using Unity.UIWidgets.foundation;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.rendering;
using Unity.UIWidgets.ui;
using Unity.UIWidgets.widgets;

namespace Unity.UIWidgets.material
{
    public static class CircleAvatarUtils
    {
        // The default radius if nothing is specified.
        public static float _defaultRadius = 20.0f;

        // The default min if only the max is specified.
        public static float _defaultMinRadius = 0.0f;

        // The default max if only the min is specified.
        public static float _defaultMaxRadius = float.PositiveInfinity;
    }

    public class CircleAvatar : StatelessWidget
    {
      /// The color with which to fill the circle. Changing the background
      /// color will cause the avatar to animate to the new color.
      /// 
      /// If a [backgroundColor] is not specified, the theme's
      /// [ThemeData.primaryColorLight] is used with dark foreground colors, and
      /// [ThemeData.primaryColorDark] with light foreground colors.
      public readonly Color backgroundColor;

      /// The background image of the circle. Changing the background
      /// image will cause the avatar to animate to the new image.
      /// 
      /// Typically used as a fallback image for [foregroundImage].
      /// 
      /// If the [CircleAvatar] is to have the user's initials, use [child] instead.
      public readonly ImageProvider backgroundImage;

      /// The widget below this widget in the tree.
      /// 
      /// Typically a [Text] widget. If the [CircleAvatar] is to have an image, use
      /// [backgroundImage] instead.
      public readonly Widget child;

      /// The default text color for text in the circle.
      /// 
      /// Defaults to the primary text theme color if no [backgroundColor] is
      /// specified.
      /// 
      /// Defaults to [ThemeData.primaryColorLight] for dark background colors, and
      /// [ThemeData.primaryColorDark] for light background colors.
      public readonly Color foregroundColor;

      /// The foreground image of the circle.
      /// 
      /// Typically used as profile image. For fallback use [backgroundImage].
      public readonly ImageProvider foregroundImage;

      /// The maximum size of the avatar, expressed as the radius (half the
      /// diameter).
      /// 
      /// If [maxRadius] is specified, then [radius] must not also be specified.
      /// 
      /// Defaults to [double.infinity].
      /// 
      /// Constraint changes are animated, but size changes due to the environment
      /// itself changing are not. For example, changing the [maxRadius] from 10 to
      /// 20 when the [CircleAvatar] is in an unconstrained environment will cause
      /// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
      /// However, if the [maxRadius] is 40 and the [CircleAvatar] has a parent
      /// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
      /// the size will snap to 40 pixels instantly.
      public readonly float? maxRadius;

      /// The minimum size of the avatar, expressed as the radius (half the
      /// diameter).
      /// 
      /// If [minRadius] is specified, then [radius] must not also be specified.
      /// 
      /// Defaults to zero.
      /// 
      /// Constraint changes are animated, but size changes due to the environment
      /// itself changing are not. For example, changing the [minRadius] from 10 to
      /// 20 when the [CircleAvatar] is in an unconstrained environment will cause
      /// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
      /// However, if the [minRadius] is 40 and the [CircleAvatar] has a parent
      /// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
      /// the size will snap to 40 pixels instantly.
      public readonly float? minRadius;

      /// An optional error callback for errors emitted when loading
      /// [backgroundImage].
      public readonly ImageErrorListener onBackgroundImageError;

      /// An optional error callback for errors emitted when loading
      /// [foregroundImage].
      public readonly ImageErrorListener onForegroundImageError;

      /// The size of the avatar, expressed as the radius (half the diameter).
      /// 
      /// If [radius] is specified, then neither [minRadius] nor [maxRadius] may be
      /// specified. Specifying [radius] is equivalent to specifying a [minRadius]
      /// and [maxRadius], both with the value of [radius].
      /// 
      /// If neither [minRadius] nor [maxRadius] are specified, defaults to 20
      /// logical pixels. This is the appropriate size for use with
      /// [ListTile.leading].
      /// 
      /// Changes to the [radius] are animated (including changing from an explicit
      /// [radius] to a [minRadius]/[maxRadius] pair or vice versa).
      public readonly float? radius;

        /// Creates a circle that represents a user.
        public CircleAvatar(
            Key key = null,
            Widget child = null,
            Color backgroundColor = null,
            Color foregroundColor = null,
            ImageProvider backgroundImage = null,
            ImageProvider foregroundImage = null,
            ImageErrorListener onBackgroundImageError = null,
            ImageErrorListener onForegroundImageError = null,
            float radius = 0.0f,
            float minRadius = 0.0f,
            float maxRadius = 0.0f
        ) : base(key)
        {
            D.assert(radius == null || minRadius == null && maxRadius == null);
            D.assert(backgroundImage != null || onBackgroundImageError == null);
            D.assert(foregroundImage != null || onForegroundImageError == null);
            this.child = child;
            this.backgroundColor = backgroundColor;
            this.backgroundImage = backgroundImage;
            this.foregroundImage = foregroundImage;
            this.onBackgroundImageError = onBackgroundImageError;
            this.onForegroundImageError = onForegroundImageError;
            this.foregroundColor = foregroundColor;
            this.radius = radius;
            this.minRadius = minRadius;
            this.maxRadius = maxRadius;
        }


        private float _minDiameter
        {
            get
            {
                if (radius == null && minRadius == null && maxRadius == null)
                    return CircleAvatarUtils._defaultRadius * 2.0f;
                return 2.0f * (radius ?? minRadius ?? CircleAvatarUtils._defaultMinRadius);
            }
        }

        private float _maxDiameter
        {
            get
            {
                if (radius == null && minRadius == null && maxRadius == null)
                    return CircleAvatarUtils._defaultRadius * 2.0f;
                return 2.0f * (radius ?? maxRadius ?? CircleAvatarUtils._defaultMaxRadius);
            }
        }

        public override Widget build(BuildContext context)
        {
            D.assert(WidgetsD.debugCheckHasMediaQuery(context));
            var theme = Theme.of(context);
            var textStyle = theme.primaryTextTheme.subtitle1.copyWith(color: foregroundColor);
            var effectiveBackgroundColor = backgroundColor;
            if (effectiveBackgroundColor == null)
                switch (ThemeData.estimateBrightnessForColor(textStyle.color))
                {
                    case Brightness.dark:
                        effectiveBackgroundColor = theme.primaryColorLight;
                        break;
                    case Brightness.light:
                        effectiveBackgroundColor = theme.primaryColorDark;
                        break;
                }
            else if (foregroundColor == null)
                switch (ThemeData.estimateBrightnessForColor(backgroundColor))
                {
                    case Brightness.dark:
                        textStyle = textStyle.copyWith(color: theme.primaryColorLight);
                        break;
                    case Brightness.light:
                        textStyle = textStyle.copyWith(color: theme.primaryColorDark);
                        break;
                }

            var minDiameter = _minDiameter;
            var maxDiameter = _maxDiameter;
            return new AnimatedContainer(
                constraints: new BoxConstraints(
                    minHeight: minDiameter,
                    minWidth: minDiameter,
                    maxWidth: maxDiameter,
                    maxHeight: maxDiameter
                ),
                duration: material_.kThemeChangeDuration,
                decoration: new BoxDecoration(
                    effectiveBackgroundColor,
                    backgroundImage != null
                        ? new DecorationImage(
                            backgroundImage,
                            onBackgroundImageError,
                            fit: BoxFit.cover
                        )
                        : null,
                    shape: BoxShape.circle
                ),
                foregroundDecoration: foregroundImage != null
                    ? new BoxDecoration(
                        image: new DecorationImage(
                            foregroundImage,
                            onForegroundImageError,
                            fit: BoxFit.cover
                        ),
                        shape: BoxShape.circle
                    )
                    : null,
                child: child == null
                    ? null
                    : new Center(
                        child: new MediaQuery(
                            // Need to ignore the ambient textScaleFactor here so that the
                            // text doesn't escape the avatar when the textScaleFactor is large.
                            data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0f),
                            child: new IconTheme(
                                data: theme.iconTheme.copyWith(textStyle.color),
                                child: new DefaultTextStyle(
                                    style: textStyle,
                                    child: child
                                )
                            )
                        )
                    )
            );
        }
    }
}