using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Globalization;
using System.IO;
using System.Drawing;

namespace Ucel.Base
{
    internal class DataGridViewClipboardProvider : IClipboardProvider
    {
        #region IClipboardProvider Members

        private DataGridView ctl;
        public System.Windows.Forms.Control Control
        {
            get { return ctl; }
            set { ctl = value as DataGridView; }
        }

        public bool CanCopy
        {
            get 
            {
                return ctl.SelectedCells.Count != 0;
            }
        }

        public bool CanCut
        {
            get { return CanCopy && CanClear; }
        }

        public bool CanPaste
        {
            get
            {
                string[,] data = GetClipboardData();
                if (data == null)
                    return false;                   // no valid data
                int height = data.GetLength(0);
                int width = data.GetLength(1);

                // Case 1: one cell selected. No support for inserting new rows
                if (ctl.SelectedCells.Count == 1)
                {
                    DataGridViewCell cell = ctl.SelectedCells[0];
                    int maxWidth = ctl.ColumnCount - cell.ColumnIndex + 1;
                    int maxHeight = ctl.RowCount - cell.RowIndex + 1;

                    return height <= maxHeight && width <= maxWidth;
                }

                // Case 2: more cells selected. Selection must be the same size as the data
                else
                {
                    if (ctl.SelectedCells.Count != height * width)
                        return false;

                    DataGridViewCell cell1 = ctl.SelectedCells[0];
                    DataGridViewCell cell2 = ctl.SelectedCells[ctl.SelectedCells.Count-1];

                    if (Math.Abs(cell2.ColumnIndex-cell1.ColumnIndex)+1 != width)
                        return false;
                    if (Math.Abs(cell2.RowIndex-cell1.RowIndex)+1 != height)
                        return false;
                }
                return true;
            }
        }

        public bool CanClear
        {
            get
            {
                if (ctl.SelectedCells.Count == 0)
                    return false;           // Nothing to clear
                bool bEnabled = true;
                foreach (DataGridViewCell c in ctl.SelectedCells)
                    bEnabled &= !c.ReadOnly;
                return bEnabled;
            }
        }

        public bool CanSelectAll
        {
            get { return true; }
        }

        public void Copy()
        {
            Clipboard.SetDataObject(ctl.GetClipboardContent());
        }

        public void Cut()
        {
            Copy();
            Clear();
        }

        public void Paste()
        {
            string[,] data = GetClipboardData();
            int height = data.GetLength(0);
            int width = data.GetLength(1);

            int baseRow = ctl.SelectedCells[0].RowIndex;
            int baseCol = ctl.SelectedCells[0].ColumnIndex;
            for (int i = 1; i < ctl.SelectedCells.Count; i++)
            {
                baseRow = Math.Min(baseRow, ctl.SelectedCells[i].RowIndex);
                baseCol = Math.Min(baseCol, ctl.SelectedCells[i].ColumnIndex);
            }

            for (int row = 0; row < height; row++)
                for (int col = 0; col < width; col++)
                    ctl.Rows[row+baseRow].Cells[col+baseCol].Value = data[row, col];
        }

        public void Clear()
        {
            foreach (DataGridViewCell c in ctl.SelectedCells)
                c.Value = null;
        }

        public void SelectAll()
        {
            ctl.SelectAll();
        }

        #endregion

        private string[,] GetClipboardData()
        {
            IDataObject obj = Clipboard.GetDataObject();
            if (obj == null)
                return null;

            string data = obj.GetData(DataFormats.CommaSeparatedValue) as string;
            if (data == null)
            {
                MemoryStream ms = obj.GetData(DataFormats.CommaSeparatedValue) as MemoryStream;
                if (ms == null)
                    return null;
                using (StreamReader sr = new StreamReader(ms))
                {
                    data = sr.ReadToEnd();
                    if (data.EndsWith("\0"))
                        data = data.Substring(0, data.LastIndexOf('\0'));

                }
            }

            string[] lines = data.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
            if (lines.Length == 0)
                return null;

            string [] elements = lines[0].Split(new char[] {'\t', CultureInfo.CurrentCulture.TextInfo.ListSeparator[0]}, StringSplitOptions.RemoveEmptyEntries);
            if (elements.Length == 0)
                return null;

            string [,] retData = new string[lines.Length, elements.Length];
            for (int i=0; i<lines.Length; i++)
            {
                elements = lines[i].Split(new char[] {'\t', CultureInfo.CurrentCulture.TextInfo.ListSeparator[0]}, StringSplitOptions.RemoveEmptyEntries);
                for (int j=0; j<elements.Length; j++)
                    retData[i, j] = elements[j];
            }

            return retData;
        }
    }
}