✨ Translate infra & post translation

lib/providers/translation.dart

@@ -0,0 +1,56 @@
+import 'dart:convert';
+
+import 'package:crypto/crypto.dart';
+import 'package:dio/dio.dart';
+import 'package:surface/logger.dart';
+
+// TODO self host translate api
+const kTranslateApiBaseUrl = 'https://translate.disroot.org';
+
+class SnTranslator {
+  final Dio client = Dio(
+    BaseOptions(
+      baseUrl: kTranslateApiBaseUrl,
+      connectTimeout: Duration(seconds: 3),
+      sendTimeout: Duration(seconds: 3),
+      receiveTimeout: Duration(seconds: 3),
+    ),
+  );
+
+  final Map<String, String> _cache = {};
+
+  Future<String> translate(
+    String text, {
+    required String to,
+    String from = 'auto',
+    bool skipCache = false,
+  }) async {
+    if (text.isEmpty) return text;
+
+    final cacheKey = md5.convert(utf8.encode('$text$from$to')).toString();
+    if (!skipCache && _cache.containsKey(cacheKey)) {
+      return _cache[cacheKey]!;
+    }
+
+    logging.info('[Translator] Translate $text from $from to $to');
+
+    final resp = await client.post(
+      '/translate',
+      data: {
+        'q': text,
+        'source': from,
+        'target': to,
+        'format': 'text',
+      },
+    );
+    if (resp.statusCode == 200) {
+      final out = resp.data['translatedText'];
+      if (out.isNotEmpty) {
+        logging.info('[Translator] Translated $text from $from to $to');
+        _cache[cacheKey] = out;
+        return out;
+      }
+    }
+    throw Exception('translate failed: $resp');
+  }
+}