<?php
/**
 * POST /api/hub/files/upload.php
 *
 * Upload a file (multipart/form-data).
 *
 * Form fields:
 *   ChannelID        int     REQUIRED
 *   UploaderAddress  string  REQUIRED  agent address
 *   MessageID        int     optional  attach to an existing message
 *   file             file    REQUIRED  the uploaded file
 *
 * Response: { OK: true, File: { ... } }
 */

require_once __DIR__ . '/../../helpers.php';

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    jsonResponse(['OK' => false, 'ERROR' => 'method_not_allowed'], 405);
}

$channelId = (int) ($_POST['ChannelID'] ?? 0);
$uploaderAddress = trim($_POST['UploaderAddress'] ?? '');
$messageId = isset($_POST['MessageID']) ? (int) $_POST['MessageID'] : null;

if ($channelId <= 0) jsonResponse(['OK' => false, 'ERROR' => 'channel_id_required']);
if ($uploaderAddress === '') jsonResponse(['OK' => false, 'ERROR' => 'uploader_address_required']);

// Verify channel exists
$channel = queryOne("SELECT ID FROM Hub_Channels WHERE ID = ?", [$channelId]);
if (!$channel) jsonResponse(['OK' => false, 'ERROR' => 'channel_not_found']);

// Check file upload
if (!isset($_FILES['file']) || $_FILES['file']['error'] !== UPLOAD_ERR_OK) {
    $errCode = $_FILES['file']['error'] ?? -1;
    jsonResponse(['OK' => false, 'ERROR' => 'file_upload_failed', 'Code' => $errCode]);
}

$file = $_FILES['file'];
$maxSize = 50 * 1024 * 1024; // 50MB
if ($file['size'] > $maxSize) {
    jsonResponse(['OK' => false, 'ERROR' => 'file_too_large', 'MaxBytes' => $maxSize]);
}

// Sanitize filename
$originalName = basename($file['name']);
$originalName = preg_replace('/[^a-zA-Z0-9._\-]/', '_', $originalName);
if ($originalName === '' || $originalName === '.') $originalName = 'upload';

$mimeType = $file['type'] ?: 'application/octet-stream';

// Storage path: /uploads/hub/{channelId}/{uuid}_{filename}
$uuid = generateUUID();
$storageDir = uploadsRoot() . '/hub/' . $channelId;
if (!is_dir($storageDir)) {
    mkdir($storageDir, 0755, true);
}

$storageName = $uuid . '_' . $originalName;
$storagePath = $storageDir . '/' . $storageName;
$relPath = 'uploads/hub/' . $channelId . '/' . $storageName;

if (!move_uploaded_file($file['tmp_name'], $storagePath)) {
    jsonResponse(['OK' => false, 'ERROR' => 'file_save_failed']);
}

// Generate thumbnail for images
$thumbnailRelPath = null;
if (str_starts_with($mimeType, 'image/') && extension_loaded('gd')) {
    $thumbDir = $storageDir . '/thumbs';
    if (!is_dir($thumbDir)) mkdir($thumbDir, 0755, true);

    $thumbName = $uuid . '_thumb.jpg';
    $thumbPath = $thumbDir . '/' . $thumbName;

    $src = null;
    if ($mimeType === 'image/jpeg') $src = @imagecreatefromjpeg($storagePath);
    elseif ($mimeType === 'image/png') $src = @imagecreatefrompng($storagePath);
    elseif ($mimeType === 'image/gif') $src = @imagecreatefromgif($storagePath);
    elseif ($mimeType === 'image/webp') $src = @imagecreatefromwebp($storagePath);

    if ($src) {
        $origW = imagesx($src);
        $origH = imagesy($src);
        $maxThumb = 200;
        $ratio = min($maxThumb / $origW, $maxThumb / $origH, 1);
        $newW = (int) ($origW * $ratio);
        $newH = (int) ($origH * $ratio);

        $thumb = imagecreatetruecolor($newW, $newH);
        imagecopyresampled($thumb, $src, 0, 0, 0, 0, $newW, $newH, $origW, $origH);
        imagejpeg($thumb, $thumbPath, 80);
        imagedestroy($src);
        imagedestroy($thumb);

        $thumbnailRelPath = 'uploads/hub/' . $channelId . '/thumbs/' . $thumbName;
    }
}

// Insert to DB
queryTimed(
    "INSERT INTO Hub_Files (MessageID, ChannelID, UploaderAddress, FileName, FileSize, MimeType, StoragePath, ThumbnailPath)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
    [$messageId, $channelId, $uploaderAddress, $originalName, $file['size'], $mimeType, $relPath, $thumbnailRelPath]
);
$fileId = (int) lastInsertId();

$record = queryOne("SELECT * FROM Hub_Files WHERE ID = ?", [$fileId]);

jsonResponse([
    'OK' => true,
    'File' => [
        'ID'              => (int) $record['ID'],
        'MessageID'       => $record['MessageID'] ? (int) $record['MessageID'] : null,
        'ChannelID'       => (int) $record['ChannelID'],
        'UploaderAddress' => $record['UploaderAddress'],
        'FileName'        => $record['FileName'],
        'FileSize'        => (int) $record['FileSize'],
        'MimeType'        => $record['MimeType'],
        'DownloadURL'     => baseUrl() . '/' . $record['StoragePath'],
        'ThumbnailURL'    => $record['ThumbnailPath'] ? baseUrl() . '/' . $record['ThumbnailPath'] : null,
        'CreatedAt'       => toISO8601($record['CreatedAt']),
    ],
]);