<?php

declare(strict_types=1);

/**
 * GET - List all active sessions for current user
 */
function handleGetSession(PDO $pdo, int $userId, ?string $currentTokenHash): void
{
    // Cleanup: expirované + rotované tokeny po grace period
    $stmt = $pdo->prepare(
        'DELETE FROM refresh_tokens WHERE user_id = ? AND (expires_at < NOW()'
        . ' OR (replaced_at IS NOT NULL AND replaced_at < DATE_SUB(NOW(), INTERVAL '
        . JWTAuth::getGracePeriod() . ' SECOND)))'
    );
    $stmt->execute([$userId]);

    // Jen aktivní sessions (nereplacované)
    $stmt = $pdo->prepare('
        SELECT
            id,
            ip_address,
            user_agent,
            created_at,
            expires_at,
            token_hash
        FROM refresh_tokens
        WHERE user_id = ? AND replaced_at IS NULL
        ORDER BY created_at DESC
    ');
    $stmt->execute([$userId]);
    $sessions = $stmt->fetchAll();

    // Process sessions to add is_current flag and parse user agent
    $processedSessions = array_map(function ($session) use ($currentTokenHash) {
        return [
            'id' => (int) $session['id'],
            'ip_address' => $session['ip_address'],
            'user_agent' => $session['user_agent'],
            'device_info' => parseUserAgent($session['user_agent']),
            'created_at' => $session['created_at'],
            'expires_at' => $session['expires_at'],
            'is_current' => $currentTokenHash && $session['token_hash'] === $currentTokenHash,
        ];
    }, $sessions);

    successResponse([
        'sessions' => $processedSessions,
        'total' => count($processedSessions),
    ]);
}

/**
 * DELETE - Delete a specific session
 */
function handleDeleteSession(PDO $pdo, int $sessionId, int $userId, ?string $currentTokenHash): void
{
    // Verify the session belongs to the current user
    $stmt = $pdo->prepare('SELECT token_hash FROM refresh_tokens WHERE id = ? AND user_id = ?');
    $stmt->execute([$sessionId, $userId]);
    $session = $stmt->fetch();

    if (!$session) {
        errorResponse('Relace nebyla nalezena', 404);
    }

    // Check if trying to delete current session
    if ($currentTokenHash && $session['token_hash'] === $currentTokenHash) {
        // Check if force parameter is set
        $input = getJsonInput();
        if (!($input['force'] ?? false)) {
            errorResponse('Nelze smazat aktuální relaci. Použijte tlačítko odhlášení.', 400);
        }
    }

    // Delete the session
    $stmt = $pdo->prepare('DELETE FROM refresh_tokens WHERE id = ? AND user_id = ?');
    $stmt->execute([$sessionId, $userId]);

    successResponse(null, 'Relace byla úspěšně ukončena');
}

/**
 * DELETE - Delete all sessions except current
 */
function handleDeleteAllSessions(PDO $pdo, int $userId, ?string $currentTokenHash): void
{
    if (!$currentTokenHash) {
        $stmt = $pdo->prepare('DELETE FROM refresh_tokens WHERE user_id = ?');
        $stmt->execute([$userId]);
        $deleted = $stmt->rowCount();
    } else {
        // Ponechat aktuální session, smazat ostatní (včetně replaced)
        $stmt = $pdo->prepare('DELETE FROM refresh_tokens WHERE user_id = ? AND token_hash != ?');
        $stmt->execute([$userId, $currentTokenHash]);
        $deleted = $stmt->rowCount();
    }

    successResponse([
        'deleted' => $deleted,
    ], $deleted > 0 ? 'Ostatní relace byly úspěšně ukončeny' : 'Žádné další relace k ukončení');
}

/**
 * Parse user agent string to extract device/browser info
 *
 * @return array{browser: string, os: string}
 */
function parseUserAgent(?string $userAgent): array
{
    if (empty($userAgent)) {
        return [
            'browser' => 'Neznámý prohlížeč',
            'os' => 'Neznámý systém',
            'device' => 'Neznámé zařízení',
            'icon' => 'device',
        ];
    }

    $browser = 'Neznámý prohlížeč';
    $os = 'Neznámý systém';
    $device = 'desktop';
    $icon = 'desktop';

    // Detect browser
    if (preg_match('/Edg(e|A|iOS)?\/[\d.]+/i', $userAgent)) {
        $browser = 'Microsoft Edge';
    } elseif (preg_match('/OPR\/[\d.]+|Opera/i', $userAgent)) {
        $browser = 'Opera';
    } elseif (preg_match('/Chrome\/[\d.]+/i', $userAgent) && !preg_match('/Chromium/i', $userAgent)) {
        $browser = 'Google Chrome';
    } elseif (preg_match('/Firefox\/[\d.]+/i', $userAgent)) {
        $browser = 'Mozilla Firefox';
    } elseif (preg_match('/Safari\/[\d.]+/i', $userAgent) && !preg_match('/Chrome/i', $userAgent)) {
        $browser = 'Safari';
    } elseif (preg_match('/MSIE|Trident/i', $userAgent)) {
        $browser = 'Internet Explorer';
    }

    // Detect OS
    if (preg_match('/Windows NT 10/i', $userAgent)) {
        $os = 'Windows 10/11';
    } elseif (preg_match('/Windows NT 6\.3/i', $userAgent)) {
        $os = 'Windows 8.1';
    } elseif (preg_match('/Windows NT 6\.2/i', $userAgent)) {
        $os = 'Windows 8';
    } elseif (preg_match('/Windows NT 6\.1/i', $userAgent)) {
        $os = 'Windows 7';
    } elseif (preg_match('/Windows/i', $userAgent)) {
        $os = 'Windows';
    } elseif (preg_match('/Macintosh|Mac OS X/i', $userAgent)) {
        $os = 'macOS';
    } elseif (preg_match('/Linux/i', $userAgent) && !preg_match('/Android/i', $userAgent)) {
        $os = 'Linux';
    } elseif (preg_match('/iPhone/i', $userAgent)) {
        $os = 'iOS';
        $device = 'mobile';
        $icon = 'smartphone';
    } elseif (preg_match('/iPad/i', $userAgent)) {
        $os = 'iPadOS';
        $device = 'tablet';
        $icon = 'tablet';
    } elseif (preg_match('/Android/i', $userAgent)) {
        $os = 'Android';
        if (preg_match('/Mobile/i', $userAgent)) {
            $device = 'mobile';
            $icon = 'smartphone';
        } else {
            $device = 'tablet';
            $icon = 'tablet';
        }
    }

    return [
        'browser' => $browser,
        'os' => $os,
        'device' => $device,
        'icon' => $icon,
    ];
}