<?php
/**
 * Authenticated media-upload endpoint (images, documents, video, audio), also used by TinyMCE for pasted images.
 *
 * Every file is checked by MediaTypes::inspect (extension allow-list, content sniffing, code scanning) before it receives a
 * server-generated filename. Trusting only the browser-supplied extension would be admirably optimistic.
 */

// Load credentials, role assignments, and shared application settings.
require_once __DIR__ . '/bootstrap.php';

use NeoCMS\Activity;
use NeoCMS\Authentication;
use NeoCMS\FileStore;
use NeoCMS\Logger;
use NeoCMS\MediaTypes;
use NeoCMS\SecurityHeaders;

SecurityHeaders::json(isset($config['security']['cookieSecure']) ? (bool) $config['security']['cookieSecure'] : null);

// Authentication is required before any upload details are processed.
$authentication = new Authentication(...\NeoCMS\UserStore::authArgs($config));
if (!$authentication->isLoggedIn()) {
    http_response_code(401);
    echo json_encode(['error' => 'Unauthorised']);
    exit;
}

// Editors may upload; unauthorised roles receive a clear forbidden response.
if (!$authentication->can('upload')) {
    http_response_code(403);
    echo json_encode(['error' => 'Your role cannot upload files']);
    exit;
}

// Uploads alter server state and therefore accept POST only.
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    header('Allow: POST');
    echo json_encode(['error' => 'Invalid request method']);
    exit;
}

// Accept the token as form data or a conventional request header.
$csrfToken = $_POST['csrf_token'] ?? $_SERVER['HTTP_X_CSRF_TOKEN'] ?? null;
if (!$authentication->isValidCsrfToken($csrfToken)) {
    http_response_code(403);
    echo json_encode(['error' => 'Invalid CSRF token']);
    exit;
}

// Apply configured byte, dimension, pixel-count, file-count, and total-storage limits.
$uploadConfig = is_array($config['uploads'] ?? null) ? $config['uploads'] : [];
$max_file_size = max(1024, (int) ($uploadConfig['maxFileBytes'] ?? 10 * 1024 * 1024));
$maxWidth = max(1, (int) ($uploadConfig['maxWidth'] ?? 8192));
$maxHeight = max(1, (int) ($uploadConfig['maxHeight'] ?? 8192));
$maxPixels = max(1, (int) ($uploadConfig['maxPixels'] ?? 24 * 1024 * 1024));
$maxFiles = max(1, (int) ($uploadConfig['maxFiles'] ?? 2000));
$maxTotalBytes = max($max_file_size, (int) ($uploadConfig['maxTotalBytes'] ?? 500 * 1024 * 1024));
if ((int) ($_SERVER['CONTENT_LENGTH'] ?? 0) > $max_file_size + 1024 * 1024) {
    http_response_code(413);
    echo json_encode(['error' => 'This file is larger than the ' . round($max_file_size / 1048576, 1) . ' MB limit.']);
    exit;
}

// Continue only when PHP reports a complete upload.
if (isset($_FILES['file']) && $_FILES['file']['error'] === UPLOAD_ERR_OK) {
    $file = $_FILES['file'];

    // Enforce the application limit even if php.ini permits larger files.
    if ($file['size'] > $max_file_size) {
        http_response_code(400);
        echo json_encode(['error' => 'This file is larger than the ' . round($max_file_size / 1048576, 1) . ' MB limit.']);
        exit;
    }

    // A pasted image may arrive without an extension; name it from its detected type so it can be checked like any other file.
    $originalName = (string) $file['name'];
    if (pathinfo($originalName, PATHINFO_EXTENSION) === '') {
        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        $detected = (string) finfo_file($finfo, $file['tmp_name']);
        finfo_close($finfo);
        $originalName .= '.' . (['image/jpeg' => 'jpg', 'image/png' => 'png', 'image/gif' => 'gif', 'image/webp' => 'webp'][$detected] ?? '');
    }

    // Extension allow-list, content sniffing, code scanning and per-format checks (see MediaTypes::inspect).
    try {
        $inspection = MediaTypes::inspect($file['tmp_name'], $originalName, [
            'maxBytes' => $max_file_size, 'maxWidth' => $maxWidth, 'maxHeight' => $maxHeight, 'maxPixels' => $maxPixels,
        ]);
    } catch (\RuntimeException $exception) {
        http_response_code(400);
        echo json_encode(['error' => $exception->getMessage()]);
        exit;
    }

    // Generated names keep the original filename out of the URL namespace and allow only one extension.
    $filename = MediaTypes::storedName($originalName, $inspection['ext']);

    // Create the public upload directory on a fresh installation.
    $uploadRoot = __DIR__ . '/../uploads';
    if (!is_dir($uploadRoot) && !mkdir($uploadRoot, 0755, true)) {
        http_response_code(500);
        echo json_encode(['error' => 'Failed to create upload directory.']);
        exit;
    }

    $upload_dir = realpath($uploadRoot);
    if ($upload_dir === false) {
        http_response_code(500);
        echo json_encode(['error' => 'Upload directory is invalid.']);
        exit;
    }
    $upload_dir .= DIRECTORY_SEPARATOR;
    @chmod($upload_dir, 0755);

    // Build the final path from the canonical upload directory and generated safe filename.
    $target_file = $upload_dir . $filename;

    // Serialise quota checks and moves so concurrent uploads cannot race past the storage ceiling.
    $store = new FileStore((string) ($config['dataDirectory'] ?? (__DIR__ . '/data')));
    $lockPath = $store->directory('locks') . 'uploads.lock';
    $uploadLock = fopen($lockPath, 'c+');
    if ($uploadLock === false || !flock($uploadLock, LOCK_EX)) {
        if (is_resource($uploadLock)) {
            fclose($uploadLock);
        }
        http_response_code(503);
        echo json_encode(['error' => 'Upload service is temporarily unavailable.']);
        exit;
    }
    @chmod($lockPath, 0600);

    $existingFiles = array_values(array_filter(glob($upload_dir . '*') ?: [], 'is_file'));
    $existingBytes = array_sum(array_map(static fn(string $path): int => (int) filesize($path), $existingFiles));
    if (count($existingFiles) >= $maxFiles || $existingBytes + (int) $file['size'] > $maxTotalBytes) {
        flock($uploadLock, LOCK_UN);
        fclose($uploadLock);
        http_response_code(507);
        echo json_encode(['error' => 'Upload storage quota has been reached.']);
        exit;
    }

    // move_uploaded_file() additionally confirms that PHP received the source as an upload.
    if (move_uploaded_file($file['tmp_name'], $target_file)) {
        // Public images need read access but no executable or world-writable permissions.
        chmod($target_file, 0644);

        // Seed media metadata from the original basename; editors can improve the alt text later.
        $location = $config['basePath'] . '/uploads/' . $filename;
        $metadata = $store->read('media');
        $originalBase = pathinfo((string) $file['name'], PATHINFO_FILENAME);
        $altText = substr(preg_replace('/[\x00-\x1F\x7F]/u', '', $originalBase) ?? '', 0, 200);
        $metadata[$filename] = ['alt' => $altText, 'original' => substr(preg_replace('/[\x00-\x1F\x7F]/u', '', basename($originalName)) ?? '', 0, 200), 'by' => $authentication->getLoggedInUser()];
        try {
            $store->write('media', $metadata);
        } catch (\Throwable $exception) {
            @unlink($target_file);
            flock($uploadLock, LOCK_UN);
            fclose($uploadLock);
            http_response_code(500);
            echo json_encode(['error' => 'Unable to record uploaded media.']);
            exit;
        }
        flock($uploadLock, LOCK_UN);
        fclose($uploadLock);
        // The file is saved by now, so a failure to write the audit entry must not fail the upload.
        try {
            (new Activity($store, new Logger($config['audit'] ?? true, $config['security'] ?? [])))
                ->record($authentication->getLoggedInUser(), 'Uploaded ' . (['imagery' => 'image', 'documents' => 'document', 'video' => 'video', 'audio' => 'audio'][$inspection['category']]), $filename . ' (' . max(1, (int) round(((int) $file['size']) / 1024)) . ' KB)');
        } catch (\Throwable $exception) {
            // Deliberately ignored.
        }
        echo json_encode(['location' => $location, 'name' => $filename, 'category' => $inspection['category']]);
    } else {
        flock($uploadLock, LOCK_UN);
        fclose($uploadLock);
        // A failed move is a server error because validation has already succeeded.
        http_response_code(500);
        echo json_encode(['error' => 'Failed to move uploaded file.']);
    }
} else {
    // Translate PHP's numeric upload failures into messages an editor can act upon.
    $error_message = 'No file uploaded.';
    if (isset($_FILES['file']['error'])) {
        switch ($_FILES['file']['error']) {
            case UPLOAD_ERR_INI_SIZE:
            case UPLOAD_ERR_FORM_SIZE:
                $error_message = 'File size exceeds the maximum limit.';
                break;
            case UPLOAD_ERR_PARTIAL:
                $error_message = 'The uploaded file was only partially uploaded.';
                break;
            case UPLOAD_ERR_NO_FILE:
                $error_message = 'No file was uploaded.';
                break;
            case UPLOAD_ERR_NO_TMP_DIR:
                $error_message = 'Missing a temporary folder.';
                break;
            case UPLOAD_ERR_CANT_WRITE:
                $error_message = 'Failed to write file to disk.';
                break;
            case UPLOAD_ERR_EXTENSION:
                $error_message = 'A PHP extension stopped the file upload.';
                break;
            default:
                $error_message = 'Unknown upload error.';
                break;
        }
    }
    http_response_code(400);
    echo json_encode(['error' => $error_message]);
}