<?php
require __DIR__ . '/../../bbs/db_conn.php';

header('Content-Type: application/json; charset=utf-8');

// PDO 연결 생성
$pdo = db_conn();

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
  echo json_encode(['success' => false, 'message' => '잘못된 요청입니다.']);
  exit;
}

$content_id = isset($_POST['content_id']) ? trim($_POST['content_id']) : '';
$seqRaw = isset($_POST['seq']) ? trim((string)$_POST['seq']) : '';
$seq = ($seqRaw !== '' ? (int)$seqRaw : null);
$title = isset($_POST['title']) ? trim($_POST['title']) : '';
$is_active = isset($_POST['is_active']) ? '1' : '0';

if ($content_id === '') {
  echo json_encode(['success' => false, 'message' => '콘텐츠 ID가 필요합니다.']);
  exit;
}

try {
  if ($seq === null) {
    // 신규 등록: seq를 순차증감(최대 3개)
    $stmt = $pdo->prepare("SELECT COALESCE(MAX(seq), 0) FROM edu_content_memos WHERE content_id = :c");
    $stmt->execute([':c' => $content_id]);
    $nextSeq = (int)$stmt->fetchColumn() + 1;
    if ($nextSeq > 3) {
      echo json_encode(['success' => false, 'message' => '포스트잇은 최대 3개까지만 등록할 수 있습니다.']);
      exit;
    }

    $ins = $pdo->prepare("INSERT INTO edu_content_memos (content_id, seq, title, is_active, created_by, created_at, updated_by, updated_at)
                          VALUES (:c, :s, :t, :a, 'admin', NOW(), 'admin', NOW())");
    $ins->execute([':c' => $content_id, ':s' => $nextSeq, ':t' => $title, ':a' => $is_active]);
    echo json_encode(['success' => true, 'seq' => $nextSeq]);
    exit;
  }

  if ($seq < 1 || $seq > 3) {
    echo json_encode(['success' => false, 'message' => 'seq는 1~3 범위만 가능합니다.']);
    exit;
  }

  // 수정: 존재하면 UPDATE, 없으면 INSERT(지정 seq)
  $sql = "INSERT INTO edu_content_memos (content_id, seq, title, is_active, created_by, created_at, updated_by, updated_at)
          VALUES (:c, :s, :t, :a, 'admin', NOW(), 'admin', NOW())
          ON DUPLICATE KEY UPDATE
            title = VALUES(title),
            is_active = VALUES(is_active),
            updated_by = 'admin',
            updated_at = NOW()";
  $stmt = $pdo->prepare($sql);
  $stmt->execute([':c' => $content_id, ':s' => $seq, ':t' => $title, ':a' => $is_active]);

  echo json_encode(['success' => true, 'seq' => $seq]);
} catch (PDOException $e) {
  echo json_encode(['success' => false, 'message' => 'DB 에러: ' . $e->getMessage()]);
}
exit;