<?php
// 保存头像到本地（避免重复），不进行过期清理
header('Content-Type: application/json; charset=utf-8');

function respond($ok, $message = '', $path = '') {
    echo json_encode(['success' => $ok, 'message' => $message, 'path' => $path], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

$raw = file_get_contents('php://input');
$data = json_decode($raw, true);
$url = $data['url'] ?? '';
if (!$url || !filter_var($url, FILTER_VALIDATE_URL)) {
    respond(false, 'URL无效');
}

$scheme = parse_url($url, PHP_URL_SCHEME);
if (!in_array(strtolower($scheme), ['http','https'])) {
    respond(false, '仅支持http/https图片地址');
}

$avatarsRoot = __DIR__ . '/../avatars';
if (!is_dir($avatarsRoot)) { @mkdir($avatarsRoot, 0777, true); }
$today = (new DateTime('now'))->format('Y-m-d');
$targetDir = $avatarsRoot . '/' . $today;
if (!is_dir($targetDir)) { @mkdir($targetDir, 0777, true); }

// 推断扩展名
$pathExt = strtolower(pathinfo(parse_url($url, PHP_URL_PATH) ?? '', PATHINFO_EXTENSION));
$allowed = ['jpg','jpeg','png','gif','webp'];
if (!$pathExt || !in_array($pathExt, $allowed)) { $pathExt = 'jpg'; }

// 使用URL的basename作为文件名，若没有则用hash
$basename = basename(parse_url($url, PHP_URL_PATH) ?: '');
if (!$basename || $basename === '/' || $basename === '\\') {
    $basename = md5($url) . '.' . $pathExt;
}
if (strpos($basename, '.') === false) { $basename .= '.' . $pathExt; }
$safeName = preg_replace('/[^\w\.-]+/u', '_', $basename);
$targetPath = $targetDir . '/' . $safeName;

// 如果已存在，跳过下载
if (file_exists($targetPath)) {
    respond(true, '文件已存在，跳过下载', str_replace($_SERVER['DOCUMENT_ROOT'], '', $targetPath));
}

// 下载保存
try {
    $read = @fopen($url, 'rb');
    if (!$read) { respond(false, '无法读取远程图片'); }
    $write = @fopen($targetPath, 'wb');
    if (!$write) { respond(false, '无法写入文件'); }
    stream_copy_to_stream($read, $write);
    fclose($read);
    fclose($write);
} catch (Throwable $e) {
    respond(false, '保存失败: ' . $e->getMessage());
}

respond(true, '保存成功', str_replace($_SERVER['DOCUMENT_ROOT'], '', $targetPath));