<?php
declare(strict_types=1);

session_start();

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

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    echo json_encode([
        'success' => false,
        'message' => 'Nur POST ist erlaubt.',
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

$sessionToken = isset($_SESSION['observation_tip_insert_token']) && is_string($_SESSION['observation_tip_insert_token'])
    ? $_SESSION['observation_tip_insert_token']
    : '';
$submittedToken = isset($_POST['observation_tip_insert_token']) ? (string) $_POST['observation_tip_insert_token'] : '';

if ($sessionToken === '' || $submittedToken === '' || !hash_equals($sessionToken, $submittedToken)) {
    http_response_code(403);
    echo json_encode([
        'success' => false,
        'message' => 'Sicherheitspruefung fehlgeschlagen. Bitte die Seite neu laden und erneut versuchen.',
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

$payloadJson = isset($_POST['observation_tip_payload']) ? (string) $_POST['observation_tip_payload'] : '';
$rows = json_decode($payloadJson, true);
if (!is_array($rows)) {
    http_response_code(400);
    echo json_encode([
        'success' => false,
        'message' => 'Ungueltige Ereignisdaten empfangen.',
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

$normalized = [];
foreach ($rows as $row) {
    if (!is_array($row)) {
        continue;
    }

    $moment = trim((string) ($row['moment'] ?? ''));
    $tip = trim((string) ($row['tip'] ?? ''));
    if ($moment === '' || $tip === '') {
        continue;
    }

    $normalized[] = [
        'moment' => $moment,
        'tip' => $tip,
    ];
}

if ($normalized === []) {
    echo json_encode([
        'success' => false,
        'message' => 'Keine gueltigen Ereignisse zum Eintragen vorhanden.',
        'inserted' => 0,
        'skipped' => 0,
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

try {
    $dbConfig = require __DIR__ . '/../../config/observationtips_database.php';
    $dsn = sprintf(
        'mysql:host=%s;dbname=%s;charset=%s',
        $dbConfig['host'],
        $dbConfig['dbname'],
        $dbConfig['charset'] ?? 'utf8mb4'
    );
    $pdo = new PDO(
        $dsn,
        $dbConfig['user'],
        $dbConfig['pass'],
        [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        ]
    );

    $checkStmt = $pdo->prepare(
        'SELECT 1 FROM `astro_sonobs_observationtips` WHERE `moment` = :moment AND `tip` = :tip LIMIT 1'
    );
    $insertStmt = $pdo->prepare(
        'INSERT INTO `astro_sonobs_observationtips` (`moment`, `tip`) VALUES (:moment, :tip)'
    );

    $inserted = 0;
    $skipped = 0;

    $pdo->beginTransaction();
    try {
        foreach ($normalized as $row) {
            $checkStmt->execute([
                ':moment' => $row['moment'],
                ':tip' => $row['tip'],
            ]);

            if ($checkStmt->fetchColumn()) {
                $skipped++;
                continue;
            }

            $insertStmt->execute([
                ':moment' => $row['moment'],
                ':tip' => $row['tip'],
            ]);
            $inserted++;
        }

        $pdo->commit();
    } catch (Throwable $e) {
        if ($pdo->inTransaction()) {
            $pdo->rollBack();
        }
        throw $e;
    }

    echo json_encode([
        'success' => true,
        'message' => sprintf('%d Ereignisse eingetragen, %d bereits vorhanden.', $inserted, $skipped),
        'inserted' => $inserted,
        'skipped' => $skipped,
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
} catch (Throwable $e) {
    http_response_code(500);
    echo json_encode([
        'success' => false,
        'message' => 'Eintragen in `astro_sonobs_observationtips` fehlgeschlagen: ' . $e->getMessage(),
        'inserted' => 0,
        'skipped' => 0,
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
}