<?php
// Simple success/error JSON response
function json_response($status, $message, $data = null) {
    header('Content-Type: application/json');
    echo json_encode([
        'status' => $status,
        'message' => $message,
        'data' => $data
    ]);
    exit;
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    json_response('error', 'Invalid request method.');
}

if (!isset($_FILES['document']) || $_FILES['document']['error'] == UPLOAD_ERR_NO_FILE) {
    json_response('error', 'No file was uploaded.');
}

$file = $_FILES['document'];

// Check for upload errors
if ($file['error'] !== UPLOAD_ERR_OK) {
    $upload_errors = [
        UPLOAD_ERR_INI_SIZE   => 'The uploaded file exceeds the upload_max_filesize directive in php.ini.',
        UPLOAD_ERR_FORM_SIZE  => 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.',
        UPLOAD_ERR_PARTIAL    => 'The uploaded file was only partially uploaded.',
        UPLOAD_ERR_NO_FILE    => 'No file was uploaded.',
        UPLOAD_ERR_NO_TMP_DIR => 'Missing a temporary folder.',
        UPLOAD_ERR_CANT_WRITE => 'Failed to write file to disk.',
        UPLOAD_ERR_EXTENSION  => 'A PHP extension stopped the file upload.',
    ];
    $error_message = $upload_errors[$file['error']] ?? 'Unknown upload error.';
    json_response('error', $error_message);
}

$upload_dir = __DIR__ . '/uploads/';
if (!is_dir($upload_dir)) {
    if (!mkdir($upload_dir, 0775, true)) {
        json_response('error', 'Failed to create upload directory.');
    }
}

$file_name = basename($file['name']);
$target_path = $upload_dir . $file_name;

// Move the file to the uploads directory
if (move_uploaded_file($file['tmp_name'], $target_path)) {
    json_response('success', 'File uploaded successfully.', ['filePath' => 'uploads/' . $file_name]);
} else {
    json_response('error', 'Failed to move uploaded file.');
}
?>