优化项目结构

lib/services/changelog_service.dart

@@ -0,0 +1,93 @@
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import 'package:package_info_plus/package_info_plus.dart';
+import 'server_config.dart';
+
+/// 更新日志数据模型
+class ChangelogItem {
+  final String version;
+  final String date;
+  final List<String> features;
+
+  ChangelogItem({
+    required this.version,
+    required this.date,
+    required this.features,
+  });
+
+  factory ChangelogItem.fromJson(Map<String, dynamic> json) {
+    return ChangelogItem(
+      version: json['version'] ?? '',
+      date: json['date'] ?? '',
+      features: (json['features'] as List<dynamic>?)
+              ?.map((e) => e.toString())
+              .toList() ??
+          [],
+    );
+  }
+}
+
+/// 版本更新检查服务
+class ChangelogService {
+  static final _apiUrl = '${ServerConfig.apiBase}/changelog';
+
+  /// 获取更新日志列表
+  static Future<List<ChangelogItem>> fetchChangelog() async {
+    try {
+      final resp = await http
+          .get(Uri.parse(_apiUrl))
+          .timeout(const Duration(seconds: 5));
+      if (resp.statusCode == 200) {
+        final data = jsonDecode(resp.body);
+        final items = (data['items'] as List<dynamic>?)
+                ?.map((e) => ChangelogItem.fromJson(e as Map<String, dynamic>))
+                .toList() ??
+            [];
+        return items;
+      }
+    } catch (_) {}
+    return [];
+  }
+
+  /// 获取最新版本号
+  static Future<String?> fetchLatestVersion() async {
+    final items = await fetchChangelog();
+    if (items.isNotEmpty) return items.first.version;
+    return null;
+  }
+
+  /// 比较两版本号，a > b 则返回 1，a < b 返回 -1，相等返回 0
+  /// v0.1.9 → 当成数字 "0.19" = 0.19，0.1.88 → "0.188" = 0.188，所以 0.19 > 0.188
+  /// 实现方式：去掉 v，把第一个点后的数字拼接再转 double 比较
+  static int compareVersion(String a, String b) {
+    double toNum(String v) {
+      final s = v.replaceFirst('v', '');
+      final dot = s.indexOf('.');
+      if (dot == -1) return double.tryParse(s) ?? 0;
+      // "0.1.9" → "0." + "19" = "0.19"；"0.1.88" → "0." + "188" = "0.188"
+      final major = s.substring(0, dot + 1); // "0."
+      final rest = s.substring(dot + 1).replaceAll('.', ''); // "19" 或 "188"
+      return double.tryParse('$major$rest') ?? 0;
+    }
+
+    final aVal = toNum(a);
+    final bVal = toNum(b);
+    debugPrint('[Update] compare: "$a"→$aVal vs "$b"→$bVal');
+    if (aVal > bVal) return 1;
+    if (aVal < bVal) return -1;
+    return 0;
+  }
+
+  /// 检查是否有新版本（远程 > 本地）
+  static Future<bool> hasUpdate() async {
+    final latest = await fetchLatestVersion();
+    if (latest == null) return false;
+    final info = await PackageInfo.fromPlatform();
+    final local = 'v${info.version}';
+    debugPrint('[Update] 远程: $latest, 本地: $local');
+    final result = compareVersion(latest, local) > 0;
+    debugPrint('[Update] 远程 > 本地? $result');
+    return result;
+  }
+}