Prevent Quit

The prevent-quit example intercepts quit and asks for confirmation first.

Preview

Code

pkgs/artisanal/example/tui/examples/prevent-quit/main.dart

/// Prevent-quit example using ProgramOptions.filter.
library;

import 'package:artisanal/bubbles.dart'
    as tui
    hide
        CodeBlockCommentDelimiters,
        CodeLanguageProfile,
        Column,
        CommonKeyBindings,
        EditBuffer,
        EditHistoryCoalescePredicate,
        EditHistoryController,
        EditHistoryMarkerBuilder,
        EditHistoryStateEquals,
        EditorCoreConfig,
        EditorState,
        GraphemePredicate,
        GraphemeReader,
        Help,
        KeyBinding,
        KeyMap,
        PasteMsg,
        Row,
        Spinner,
        SpinnerModel,
        SpinnerTickMsg,
        Spinners,
        Text,
        TextCommandResult,
        TextCursorCommandResult,
        TextDecorationLayerKey,
        TextDecorationRange,
        TextDiagnosticRange,
        TextDiagnosticSeverity,
        TextDocument,
        TextDocumentChange,
        TextDocumentEditResult,
        TextEditResult,
        TextExtmark,
        TextExtmarkOptions,
        TextExtmarkPositionRange,
        TextExtmarksController,
        TextHighlightRange,
        TextHitResult,
        TextLineCommandResult,
        TextLineDecoration,
        TextLineStateCommandExtensions,
        TextLineStateSnapshot,
        TextOffsetStateCommandExtensions,
        TextOffsetStateDocumentEditingExtensions,
        TextOffsetStateSnapshot,
        TextPasteChunk,
        TextPasteChunkStep,
        TextPasteController,
        TextPasteMode,
        TextPastePlan,
        TextPasteReference,
        TextPasteReferenceStore,
        TextPasteSession,
        TextPatternDiagnosticRule,
        TextPosition,
        TextPositionDiagnosticRange,
        TextSelection,
        TextSyntaxBuildResult,
        TextSyntaxChangeWindow,
        TextSyntaxDecorationPatch,
        TextSyntaxLineWindow,
        TextSyntaxProvider,
        TextSyntaxSession,
        TextSyntaxSnapshot,
        TextView,
        TextViewLine,
        TextViewport,
        TextVisualCursorPosition,
        UndoCommandDecoder,
        UndoCommandJournalEntry,
        UndoManager,
        UndoableCommand;
import 'package:artisanal/bubbles.dart'
    hide
        CodeBlockCommentDelimiters,
        CodeLanguageProfile,
        Column,
        CommonKeyBindings,
        EditBuffer,
        EditHistoryCoalescePredicate,
        EditHistoryController,
        EditHistoryMarkerBuilder,
        EditHistoryStateEquals,
        EditorCoreConfig,
        EditorState,
        GraphemePredicate,
        GraphemeReader,
        Help,
        KeyBinding,
        KeyMap,
        PasteMsg,
        Row,
        Spinner,
        SpinnerModel,
        SpinnerTickMsg,
        Spinners,
        Text,
        TextCommandResult,
        TextCursorCommandResult,
        TextDecorationLayerKey,
        TextDecorationRange,
        TextDiagnosticRange,
        TextDiagnosticSeverity,
        TextDocument,
        TextDocumentChange,
        TextDocumentEditResult,
        TextEditResult,
        TextExtmark,
        TextExtmarkOptions,
        TextExtmarkPositionRange,
        TextExtmarksController,
        TextHighlightRange,
        TextHitResult,
        TextLineCommandResult,
        TextLineDecoration,
        TextLineStateCommandExtensions,
        TextLineStateSnapshot,
        TextOffsetStateCommandExtensions,
        TextOffsetStateDocumentEditingExtensions,
        TextOffsetStateSnapshot,
        TextPasteChunk,
        TextPasteChunkStep,
        TextPasteController,
        TextPasteMode,
        TextPastePlan,
        TextPasteReference,
        TextPasteReferenceStore,
        TextPasteSession,
        TextPatternDiagnosticRule,
        TextPosition,
        TextPositionDiagnosticRange,
        TextSelection,
        TextSyntaxBuildResult,
        TextSyntaxChangeWindow,
        TextSyntaxDecorationPatch,
        TextSyntaxLineWindow,
        TextSyntaxProvider,
        TextSyntaxSession,
        TextSyntaxSnapshot,
        TextView,
        TextViewLine,
        TextViewport,
        TextVisualCursorPosition,
        UndoCommandDecoder,
        UndoCommandJournalEntry,
        UndoManager,
        UndoableCommand;

import 'package:artisanal/style.dart';
import 'package:artisanal/tui.dart' as tui;

class PreventQuitKeys {
  PreventQuitKeys()
    : save = tui.KeyBinding.withHelp(['ctrl+s'], 'ctrl+s', 'save'),
      quit = tui.KeyBinding.withHelp(['esc', 'ctrl+c'], 'esc', 'quit');

  final tui.KeyBinding save;
  final tui.KeyBinding quit;
}

class PreventQuitModel implements tui.Model {
  PreventQuitModel({
    tui.TextAreaModel? textarea,
    PreventQuitKeys? keys,
    this.saveText = '',
    this.hasChanges = false,
    this.quitting = false,
  }) : textarea =
           textarea ?? tui.TextAreaModel(placeholder: 'Only the best words')
             ..focus(),
       keys = keys ?? PreventQuitKeys();

  final tui.TextAreaModel textarea;
  final PreventQuitKeys keys;
  final String saveText;
  final bool hasChanges;
  final bool quitting;

  PreventQuitModel copyWith({
    tui.TextAreaModel? textarea,
    PreventQuitKeys? keys,
    String? saveText,
    bool? hasChanges,
    bool? quitting,
  }) {
    return PreventQuitModel(
      textarea: textarea ?? this.textarea,
      keys: keys ?? this.keys,
      saveText: saveText ?? this.saveText,
      hasChanges: hasChanges ?? this.hasChanges,
      quitting: quitting ?? this.quitting,
    );
  }

  @override
  tui.Cmd? init() => textarea.focus();

  @override
  (tui.Model, tui.Cmd?) update(tui.Msg msg) {
    if (quitting) return _updatePromptView(msg);
    return _updateTextView(msg);
  }

  (tui.Model, tui.Cmd?) _updateTextView(tui.Msg msg) {
    var saveText = this.saveText;
    var hasChanges = this.hasChanges;
    var quitting = this.quitting;
    final cmds = <tui.Cmd>[];

    switch (msg) {
      case tui.KeyMsg(key: final key):
        saveText = '';
        if (key.matchesSingle(keys.save)) {
          saveText = 'Changes saved!';
          hasChanges = false;
        } else if (key.matchesSingle(keys.quit)) {
          quitting = true;
          return (
            copyWith(
              saveText: saveText,
              hasChanges: hasChanges,
              quitting: quitting,
            ),
            tui.Cmd.quit(),
          );
        } else if (key.type == tui.KeyType.runes) {
          saveText = '';
          hasChanges = true;
        }

        // Ensure textarea is focused after any keypress.
        if (!textarea.focused) {
          final focusCmd = textarea.focus();
          if (focusCmd != null) cmds.add(focusCmd);
        }
    }

    final (newTextarea, cmd) = textarea.update(msg);
    if (cmd != null) cmds.add(cmd);

    return (
      copyWith(
        saveText: saveText,
        hasChanges: hasChanges,
        quitting: quitting,
        textarea: newTextarea,
      ),
      cmds.isNotEmpty ? tui.Cmd.batch(cmds) : null,
    );
  }

  (tui.Model, tui.Cmd?) _updatePromptView(tui.Msg msg) {
    if (msg is tui.KeyMsg) {
      // Treat any key besides 'y' or quit binding as "no"
      final isYes =
          msg.key.type == tui.KeyType.runes &&
          msg.key.runes.isNotEmpty &&
          msg.key.runes.first == 0x79; // y
      if (msg.key.matchesSingle(keys.quit) || isYes) {
        return (
          copyWith(saveText: saveText, hasChanges: false, quitting: true),
          tui.Cmd.quit(),
        );
      }
      // Cancel quit
      return (
        copyWith(saveText: saveText, hasChanges: hasChanges, quitting: false),
        null,
      );
    }
    return (this, null);
  }

  @override
  String view() {
    if (quitting) {
      if (hasChanges) {
        final text = 'You have unsaved changes. Quit without saving? ';
        final choice = Style()
            .paddingLeft(1)
            .foreground(const AnsiColor(241))
            .render('[yn]');
        final box = Style()
            .padding(1)
            .border(Border.rounded)
            .borderForeground(const AnsiColor(170))
            .render('$text$choice');
        return box;
      }
      return 'Very important, thank you\n';
    }

    final help = tui.HelpModel().shortHelpView([keys.save, keys.quit]);
    final saveTextStyled = Style()
        .foreground(const AnsiColor(170))
        .render(saveText);

    return '\nType some important things.\n\n'
        '${textarea.view()}\n\n '
        '$saveTextStyled\n $help\n\n';
  }
}

tui.Msg? preventQuitFilter(tui.Model model, tui.Msg msg) {
  if (msg is! tui.QuitMsg) return msg;
  if (model is! PreventQuitModel) return msg;
  if (model.hasChanges) return null; // Block quit when unsaved changes
  return msg;
}

Future<void> main() async {
  await tui.runProgram(
    PreventQuitModel(),
    options: const tui.ProgramOptions(
      altScreen: false,
      hideCursor: false,
      filter: preventQuitFilter,
    ),
  );
}

Run it

dart run pkgs/artisanal/example/tui/examples/prevent-quit/main.dart