<?php
/**
 * Helper Functions
 */

/**
 * Set CORS headers
 */
function setCorsHeaders() {
    $origin = isset($_SERVER['HTTP_ORIGIN']) ? $_SERVER['HTTP_ORIGIN'] : '';
    
    if ($origin && (ALLOWED_ORIGINS === '*' || strpos(ALLOWED_ORIGINS, $origin) !== false)) {
        header("Access-Control-Allow-Origin: $origin");
    } else {
        header("Access-Control-Allow-Origin: " . ALLOWED_ORIGINS);
    }
    
    header("Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS");
    header("Access-Control-Allow-Headers: Content-Type, Authorization");
    header("Access-Control-Allow-Credentials: true");
    
    // Handle preflight requests
    if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
        http_response_code(200);
        exit;
    }
}

/**
 * Send JSON response
 */
function jsonResponse($data, $statusCode = 200) {
    http_response_code($statusCode);
    header('Content-Type: application/json');
    echo json_encode($data);
    exit;
}

/**
 * Get JSON input
 */
function getJsonInput() {
    $input = file_get_contents('php://input');
    return json_decode($input, true);
}

/**
 * Validate email
 */
function isValidEmail($email) {
    return filter_var($email, FILTER_VALIDATE_EMAIL) !== false;
}

/**
 * Generate UUID v4
 */
function generateUuid() {
    return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
        mt_rand(0, 0xffff), mt_rand(0, 0xffff),
        mt_rand(0, 0xffff),
        mt_rand(0, 0x0fff) | 0x4000,
        mt_rand(0, 0x3fff) | 0x8000,
        mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
    );
}

/**
 * Sanitize string
 */
function sanitizeString($string) {
    return htmlspecialchars(strip_tags(trim($string)), ENT_QUOTES, 'UTF-8');
}

/**
 * Validate required fields
 */
function validateRequired($data, $requiredFields) {
    $errors = [];
    
    foreach ($requiredFields as $field) {
        if (!isset($data[$field]) || empty(trim($data[$field]))) {
            $errors[] = "$field is required";
        }
    }
    
    return $errors;
}

/**
 * Validate an uploaded image file ($_FILES['file']) and move it into
 * UPLOAD_DIR under a fresh UUID filename. Shared by all endpoints that
 * accept image uploads (was previously duplicated per-endpoint).
 *
 * Returns ['url' => ..., 'filename' => ...] on success, or
 * ['error' => ..., 'status' => ...] on failure.
 */
function handleImageUpload($file) {
    if (!$file || $file['error'] !== UPLOAD_ERR_OK) {
        return ['error' => 'File upload failed', 'status' => 400];
    }

    if ($file['size'] > MAX_UPLOAD_SIZE) {
        return ['error' => 'File too large. Maximum size is 5MB', 'status' => 400];
    }

    $allowedTypes = ['image/jpeg', 'image/jpg', 'image/png', 'image/webp'];
    $finfo = finfo_open(FILEINFO_MIME_TYPE);
    $mimeType = finfo_file($finfo, $file['tmp_name']);
    finfo_close($finfo);

    if (!in_array($mimeType, $allowedTypes)) {
        return ['error' => 'Invalid file type. Only JPG, PNG, and WebP allowed', 'status' => 400];
    }

    $extension = strtolower(pathinfo($file['name'], PATHINFO_EXTENSION));
    $filename = generateUuid() . '.' . $extension;
    $filepath = UPLOAD_DIR . $filename;

    if (!move_uploaded_file($file['tmp_name'], $filepath)) {
        return ['error' => 'Failed to save file', 'status' => 500];
    }

    return ['url' => '/api/uploads/' . $filename, 'filename' => $filename];
}