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

// PDO 연결 생성
$pdo = db_conn();

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

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

$content_id = isset($_POST['content_id']) ? trim($_POST['content_id']) : '';

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

try {
    // 1. 제약사항 검사: 학습이력(edu_learning_histories) 또는 찜목록(edu_content_wishlist) 확인
    $check_stmt = $pdo->prepare("
        SELECT 
            (SELECT COUNT(*) FROM edu_learning_histories WHERE content_id = :content_id1) as history_count,
            (SELECT COUNT(*) FROM edu_content_wishlist WHERE content_id = :content_id2) as wishlist_count
    ");
    $check_stmt->execute([
        ':content_id1' => $content_id,
        ':content_id2' => $content_id
    ]);
    $check_result = $check_stmt->fetch(PDO::FETCH_ASSOC);

    if ($check_result['history_count'] > 0 || $check_result['wishlist_count'] > 0) {
        echo json_encode(['success' => false, 'message' => '학습이력이나 찜 목록에 존재하는 콘텐츠는 삭제할 수 없습니다.']);
        exit;
    }

    // 2. 연관 데이터 삭제를 위한 트랜잭션 시작
    $pdo->beginTransaction();

    // 키워드 삭제
    $stmt_keywords = $pdo->prepare("DELETE FROM edu_content_keywords WHERE content_id = :content_id");
    $stmt_keywords->execute([':content_id' => $content_id]);

    // 포스트잇(메모) 삭제
    $stmt_memos = $pdo->prepare("DELETE FROM edu_content_memos WHERE content_id = :content_id");
    $stmt_memos->execute([':content_id' => $content_id]);

    // 본 콘텐츠 삭제
    $stmt_content = $pdo->prepare("DELETE FROM edu_contents WHERE content_id = :content_id");
    $stmt_content->execute([':content_id' => $content_id]);

    // 3. 트랜잭션 커밋
    $pdo->commit();

    echo json_encode(['success' => true]);
} catch (PDOException $e) {
    // 오류 발생 시 롤백
    if ($pdo->inTransaction()) {
        $pdo->rollBack();
    }
    echo json_encode(['success' => false, 'message' => '삭제 실패: ' . $e->getMessage()]);
}