using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Biff8Excel.Interfaces;

namespace Biff8Excel.Formulas
{
    [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
    struct sReferencer1
    {
        [MarshalAs(UnmanagedType.U1, SizeConst = 1)]        public byte area;
        public ushort firstrow;
        public ushort lastrow;
        public ushort firstcol;
        public ushort lastcol;
    }

    [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
    struct sReferencer2
    {
        [MarshalAs(UnmanagedType.U1, SizeConst = 1)]        public byte area;
        public ushort externIndex;
        public ushort firstrow;
        public ushort lastrow;
        public ushort firstcol;
        public ushort lastcol;
    }


    public class Referencer  
    {
        const byte tRef = 0x44;
        const byte tRef3D = 0x5A;
        const byte tArea = 0x25;
        const byte tArea3D = 0x3B;
        IExternSheet m_externSheet;

        public Referencer()
        {
        }

        public IExternSheet ExternSheet
        {
            set { m_externSheet = value; }
        }

        private byte[] WriteAreaNoSheets(string cell1, string cell2)
        {
            sReferencer1 reference;

            reference.area = tArea;

            reference.firstrow = Globals.ConvertRowStringToNum(cell1);
            reference.firstcol = Globals.ConvertColStringToNum(cell1);

            reference.lastrow = Globals.ConvertRowStringToNum(cell2);
            reference.lastcol = Globals.ConvertColStringToNum(cell2);

            // not using Absolute positions ("$") character
            reference.firstcol = (ushort)(reference.firstcol | 0x8000 | 0x4000);
            reference.lastcol = (ushort)(reference.lastcol | 0x8000 | 0x4000);

            return Globals.GetStructToBytes(reference);
        }

        private byte[] WriteAreaWithSheets(ushort externIndex, string cell1, string cell2)
        {
            sReferencer2 reference;

            reference.area = tArea3D;
            reference.externIndex = externIndex;

            reference.firstrow = Globals.ConvertRowStringToNum(cell1);
            reference.firstcol = Globals.ConvertColStringToNum(cell1);

            reference.lastrow = Globals.ConvertRowStringToNum(cell2);
            reference.lastcol = Globals.ConvertColStringToNum(cell2);

            // not using Absolute positions ("$") character
            reference.firstcol = (ushort)(reference.firstcol | 0x8000 | 0x4000);
            reference.lastcol = (ushort)(reference.lastcol | 0x8000 | 0x4000);

            return Globals.GetStructToBytes(reference);
        }

        private byte[] WriteRefNoSheets(string cell)
        {
            byte[] b = new byte[5];
            ushort row, col;

            row = Globals.ConvertRowStringToNum(cell);
            col = Globals.ConvertColStringToNum(cell);

            // not using Absolute positions ("$") character
            col = (ushort)((ushort)col | 0x8000 | 0x4000);

            b[0] = tRef;
            BitConverter.GetBytes(row).CopyTo(b, 1);
            BitConverter.GetBytes(col).CopyTo(b, 3);

            return b;
        }

        private byte[] WriteRefWithSheets(ushort externIndex, string cell)
        {
            byte[] b = new byte[7];
            ushort row, col;

            row = Globals.ConvertRowStringToNum(cell);
            col = Globals.ConvertColStringToNum(cell);

            // not using Absolute positions ("$") character
            col = (ushort)(col | 0x8000 | 0x4000);

            b[0] = tRef3D;
            BitConverter.GetBytes(externIndex).CopyTo(b, 1);
            BitConverter.GetBytes(row).CopyTo(b, 3);
            BitConverter.GetBytes(col).CopyTo(b, 5);

            return b;
        }

        public byte[] Serialize(string reference)
        {
            string sheet1, sheet2, sheets;
            string cell1, cell2, cells;
            string s;
            int pos;
            ushort x, idx, token;
            sheet1 = sheet2 = sheets = "";
            cell1 = cell2 = cells = "";
            idx = 0;

            if (reference == null)
                throw new ArgumentNullException("reference", " not null");

            //   See if this ref is part of a built in function eg SUM(Sheet1!A1:A2)
            //   we only want the Sheet1!A1:A2 part

            pos = reference.IndexOf("(");
            if (pos > -1)
            {
                //reference = reference.Substring(pos + 1);
                //reference = reference.Substring(0, reference.Length - 1);       //remove the closing bracket

                //得到括号中的内容
                reference = reference.Substring(pos + 1, reference.Length - 2 - pos);
            }
            pos = reference.IndexOf("!");

            if (pos > -1)       // we have sheet refs
            {
                //split out the sheet(s)
                x = (ushort)(pos - 1);
                do
                {
                    s = reference.Substring(x, 1);
                    if (s == "(" || s == "$")
                        break;
                    sheets += s;
                    x--;
                } while (x > 0);

                sheets = Globals.StrReverse(sheets);

                // how many sheets are their
                pos = (ushort)sheets.IndexOf(":");
                if (pos > -1)
                {
                    sheet1 = sheets.Substring(0, pos - 1);
                    if (sheets.Substring(pos + 1) == "$")
                        sheet2 = sheets.Substring(pos + 2);
                    else
                        sheet2 = sheets.Substring(pos + 1);
                }
                else
                {
                    sheet1 = sheets;
                    sheet2 = sheets;
                }

                // Get an index into the Extern Sheet record
                idx = m_externSheet.AddEntry(sheet1, sheet2);
            }
            
            // get the cell references
            pos =reference.IndexOf("!");
            if (pos > -1)
                cells = reference.Substring(pos + 1);
            else
                cells = reference;

            // Is it an AreaRef (A1:B1) or CellRef (A1).
            pos = cells.IndexOf(":");
            if (pos > -1)
            {
                token = (sheet1.Length == 0 ? tArea : tArea3D);

                cell1 = cells.Substring(0, pos );
                cell2 = cells.Substring(pos + 1);

                if (token == tArea)
                    return WriteAreaNoSheets(cell1, cell2);
                else
                    return WriteAreaWithSheets(idx, cell1, cell2);
            }
            else
            {
                token = (sheet1.Length == 0 ? tRef : tRef3D);

                cell1 = cells;

                if (token == tRef)
                    return WriteRefNoSheets(cell1);
                else
                    return WriteRefWithSheets(idx, cell1);
            }
        }

    }
}