echo-loop · Evelynzzzz · Aug 3, 2026
diff --git a/assets/icon/unlock.svg b/assets/icon/unlock.svg
diff --git a/lib/features/subtitle_editor/edit_text_sheet.dart b/lib/features/subtitle_editor/edit_text_sheet.dart
@@ -0,0 +1,162 @@
+import 'package:flutter/material.dart';
+
+import '../../l10n/app_localizations.dart';
+import '../../theme/app_theme.dart';
+
+/// 显示编辑句子文本的底部面板。
+///
+/// 返回修改后的文本（已 trim），取消时返回 `null`。
+Future<String?> showEditTextSheet({
+  required BuildContext context,
+  required int sentenceIndex,
+  required String initialText,
+}) {
+  return showModalBottomSheet<String>(
+    context: context,
+    isScrollControlled: true,
+    useSafeArea: true,
+    shape: const RoundedRectangleBorder(
+      borderRadius: BorderRadius.vertical(top: Radius.circular(16)),
+    ),
+    builder: (_) => _EditTextSheet(
+      sentenceIndex: sentenceIndex,
+      initialText: initialText,
+    ),
+  );
+}
+
+class _EditTextSheet extends StatefulWidget {
+  final int sentenceIndex;
+  final String initialText;
+
+  const _EditTextSheet({
+    required this.sentenceIndex,
+    required this.initialText,
+  });
+
+  @override
+  State<_EditTextSheet> createState() => _EditTextSheetState();
+}
+
+class _EditTextSheetState extends State<_EditTextSheet> {
+  late final TextEditingController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TextEditingController(text: widget.initialText);
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  void _submit() {
+    final text = _controller.text.trim();
+    if (text.isEmpty) return;
+    Navigator.pop(context, text);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context)!;
+    final theme = Theme.of(context);
+    final colorScheme = theme.colorScheme;
+
+    return Padding(
+      padding: EdgeInsets.only(
+        bottom: MediaQuery.of(context).viewInsets.bottom,
+      ),
+      child: SafeArea(
+        child: Padding(
+          padding: const EdgeInsets.fromLTRB(
+            AppSpacing.l,
+            AppSpacing.s,
+            AppSpacing.l,
+            AppSpacing.l,
+          ),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              // 拖拽指示条
+              Center(
+                child: Container(
+                  width: 32,
+                  height: 4,
+                  margin: const EdgeInsets.only(bottom: AppSpacing.m),
+                  decoration: BoxDecoration(
+                    color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4),
+                    borderRadius: BorderRadius.circular(2),
+                  ),
+                ),
+              ),
+
+              // 标题
+              Text(
+                l10n.editSentenceTitle,
+                style: theme.textTheme.titleMedium?.copyWith(
+                  fontWeight: FontWeight.w600,
+                ),
+              ),
+              const SizedBox(height: AppSpacing.m),
+
+              // 输入框
+              TextField(
+                controller: _controller,
+                autofocus: true,
+                style: theme.textTheme.bodyMedium?.copyWith(
+                  color: colorScheme.onSurface,
+                  height: 1.25,
+                ),
+                decoration: InputDecoration(
+                  labelText: l10n.editSentenceLabel,
+                  contentPadding: const EdgeInsets.symmetric(
+                    horizontal: 16,
+                    vertical: 12,
+                  ),
+                  labelStyle: theme.textTheme.bodySmall?.copyWith(
+                    color: colorScheme.onSurfaceVariant.withValues(alpha: 0.72),
+                    fontWeight: FontWeight.w500,
+                    height: 1.2,
+                  ),
+                  floatingLabelStyle: theme.textTheme.bodySmall?.copyWith(
+                    color: colorScheme.primary.withValues(alpha: 0.78),
+                    fontWeight: FontWeight.w500,
+                    height: 1.2,
+                  ),
+                ),
+                onSubmitted: (_) => _submit(),
+                onChanged: (_) => setState(() {}),
+              ),
+
+              const SizedBox(height: AppSpacing.m),
+
+              // 按钮行
+              Row(
+                children: [
+                  Expanded(
+                    child: TextButton(
+                      onPressed: () => Navigator.pop(context),
+                      child: Text(l10n.cancel),
+                    ),
+                  ),
+                  const SizedBox(width: AppSpacing.s),
+                  Expanded(
+                    child: FilledButton(
+                      onPressed:
+                          _controller.text.trim().isEmpty ? null : _submit,
+                      child: Text(l10n.save),
+                    ),
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
diff --git a/lib/features/subtitle_editor/subtitle_editor_controller.dart b/lib/features/subtitle_editor/subtitle_editor_controller.dart
@@ -308,6 +308,12 @@ class SubtitleEditorController extends StateNotifier<SubtitleEditorState> {
     return _sentenceWords(index);
   }
 
+  /// 当前编辑状态快照（供对话框等外部组件读取只读状态）。
+  ///
+  /// 注意：`state` 是 StateNotifier 的 protected 成员，不能在 controller 之外的
+  /// 实例中直接读取，这里暴露一个公开只读入口。
+  SubtitleEditorState get snapshot => state;
+
   /// 波形要绘制 / 可拖动的全部单词边界：选中句 + 前后相邻句的所有词。
   ///
   /// 句子的起止边界即首词起点 / 末词终点，统一为单词边界（见 [adjustWord]），不再
@@ -697,6 +703,132 @@ class SubtitleEditorController extends StateNotifier<SubtitleEditorState> {
     );
   }
 
+  /// 替换第 [index] 句的全部文本为 [newText]，保持原起止时间不变。
+  ///
+  /// 新文本按字符数比例重建词级时间戳，首尾词贴合句界。句子数量不变，
+  /// 不会打乱索引对应的学习进度和收藏。
+  void editSentenceText(int index, String newText) {
+    if (index < 0 || index >= state.sentences.length) return;
+    final trimmed = newText.trim();
+    if (trimmed.isEmpty) return;
+    final sentence = state.sentences[index];
+
+    // 文本没变时不操作。
+    if (trimmed == sentence.text) return;
+
+    final newTokens = _splitTokens(trimmed);
+    if (newTokens.isEmpty) return;
+
+    // 更新句子文本，起止时间不变。
+    final updatedSentence = sentence.copyWith(text: trimmed);
+
+    // 用字符比例重建词级时间戳。
+    final newSentenceWords = _proportionalTokens(newTokens, updatedSentence);
+    newSentenceWords[0] =
+        newSentenceWords.first.copyWith(startTime: sentence.startTime);
+    newSentenceWords[newSentenceWords.length - 1] =
+        newSentenceWords.last.copyWith(endTime: sentence.endTime);
+
+    // 替换全篇词列表中本句对应的区间。
+    final range = _sentenceTokenRange(index);
+    final nextSentences = [...state.sentences];
+    nextSentences[index] = updatedSentence;
+
+    List<WordTimestamp> nextWords;
+    if (range != null) {
+      nextWords = [
+        ...state.words.sublist(0, range.offset),
+        ...newSentenceWords,
+        ...state.words.sublist(range.offset + range.count),
+      ];
+    } else {
+      nextWords = _buildWords(nextSentences, state.words);
+    }
+
+    final wasPlaying = state.isPlaying;
+    if (wasPlaying) _cancelPlaybackSession();
+    state = state.copyWith(
+      sentences: nextSentences,
+      words: nextWords,
+      focusedWordIndex: null,
+      isDirty: _sentencesChanged(nextSentences) || _wordsDirty,
+      playingSentenceIndex: wasPlaying ? null : state.playingSentenceIndex,
+      isPlaying: wasPlaying ? false : state.isPlaying,
+      playbackMode: wasPlaying
+          ? SubtitleEditorPlaybackMode.idle
+          : state.playbackMode,
+    );
+  }
+
+  /// 调整第 [index] 句的起止时间戳。
+  ///
+  /// [startTime] / [endTime] 为可选：仅传需调整的一端，未传的保持不变。
+  /// 调整后按字符比例重建本句词级时间戳；句子数量不变，不打乱索引对应关系。
+  void updateSentenceTimestamps(
+    int index, {
+    Duration? startTime,
+    Duration? endTime,
+  }) {
+    if (index < 0 || index >= state.sentences.length) return;
+    final sentence = state.sentences[index];
+
+    // 未提供任何调整则不操作。
+    if (startTime == null && endTime == null) return;
+
+    // 钳制到合法范围。
+    final lower = _prevSentenceEnd(index);
+    final upper = _nextSentenceStart(index);
+    final newStart = _clampDuration(startTime ?? sentence.startTime, lower, upper);
+    final newEnd = _clampDuration(endTime ?? sentence.endTime, newStart + kMinWordDuration, upper);
+
+    // 时间没变时不操作。
+    if (newStart == sentence.startTime && newEnd == sentence.endTime) return;
+
+    final updatedSentence = sentence.copyWith(startTime: newStart, endTime: newEnd);
+
+    // 按字符比例重建词级时间戳。
+    final tokens = _splitTokens(sentence.text);
+    final newSentenceWords = tokens.isEmpty
+        ? const <WordTimestamp>[]
+        : _proportionalTokens(tokens, updatedSentence);
+    if (newSentenceWords.isNotEmpty) {
+      newSentenceWords[0] =
+          newSentenceWords.first.copyWith(startTime: newStart);
+      newSentenceWords[newSentenceWords.length - 1] =
+          newSentenceWords.last.copyWith(endTime: newEnd);
+    }
+
+    final nextSentences = [...state.sentences];
+    nextSentences[index] = updatedSentence;
+
+    // 替换全篇词列表中本句对应的区间。
+    final range = _sentenceTokenRange(index);
+    List<WordTimestamp> nextWords;
+    if (range != null && tokens.isNotEmpty) {
+      nextWords = [
+        ...state.words.sublist(0, range.offset),
+        ...newSentenceWords,
+        ...state.words.sublist(range.offset + range.count),
+      ];
+    } else {
+      nextWords = _buildWords(nextSentences, state.words);
+    }
+
+    final wasPlaying = state.isPlaying;
+    if (wasPlaying) _cancelPlaybackSession();
+    state = state.copyWith(
+      sentences: nextSentences,
+      words: nextWords,
+      focusedWordIndex: null,
+      isDirty: _sentencesChanged(nextSentences) || _wordsDirty,
+      playingSentenceIndex: wasPlaying ? null : state.playingSentenceIndex,
+      isPlaying: wasPlaying ? false : state.isPlaying,
+      playbackMode: wasPlaying
+          ? SubtitleEditorPlaybackMode.idle
+          : state.playbackMode,
+    );
+  }
+
   /// 把选中句从第 [localWordIndex] 个词处分成两句（剪刀分句时调用）。
   ///
   /// 该词成为新句（后半）的首词；前半保留原起点、终点贴前一词终点，后半起点贴该词
@@ -780,6 +912,40 @@ class SubtitleEditorController extends StateNotifier<SubtitleEditorState> {
     }
   }
 
+  /// 播放指定时间区间 [start] 到 [end] 的音频片段。
+  ///
+  /// 供时间戳编辑弹窗调用：点击起始/结束时间时播放对应端的音频。
+  /// 播放期间不影响选中句和词聚焦态；播放完成后状态恢复 idle。
+  Future<void> playRange(Duration start, Duration end) async {
+    if (start >= end) return;
+    await _stopActivePlayback(invalidateSession: true);
+    final sessionId = _audioEngine.newSession();
+    _startPlayheadTicker(
+      sessionId: sessionId,
+      start: start,
+      end: end,
+    );
+    state = state.copyWith(
+      playingSentenceIndex: null,
+      isPlaying: true,
+      playbackMode: SubtitleEditorPlaybackMode.word,
+      playbackPosition: start,
+    );
+    try {
+      await _audioEngine.setSpeed(state.playbackSpeed);
+      await _audioEngine.playRangeOnce(start, end, sessionId);
+    } finally {
+      if (mounted && _audioEngine.isActiveSession(sessionId)) {
+        state = state.copyWith(
+          isPlaying: false,
+          playbackMode: SubtitleEditorPlaybackMode.idle,
+          playbackPosition: end,
+        );
+        await _stopActivePlayback(invalidateSession: false);
+      }
+    }
+  }
+
   Future<void> playSentence(int index) async {
     if (index < 0 || index >= state.sentences.length) return;
     await _stopActivePlayback(invalidateSession: true);