293 lines
9.3 KiB
Dart
293 lines
9.3 KiB
Dart
import 'dart:math';
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import '../model/song_model.dart';
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class RecommendationHelper {
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/// 基于 Java MusicService 逻辑的智能推荐
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///
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/// [allSongs]: 全量歌曲库 (SongModel)
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/// [userMusicList]: 用户成绩列表 (dynamic)
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/// - 情况A: List<Map>，每个 Map 包含 musicId, level, achievement, dx_rating
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/// - 情况B: List<Map>，每个 Map 包含 userMusicDetailList (嵌套结构)
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/// [userRating]: 用户当前总 Rating (DX Rating)，用于确定推荐难度区间
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/// [b35MinRating]: 用户当前 B35 中最低的那首曲子的 Rating (用于判断推分是否有意义)
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/// [count]: 推荐数量
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static List<SongModel> getSmartRecommendations({
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required List<SongModel> allSongs,
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required List<dynamic> userMusicList,
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required int userRating,
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required int b35MinRating,
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int count = 6,
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}) {
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if (allSongs.isEmpty) return [];
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final random = Random();
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// 1. 解析用户成绩，构建映射: Key = "musicId_level", Value = { achievement, rating }
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// 使用 HashMap 提高查找速度
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final Map<String, Map<String, dynamic>> playedMap = {};
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for (var group in userMusicList) {
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if (group is! Map) continue;
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List<dynamic> details = [];
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// 兼容两种数据结构：
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if (group.containsKey('userMusicDetailList')) {
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details = group['userMusicDetailList'] as List? ?? [];
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} else if (group.containsKey('achievement') || group.containsKey('dx_rating')) {
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// 如果当前 group 本身就是成绩对象
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details = [group];
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}
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if (details.isEmpty) continue;
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for (var detail in details) {
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if (detail is! Map) continue;
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// 提取关键字段
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final int musicId = detail['musicId'] ?? detail['id'] ?? 0;
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if(musicId>16000) continue;
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final int level = detail['level'] ?? detail['levelIndex'] ?? 3; // 默认 Master
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final int achievement = detail['achievement'] ?? 0;
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// 确保 rating 是 double
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final dynamic rawRating = detail['dx_rating'] ?? detail['rating'] ?? 0;
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final double rating = rawRating is num ? rawRating.toDouble() : 0.0;
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if (musicId == 0) continue;
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String key = "${musicId}_${level}";
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// 只保留该难度下的最高成绩
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if (!playedMap.containsKey(key) || achievement > (playedMap[key]!['achievement'] as int)) {
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playedMap[key] = {
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'musicId': musicId,
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'level': level,
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'achievement': achievement,
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'rating': rating,
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};
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}
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}
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}
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// 2. 计算推荐难度区间 (基于 Java logic)
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double minRecommendedLevel = 0.0;
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if (userRating >= 15500) {
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minRecommendedLevel = 13.6;
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} else if (userRating >= 15000) {
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minRecommendedLevel = 13.0;
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} else if (userRating >= 14500) {
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minRecommendedLevel = 12.5;
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} else if (userRating >= 14000) {
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minRecommendedLevel = 12.0;
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} else if (userRating >= 13000) {
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minRecommendedLevel = 11.5;
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} else if (userRating >= 12000) {
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minRecommendedLevel = 11.0;
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} else if (userRating >= 11000) {
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minRecommendedLevel = 10.5;
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} else {
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minRecommendedLevel = 9.0; // 新手保护线
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}
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List<SongModel> candidatesForImprovement = []; // 用于推分
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List<SongModel> candidatesNew = []; // 新曲/未玩
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// 用于快速判断是否已加入结果集，避免 O(N^2) 的 contains 检查
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final Set<int> addedSongIds = {};
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for (var song in allSongs) {
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// 过滤无效 ID
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if (song.id < 100) continue;
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// 获取 Master (Level 3) 的定数，如果没有则获取 Expert (Level 2)
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double? masterLevel = _getSongLevel(song, 3);
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double? expertLevel = _getSongLevel(song, 2);
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double? targetLevel;
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int targetLevelIndex = 3; // 默认优先推荐 Master
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if (masterLevel != null) {
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targetLevel = masterLevel;
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} else if (expertLevel != null) {
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targetLevel = expertLevel;
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targetLevelIndex = 2;
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} else {
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continue; // 没有可用难度数据
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}
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// --- 检查是否已游玩 ---
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bool isPlayed = false;
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Map<String, dynamic>? bestChart;
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// 尝试直接匹配 (SD 或 基础ID)
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String keyDirect = "${song.id}_$targetLevelIndex";
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if (playedMap.containsKey(keyDirect)) {
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isPlayed = true;
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bestChart = playedMap[keyDirect];
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}
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// 尝试匹配 DX 偏移 (DX 歌曲 ID 通常 +10000)
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else {
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int dxId = song.id + 10000;
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String keyDx = "${dxId}_$targetLevelIndex";
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if (playedMap.containsKey(keyDx)) {
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isPlayed = true;
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bestChart = playedMap[keyDx];
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}
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}
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if (isPlayed && bestChart != null) {
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// --- 策略 A: 推分逻辑 (Improvement) ---
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int currentAch = bestChart['achievement'] as int;
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// 如果已经 AP+ (100.5%)，跳过
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if (currentAch >= 1005000) continue;
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// 计算下一个档位的目标达成率
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double nextTargetAch = 0;
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const List<double> targets = [97.0, 98.0, 99.0, 99.5, 100.0, 100.5];
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double currentPercent = currentAch / 10000.0;
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for (double t in targets) {
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if (currentPercent < t) {
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nextTargetAch = t;
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break;
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}
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}
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if (nextTargetAch == 0) continue;
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// 计算目标 Rating
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int targetRating = _calculateRating(targetLevel!, nextTargetAch);
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// 核心判断：如果推分后的 Rating 大于当前 B35 最低分，则值得推荐
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if (targetRating > b35MinRating) {
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candidatesForImprovement.add(song);
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}
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} else {
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// --- 策略 B: 新曲逻辑 (New) ---
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// 判断定数是否在用户能力范围内
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if (targetLevel != null && targetLevel >= minRecommendedLevel && targetLevel <= 15.0) {
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candidatesNew.add(song);
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}
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}
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}
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// 3. 混合推荐结果
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List<SongModel> result = [];
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// 60% 来自“提升空间大”的曲子
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candidatesForImprovement.shuffle(random);
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int improveCount = (count * 0.6).round();
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for (int i = 0; i < improveCount && i < candidatesForImprovement.length; i++) {
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final song = candidatesForImprovement[i];
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result.add(song);
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addedSongIds.add(song.id);
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}
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// 40% 来自“新曲/潜力曲”
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candidatesNew.shuffle(random);
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int remaining = count - result.length;
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for (int i = 0; i < remaining && i < candidatesNew.length; i++) {
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final song = candidatesNew[i];
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// 避免重复添加（虽然逻辑上 New 和 Improve 不重叠，但防万一）
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if (!addedSongIds.contains(song.id)) {
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result.add(song);
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addedSongIds.add(song.id);
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}
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}
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// 如果不够，用纯随机补齐
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if (result.length < count) {
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// 复制一份并打乱，避免修改原数组
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List<SongModel> fallback = List.from(allSongs);
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fallback.shuffle(random);
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for (var s in fallback) {
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if (result.length >= count) break;
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// 使用 Set 进行 O(1) 查找，避免 List.contains 的 O(N) 查找
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if (!addedSongIds.contains(s.id)) {
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result.add(s);
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addedSongIds.add(s.id);
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}
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}
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}
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return result.take(count).toList();
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}
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/// 辅助：获取歌曲指定难度的定数 (Level Value)
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static double? _getSongLevel(SongModel song, int levelIndex) {
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// levelIndex: 0=Basic, 1=Advanced, 2=Expert, 3=Master, 4=Re:Master
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// 1. 尝试从 SD (Standard) 获取
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if (song.sd != null && song.sd is Map) {
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final sdMap = song.sd as Map;
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// 键可能是字符串 "3" 或整数 3，这里做兼容
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var data = sdMap["$levelIndex"] ?? sdMap[levelIndex];
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if (data is Map && data.containsKey("level_value")) {
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final val = data["level_value"];
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if (val is num) return val.toDouble();
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}
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}
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// 2. 尝试从 DX 获取
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if (song.dx != null && song.dx is Map) {
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final dxMap = song.dx as Map;
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var data = dxMap["$levelIndex"] ?? dxMap[levelIndex];
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if (data is Map && data.containsKey("level_value")) {
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final val = data["level_value"];
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if (val is num) return val.toDouble();
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}
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}
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return null;
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}
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/// 辅助：根据定数和达成率计算 Rating (完全复刻 Java getRatingChart)
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static int _calculateRating(double diff, double achievementPercent) {
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double sys = 22.4;
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double ach = achievementPercent; // 例如 99.5
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if (ach >= 100.5000) {
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return (diff * 22.512).floor();
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}
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if (ach == 100.4999) {
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sys = 22.2;
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} else if (ach >= 100.0000) {
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sys = 21.6;
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} else if (ach == 99.9999) {
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sys = 21.4;
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} else if (ach >= 99.5000) {
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sys = 21.1;
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} else if (ach >= 99.0000) {
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sys = 20.8;
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} else if (ach >= 98.0000) {
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sys = 20.3;
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} else if (ach >= 97.0000) {
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sys = 20.0;
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} else if (ach >= 94.0000) {
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sys = 16.8;
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} else if (ach >= 90.0000) {
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sys = 15.2;
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} else if (ach >= 80.0000) {
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sys = 13.6;
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} else if (ach >= 75.0000) {
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sys = 12.0;
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} else if (ach >= 70.0000) {
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sys = 11.2;
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} else if (ach >= 60.0000) {
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sys = 9.6;
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} else if (ach >= 50.0000) {
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sys = 8.0;
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} else {
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sys = 0.0;
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}
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if (sys == 0.0) return 0;
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// Java: (int) (diff * sys * achievement / 100)
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return (diff * sys * ach / 100).floor();
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}
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} |