ente/lib/ui/components/button_widget.dart

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:photos/theme/colors.dart';
import 'package:photos/theme/ente_theme.dart';
import 'package:photos/theme/text_style.dart';
import 'package:photos/ui/common/loading_widget.dart';
import 'package:photos/ui/components/models/button_type.dart';
import 'package:photos/ui/components/models/custom_button_style.dart';
import 'package:photos/utils/debouncer.dart';

enum ExecutionState {
  idle,
  inProgress,
  error,
  successful;
}

enum ButtonSize {
  small,
  large;
}

enum ButtonAction {
  first,
  second,
  third,
  cancel,
  error;
}

typedef FutureVoidCallback = Future<void> Function();

class ButtonWidget extends StatelessWidget {
  final IconData? icon;
  final String? labelText;
  final ButtonType buttonType;
  final FutureVoidCallback? onTap;
  final bool isDisabled;
  final ButtonSize buttonSize;

  ///Button action will only work if isInAlert is true
  final ButtonAction? buttonAction;

  ///setting this flag to true will make the button appear like how it would
  ///on dark theme irrespective of the app's theme.
  final bool shouldStickToDarkTheme;

  ///isInAlert is to dismiss the alert if the action on the button is completed.
  ///This should be set to true if the alert which uses this button needs to
  ///return the Button's action.
  final bool isInAlert;
  const ButtonWidget({
    required this.buttonType,
    required this.buttonSize,
    this.icon,
    this.labelText,
    this.onTap,
    this.shouldStickToDarkTheme = false,
    this.isDisabled = false,
    this.buttonAction,
    this.isInAlert = false,
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    final colorScheme =
        shouldStickToDarkTheme ? darkScheme : getEnteColorScheme(context);
    final inverseColorScheme = shouldStickToDarkTheme
        ? lightScheme
        : getEnteColorScheme(context, inverse: true);
    final textTheme =
        shouldStickToDarkTheme ? darkTextTheme : getEnteTextTheme(context);
    final inverseTextTheme = shouldStickToDarkTheme
        ? lightTextTheme
        : getEnteTextTheme(context, inverse: true);
    final buttonStyle = CustomButtonStyle(
      //Dummy default values since we need to keep these properties non-nullable
      defaultButtonColor: Colors.transparent,
      defaultBorderColor: Colors.transparent,
      defaultIconColor: Colors.transparent,
      defaultLabelStyle: textTheme.body,
    );
    buttonStyle.defaultButtonColor = buttonType.defaultButtonColor(colorScheme);
    buttonStyle.pressedButtonColor = buttonType.pressedButtonColor(colorScheme);
    buttonStyle.disabledButtonColor =
        buttonType.disabledButtonColor(colorScheme, buttonSize);
    buttonStyle.defaultBorderColor =
        buttonType.defaultBorderColor(colorScheme, buttonSize);
    buttonStyle.pressedBorderColor = buttonType.pressedBorderColor(
      colorScheme: colorScheme,
      inverseColorScheme: inverseColorScheme,
      buttonSize: buttonSize,
    );
    buttonStyle.disabledBorderColor =
        buttonType.disabledBorderColor(colorScheme, buttonSize);
    buttonStyle.defaultIconColor = buttonType.defaultIconColor(
      colorScheme: colorScheme,
      inverseColorScheme: inverseColorScheme,
    );
    buttonStyle.pressedIconColor =
        buttonType.pressedIconColor(colorScheme, buttonSize);
    buttonStyle.disabledIconColor =
        buttonType.disabledIconColor(colorScheme, buttonSize);
    buttonStyle.defaultLabelStyle = buttonType.defaultLabelStyle(
      textTheme: textTheme,
      inverseTextTheme: inverseTextTheme,
    );
    buttonStyle.pressedLabelStyle =
        buttonType.pressedLabelStyle(textTheme, colorScheme, buttonSize);
    buttonStyle.disabledLabelStyle =
        buttonType.disabledLabelStyle(textTheme, colorScheme);
    buttonStyle.checkIconColor = buttonType.checkIconColor(colorScheme);

    return ButtonChildWidget(
      buttonStyle: buttonStyle,
      buttonType: buttonType,
      isDisabled: isDisabled,
      buttonSize: buttonSize,
      isInAlert: isInAlert,
      onTap: onTap,
      labelText: labelText,
      icon: icon,
      buttonAction: buttonAction,
    );
  }
}

class ButtonChildWidget extends StatefulWidget {
  final CustomButtonStyle buttonStyle;
  final FutureVoidCallback? onTap;
  final ButtonType buttonType;
  final String? labelText;
  final IconData? icon;
  final bool isDisabled;
  final ButtonSize buttonSize;
  final ButtonAction? buttonAction;
  final bool isInAlert;
  const ButtonChildWidget({
    required this.buttonStyle,
    required this.buttonType,
    required this.isDisabled,
    required this.buttonSize,
    required this.isInAlert,
    this.onTap,
    this.labelText,
    this.icon,
    this.buttonAction,
    super.key,
  });

  @override
  State<ButtonChildWidget> createState() => _ButtonChildWidgetState();
}

class _ButtonChildWidgetState extends State<ButtonChildWidget> {
  late Color buttonColor;
  late Color borderColor;
  late Color iconColor;
  late TextStyle labelStyle;
  late Color checkIconColor;
  late Color loadingIconColor;

  ///This is used to store the width of the button in idle state (small button)
  ///to be used as width for the button when the loading/succes states comes.
  double? widthOfButton;
  final _debouncer = Debouncer(const Duration(milliseconds: 300));
  ExecutionState executionState = ExecutionState.idle;
  @override
  void initState() {
    checkIconColor = widget.buttonStyle.checkIconColor ??
        widget.buttonStyle.defaultIconColor;
    loadingIconColor = widget.buttonStyle.defaultIconColor;
    if (widget.isDisabled) {
      buttonColor = widget.buttonStyle.disabledButtonColor ??
          widget.buttonStyle.defaultButtonColor;
      borderColor = widget.buttonStyle.disabledBorderColor ??
          widget.buttonStyle.defaultBorderColor;
      iconColor = widget.buttonStyle.disabledIconColor ??
          widget.buttonStyle.defaultIconColor;
      labelStyle = widget.buttonStyle.disabledLabelStyle ??
          widget.buttonStyle.defaultLabelStyle;
    } else {
      buttonColor = widget.buttonStyle.defaultButtonColor;
      borderColor = widget.buttonStyle.defaultBorderColor;
      iconColor = widget.buttonStyle.defaultIconColor;
      labelStyle = widget.buttonStyle.defaultLabelStyle;
    }
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: _shouldRegisterGestures ? _onTap : null,
      onTapDown: _shouldRegisterGestures ? _onTapDown : null,
      onTapUp: _shouldRegisterGestures ? _onTapUp : null,
      onTapCancel: _shouldRegisterGestures ? _onTapCancel : null,
      child: AnimatedContainer(
        duration: const Duration(milliseconds: 16),
        width: widget.buttonSize == ButtonSize.large ? double.infinity : null,
        decoration: BoxDecoration(
          borderRadius: const BorderRadius.all(Radius.circular(4)),
          color: buttonColor,
          border: Border.all(color: borderColor),
        ),
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 14, horizontal: 16),
          child: AnimatedSwitcher(
            duration: const Duration(milliseconds: 175),
            switchInCurve: Curves.easeInOutExpo,
            switchOutCurve: Curves.easeInOutExpo,
            child: executionState == ExecutionState.idle
                ? widget.buttonType.hasTrailingIcon
                    ? Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          widget.labelText == null
                              ? const SizedBox.shrink()
                              : Flexible(
                                  child: Padding(
                                    padding: widget.icon == null
                                        ? const EdgeInsets.symmetric(
                                            horizontal: 8,
                                          )
                                        : const EdgeInsets.only(right: 16),
                                    child: Text(
                                      widget.labelText!,
                                      overflow: TextOverflow.ellipsis,
                                      maxLines: 2,
                                      style: labelStyle,
                                    ),
                                  ),
                                ),
                          widget.icon == null
                              ? const SizedBox.shrink()
                              : Icon(
                                  widget.icon,
                                  size: 20,
                                  color: iconColor,
                                ),
                        ],
                      )
                    : Builder(
                        builder: (context) {
                          SchedulerBinding.instance.addPostFrameCallback(
                            (timeStamp) {
                              final box =
                                  context.findRenderObject() as RenderBox;
                              widthOfButton = box.size.width;
                            },
                          );
                          return Row(
                            mainAxisSize: widget.buttonSize == ButtonSize.large
                                ? MainAxisSize.max
                                : MainAxisSize.min,
                            mainAxisAlignment: MainAxisAlignment.center,
                            children: [
                              widget.icon == null
                                  ? const SizedBox.shrink()
                                  : Icon(
                                      widget.icon,
                                      size: 20,
                                      color: iconColor,
                                    ),
                              widget.icon == null || widget.labelText == null
                                  ? const SizedBox.shrink()
                                  : const SizedBox(width: 8),
                              widget.labelText == null
                                  ? const SizedBox.shrink()
                                  : Flexible(
                                      child: Padding(
                                        padding: const EdgeInsets.symmetric(
                                          horizontal: 8,
                                        ),
                                        child: Text(
                                          widget.labelText!,
                                          style: labelStyle,
                                          maxLines: 2,
                                          overflow: TextOverflow.ellipsis,
                                        ),
                                      ),
                                    )
                            ],
                          );
                        },
                      )
                : executionState == ExecutionState.inProgress
                    ? SizedBox(
                        width: widthOfButton,
                        child: Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            EnteLoadingWidget(
                              is20pts: true,
                              color: loadingIconColor,
                            ),
                          ],
                        ),
                      )
                    : executionState == ExecutionState.successful
                        ? SizedBox(
                            width: widthOfButton,
                            child: Icon(
                              Icons.check_outlined,
                              size: 20,
                              color: checkIconColor,
                            ),
                          )
                        : const SizedBox.shrink(), //fallback
          ),
        ),
      ),
    );
  }

  bool get _shouldRegisterGestures =>
      !widget.isDisabled &&
      (widget.onTap != null) &&
      executionState == ExecutionState.idle;

  void _onTap() async {
    _debouncer.run(
      () => Future(() {
        setState(() {
          executionState = ExecutionState.inProgress;
        });
      }),
    );
    await widget.onTap!.call().onError((error, stackTrace) {
      executionState = ExecutionState.error;
      _debouncer.cancelDebounce();
    });
    _debouncer.cancelDebounce();
    // when the time taken by widget.onTap is approximately equal to the debounce
    // time, the callback is getting executed when/after the if condition
    // below is executing/executed which results in execution state stuck at
    // idle state. This Future is for delaying the execution of the if
    // condition so that the calback in the debouncer finishes execution before.
    await Future.delayed(const Duration(milliseconds: 5));
    if (executionState == ExecutionState.inProgress ||
        executionState == ExecutionState.error) {
      if (executionState == ExecutionState.inProgress) {
        setState(() {
          executionState = ExecutionState.successful;
          Future.delayed(Duration(seconds: widget.isInAlert ? 1 : 2), () {
            widget.isInAlert
                ? Navigator.of(context, rootNavigator: true)
                    .pop(widget.buttonAction)
                : null;
            if (mounted) {
              setState(() {
                executionState = ExecutionState.idle;
              });
            }
          });
        });
      }
      if (executionState == ExecutionState.error) {
        setState(() {
          executionState = ExecutionState.idle;
          widget.isInAlert
              ? Future.delayed(
                  const Duration(seconds: 0),
                  () => Navigator.of(context, rootNavigator: true).pop(
                    ButtonAction.error,
                  ),
                )
              : null;
        });
      }
    } else {
      if (widget.isInAlert) {
        Navigator.of(context).pop(widget.buttonAction);
      }
    }
  }

  void _onTapDown(details) {
    setState(() {
      buttonColor = widget.buttonStyle.pressedButtonColor ??
          widget.buttonStyle.defaultButtonColor;
      borderColor = widget.buttonStyle.pressedBorderColor ??
          widget.buttonStyle.defaultBorderColor;
      iconColor = widget.buttonStyle.pressedIconColor ??
          widget.buttonStyle.defaultIconColor;
      labelStyle = widget.buttonStyle.pressedLabelStyle ??
          widget.buttonStyle.defaultLabelStyle;
    });
  }

  void _onTapUp(details) {
    Future.delayed(
      const Duration(milliseconds: 84),
      () => setState(() {
        setAllStylesToDefault();
      }),
    );
  }

  void _onTapCancel() {
    setState(() {
      setAllStylesToDefault();
    });
  }

  void setAllStylesToDefault() {
    buttonColor = widget.buttonStyle.defaultButtonColor;
    borderColor = widget.buttonStyle.defaultBorderColor;
    iconColor = widget.buttonStyle.defaultIconColor;
    labelStyle = widget.buttonStyle.defaultLabelStyle;
  }
}