<?php
/**
 * admin/nav.php —— 导航内容管理（块/链接增删改查 + 顺序）
 * 完整重同步保存：提交的 JSON 中不存在的老块/老链接将被删除。
 */
$P = '../';
require_once __DIR__ . '/_guard.php';

$pdo = db();
$catKeys = ['popular', 'red', 'blue'];
$cat = isset($_GET['c']) ? (string)$_GET['c'] : 'popular';
if (!in_array($cat, $catKeys, true)) {
    $cat = 'popular';
}
$stCat = $pdo->prepare('SELECT * FROM categories WHERE key = ? LIMIT 1');
$stCat->execute([$cat]);
$catRow = $stCat->fetch();
if (!$catRow) {
    http_response_code(404);
    die('分类不存在');
}

$saved = isset($_GET['ok']);
$errorMsg = '';

// ---------- 保存处理 ----------
if ($_SERVER['REQUEST_METHOD'] === 'POST' && ($_POST['action'] ?? '') === 'save') {
    if (!csrf_verify()) {
        $errorMsg = '安全校验失败，请刷新页面重试。';
    } else {
        $raw = (string)($_POST['data'] ?? '');
        $data = json_decode($raw, true);
        if (!is_array($data)) {
            $errorMsg = '提交数据格式错误。';
        } else {
            try {
                $pdo->beginTransaction();
                // 现有块
                $st = $pdo->prepare('SELECT id FROM nav_blocks WHERE cat_id = ?');
                $st->execute([(int)$catRow['id']]);
                $oldBlocks = array_map('intval', array_column($st->fetchAll(), 'id'));
                // 现有链接（按块分组）
                $oldItemsByBlock = [];
                foreach ($oldBlocks as $bid) {
                    $st = $pdo->prepare('SELECT id FROM nav_items WHERE block_id = ?');
                    $st->execute([$bid]);
                    $oldItemsByBlock[$bid] = array_map('intval', array_column($st->fetchAll(), 'id'));
                }
                // 本轮保留的块 id
                $keepBlocks = [];
                $keepItems = [];
                foreach ($data as $b) {
                    if (is_array($b) && isset($b['title'])) {
                        $id = (int)($b['id'] ?? 0);
                        if ($id > 0) $keepBlocks[] = $id;
                        foreach (($b['items'] ?? []) as $it) {
                            if (is_array($it) && (int)($it['id'] ?? 0) > 0) {
                                $keepItems[] = (int)$it['id'];
                            }
                        }
                    }
                }
                // 删除被移除的块及其链接
                $delBlocks = array_values(array_diff($oldBlocks, $keepBlocks));
                foreach ($delBlocks as $dbid) {
                    $pdo->prepare('DELETE FROM nav_items WHERE block_id = ?')->execute([$dbid]);
                    $pdo->prepare('DELETE FROM nav_blocks WHERE id = ?')->execute([$dbid]);
                    unset($oldItemsByBlock[$dbid]);
                }
                // 删除被移除的链接
                foreach ($oldItemsByBlock as $bid => $ids) {
                    $del = array_values(array_diff($ids, $keepItems));
                    foreach ($del as $did) {
                        $pdo->prepare('DELETE FROM nav_items WHERE id = ?')->execute([$did]);
                    }
                }
                // 写回块与链接
                $stInsBlock = $pdo->prepare('INSERT INTO nav_blocks (cat_id, title, sort) VALUES (?,?,?)');
                $stUpdBlock = $pdo->prepare('UPDATE nav_blocks SET title = ?, sort = ? WHERE id = ?');
                $stInsItem = $pdo->prepare('INSERT INTO nav_items (block_id, label, url, note, sort) VALUES (?,?,?,?,?)');
                $stUpdItem = $pdo->prepare('UPDATE nav_items SET label = ?, url = ?, note = ?, sort = ? WHERE id = ? AND block_id = ?');
                $blockSort = 0;
                foreach ($data as $b) {
                    if (!is_array($b) || !isset($b['title'])) continue;
                    $title = trim((string)$b['title']);
                    if ($title === '') continue;
                    $bid = (int)($b['id'] ?? 0);
                    $blockBelongs = in_array($bid, $oldBlocks, true);
                    if ($bid > 0 && $blockBelongs) {
                        $stUpdBlock->execute([$title, $blockSort, $bid]);
                    } else {
                        $stInsBlock->execute([(int)$catRow['id'], $title, $blockSort]);
                        $bid = (int)$pdo->lastInsertId();
                    }
                    $itemSort = 0;
                    foreach (($b['items'] ?? []) as $it) {
                        if (!is_array($it)) continue;
                        $label = trim((string)($it['label'] ?? ''));
                        $url = trim((string)($it['url'] ?? ''));
                        $note = trim((string)($it['note'] ?? ''));
                        if ($label === '' && $url === '') continue;
                        $iid = (int)($it['id'] ?? 0);
                        if ($iid > 0 && in_array($iid, $oldItemsByBlock[$bid] ?? [], true)) {
                            $stUpdItem->execute([$label, $url, $note, $itemSort, $iid, $bid]);
                        } else {
                            $stInsItem->execute([$bid, $label, $url, $note, $itemSort]);
                        }
                        $itemSort++;
                    }
                    $blockSort++;
                }
                $pdo->commit();
                touch_last_updated();
                header('Location: nav.php?c=' . urlencode($cat) . '&ok=1');
                exit;
            } catch (Throwable $e) {
                if ($pdo->inTransaction()) {
                    $pdo->rollBack();
                }
                $errorMsg = '保存失败：' . $e->getMessage();
            }
        }
    }
}

// ---------- 读取现有数据用于展示 ----------
$st = $pdo->prepare('SELECT * FROM nav_blocks WHERE cat_id = ? ORDER BY sort ASC, id ASC');
$st->execute([(int)$catRow['id']]);
$blocks = $st->fetchAll();
$itemsMap = [];
if ($blocks) {
    $ids = array_map('intval', array_column($blocks, 'id'));
    $in = implode(',', array_fill(0, count($ids), '?'));
    $st = $pdo->prepare("SELECT * FROM nav_items WHERE block_id IN ($in) ORDER BY sort ASC, id ASC");
    $st->execute($ids);
    foreach ($st->fetchAll() as $it) {
        $itemsMap[(int)$it['block_id']][] = $it;
    }
}

$catNames = [];
foreach ($catKeys as $ck) {
    $row = $pdo->query("SELECT key, name FROM categories WHERE key = '" . $ck . "'")->fetch();
    $catNames[$ck] = $row['name'] ?? $ck;
}

$csrfVal = csrf_token();

layout_head('导航内容管理');
admin_topbar('nav');
?>
<main class="page-main">
  <div class="wrap page-body">
    <h2 style="margin-bottom:6px">导航内容管理</h2>
    <p class="tip">管理 <?= he($catNames[$cat]) ?> 的导航块与链接；块内最多 15 个链接（3 小列 × 5 行），超出部分请拆分到新块。</p>

    <!-- 分类切换 -->
    <div class="field-row" style="margin:12px 0">
      <?php foreach ($catKeys as $ck): ?>
        <a class="btn <?= $cat === $ck ? 'btn-primary' : '' ?>" href="nav.php?c=<?= he($ck) ?>"><?= he($catNames[$ck]) ?></a>
      <?php endforeach; ?>
    </div>

    <?php if ($saved): ?>
      <div class="ok-msg">保存成功，前台页面已同步更新。</div>
    <?php endif; ?>
    <?php if ($errorMsg !== ''): ?>
      <div class="err-msg"><?= he($errorMsg) ?></div>
    <?php endif; ?>

    <form method="post" id="navForm" autocomplete="off">
      <?= csrf_field() ?>
      <input type="hidden" name="action" value="save">
      <input type="hidden" name="cat" value="<?= he($cat) ?>">
      <textarea name="data" id="jsonData" hidden></textarea>

      <div id="blocksWrap">
        <?php foreach ($blocks as $b):
          $items = $itemsMap[(int)$b['id']] ?? []; ?>
          <div class="m-block" data-id="<?= (int)$b['id'] ?>">
            <div class="m-block-head">
              <input type="text" class="b-title" value="<?= he((string)$b['title']) ?>" placeholder="导航块标题（必填）">
              <span class="ops">
                <button type="button" class="btn btn-sm b-up" title="上移">↑</button>
                <button type="button" class="btn btn-sm b-down" title="下移">↓</button>
                <button type="button" class="btn btn-sm btn-danger b-del" title="删除该块及其链接">删除块</button>
              </span>
            </div>
            <div class="m-items">
              <?php foreach (array_slice($items, 0, 15) as $it): ?>
                <div class="m-item">
                  <input type="text" class="i-label" value="<?= he((string)$it['label']) ?>" placeholder="文字（必填）">
                  <input type="text" class="i-url" value="<?= he((string)$it['url']) ?>" placeholder="链接，如 https://…（必填）">
                  <input type="text" class="i-note" value="<?= he((string)$it['note']) ?>" placeholder="备注（可选，前台悬浮提示）">
                  <button type="button" class="btn btn-sm btn-danger i-del" title="删除该链接">✕</button>
                </div>
              <?php endforeach; ?>
              <button type="button" class="btn btn-sm b-add-item" style="margin-top:8px">+ 添加链接</button>
            </div>
          </div>
        <?php endforeach; ?>
      </div>

      <button type="button" class="btn btn-sm add-btn" id="btnAddBlock">+ 新建导航块</button>
      <div>
        <button type="button" class="btn btn-primary" id="btnSave">保存全部修改</button>
        <span class="tip" id="saveTip"></span>
      </div>
    </form>
  </div>
</main>

<?php layout_theme_fab(); ?>
<script src="../assets/js/common.js"></script>
<script>
(function () {
    'use strict';
    var wrap = document.getElementById('blocksWrap');
    var jsonData = document.getElementById('jsonData');

    /* ---------- 模板 ---------- */
    function itemHTML(label, url, note) {
        return '<div class="m-item">' +
            '<input type="text" class="i-label" value="' + escAttr(label) + '" placeholder="文字（必填）">' +
            '<input type="text" class="i-url" value="' + escAttr(url) + '" placeholder="链接，如 https://…（必填）">' +
            '<input type="text" class="i-note" value="' + escAttr(note) + '" placeholder="备注（可选，前台悬浮提示）">' +
            '<button type="button" class="btn btn-sm btn-danger i-del" title="删除该链接">✕</button>' +
            '</div>';
    }
    function blockHTML(id, title, items) {
        var inner = items.map(function (it) {
            return itemHTML(it.label || '', it.url || '', it.note || '');
        }).join('');
        return '<div class="m-block" data-id="' + (id || 0) + '">' +
            '<div class="m-block-head">' +
            '<input type="text" class="b-title" value="' + escAttr(title) + '" placeholder="导航块标题（必填）">' +
            '<span class="ops">' +
            '<button type="button" class="btn btn-sm b-up" title="上移">↑</button>' +
            '<button type="button" class="btn btn-sm b-down" title="下移">↓</button>' +
            '<button type="button" class="btn btn-sm btn-danger b-del" title="删除该块及其链接">删除块</button>' +
            '</span></div>' +
            '<div class="m-items">' + inner + '<button type="button" class="btn btn-sm b-add-item" style="margin-top:8px">+ 添加链接</button></div>' +
            '</div>';
    }
    function escAttr(s) {
        return String(s).replace(/&/g, '&amp;').replace(/"/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
    }

    /* ---------- 行内事件代理 ---------- */
    wrap.addEventListener('click', function (ev) {
        var target = ev.target;
        var block = target.closest('.m-block');
        if (!block) return;

        if (target.classList.contains('b-del')) {
            if (confirm('确认删除该导航块及其全部链接？')) block.remove();
            return;
        }
        if (target.classList.contains('b-up') || target.classList.contains('b-down')) {
            var sib = target.classList.contains('b-up') ? block.previousElementSibling : block.nextElementSibling;
            if (sib && sib.classList.contains('m-block')) {
                if (target.classList.contains('b-up')) wrap.insertBefore(block, sib);
                else wrap.insertBefore(sib, block);
            }
            return;
        }
        if (target.classList.contains('b-add-item')) {
            var list = block.querySelector('.m-items');
            var count = list.querySelectorAll('.m-item').length;
            if (count >= 15) { alert('单个导航块最多 15 个链接，请新建导航块。'); return; }
            list.insertBefore(createElFromHTML(itemHTML('', '', '')), target);
            return;
        }
        if (target.classList.contains('i-del')) {
            target.closest('.m-item').remove();
        }
    });

    document.getElementById('btnAddBlock').addEventListener('click', function () {
        wrap.insertAdjacentHTML('beforeend', blockHTML(0, '', []));
    });

    function createElFromHTML(html) {
        var t = document.createElement('template');
        t.innerHTML = html.trim();
        return t.content.firstChild;
    }

    /* ---------- 收集并保存 ---------- */
    document.getElementById('btnSave').addEventListener('click', function () {
        var blocks = Array.prototype.slice.call(wrap.querySelectorAll('.m-block'));
        var data = [];
        var hasInvalid = false;

        blocks.forEach(function (block) {
            if (hasInvalid) return;
            var title = block.querySelector('.b-title').value.trim();
            if (!title) { alert('存在未填写标题的导航块，请填写或删除。'); hasInvalid = true; return; }
            var items = [];
            Array.prototype.slice.call(block.querySelectorAll('.m-item')).forEach(function (row) {
                var label = row.querySelector('.i-label').value.trim();
                var url = row.querySelector('.i-url').value.trim();
                var note = row.querySelector('.i-note').value.trim();
                if (label === '' && url === '') return; // 空行忽略
                if (label === '' || url === '') {
                    alert('链接的“文字”与“链接”不能为空。');
                    hasInvalid = true;
                    return;
                }
                items.push({ id: 0, label: label, url: url, note: note });
            });
            if (hasInvalid) return;
            data.push({ id: parseInt(block.getAttribute('data-id'), 10) || 0, title: title, items: items });
        });
        if (hasInvalid) return;
        jsonData.value = JSON.stringify(data);
        document.getElementById('navForm').submit();
    });
})();
</script>
</body>
</html>