using System.Linq;
using System.Windows;
using SHJX.Service.WorkFlowEdit;
using SHJX.Service.Common.Utils;

namespace Flowchart
{
    class DragDropTool : IDragDropTool
    {
        DiagramView _view;
        FlowchartModel _model;
        int _row, _column;

        public DragDropTool(DiagramView view, FlowchartModel model)
        {
            _view = view;
            _model = model;
        }

        #region 继承
        public void OnDragEnter(DragEventArgs e)
        {
        }

        public void OnDragLeave(DragEventArgs e)
        {
        }
        #endregion

        public void OnDragOver(DragEventArgs e)
        {
            e.Effects = DragDropEffects.None;
            if (e.Data.GetDataPresent(typeof(NodeKinds)))
            {
                var position = e.GetPosition(_view);
                _column = (int)(position.X / _view.GridCellSize.Width);
                _row = (int)(position.Y / _view.GridCellSize.Height);
                if (_column >= 0 && _row >= 0)
                    if (!_model.Nodes.Where(p => p.Column.Equals(_column) && p.Row.Equals(_row)).Any())
                        e.Effects = e.AllowedEffects;
            }
            e.Handled = true;
        }

        public void OnDrop(DragEventArgs e)
        {
            var node = new FlowNode((NodeKinds)e.Data.GetData(typeof(NodeKinds)))
            {
                Row = _row,
                Column = _column
            };
            if (node.Kind.BeIn(NodeKinds.Start, NodeKinds.End))
            {
                if (_model.Nodes.Any(item => item.Kind.Equals(node.Kind)))
                {
                    e.Handled = false;
                    return;
                }
            }
            _model.Nodes.Add(node);
            e.Handled = true;
        }
    }
}