using System.Collections.Generic;
using System.Text.RegularExpressions;
using ChatComponents;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.material;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.rendering;
using Unity.UIWidgets.widgets;

namespace UIWidgetsSample
{
    internal class TextMessage : StatelessWidget
    {
        /// [types.TextMessage]
        public readonly ChatComponents.TextMessage message;

        /// See [LinkPreview.onPreviewDataFetched]
        public readonly OnPreviewDataFetched
            onPreviewDataFetched;

        /// Show user name for the received message. Useful for a group chat.
        public readonly bool showName;

        /// Enables link (URL) preview
        public readonly bool usePreviewData;

        /// Creates a text message widget from a [types.TextMessage] class
        public TextMessage(
            ChatComponents.TextMessage message,
            bool usePreviewData,
            bool showName,
            Key key = null,
            OnPreviewDataFetched onPreviewDataFetched = null
        ) : base(key)
        {
            this.message = message;
            this.usePreviewData = usePreviewData;
            this.showName = showName;
            this.onPreviewDataFetched = onPreviewDataFetched;
        }

        private void _onPreviewDataFetched(PreviewData previewData)
        {
            if (message.previewData == null) 
                onPreviewDataFetched?.Invoke(previewData,message);
        }

        private Widget _linkPreview(
            User user,
            float width,
            BuildContext context
        )
        {
            var bodyTextStyle = user.id == message.author.id
                ? InheritedChatTheme.of(context).theme.sentMessageBodyTextStyle
                : InheritedChatTheme.of(context).theme.receivedMessageBodyTextStyle;
            var linkDescriptionTextStyle = user.id == message.author.id
                ? InheritedChatTheme.of(context)
                    .theme
                    .sentMessageLinkDescriptionTextStyle
                : InheritedChatTheme.of(context)
                    .theme
                    .receivedMessageLinkDescriptionTextStyle;
            var linkTitleTextStyle = user.id == message.author.id
                ? InheritedChatTheme.of(context).theme.sentMessageLinkTitleTextStyle
                : InheritedChatTheme.of(context)
                    .theme
                    .receivedMessageLinkTitleTextStyle;
            var test = InheritedChatTheme.of(context);
            var color =  ChatUtils.getUserAvatarNameColor(message.author, InheritedChatTheme.of(context).theme.userAvatarNameColors);
            var name =  ChatUtils.getUserName(message.author);

            return new LinkPreview(
                width: width,
                enableAnimation: true,
                header: showName ? name : null,
                headerStyle: InheritedChatTheme.of(context)
                    .theme
                    .userNameTextStyle
                    .copyWith(color: color),
                linkStyle: bodyTextStyle,
                metadataTextStyle: linkDescriptionTextStyle,
                metadataTitleStyle: linkTitleTextStyle,
                onPreviewDataFetched: (previewData,textMessage)=>
                {
                    _onPreviewDataFetched(previewData);
                },
                padding: EdgeInsets.symmetric(
                    horizontal: 24,
                    vertical: 16
                ),
                previewData: message.previewData,
                text: message.text,
                textStyle: bodyTextStyle
                
            );
        }

        private Widget _textWidget(User user, BuildContext context)
        {
            var color =  ChatUtils.getUserAvatarNameColor(message.author,
                InheritedChatTheme.of(context).theme.userAvatarNameColors);
            var name =  ChatUtils.getUserName(message.author);
            var results = new List<Widget>();
            if (showName)
                results.Add(new Padding(
                    padding: EdgeInsets.only(bottom: 6.0f),
                    child: new Text(
                        name,
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: InheritedChatTheme.of(context)
                            .theme
                            .userNameTextStyle
                            .copyWith(color: color)
                    )
                ));
            var test = InheritedChatTheme.of(context);
            var style = user.id == message.author.id
                ? InheritedChatTheme.of(context).theme.sentMessageBodyTextStyle
                : InheritedChatTheme.of(context)
                    .theme
                    .receivedMessageBodyTextStyle;
            results.Add(//new SelectableText(
                new Text(
                data: message.text,
                style: style ,
                textWidthBasis: TextWidthBasis.longestLine
            ));
            return new Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: results
            );
        }

        public override Widget build(BuildContext context)
        {
            var _user = InheritedUser.of(context).user;
            var _width = MediaQuery.of(context).size.width;

            var urlRegexp = new Regex(ChatUtils.REGEX_LINK);
            var matches = urlRegexp.Match(message.text.ToLower());

            if (matches.Length !=0 && usePreviewData && onPreviewDataFetched != null)
                return _linkPreview(_user, _width, context);

            return new Container(
                margin: EdgeInsets.symmetric(
                    horizontal: 24,
                    vertical: 16
                ),
                child: _textWidget(_user, context)
            );
        }
    }
}