import 'dart:async';

import 'dart:math';

import 'package:flutter/material.dart';

import 'package:flutter/services.dart';

import 'package:linked_scroll_controller/linked_scroll_controller.dart';

import '../code_theme/code_theme.dart';

import '../gutter/gutter.dart';

import '../line_numbers/line_number_style.dart';

import '../sizes.dart';

import '../wip/autocomplete/popup.dart';

import 'actions/comment_uncomment.dart';

import 'actions/indent.dart';

import 'actions/outdent.dart';

import 'code_controller.dart';

final _shortcuts = <ShortcutActivator, Intent>{

// Copy

LogicalKeySet(

LogicalKeyboardKey.control,

LogicalKeyboardKey.keyC,

): CopySelectionTextIntent.copy,

const SingleActivator(

LogicalKeyboardKey.keyC,

meta: true,

): CopySelectionTextIntent.copy,

LogicalKeySet(

LogicalKeyboardKey.control,

LogicalKeyboardKey.insert,

): CopySelectionTextIntent.copy,

// Cut

LogicalKeySet(

LogicalKeyboardKey.control,

LogicalKeyboardKey.keyX,

): const CopySelectionTextIntent.cut(SelectionChangedCause.keyboard),

const SingleActivator(

LogicalKeyboardKey.keyX,

meta: true,

): const CopySelectionTextIntent.cut(SelectionChangedCause.keyboard),

LogicalKeySet(

LogicalKeyboardKey.shift,

LogicalKeyboardKey.delete,

): const CopySelectionTextIntent.cut(SelectionChangedCause.keyboard),

// Undo

LogicalKeySet(

LogicalKeyboardKey.control,

LogicalKeyboardKey.keyZ,

): const UndoTextIntent(SelectionChangedCause.keyboard),

const SingleActivator(

LogicalKeyboardKey.keyZ,

meta: true,

): const UndoTextIntent(SelectionChangedCause.keyboard),

// Redo

LogicalKeySet(

LogicalKeyboardKey.shift,

LogicalKeyboardKey.control,

LogicalKeyboardKey.keyZ,

): const RedoTextIntent(SelectionChangedCause.keyboard),

LogicalKeySet(

LogicalKeyboardKey.shift,

LogicalKeyboardKey.meta,

LogicalKeyboardKey.keyZ,

): const RedoTextIntent(SelectionChangedCause.keyboard),

// Indent

LogicalKeySet(

LogicalKeyboardKey.tab,

): const IndentIntent(),

// Outdent

LogicalKeySet(

LogicalKeyboardKey.shift,

LogicalKeyboardKey.tab,

): const OutdentIntent(),

// Comment Uncomment

LogicalKeySet(

LogicalKeyboardKey.control,

LogicalKeyboardKey.slash,

): const CommentUncommentIntent(),

const SingleActivator(

LogicalKeyboardKey.slash,

meta: true,

): const CommentUncommentIntent(),

};

class CodeField extends StatefulWidget {

/// {@macro flutter.widgets.textField.minLines}

final int? minLines;

/// {@macro flutter.widgets.textField.maxLInes}

final int? maxLines;

/// {@macro flutter.widgets.textField.expands}

final bool expands;

/// Whether overflowing lines should wrap around

final bool wrap;

/// A CodeController instance to apply

final CodeController controller;

/// A LineNumberStyle instance to tweak the line number column styling

final LineNumberStyle lineNumberStyle;

/// {@macro flutter.widgets.textField.cursorColor}

final Color? cursorColor;

/// {@macro flutter.widgets.textField.textStyle}

final TextStyle? textStyle;

/// A way to replace specific line numbers by a custom TextSpan

final TextSpan Function(int, TextStyle?)? lineNumberBuilder;

/// {@macro flutter.widgets.textField.enabled}

final bool? enabled;

/// {@macro flutter.widgets.editableText.onChanged}

final void Function(String)? onChanged;

/// {@macro flutter.widgets.editableText.readOnly}

final bool readOnly;

final Color? background;

final EdgeInsets padding;

final Decoration? decoration;

final TextSelectionThemeData? textSelectionTheme;

final FocusNode? focusNode;

final bool lineNumbers;

const CodeField({

super.key,

required this.controller,

this.minLines,

this.maxLines,

this.expands = false,

this.wrap = false,

this.background,

this.decoration,

this.textStyle,

this.padding = EdgeInsets.zero,

this.lineNumberStyle = const LineNumberStyle(),

this.enabled,

this.readOnly = false,

this.cursorColor,

this.textSelectionTheme,

this.lineNumberBuilder,

this.focusNode,

this.onChanged,

this.lineNumbers = true,

});

@override

State<CodeField> createState() => _CodeFieldState();

}

class _CodeFieldState extends State<CodeField> {

// Add a controller

LinkedScrollControllerGroup? _controllers;

ScrollController? _numberScroll;

ScrollController? _codeScroll;

ScrollController? _horizontalCodeScroll;

final _codeFieldKey = GlobalKey();

Offset _normalPopupOffset = Offset.zero;

Offset _flippedPopupOffset = Offset.zero;

double painterWidth = 0;

double painterHeight = 0;

StreamSubscription<bool>? _keyboardVisibilitySubscription;

FocusNode? _focusNode;

String? lines;

String longestLine = '';

late Size windowSize;

late TextStyle textStyle;

@override

void initState() {

super.initState();

_controllers = LinkedScrollControllerGroup();

_numberScroll = _controllers?.addAndGet();

_codeScroll = _controllers?.addAndGet();

widget.controller.addListener(_onTextChanged);

widget.controller.addListener(_updatePopupOffset);

_horizontalCodeScroll = ScrollController();

_focusNode = widget.focusNode ?? FocusNode();

_focusNode!.attach(context, onKeyEvent: _onKeyEvent);

WidgetsBinding.instance.addPostFrameCallback((_) {

final double width = _codeFieldKey.currentContext!.size!.width;

final double height = _codeFieldKey.currentContext!.size!.height;

windowSize = Size(width, height);

});

_onTextChanged();

}

KeyEventResult _onKeyEvent(FocusNode node, KeyEvent event) {

return widget.controller.onKey(event);

}

@override

void dispose() {

widget.controller.removeListener(_onTextChanged);

widget.controller.removeListener(_updatePopupOffset);

_numberScroll?.dispose();

_codeScroll?.dispose();

_horizontalCodeScroll?.dispose();

unawaited(_keyboardVisibilitySubscription?.cancel());

super.dispose();

}

void rebuild() {

setState(() {

WidgetsBinding.instance.addPostFrameCallback((_) {

// For some reason _codeFieldKey.currentContext is null in tests

// so check first.

final context = _codeFieldKey.currentContext;

if (context != null) {

final double width = context.size!.width;

final double height = context.size!.height;

windowSize = Size(width, height);

}

});

});

}

void _onTextChanged() {

// Rebuild line number

final str = widget.controller.text.split('\n');

final buf = <String>[];

for (var k = 0; k < str.length; k++) {

buf.add((k + 1).toString());

}

// Find longest line

longestLine = '';

widget.controller.text.split('\n').forEach((line) {

if (line.length > longestLine.length) longestLine = line;

});

rebuild();

}

// Wrap the codeField in a horizontal scrollView

Widget _wrapInScrollView(

Widget codeField,

TextStyle textStyle,

double minWidth,

) {

final intrinsic = IntrinsicWidth(

child: Column(

mainAxisSize: MainAxisSize.min,

crossAxisAlignment: CrossAxisAlignment.stretch,

children: [

ConstrainedBox(

constraints: BoxConstraints(

maxHeight: 0,

minWidth: minWidth,

),

child: Padding(

padding: const EdgeInsets.only(right: 16),

child: Text(longestLine, style: textStyle),

), // Add extra padding

),

// ignore: prefer_if_elements_to_conditional_expressions

widget.expands ? Expanded(child: codeField) : codeField,

],

),

);

return SingleChildScrollView(

padding: EdgeInsets.only(

right: widget.padding.right,

),

scrollDirection: Axis.horizontal,

controller: _horizontalCodeScroll,

child: intrinsic,

);

}

@override

Widget build(BuildContext context) {

// Default color scheme

const rootKey = 'root';

final defaultBg = Colors.grey.shade900;

final defaultText = Colors.grey.shade200;

final themeData = Theme.of(context);

final styles = CodeTheme.of(context)?.styles;

Color? backgroundCol =

widget.background ?? styles?[rootKey]?.backgroundColor ?? defaultBg;

if (widget.decoration != null) {

backgroundCol = null;

}

final defaultTextStyle = TextStyle(

color: styles?[rootKey]?.color ?? defaultText,

fontSize: themeData.textTheme.subtitle1?.fontSize,

);

textStyle = defaultTextStyle.merge(widget.textStyle);

final lineNumberSize = textStyle.fontSize;

final lineNumberColor = widget.lineNumberStyle.textStyle?.color ??

textStyle.color?.withOpacity(.5);

final lineNumberTextStyle =

(widget.lineNumberStyle.textStyle ?? textStyle).copyWith(

color: lineNumberColor,

fontFamily: textStyle.fontFamily,

fontSize: lineNumberSize,

);

final lineNumberStyle = widget.lineNumberStyle.copyWith(

textStyle: lineNumberTextStyle,

);

Widget? numberCol;

if (widget.lineNumbers) {

numberCol = GutterWidget(

codeController: widget.controller,

style: lineNumberStyle,

);

}

final codeField = TextField(

focusNode: _focusNode,

scrollPadding: widget.padding,

style: textStyle,

controller: widget.controller,

minLines: widget.minLines,

maxLines: widget.maxLines,

expands: widget.expands,

scrollController: _codeScroll,

decoration: const InputDecoration(

isCollapsed: true,

contentPadding: EdgeInsets.symmetric(vertical: 16),

disabledBorder: InputBorder.none,

border: InputBorder.none,

focusedBorder: InputBorder.none,

),

cursorColor: widget.cursorColor ?? defaultTextStyle.color,

autocorrect: false,

enableSuggestions: false,

enabled: widget.enabled,

onChanged: widget.onChanged,

readOnly: widget.readOnly,

);

final editingField = Theme(

data: Theme.of(context).copyWith(

textSelectionTheme: widget.textSelectionTheme,

),

child: LayoutBuilder(

builder: (BuildContext context, BoxConstraints constraints) {

// Control horizontal scrolling

return _wrapInScrollView(codeField, textStyle, constraints.maxWidth);

},

),

);

return FocusableActionDetector(

actions: widget.controller.actions,

shortcuts: _shortcuts,

child: Container(

decoration: widget.decoration,

color: backgroundCol,

key: _codeFieldKey,

padding: !widget.lineNumbers ? const EdgeInsets.only(left: 8) : null,

child: Row(

crossAxisAlignment: CrossAxisAlignment.start,

children: [

if (widget.lineNumbers && numberCol != null) numberCol,

Expanded(

child: Stack(

children: [

editingField,

if (widget.controller.popupController.isPopupShown)

Popup(

normalOffset: _normalPopupOffset,

flippedOffset: _flippedPopupOffset,

controller: widget.controller.popupController,

editingWindowSize: windowSize,

style: textStyle,

backgroundColor: backgroundCol,

parentFocusNode: _focusNode!,

),

],

),

),

],

),

),

);

}

void _updatePopupOffset() {

final TextPainter textPainter = _getTextPainter(widget.controller.text);

final caretHeight = _getCaretHeight(textPainter);

final double leftOffset = _getPopupLeftOffset(textPainter);

final double normalTopOffset = _getPopupTopOffset(textPainter, caretHeight);

final double flippedTopOffset = normalTopOffset -

(Sizes.autocompletePopupMaxHeight + caretHeight + Sizes.caretPadding);

setState(() {

_normalPopupOffset = Offset(leftOffset, normalTopOffset);

_flippedPopupOffset = Offset(leftOffset, flippedTopOffset);

});

}

TextPainter _getTextPainter(String text) {

return TextPainter(

textDirection: TextDirection.ltr,

text: TextSpan(text: text, style: textStyle),

)..layout();

}

Offset _getCaretOffset(TextPainter textPainter) {

return textPainter.getOffsetForCaret(

widget.controller.selection.base,

Rect.zero,

);

}

double _getCaretHeight(TextPainter textPainter) {

final double? caretFullHeight = textPainter.getFullHeightForCaret(

widget.controller.selection.base,

Rect.zero,

);

return (widget.controller.selection.base.offset > 0) ? caretFullHeight! : 0;

}

double _getPopupLeftOffset(TextPainter textPainter) {

return max(

_getCaretOffset(textPainter).dx +

widget.padding.left -

_horizontalCodeScroll!.offset,

0,

);

}

double _getPopupTopOffset(TextPainter textPainter, double caretHeight) {

return max(

_getCaretOffset(textPainter).dy +

caretHeight +

16 +

widget.padding.top -

_codeScroll!.offset,

0,

);

}

}