<?php

declare(strict_types=1);

/**
 * GET - List all users
 */
function handleGetUser(PDO $pdo): void
{
    $stmt = $pdo->query('
        SELECT
            u.id,
            u.username,
            u.email,
            u.first_name,
            u.last_name,
            u.role_id,
            u.is_active,
            u.last_login,
            u.created_at,
            r.name as role_name,
            r.display_name as role_display_name
        FROM users u
        LEFT JOIN roles r ON u.role_id = r.id
        ORDER BY u.created_at DESC
    ');
    $users = $stmt->fetchAll();

    // Get roles for dropdown
    $stmt = $pdo->query('SELECT id, name, display_name FROM roles ORDER BY id');
    $roles = $stmt->fetchAll();

    successResponse([
        'users' => $users,
        'roles' => $roles,
    ]);
}

/**
 * POST - Create new user
 *
 * @param array<string, mixed> $authData
 */
function handleCreateUser(PDO $pdo, array $authData): void
{
    $input = getJsonInput();

    // Validate required fields
    $requiredFields = [
        'username' => 'Uživatelské jméno',
        'email' => 'E-mail',
        'password' => 'Heslo',
        'first_name' => 'Jméno',
        'last_name' => 'Příjmení',
        'role_id' => 'Role',
    ];
    foreach ($requiredFields as $field => $label) {
        if (empty($input[$field])) {
            errorResponse("$label je povinné");
        }
    }

    $username = sanitize($input['username']);
    $email = sanitize($input['email']);
    $password = $input['password'];
    $firstName = sanitize($input['first_name']);
    $lastName = sanitize($input['last_name']);
    $roleId = (int) $input['role_id'];
    $isActive = isset($input['is_active']) ? ($input['is_active'] ? 1 : 0) : 1;

    // Non-admin nesmí přiřadit admin roli
    if (!($authData['user']['is_admin'] ?? false)) {
        $stmt = $pdo->prepare('SELECT name FROM roles WHERE id = ?');
        $stmt->execute([$roleId]);
        $targetRole = $stmt->fetch();
        if ($targetRole && $targetRole['name'] === 'admin') {
            errorResponse('Nemáte oprávnění přiřadit roli administrátora', 403);
        }
    }

    // Validate email format
    if (!isValidEmail($email)) {
        errorResponse('Neplatný formát e-mailu');
    }

    // Validate password length
    if (strlen($password) < 8) {
        errorResponse('Heslo musí mít alespoň 8 znaků');
    }

    // Check username uniqueness
    $stmt = $pdo->prepare('SELECT id FROM users WHERE username = ?');
    $stmt->execute([$username]);
    if ($stmt->fetch()) {
        errorResponse('Uživatelské jméno již existuje');
    }

    // Check email uniqueness
    $stmt = $pdo->prepare('SELECT id FROM users WHERE email = ?');
    $stmt->execute([$email]);
    if ($stmt->fetch()) {
        errorResponse('E-mail již existuje');
    }

    // Validate role exists
    $stmt = $pdo->prepare('SELECT id FROM roles WHERE id = ?');
    $stmt->execute([$roleId]);
    if (!$stmt->fetch()) {
        errorResponse('Neplatná role');
    }

    // Hash password
    $passwordHash = password_hash($password, PASSWORD_BCRYPT, ['cost' => BCRYPT_COST]);

    // Insert user
    $stmt = $pdo->prepare('
        INSERT INTO users (username, email, password_hash, first_name, last_name, role_id, is_active)
        VALUES (?, ?, ?, ?, ?, ?, ?)
    ');
    $stmt->execute([$username, $email, $passwordHash, $firstName, $lastName, $roleId, $isActive]);

    $newUserId = (int)$pdo->lastInsertId();

    // Audit log
    AuditLog::logCreate('user', $newUserId, [
        'username' => $username,
        'email' => $email,
        'first_name' => $firstName,
        'last_name' => $lastName,
        'role_id' => $roleId,
        'is_active' => $isActive,
    ], "Vytvořen uživatel '$username'");

    successResponse(['id' => $newUserId], 'Uživatel byl úspěšně vytvořen');
}

/**
 * PUT - Update user
 *
 * @param array<string, mixed> $authData
 */
function handleUpdateUser(PDO $pdo, int $userId, int $currentUserId, array $authData): void
{
    // Get existing user
    $stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?');
    $stmt->execute([$userId]);
    $existingUser = $stmt->fetch();

    if (!$existingUser) {
        errorResponse('Uživatel nebyl nalezen', 404);
    }

    $input = getJsonInput();

    $username = isset($input['username']) ? sanitize($input['username']) : $existingUser['username'];
    $email = isset($input['email']) ? sanitize($input['email']) : $existingUser['email'];
    $firstName = isset($input['first_name']) ? sanitize($input['first_name']) : $existingUser['first_name'];
    $lastName = isset($input['last_name']) ? sanitize($input['last_name']) : $existingUser['last_name'];
    $roleId = isset($input['role_id']) ? (int) $input['role_id'] : $existingUser['role_id'];
    $isActive = isset($input['is_active']) ? ($input['is_active'] ? 1 : 0) : $existingUser['is_active'];

    // Validate email format
    if (!isValidEmail($email)) {
        errorResponse('Neplatný formát e-mailu');
    }

    // Check username uniqueness (excluding current user)
    $stmt = $pdo->prepare('SELECT id FROM users WHERE username = ? AND id != ?');
    $stmt->execute([$username, $userId]);
    if ($stmt->fetch()) {
        errorResponse('Uživatelské jméno již existuje');
    }

    // Check email uniqueness (excluding current user)
    $stmt = $pdo->prepare('SELECT id FROM users WHERE email = ? AND id != ?');
    $stmt->execute([$email, $userId]);
    if ($stmt->fetch()) {
        errorResponse('E-mail již existuje');
    }

    // Validate role exists
    $stmt = $pdo->prepare('SELECT id, name FROM roles WHERE id = ?');
    $stmt->execute([$roleId]);
    $targetRole = $stmt->fetch();
    if (!$targetRole) {
        errorResponse('Neplatná role');
    }

    // Non-admin nesmí přiřadit admin roli
    if (!($authData['user']['is_admin'] ?? false) && $targetRole['name'] === 'admin') {
        errorResponse('Nemáte oprávnění přiřadit roli administrátora', 403);
    }

    // Update user
    if (!empty($input['password'])) {
        // Validate password length
        if (strlen($input['password']) < 8) {
            errorResponse('Heslo musí mít alespoň 8 znaků');
        }

        $passwordHash = password_hash($input['password'], PASSWORD_BCRYPT, ['cost' => BCRYPT_COST]);

        $stmt = $pdo->prepare('
            UPDATE users
            SET username = ?, email = ?, password_hash = ?,
                first_name = ?, last_name = ?, role_id = ?,
                is_active = ?, password_changed_at = NOW()
            WHERE id = ?
        ');
        $stmt->execute([$username, $email, $passwordHash, $firstName, $lastName, $roleId, $isActive, $userId]);
    } else {
        $stmt = $pdo->prepare('
            UPDATE users
            SET username = ?, email = ?, first_name = ?, last_name = ?, role_id = ?, is_active = ?
            WHERE id = ?
        ');
        $stmt->execute([$username, $email, $firstName, $lastName, $roleId, $isActive, $userId]);
    }

    // Note: With JWT, user data is in the token - no session to update

    // Audit log
    AuditLog::logUpdate('user', $userId, [
        'username' => $existingUser['username'],
        'email' => $existingUser['email'],
        'first_name' => $existingUser['first_name'],
        'last_name' => $existingUser['last_name'],
        'role_id' => $existingUser['role_id'],
        'is_active' => $existingUser['is_active'],
    ], [
        'username' => $username,
        'email' => $email,
        'first_name' => $firstName,
        'last_name' => $lastName,
        'role_id' => $roleId,
        'is_active' => $isActive,
    ], "Upraven uživatel '$username'");

    successResponse(null, 'Uživatel byl úspěšně aktualizován');
}

/**
 * DELETE - Delete user
 */
function handleDeleteUser(PDO $pdo, int $userId, int $currentUserId): void
{
    // Prevent self-deletion
    if ($userId === $currentUserId) {
        errorResponse('Nemůžete smazat svůj vlastní účet');
    }

    // Get user for audit log
    $stmt = $pdo->prepare('SELECT username FROM users WHERE id = ?');
    $stmt->execute([$userId]);
    $user = $stmt->fetch();

    if (!$user) {
        errorResponse('Uživatel nebyl nalezen', 404);
    }

    // Delete related records first (refresh tokens for JWT auth)
    $stmt = $pdo->prepare('DELETE FROM refresh_tokens WHERE user_id = ?');
    $stmt->execute([$userId]);

    // Delete user
    $stmt = $pdo->prepare('DELETE FROM users WHERE id = ?');
    $stmt->execute([$userId]);

    // Audit log
    AuditLog::logDelete('user', $userId, ['username' => $user['username']], "Smazán uživatel '{$user['username']}'");

    successResponse(null, 'Uživatel byl úspěšně smazán');
}