko) || '';
            var cat = getCategory(post);
            var thumb = post.thumbnail ? '/blog/posts/' + post.slug + '/' + post.thumbnail : '';
            var url = prefix + '/devlog/' + post.slug;
            var date = formatDate(post.date);

            html += '<article class="blog-card">';
            html += '<a href="' + url + '">';
            if (thumb) {
                html += '<img class="blog-card-thumb" src="' + thumb + '" alt="' + escapeHtml(title) + '" loading="lazy">';
            } else {
                html += '<div class="blog-card-thumb-placeholder"><i class="fas fa-pen-fancy"></i></div>';
            }
            html += '</a>';
            html += '<div class="blog-card-body">';
            if (cat) html += '<span class="blog-card-category">' + escapeHtml(cat) + '</span>';
            html += '<h2 class="blog-card-title"><a href="' + url + '" style="color:inherit;text-decoration:none">' + escapeHtml(title) + '</a></h2>';
            html += '<p class="blog-card-desc">' + escapeHtml(desc) + '</p>';
            html += '<div class="blog-card-footer">';
            html += '<span class="blog-card-date"><i class="far fa-calendar-alt"></i> ' + date + '</span>';
            html += '<a href="' + url + '" class="blog-card-link">' + readMore[lang] + ' →</a>';
            html += '</div></div></article>';
        });

        grid.innerHTML = html;
    }

    function formatDate(dateStr) {
        if (!dateStr) return '';
        var d = new Date(dateStr + 'T00:00:00');
        if (isNaN(d)) return dateStr;
        var y = d.getFullYear(), m = d.getMonth() + 1, day = d.getDate();
        if (lang === 'ko') return y + '.' + m + '.' + day;
        if (lang === 'ja' || lang === 'zh') return y + '/' + m + '/' + day;
        var months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
        return months[m - 1] + ' ' + day + ', ' + y;
    }

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

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
})();