using System;
using System.Collections;
using System.Runtime.InteropServices;
using System.Text;

namespace Xpace
{
    #region external struct Xpace_RefListCursor
    #if _WIN64
    [StructLayout(LayoutKind.Explicit, Size = 8)]
    #else
    [StructLayout(LayoutKind.Explicit, Size = 4)]
    #endif
    public unsafe struct Xpace_RefListCursor
    {
        [FieldOffset(0)]
        public void* v;
    }
    #endregion

    public class RefList : IDisposable
    {
        #region DLL calls
        //void _stdcall Xpace_RefListCursor_Destroy
        //  (Xpace_RefListCursor rlc);
        [DllImport("xpace.dll")]
        private static unsafe extern void Xpace_RefListCursor_Destroy
          (Xpace_RefListCursor rlc);

        //Xpace_Error _stdcall Xpace_RefListCursor_getCount
        //  (Xpace_RefListCursor rlc,
        //   uint64* result)
        [DllImport("xpace.dll")]
        private static unsafe extern IntPtr Xpace_RefListCursor_getCount
          (Xpace_RefListCursor rlc,
           UInt64* result);

        //Xpace_Error _stdcall Xpace_RefListCursor_getPosition
        //  (Xpace_RefListCursor rlc,
        //   uint64* result)
        [DllImport("xpace.dll")]
        private static unsafe extern IntPtr Xpace_RefListCursor_getPosition
          (Xpace_RefListCursor rlc,
           UInt64* result);

        //Xpace_Error _stdcall Xpace_RefListCursor_Move
        //  (Xpace_RefListCursor rlc,
        //   int64 distance,
        //   bool relative,
        //   bool* result)
        [DllImport("xpace.dll")]
        private static unsafe extern IntPtr Xpace_RefListCursor_Move
          (Xpace_RefListCursor rlc,
           Int64 distance,
           bool relative,
           bool* result);

        //Xpace_Error _stdcall Xpace_RefListCursor_getDocNum
        //  (Xpace_RefListCursor rlc,
        //   uint64* result)
        [DllImport("xpace.dll")]
        private static unsafe extern IntPtr Xpace_RefListCursor_getDocNum
          (Xpace_RefListCursor rlc,
           UInt64* result);
        #endregion

        #region private data
        Xpace_RefListCursor _ref_list_cursor;

        private bool _disposed = false;
        #endregion

        #region Constructor / Destructor
        internal RefList
            (Xpace_RefListCursor rlc)
        {
            _ref_list_cursor = rlc;
            //_pos = 0;
        }

        public void Dispose
            ()
        {
            CleanUp();
            GC.SuppressFinalize(this);
        }

        private void CleanUp
            ()
        {
            if (!_disposed)
            {
                Xpace_RefListCursor_Destroy(_ref_list_cursor);
                _disposed = false;
            }
        }
     
        ~RefList
            ()
        {
            CleanUp();
        }
        #endregion

        #region properties
        public UInt64 Count
        {
            get
            {
                unsafe
                {
                    UInt64 result;
                    IntPtr err = Xpace_RefListCursor_getCount(_ref_list_cursor, &result);
                    if (err != IntPtr.Zero)
                        throw new XpaceException(err);
                    return result;
                }         
            }
        }

        /**
        public UInt64 this[int pos]
        {
            get
            {
                unsafe
                {
                    if (pos != _pos)
                    {
                        bool res;
                        IntPtr err = Xpace_RefListCursor_Move(_ref_list_cursor, pos, false, &res);
                        if (err != IntPtr.Zero)
                            throw new XpaceException(err);
                        if (!pos)
                            throw new IndexOutOfRangeException();
                    }
                    UInt64 res;
                    IntPtr err = Xpace_RefListCursor_getDocNum(_ref_list_cursor, &res);
                    if (err != IntPtr.Zero)
                        throw new XpaceException(err);
                    return res;
                }
            }
        }
        **/
        #endregion
    }

    /// <summary>
    /// A collection of static methods to search indexes and return results
    /// </summary>
    public class Search
    {
        #region DLL calls
        //XPACE_EXPORT Xpace_Error _stdcall Xpace_Search_Table
        //  (const Xpace_Index index,
        //   Xpace_TableCursor table,
        //   Xpace_String query,
        //   uint64 start,
        //   uint64 count,
        //   Xpace_Result* result);
        [DllImport("xpace.dll", CharSet = CharSet.Unicode)]
        private static unsafe extern IntPtr Xpace_Search_Table
            (Xpace_Index index,
             Xpace_TableCursor table,
             [MarshalAs(UnmanagedType.LPWStr)] string query,
             UInt64 start,
             UInt64 count,
             Xpace_Result* result);

        //XPACE_EXPORT Xpace_Error _stdcall Xpace_Search_List_Table
        //  (const Xpace_IndexList indexList,
        //   Xpace_TableCursor table,
        //   Xpace_String query,
        //   uint64 start,
        //   uint64 count,
        //   Xpace_Result* result);
        [DllImport("xpace.dll", CharSet = CharSet.Unicode)]
        private static unsafe extern IntPtr Xpace_Search_List_Table
            (Xpace_IndexList indexList,
             Xpace_TableCursor table,
             [MarshalAs(UnmanagedType.LPWStr)] string query,
             UInt64 start,
             UInt64 count,
             Xpace_Result* result);
        #endregion

        public static Result Table
            (Index index,
             TableCursor table,
             string query,
             UInt64 start,
             UInt64 count)
        {
            unsafe
            {
                Xpace_Result res;
                IntPtr err = Xpace_Search_Table(index._index, table._table_cursor, query, start, count, &res);
                if (err != IntPtr.Zero)
                    throw new XpaceException(err);
                return new Result(&res);
            }
        }

        public static Result Table
            (IndexList indexList,
             TableCursor table,
             string query,
             UInt64 start,
             UInt64 count)
        {
            unsafe
            {
                Xpace_Result res;
                IntPtr err = Xpace_Search_List_Table(indexList._index_list, table._table_cursor, query, start, count, &res);
                if (err != IntPtr.Zero)
                    throw new XpaceException(err);
                return new Result(&res);
            }
        }
    }
}