<?php
/**
 * MSPE Admin Users API
 */

require_once 'config.php';

$method = $_SERVER['REQUEST_METHOD'];
$id = $_GET['id'] ?? null;

$currentUser = requireAuth();
requireAdminRole($currentUser);

// CSRF protection for write operations
if ($method !== 'GET') {
    requireSameOriginRequest();
}

switch ($method) {
    case 'GET':
        if ($id) {
            getUser($id);
        } else {
            getUsers();
        }
        break;
        
    case 'POST':
        $postData = !empty($_POST) ? $_POST : getRequestBody();
        if (!empty($postData['id'])) {
            updateUser($postData['id']);
        } else {
            createUser();
        }
        break;
        
    case 'PUT':
        if (!$id) {
            jsonResponse(['success' => false, 'message' => 'User ID required'], 400);
        }
        updateUser($id);
        break;
        
    case 'DELETE':
        if (!$id) {
            jsonResponse(['success' => false, 'message' => 'ID required'], 400);
        }
        deleteUser($id);
        break;
        
    default:
        jsonResponse(['success' => false, 'message' => 'Method not allowed'], 405);
}

function getUsers() {
    global $db;
    $users = $db->getAll('users');
    
    // Remove sensitive data
    foreach ($users as &$user) {
        unset($user['password']);
    }
    
    jsonResponse(['success' => true, 'data' => array_values($users)]);
}

function getUser($id) {
    global $db;
    $user = $db->get('users', $id);
    if (!$user) jsonResponse(['success' => false, 'message' => 'Not found'], 404);
    
    unset($user['password']);
    jsonResponse(['success' => true, 'data' => $user]);
}

function createUser() {
    global $db;
    $data = !empty($_POST) ? $_POST : getRequestBody();
    
    if (empty($data['username']) || empty($data['password']) || empty($data['email'])) {
        jsonResponse(['success' => false, 'message' => 'Username, Email and Password required'], 400);
    }

    // Enforce minimum password strength
    if (strlen($data['password']) < 12) {
        jsonResponse(['success' => false, 'message' => 'Password must be at least 12 characters'], 400);
    }
    
    // Check if username exists
    $existing = $db->query('users', ['username' => $data['username']]);
    if (!empty($existing)) {
        jsonResponse(['success' => false, 'message' => 'Username already exists'], 400);
    }
    
    // Check if email exists
    $existingEmail = $db->query('users', ['email' => $data['email']]);
    if (!empty($existingEmail)) {
        jsonResponse(['success' => false, 'message' => 'Email already in use'], 400);
    }
    
    // Validate email format
    if (!filter_var($data['email'], FILTER_VALIDATE_EMAIL)) {
        jsonResponse(['success' => false, 'message' => 'Invalid email address'], 400);
    }

    // Whitelist allowed roles and statuses
    $allowedRoles = ['admin', 'editor'];
    $role = in_array($data['role'] ?? 'editor', $allowedRoles, true) ? $data['role'] : 'editor';
    $allowedStatuses = ['active', 'inactive'];
    $status = in_array($data['status'] ?? 'active', $allowedStatuses, true) ? $data['status'] : 'active';

    $user = [
        'name' => sanitize($data['name'] ?? ''),
        'username' => sanitize($data['username']),
        'email' => sanitize($data['email']),
        'role' => $role,
        'status' => $status,
        'password' => password_hash($data['password'], PASSWORD_DEFAULT),
        'last_login' => null
    ];
    
    $created = $db->insert('users', $user);
    unset($created['password']);
    
    jsonResponse(['success' => true, 'message' => 'User created', 'data' => $created]);
}

function updateUser($id) {
    global $db;
    $existing = $db->get('users', $id);
    if (!$existing) jsonResponse(['success' => false, 'message' => 'Not found'], 404);
    
    $data = !empty($_POST) ? $_POST : getRequestBody();
    $updateData = [];
    
    if (!empty($data['name'])) $updateData['name'] = sanitize($data['name']);
    if (!empty($data['email'])) {
        if (!filter_var($data['email'], FILTER_VALIDATE_EMAIL)) {
            jsonResponse(['success' => false, 'message' => 'Invalid email address'], 400);
        }
        $updateData['email'] = sanitize($data['email']);
    }
    if (!empty($data['role'])) {
        $allowedRoles = ['admin', 'editor'];
        $updateData['role'] = in_array($data['role'], $allowedRoles, true) ? $data['role'] : ($existing['role'] ?? 'editor');
    }
    if (!empty($data['status'])) {
        $allowedStatuses = ['active', 'inactive'];
        $updateData['status'] = in_array($data['status'], $allowedStatuses, true) ? $data['status'] : ($existing['status'] ?? 'active');
    }
    
    // Password update
    if (!empty($data['password'])) {
        if (strlen($data['password']) < 12) {
            jsonResponse(['success' => false, 'message' => 'Password must be at least 12 characters'], 400);
        }
        $updateData['password'] = password_hash($data['password'], PASSWORD_DEFAULT);
    }
    
    $updated = $db->update('users', $id, $updateData);
    unset($updated['password']);
    
    jsonResponse(['success' => true, 'message' => 'User updated', 'data' => $updated]);
}

function deleteUser($id) {
    global $db;
    global $currentUser;
    
    // Prevent deleting self (simplistic check)
    if ($currentUser['user_id'] === $id) {
        jsonResponse(['success' => false, 'message' => 'Cannot delete yourself'], 400);
    }
    
    $db->delete('users', $id);
    jsonResponse(['success' => true, 'message' => 'User deleted']);
}

function requireAdminRole($user) {
    if (($user['role'] ?? '') !== 'admin') {
        jsonResponse(['success' => false, 'message' => 'Forbidden'], 403);
    }
}