// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';

import 'package:flutter/widgets.dart';

import 'colors.dart';
import 'icons.dart';
import 'theme.dart';

// These constants were eyeballed from iOS 14.4 Settings app for base, Notes for
// notched without leading, and Reminders app for notched with leading.
const double _kLeadingSize = 28.0;
const double _kNotchedLeadingSize = 30.0;
const double _kMinHeight = _kLeadingSize + 2 * 8.0;
const double _kMinHeightWithSubtitle = _kLeadingSize + 2 * 10.0;
const double _kNotchedMinHeight = _kNotchedLeadingSize + 2 * 12.0;
const double _kNotchedMinHeightWithoutLeading = _kNotchedLeadingSize + 2 * 10.0;
const EdgeInsetsDirectional _kPadding = EdgeInsetsDirectional.only(start: 20.0, end: 14.0);
const EdgeInsetsDirectional _kPaddingWithSubtitle = EdgeInsetsDirectional.only(start: 20.0, end: 14.0);
const EdgeInsets _kNotchedPadding = EdgeInsets.symmetric(horizontal: 14.0);
const EdgeInsetsDirectional _kNotchedPaddingWithoutLeading = EdgeInsetsDirectional.fromSTEB(28.0, 10.0, 14.0, 10.0);
const double _kLeadingToTitle = 16.0;
const double _kNotchedLeadingToTitle = 12.0;
const double _kNotchedTitleToSubtitle = 3.0;
const double _kAdditionalInfoToTrailing = 6.0;
const double _kNotchedTitleWithSubtitleFontSize = 16.0;
const double _kSubtitleFontSize = 12.0;
const double _kNotchedSubtitleFontSize = 14.0;

enum _CupertinoListTileType { base, notched }

/// An iOS-style list tile.
///
/// The [CupertinoListTile] is a Cupertino equivalent of Material [ListTile].
/// It comes in two forms, an old-fashioned edge-to-edge variant known from iOS
/// Settings app and in a new, "Inset Grouped" form, known from either iOS Notes
/// or Reminders app. The first is constructed using default constructor, and
/// the latter using named constructor [CupertinoListTile.notched].
///
/// The [title], [subtitle], and [additionalInfo] are usually [Text] widgets.
/// They are all limited to one line so it is a responsibility of the caller to
/// take care of text wrapping.
///
/// The size of [leading] is by default constrained to match the iOS size,
/// depending of the type of list tile. This can however be overriden by
/// providing [leadingSize]. The [trailing] widget is not constrained and is
/// therefore a responsibility of the caller to ensure reasonable size of the
/// [trailing] widget.
///
/// The background color of the tile can be set with [backgroundColor] for the
/// state before tile was tapped and with [backgroundColorActivated] for the
/// state after the tile was tapped. By default, both values are set to match
/// the default iOS appearance.
///
/// The [padding] and [leadingToTitle] are by default set to match iOS but can
/// be overwritten if necessary.
///
/// The [onTap] callback provides an option to react to taps anywhere inside the
/// list tile. This can be used to navigate routes and according to iOS
/// behaviour it should not be used for example to toggle the [CupertinoSwitch]
/// in the trailing widget.
///
/// See also:
///
///  * [CupertinoListSection], an iOS-style list that is a typical container for
///    [CupertinoListTile].
///  * [ListTile], a Material Design list tile.
class CupertinoListTile extends StatefulWidget {
  /// Creates an edge-to-edge iOS-style list tile like the tiles in iOS Settings
  /// app.
  ///
  /// The [title] parameter is required. It is used to convey the most important
  /// information of list tile. It is typically a [Text].
  ///
  /// The [subtitle] parameter is used to display additional information. It is
  /// placed below the [title].
  ///
  /// The [additionalInfo] parameter is used to display additional information.
  /// It is placed at the end of the tile, before the [trailing] if supplied.
  ///
  /// The [leading] parameter is typically an [Icon] or an [Image] and it comes
  /// at the start of the tile. If omitted in all list tiles, a `hasLeading` of
  /// enclosing [CupertinoListSection] should be set to `false` to ensure
  /// correct margin of divider between tiles.
  ///
  /// The [trailing] parameter is typically a [CupertinoListTileChevron], an
  /// [Icon], or a [CupertinoButton]. It is placed at the very end of the tile.
  ///
  /// The [onTap] parameter is used to provide an action that is called when the
  /// tile is tapped. It is mainly used for navigating to a new route. It should
  /// not be used to toggle a trailing [CupertinoSwitch] and similar usecases
  /// because when tile is tapped, it switches the background color and remains
  /// changed. This is according to iOS behaviour.
  ///
  /// The [backgroundColor] provides a custom background color for the tile in
  /// a state before tapped. By default, it matches the theme's background color
  /// which is by default a [CupertinoColors.systemBackground].
  ///
  /// The [backgroundColorActivated] provides a custom background color for the
  /// tile after it was tapped. By default, it matches the theme's background
  /// color which is by default a [CupertinoColors.systemGrey4].
  ///
  /// The [padding] parameter sets the padding of the content inside the tile.
  /// It defaults to a value that matches the iOS look, depending on a type of
  /// [CupertinoListTile]. For native look, it should not be provided.
  ///
  /// The [leadingSize] constrains the width and height of the leading widget.
  /// By default, it is set to a value that matches the iOS look, depending on a
  /// type of [CupertinoListTile]. For native look, it should not be provided.
  ///
  /// The [leadingToTitle] specifies the horizontal space between [leading] and
  /// [title] widgets. By default, it is set to a value that matched the iOS
  /// look, depending on a type of [CupertinoListTile]. For native look, it
  /// should not be provided.
  const CupertinoListTile({
    super.key,
    required this.title,
    this.subtitle,
    this.additionalInfo,
    this.leading,
    this.trailing,
    this.onTap,
    this.backgroundColor,
    this.backgroundColorActivated,
    this.padding,
    this.leadingSize = _kLeadingSize,
    this.leadingToTitle = _kLeadingToTitle,
  }) : _type = _CupertinoListTileType.base;

  /// Creates a notched iOS-style list tile like the tiles in iOS Notes app or
  /// Reminders app.
  ///
  /// The [title] parameter is required. It is used to convey the most important
  /// information of list tile. It is typically a [Text].
  ///
  /// The [subtitle] parameter is used to display additional information. It is
  /// placed below the [title].
  ///
  /// The [additionalInfo] parameter is used to display additional information.
  /// It is placed at the end of the tile, before the [trailing] if supplied.
  ///
  /// The [leading] parameter is typically an [Icon] or an [Image] and it comes
  /// at the start of the tile. If omitted in all list tiles, a `hasLeading` of
  /// enclosing [CupertinoListSection] should be set to `false` to ensure
  /// correct margin of divider between tiles. For Notes-like tile appearance,
  /// the [leading] can be left `null`.
  ///
  /// The [trailing] parameter is typically a [CupertinoListTileChevron], an
  /// [Icon], or a [CupertinoButton]. It is placed at the very end of the tile.
  /// For Notes-like tile appearance, the [trailing] can be left `null`.
  ///
  /// The [onTap] parameter is used to provide an action that is called when the
  /// tile is tapped. It is mainly used for navigating to a new route. It should
  /// not be used to toggle a trailing [CupertinoSwitch] and similar usecases
  /// because when tile is tapped, it switches the background color and remains
  /// changed. This is according to iOS behaviour.
  ///
  /// The [backgroundColor] provides a custom background color for the tile in
  /// a state before tapped. By default, it matches the theme's background color
  /// which is by default a [CupertinoColors.systemBackground].
  ///
  /// The [backgroundColorActivated] provides a custom background color for the
  /// tile after it was tapped. By default, it matches the theme's background
  /// color which is by default a [CupertinoColors.systemGrey4].
  ///
  /// The [padding] parameter sets the padding of the content inside the tile.
  /// It defaults to a value that matches the iOS look, depending on a type of
  /// [CupertinoListTile]. For native look, it should not be provided.
  ///
  /// The [leadingSize] constrains the width and height of the leading widget.
  /// By default, it is set to a value that matches the iOS look, depending on a
  /// type of [CupertinoListTile]. For native look, it should not be provided.
  ///
  /// The [leadingToTitle] specifies the horizontal space between [leading] and
  /// [title] widgets. By default, it is set to a value that matched the iOS
  /// look, depending on a type of [CupertinoListTile]. For native look, it
  /// should not be provided.
  const CupertinoListTile.notched({
    super.key,
    required this.title,
    this.subtitle,
    this.additionalInfo,
    this.leading,
    this.trailing,
    this.onTap,
    this.backgroundColor,
    this.backgroundColorActivated,
    this.padding,
    this.leadingSize = _kNotchedLeadingSize,
    this.leadingToTitle = _kNotchedLeadingToTitle,
  }) : _type = _CupertinoListTileType.notched;

  final _CupertinoListTileType _type;

  /// A [title] is used to convey the central information. Usually a [Text].
  final Widget title;

  /// A [subtitle] is used to display additional information. It is located
  /// below [title]. Usually a [Text] widget.
  final Widget? subtitle;

  /// Similar to [subtitle], an [additionalInfo] is used to display additional
  /// information. However, instead of being displayed below [title], it is
  /// displayed on the right, before [trailing]. Usually a [Text] widget.
  final Widget? additionalInfo;

  /// A widget displayed at the start of the [CupertinoListTile]. This is
  /// typically an `Icon` or an `Image`.
  final Widget? leading;

  /// A widget displayed at the end of the [CupertinoListTile]. This is usually
  /// a right chevron icon (e.g. `CupertinoListTileChevron`), or an `Icon`.
  final Widget? trailing;

  /// The [onTap] function is called when a user taps on [CupertinoListTile]. If
  /// left `null`, the [CupertinoListTile] will not react on taps. If this is a
  /// `Future<void> Function()`, then the [CupertinoListTile] remains activated
  /// until the returned future is awaited. This is according to iOS behaviour.
  /// However, if this function is a `void Function()`, then the tile is active
  /// only for the duration of invocation.
  final FutureOr<void> Function()? onTap;

  /// The [backgroundColor] of the tile in normal state. Once the tile is
  /// tapped, the background color switches to [backgroundColorActivated]. It is
  /// set to match the iOS look by default.
  final Color? backgroundColor;

  /// The [backgroundColorActivated] is the background color of the tile after
  /// the tile was tapped. It is set to match the iOS look by default.
  final Color? backgroundColorActivated;

  /// Padding of the content inside [CupertinoListTile].
  final EdgeInsetsGeometry? padding;

  /// The [leadingSize] is used to constrain the width and height of [leading]
  /// widget.
  final double leadingSize;

  /// The horizontal space between [leading] widget and [title].
  final double leadingToTitle;

  @override
  State<CupertinoListTile> createState() => _CupertinoListTileState();
}

class _CupertinoListTileState extends State<CupertinoListTile> {
  bool _tapped = false;

  @override
  Widget build(BuildContext context) {
    final TextStyle titleTextStyle =
        widget._type == _CupertinoListTileType.base || widget.subtitle == null
            ? CupertinoTheme.of(context).textTheme.textStyle
            : CupertinoTheme.of(context).textTheme.textStyle.merge(
                  TextStyle(
                    fontWeight: FontWeight.w600,
                    fontSize: widget.leading == null ? _kNotchedTitleWithSubtitleFontSize : null,
                  ),
                );

    final TextStyle subtitleTextStyle = widget._type == _CupertinoListTileType.base
        ? CupertinoTheme.of(context).textTheme.textStyle.merge(
              TextStyle(
                fontSize: _kSubtitleFontSize,
                color: CupertinoColors.secondaryLabel.resolveFrom(context),
              ),
            )
        : CupertinoTheme.of(context).textTheme.textStyle.merge(
              TextStyle(
                fontSize: _kNotchedSubtitleFontSize,
                color: CupertinoColors.secondaryLabel.resolveFrom(context),
              ),
            );

    final TextStyle? additionalInfoTextStyle = widget.additionalInfo != null
        ? CupertinoTheme.of(context).textTheme.textStyle.merge(
            TextStyle(color: CupertinoColors.secondaryLabel.resolveFrom(context)))
        : null;

    final Widget title = DefaultTextStyle(
      style: titleTextStyle,
      maxLines: 1,
      child: widget.title,
    );

    EdgeInsetsGeometry? padding = widget.padding;
    if (padding == null) {
      switch (widget._type) {
        case _CupertinoListTileType.base:
          padding = widget.subtitle == null ? _kPadding : _kPaddingWithSubtitle;
          break;
        case _CupertinoListTileType.notched:
          padding = widget.leading == null ? _kNotchedPaddingWithoutLeading : _kNotchedPadding;
          break;
      }
    }

    Widget? subtitle;
    if (widget.subtitle != null) {
      subtitle = DefaultTextStyle(
        style: subtitleTextStyle,
        maxLines: 1,
        child: widget.subtitle!,
      );
    }

    Widget? additionalInfo;
    if (widget.additionalInfo != null) {
      additionalInfo = DefaultTextStyle(
        style: additionalInfoTextStyle!,
        maxLines: 1,
        child: widget.additionalInfo!,
      );
    }

    // The color for default state tile is set to either what user provided or
    // null and it will resolve to the correct color provided by context. But if
    // the tile was tapped, it is set to what user provided or if null to the
    // default color that matched the iOS-style.
    Color? backgroundColor = widget.backgroundColor;
    if (_tapped) {
      backgroundColor = widget.backgroundColorActivated ?? CupertinoColors.systemGrey4.resolveFrom(context);
    }

    double minHeight;
    switch (widget._type) {
      case _CupertinoListTileType.base:
        minHeight = subtitle == null ? _kMinHeight : _kMinHeightWithSubtitle;
        break;
      case _CupertinoListTileType.notched:
        minHeight = widget.leading == null ? _kNotchedMinHeightWithoutLeading : _kNotchedMinHeight;
        break;
    }

    final Widget child = Container(
      constraints: BoxConstraints(minWidth: double.infinity, minHeight: minHeight),
      color: backgroundColor,
      child: Padding(
        padding: padding,
        child: Row(
          children: <Widget>[
            if (widget.leading != null) ...<Widget>[
              SizedBox(
                width: widget.leadingSize,
                height: widget.leadingSize,
                child: Center(
                  child: widget.leading,
                ),
              ),
              SizedBox(width: widget.leadingToTitle),
            ] else
              SizedBox(height: widget.leadingSize),
            Column(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                title,
                if (subtitle != null) ...<Widget>[
                  const SizedBox(height: _kNotchedTitleToSubtitle),
                  subtitle,
                ],
              ],
            ),
            const Spacer(),
            if (additionalInfo != null) ...<Widget>[
              additionalInfo,
              if (widget.trailing != null)
                const SizedBox(width: _kAdditionalInfoToTrailing),
            ],
            if (widget.trailing != null) widget.trailing!
          ],
        ),
      ),
    );

    if (widget.onTap == null) {
      return child;
    }

    return GestureDetector(
      onTapDown: (_) => setState(() { _tapped = true; }),
      onTapCancel: () => setState(() { _tapped = false; }),
      onTap: () async {
        await widget.onTap!();
        setState(() { _tapped = false; });
      },
      behavior: HitTestBehavior.opaque,
      child: child,
    );
  }
}

/// A typical iOS trailing widget used to denote that a `CupertinoListTile` is a
/// button with an action.
///
/// The [CupertinoListTileChevron] is meant as a convenience implementation of
/// trailing right chevron.
class CupertinoListTileChevron extends StatelessWidget {
  /// Creates a typical widget used to denote that a `CupertinoListTile` is a
  /// button with action.
  const CupertinoListTileChevron({super.key});

  @override
  Widget build(BuildContext context) {
    return Icon(
      CupertinoIcons.right_chevron,
      size: CupertinoTheme.of(context).textTheme.textStyle.fontSize,
      color: CupertinoColors.systemGrey2.resolveFrom(context),
    );
  }
}
