fix/opt: 重构弹幕逻辑

改用map存储，将同属于100毫秒内的弹幕归入一个元素，无需再排序和二分比较取得，降低时间复杂度与播放时功耗；
分离PlDanmakuController与playerController的功能，避免代码耦合；
精简用于表示状态的变量与相关逻辑，修复播放完毕后因currentSegIndex永久增加而无法再显示弹幕的错误；
为PlDanmakuController添加dispose()。

lib/pages/danmaku/controller.dart

@@ -3,74 +3,57 @@ import 'package:pilipala/models/danmaku/dm.pb.dart';
 import 'package:pilipala/plugin/pl_player/index.dart';
 
 class PlDanmakuController {
-  PlDanmakuController(this.cid, this.playerController);
+  PlDanmakuController(this.cid);
   final int cid;
-  final PlPlayerController playerController;
   late Duration videoDuration;
-  // 按 6min 分段
+  Map<int,List<DanmakuElem>> dmSegMap = {};
-  int segCount = 0;
-  List<DmSegMobileReply> dmSegList = [];
   // 已请求的段落标记
-  List<int> hasrequestSeg = [];
+  List<bool> requestedSeg = [];
-  int currentSegIndex = 1;
-  int currentDmIndex = 0;
 
-  void calcSegment() {
+  bool get initiated => requestedSeg.isNotEmpty;
-    dmSegList.clear();
+
-    // 视频分段数
+  static int SEGMENT_LENGTH = 60 * 6 * 1000;
-    segCount = (videoDuration.inSeconds / (60 * 6)).ceil();
+
-    dmSegList = List<DmSegMobileReply>.generate(
+  void initiate(int progress) {
-        segCount < 1 ? 1 : segCount, (index) => DmSegMobileReply());
+    if (requestedSeg.isEmpty) {
-    // 当前分段
+      int segCount = (videoDuration.inSeconds / (60 * 6)).ceil();
-    try {
+      requestedSeg = List<bool>.generate(segCount, (index) => false);
-      currentSegIndex =
+    }
-          (playerController.position.value.inSeconds / (60 * 6)).ceil();
+    queryDanmaku(
-      currentSegIndex = currentSegIndex < 1 ? 1 : currentSegIndex;
+        calcSegment(progress)
-    } catch (_) {}
+    );
   }
 
-  Future<List<DmSegMobileReply>> queryDanmaku() async {
+  void dispose() {
-    // dmSegList.clear();
+    dmSegMap.clear();
+    requestedSeg.clear();
+  }
+
+  int calcSegment(int progress) {
+    return progress ~/ SEGMENT_LENGTH;
+  }
+
+  void queryDanmaku(int segmentIndex) async {
+    assert(requestedSeg[segmentIndex] == false);
+    requestedSeg[segmentIndex] = true;
     DmSegMobileReply result =
-        await DanmakaHttp.queryDanmaku(cid: cid, segmentIndex: currentSegIndex);
+        await DanmakaHttp.queryDanmaku(cid: cid, segmentIndex: segmentIndex + 1);
     if (result.elems.isNotEmpty) {
-      result.elems.sort((a, b) => (a.progress).compareTo(b.progress));
+      for (var element in result.elems) {
-      // dmSegList.add(result);
+        int pos = element.progress ~/ 100;//每0.1秒存储一次
-      currentSegIndex = currentSegIndex < 1 ? 1 : currentSegIndex;
+        if (dmSegMap[pos] == null) {
-      dmSegList[currentSegIndex - 1] = result;
+          dmSegMap[pos] = [];
+        }
+        dmSegMap[pos]!.add(element);
+      }
     }
-    if (dmSegList.isNotEmpty) {
-      findClosestPositionIndex(playerController.position.value.inMilliseconds);
-    }
-    return dmSegList;
   }
 
-  /// 查询当前最接近的弹幕
+  List<DanmakuElem>? getCurrentDanmaku(int progress) {
-  void findClosestPositionIndex(int position) {
+    int segmentIndex = calcSegment(progress);
-    int segIndex = (position / (6 * 60 * 1000)).ceil() - 1;
+    if (!requestedSeg[segmentIndex]) {
-    if (segIndex < 0) segIndex = 0;
+      queryDanmaku(segmentIndex);
-    List elems = dmSegList[segIndex].elems;
-
-    if (segIndex < dmSegList.length) {
-      int left = 0;
-      int right = elems.length;
-
-      while (left < right) {
-        int mid = (right + left) ~/ 2;
-        var midPosition = elems[mid].progress;
-
-        if (midPosition >= position) {
-          right = mid;
-        } else {
-          left = mid + 1;
-        }
-      }
-
-      currentSegIndex = segIndex;
-      currentDmIndex = right;
-    } else {
-      currentSegIndex = segIndex;
-      currentDmIndex = 0;
     }
+    return dmSegMap[progress ~/ 100];
   }
 }

lib/pages/danmaku/view.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:get/get.dart';
 import 'package:hive/hive.dart';
 import 'package:ns_danmaku/ns_danmaku.dart';
+import 'package:pilipala/models/danmaku/dm.pb.dart';
 import 'package:pilipala/pages/danmaku/index.dart';
 import 'package:pilipala/plugin/pl_player/index.dart';
 import 'package:pilipala/utils/danmaku.dart';
@@ -27,7 +28,7 @@ class _PlDanmakuState extends State<PlDanmaku> {
   late PlPlayerController playerController;
   late PlDanmakuController _plDanmakuController;
   DanmakuController? _controller;
-  bool danmuPlayStatus = true;
+  // bool danmuPlayStatus = true;
   Box setting = GStrorage.setting;
   late bool enableShowDanmaku;
   late List blockTypes;
@@ -35,6 +36,7 @@ class _PlDanmakuState extends State<PlDanmaku> {
   late double opacityVal;
   late double fontSizeVal;
   late double danmakuDurationVal;
+  int latestAddedPosition = -1;
 
   @override
   void initState() {
@@ -42,26 +44,24 @@ class _PlDanmakuState extends State<PlDanmaku> {
     enableShowDanmaku =
         setting.get(SettingBoxKey.enableShowDanmaku, defaultValue: false);
     _plDanmakuController =
-        PlDanmakuController(widget.cid, widget.playerController);
+        PlDanmakuController(widget.cid);
     if (mounted) {
       playerController = widget.playerController;
       _plDanmakuController.videoDuration = playerController.duration.value;
       if (enableShowDanmaku || playerController.isOpenDanmu.value) {
-        _plDanmakuController
+        _plDanmakuController.initiate(
-          ..calcSegment()
+            playerController.position.value.inMilliseconds
-          ..queryDanmaku();
+        );
       }
       playerController
         ..addStatusLister(playerListener)
         ..addPositionListener(videoPositionListen);
     }
     playerController.isOpenDanmu.listen((p0) {
-      if (p0) {
+      if (p0 && !_plDanmakuController.initiated) {
-        if (_plDanmakuController.dmSegList.isEmpty) {
+        _plDanmakuController.initiate(
-          _plDanmakuController
+            playerController.position.value.inMilliseconds
-            ..calcSegment()
+        );
-            ..queryDanmaku();
-        }
       }
     });
     blockTypes = playerController.blockTypes;
@@ -82,68 +82,32 @@ class _PlDanmakuState extends State<PlDanmaku> {
   }
 
   void videoPositionListen(Duration position) {
-    if (!danmuPlayStatus) {
-      _controller!.onResume();
-      danmuPlayStatus = true;
-    }
     if (!playerController.isOpenDanmu.value) {
       return;
     }
-    PlDanmakuController ctr = _plDanmakuController;
     int currentPosition = position.inMilliseconds;
-    blockTypes = playerController.blockTypes;
+    currentPosition -= currentPosition % 100;//取整百的毫秒数
-    // 根据position判断是否有已缓存弹幕。没有则请求对应段
-    int segIndex = (currentPosition / (6 * 60 * 1000)).ceil();
-    segIndex = segIndex < 1 ? 1 : segIndex;
-    // print('🌹🌹： ${segIndex}');
-    // print('🌹🌹： ${ctr.dmSegList.length}');
-    // print('🌹🌹： ${ctr.hasrequestSeg.contains(segIndex - 1)}');
-    if (segIndex - 1 >= ctr.dmSegList.length ||
-        (ctr.dmSegList[segIndex - 1].elems.isEmpty &&
-            !ctr.hasrequestSeg.contains(segIndex - 1))) {
-      ctr.hasrequestSeg.add(segIndex - 1);
-      ctr.currentSegIndex = segIndex;
-      EasyThrottle.throttle('follow', const Duration(seconds: 1), () {
-        ctr.queryDanmaku();
-      });
-    }
-    // 超出分段数返回
-    if (ctr.currentSegIndex >= ctr.dmSegList.length) {
-      return;
-    }
-    if (ctr.dmSegList.isEmpty ||
-        ctr.dmSegList[ctr.currentSegIndex].elems.isEmpty) {
-      return;
-    }
-    // 超出当前分段的弹幕总数返回
-    if (ctr.currentDmIndex >= ctr.dmSegList[ctr.currentSegIndex].elems.length) {
-      ctr.currentDmIndex = 0;
-      ctr.currentSegIndex++;
-      return;
-    }
-    var element = ctr.dmSegList[ctr.currentSegIndex].elems[ctr.currentDmIndex];
-    var delta = currentPosition - element.progress;
 
-    if (delta >= 0 && delta < 200) {
+    if (currentPosition == latestAddedPosition) {
-      // 屏蔽彩色弹幕
+      return;
-      if (blockTypes.contains(6) ? element.color == 16777215 : true) {
+    }
-        _controller!.addItems([
+    latestAddedPosition = currentPosition;
-          DanmakuItem(
+
-            element.content,
+    List<DanmakuElem>? currentDanmakuList =
-            color: DmUtils.decimalToColor(element.color),
+        _plDanmakuController.getCurrentDanmaku(currentPosition);
-            time: element.progress,
+
-            type: DmUtils.getPosition(element.mode),
+    if (currentDanmakuList != null) {
-          )
+      Color? defaultColor = playerController.blockTypes.contains(6) ?
-        ]);
+        DmUtils.decimalToColor(16777215) : null;
-      }
+
-      ctr.currentDmIndex++;
+      _controller!.addItems(
-    } else {
+        currentDanmakuList.map((e) => DanmakuItem(
-      if (!playerController.isOpenDanmu.value) {
+          e.content,
-        _controller!.pause();
+          color: defaultColor ?? DmUtils.decimalToColor(e.color),
-        danmuPlayStatus = false;
+          time: e.progress,
-        return;
+          type: DmUtils.getPosition(e.mode),
-      }
+        )).toList()
-      ctr.findClosestPositionIndex(position.inMilliseconds);
+      );
     }
   }