using System.Collections.Generic;
using UnityEngine;

namespace WeChatWASM.MDV
{
    public class BlockContent : Block
    {
        Content       mPrefix    = null;
        List<Content> mContent   = new List<Content>();

        public bool IsEmpty { get { return mContent.Count == 0; } }

        public BlockContent( float indent ) : base( indent ) { }

        public void Add( Content content )
        {
            mContent.Add( content );
        }

        public void Prefix( Content content )
        {
            mPrefix = content;
        }

        public override void Arrange( Context context, Vector2 pos, float maxWidth )
        {
            var origin = pos;

            pos.x += Indent;
            maxWidth = Mathf.Max( maxWidth - Indent, context.MinWidth );

            Rect.position = pos;

            // prefix

            if( mPrefix != null )
            {
                mPrefix.Location.x = pos.x - context.IndentSize * 0.5f;
                mPrefix.Location.y = pos.y;
            }

            // content

            if( mContent.Count == 0 )
            {
                Rect.width = 0.0f;
                Rect.height = 0.0f;
                return;
            }

            mContent.ForEach( c => c.Update( context ) );

            var rowWidth   = mContent[0].Width;
            var rowHeight  = mContent[0].Height;
            var startIndex = 0;

            for( var i = 1; i < mContent.Count; i++ )
            {
                var content = mContent[i];

                if( rowWidth + content.Width > maxWidth )
                {
                    LayoutRow( pos, startIndex, i, rowHeight );
                    pos.y += rowHeight;

                    startIndex = i;
                    rowWidth = content.Width;
                    rowHeight = content.Height;
                }
                else
                {
                    rowWidth += content.Width;
                    rowHeight = Mathf.Max( rowHeight, content.Height );
                }
            }

            if( startIndex < mContent.Count )
            {
                LayoutRow( pos, startIndex, mContent.Count, rowHeight );
                pos.y += rowHeight;
            }

            Rect.width = maxWidth;
            Rect.height = pos.y - origin.y;
        }

        void LayoutRow( Vector2 pos, int from, int until, float rowHeight )
        {
            for( var i = from; i < until; i++ )
            {
                var content = mContent[i];

                content.Location.x = pos.x;
                content.Location.y = pos.y + rowHeight - content.Height;

                pos.x += content.Width;
            }
        }

        public override void Draw( Context context )
        {
            mContent.ForEach( c => c.Draw( context ) );

            if( mPrefix != null )
            {
                mPrefix.Draw( context );
            }
        }
    }
}