// ==++==
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--==
namespace System
{

    using System;
    using System.Diagnostics;
    using System.Text;
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices;
    using System.Globalization;

    // Represents a Globally Unique Identifier.
        //| <include path='docs/doc[@for="Guid"]/*' />
    [StructLayout(LayoutKind.Sequential)]
    public struct Guid : IFormattable, IComparable
    {
        //| <include path='docs/doc[@for="Guid.Empty"]/*' />
        public static readonly Guid Empty = new Guid();
        ////////////////////////////////////////////////////////////////////////////////
        //  Member variables
        ////////////////////////////////////////////////////////////////////////////////
        private int        _a;
        private short      _b;
        private short      _c;
        private byte       _d;
        private byte       _e;
        private byte       _f;
        private byte       _g;
        private byte       _h;
        private byte       _i;
        private byte       _j;
        private byte       _k;

        ////////////////////////////////////////////////////////////////////////////////
        //  Constructors
        ////////////////////////////////////////////////////////////////////////////////

        // Creates a new guid from an array of bytes.
        //
        //| <include path='docs/doc[@for="Guid.Guid"]/*' />
        public Guid(byte[] b)
        {
            if (b == null)
                throw new ArgumentNullException("b");
            if (b.Length != 16)
                throw new ArgumentException(String.Format("Arg_GuidArrayCtor", "16"));
            _a = BitConverter.ToInt32(b, 0);
            _b = BitConverter.ToInt16(b, 4);
            _c = BitConverter.ToInt16(b, 6);
            _d = b[8];
            _e = b[9];
            _f = b[10];
            _g = b[11];
            _h = b[12];
            _i = b[13];
            _j = b[14];
            _k = b[15];
        }

        //| <include path='docs/doc[@for="Guid.Guid1"]/*' />
        [CLSCompliant(false)]
        public Guid (uint a, ushort b, ushort c, byte d, byte e, byte f, byte g, byte h, byte i, byte j, byte k)
        {
            _a = (int)a;
            _b = (short)b;
            _c = (short)c;
            _d = d;
            _e = e;
            _f = f;
            _g = g;
            _h = h;
            _i = i;
            _j = j;
            _k = k;
        }

        // Creates a new guid with all contents having value of 0
        private Guid(bool blank)
        {
            // Must initialize value class members even if the native
            // function reinitializes them.  Compiler appeasement.
            _a = 0;
            _b = 0;
            _c = 0;
            _d = 0;
            _e = 0;
            _f = 0;
            _g = 0;
            _h = 0;
            _i = 0;
            _j = 0;
            _k = 0;
            if (!blank) {
                // Create a new Guid...
                Counter++;
                _k = (byte) (Counter & 0xff);
                _j = (byte) (Counter >> 8);
                VTable.DebugPrint("CreateGuid.Guid(" + Counter + ")\n");
            }
        }
        private static int Counter = 0;

        // Creates a new guid based on the value in the string.  The value is made up
        // of hex digits speared by the dash ("-"). The string may begin and end with
        // brackets ("{", "}").
        //
        // The string must be of the form dddddddd-dddd-dddd-dddd-dddddddddddd. where
        // d is a hex digit. (That is 8 hex digits, followed by 4, then 4, then 4,
        // then 12) such as: "CA761232-ED42-11CE-BACD-00AA0057B223"
        //
        //| <include path='docs/doc[@for="Guid.Guid2"]/*' />
        public Guid(String g)
        {
            if (g == null)
                throw new ArgumentNullException("g", "ArgumentNull_String");

            int startPos=0;
            long _dTemp;
            int _dStartTemp = 0;
            int[] spArray = new int[1];
            byte []dstartArray;
            byte []dArray;

            try {
                // Check if it's of the form dddddddd-dddd-dddd-dddd-dddddddddddd
                if (g.IndexOf('-', 0) >= 0) {

                    String guidString = g.Trim();  //Remove Whitespace

                    // check to see that it's the proper length
                    if (guidString[0] =='{') {
                        if (guidString.Length != 38 || guidString[37]!='}') {
                            throw new FormatException("Format_GuidInvLen");
                        }
                        startPos=1;
                    }
                    else if (guidString[0] =='(') {
                        if (guidString.Length != 38 || guidString[37]!=')') {
                            throw new FormatException("Format_GuidInvLen");
                        }
                        startPos=1;
                    }
                    else if(guidString.Length != 36) {
                        throw new FormatException("Format_GuidInvLen");
                    }
                    if (guidString[8+startPos] != '-' ||
                        guidString[13+startPos] != '-' ||
                        guidString[18+startPos] != '-' ||
                        guidString[23+startPos] != '-') {
                        throw new FormatException("Format_GuidDashes");
                    }

                    spArray[0]=startPos;
                    _a = TryParse(guidString, spArray,8);
                    spArray[0]++; //Increment past the '-';
                    _b = (short)TryParse(guidString, spArray,4);
                    spArray[0]++; //Increment past the '-';
                    _c = (short)TryParse(guidString, spArray,4);
                    spArray[0]++; //Increment past the '-';
                    _dStartTemp =TryParse(guidString, spArray,4);
                    spArray[0]++; //Increment past the '-';
                    startPos=spArray[0];
                    _dTemp = ParseNumbers.StringToLong(guidString, 16, 0, spArray);
                    if (spArray[0] - startPos != 12) {
                        throw new FormatException(String.Format("Format_GuidInvLen"));
                    }
                    dstartArray = BitConverter.GetBytes(_dStartTemp);
                    dArray = BitConverter.GetBytes(_dTemp);

                    if (BitConverter.IsLittleEndian) {
                        _d = dstartArray[1];
                        _e = dstartArray[0];
                        _f = dArray[5];
                        _g = dArray[4];
                        _h = dArray[3];
                        _i = dArray[2];
                        _j = dArray[1];
                        _k = dArray[0];
                    }
                    else {
                        _d = dstartArray[0];
                        _e = dstartArray[1];
                        _f = dArray[0];
                        _g = dArray[1];
                        _h = dArray[2];
                        _i = dArray[3];
                        _j = dArray[4];
                        _k = dArray[5];
                    }
                }

                // Else check if it is of the form
                // {0xdddddddd,0xdddd,0xdddd,{0xdd,0xdd,0xdd,0xdd,0xdd,0xdd,0xdd,0xdd}}
                else if(g.IndexOf('{', 0) >= 0) {
                    int numStart = 0;
                    int numLen = 0;

                    // Convert to lower case
                    //g = g.ToLower();

                    // Eat all of the whitespace
                    g = EatAllWhitespace(g);

                    // Check for leading '{'
                    if (g[0] != '{')
                        throw new FormatException("Format_GuidBrace");

                    // Check for '0x'
                    if (!IsHexPrefix(g, 1))
                        throw new FormatException(String.Format("Format_GuidHexPrefix", "{0xdddddddd, etc}"));

                    // Find the end of this hex number (since it is not fixed length)
                    numStart = 3;
                    numLen = g.IndexOf(',', numStart) - numStart;
                    if (numLen <= 0)
                        throw new FormatException("Format_GuidComma");

                    // Read in the number
                    _a = (int) ParseNumbers.StringToInt(g.Substring(numStart, numLen), // first DWORD
                                                        16,                            // hex
                                                        ParseNumbers.IsTight);         // tight parsing

                    // Check for '0x'
                    if (!IsHexPrefix(g, numStart + numLen + 1))
                        throw new FormatException(String.Format("Format_GuidHexPrefix", "{0xdddddddd, 0xdddd, etc}"));

                    // +3 to get by ',0x'
                    numStart = numStart + numLen + 3;
                    numLen = g.IndexOf(',', numStart) - numStart;
                    if (numLen <= 0)
                        throw new FormatException("Format_GuidComma");

                    // Read in the number
                    _b = (short) ParseNumbers.StringToInt(
                                                          g.Substring(numStart, numLen), // first DWORD
                                                          16,                            // hex
                                                          ParseNumbers.IsTight);         // tight parsing

                    // Check for '0x'
                    if (!IsHexPrefix(g, numStart + numLen + 1))
                        throw new FormatException(String.Format("Format_GuidHexPrefix", "{0xdddddddd, 0xdddd, 0xdddd, etc}"));

                    // +3 to get by ',0x'
                    numStart = numStart + numLen + 3;
                    numLen = g.IndexOf(',', numStart) - numStart;
                    if (numLen <= 0)
                        throw new FormatException("Format_GuidComma");

                    // Read in the number
                    _c = (short) ParseNumbers.StringToInt(
                                                          g.Substring(numStart, numLen), // first DWORD
                                                          16,                            // hex
                                                          ParseNumbers.IsTight);         // tight parsing

                    // Check for '{'
                    if (g.Length <= numStart + numLen + 1 || g[numStart + numLen + 1] != '{')
                        throw new FormatException("Format_GuidBrace");

                    // Prepare for loop
                    numLen++;
                    byte[] bytes = new byte[8];

                    for (int i = 0; i < 8; i++) {
                        // Check for '0x'
                        if (!IsHexPrefix(g, numStart + numLen + 1))
                            throw new FormatException(String.Format("Format_GuidHexPrefix", "{... { ... 0xdd, ...}}"));

                        // +3 to get by ',0x' or '{0x' for first case
                        numStart = numStart + numLen + 3;

                        // Calculate number length
                        if (i < 7) // first 7 cases
                        {
                            numLen = g.IndexOf(',', numStart) - numStart;
                        }
                        else       // last case ends with '}', not ','
                        {
                            numLen = g.IndexOf('}', numStart) - numStart;
                        }
                        if (numLen <= 0)
                            throw new FormatException("Format_GuidComma");

                        // Read in the number
                        bytes[i] = (byte)ParseNumbers.StringToInt(g.Substring(numStart, numLen),
                                                                  16,
                                                                  ParseNumbers.IsTight);
                    }

                    _d = bytes[0];
                    _e = bytes[1];
                    _f = bytes[2];
                    _g = bytes[3];
                    _h = bytes[4];
                    _i = bytes[5];
                    _j = bytes[6];
                    _k = bytes[7];

                    // Check for last '}'
                    if (numStart + numLen + 1 >= g.Length || g[numStart + numLen + 1] != '}')
                        throw new FormatException("Format_GuidEndBrace");

                    return;
                }
                else
                // Check if it's of the form dddddddddddddddddddddddddddddddd
                {
                    String guidString = g.Trim();  //Remove Whitespace

                    if (guidString.Length != 32) {
                        throw new FormatException("Format_GuidInvLen");
                    }

                    _a = (int) ParseNumbers.StringToInt(g.Substring(startPos, 8), // first DWORD
                                                        16,                            // hex
                                                        ParseNumbers.IsTight);         // tight parsing
                    startPos += 8;
                    _b = (short) ParseNumbers.StringToInt(g.Substring(startPos, 4),
                                                        16,
                                                        ParseNumbers.IsTight);
                    startPos += 4;
                    _c = (short) ParseNumbers.StringToInt(g.Substring(startPos, 4),
                                                        16,
                                                        ParseNumbers.IsTight);

                    startPos += 4;
                    _dStartTemp =(short) ParseNumbers.StringToInt(g.Substring(startPos, 4),
                                                        16,
                                                        ParseNumbers.IsTight);
                    startPos += 4;
                    spArray[0] = startPos;
                    _dTemp = ParseNumbers.StringToLong(guidString, 16, startPos, spArray);
                    if (spArray[0] - startPos != 12) {
                        throw new FormatException(String.Format("Format_GuidInvLen"));
                    }
                    dstartArray = BitConverter.GetBytes(_dStartTemp);
                    dArray = BitConverter.GetBytes(_dTemp);

                    if (BitConverter.IsLittleEndian) {
                        _d = dstartArray[1];
                        _e = dstartArray[0];
                        _f = dArray[5];
                        _g = dArray[4];
                        _h = dArray[3];
                        _i = dArray[2];
                        _j = dArray[1];
                        _k = dArray[0];
                    }
                    else {
                        _d = dstartArray[0];
                        _e = dstartArray[1];
                        _f = dArray[0];
                        _g = dArray[1];
                        _h = dArray[2];
                        _i = dArray[3];
                        _j = dArray[4];
                        _k = dArray[5];
                    }
                }
            }
            catch (IndexOutOfRangeException) {
                throw new FormatException("Format_GuidUnrecognized");
            }
        }

        // Creates a new GUID initialized to the value represented by the arguments.
        //
        //| <include path='docs/doc[@for="Guid.Guid3"]/*' />
        public Guid(int a, short b, short c, byte[] d)
        {
            if (d == null)
                throw new ArgumentNullException("d");
            // Check that array is not too big
            if (d.Length != 8)
                throw new ArgumentException(String.Format("Arg_GuidArrayCtor", "8"));

            _a  = a;
            _b  = b;
            _c  = c;
            _d = d[0];
            _e = d[1];
            _f = d[2];
            _g = d[3];
            _h = d[4];
            _i = d[5];
            _j = d[6];
            _k = d[7];
        }

        // Creates a new GUID initialized to the value represented by the
        // arguments.  The bytes are specified like this to avoid endianness issues.
        //
        //| <include path='docs/doc[@for="Guid.Guid4"]/*' />
        public Guid(int a, short b, short c, byte d, byte e, byte f, byte g, byte h, byte i, byte j, byte k)
        {
            _a = a;
            _b = b;
            _c = c;
            _d = d;
            _e = e;
            _f = f;
            _g = g;
            _h = h;
            _i = i;
            _j = j;
            _k = k;
        }


        private static int TryParse(String str, int []parsePos, int requiredLength) {
            int currStart = parsePos[0];
            int retVal;
            try {
                retVal = ParseNumbers.StringToInt(str, 16, 0, parsePos);
            }
            catch (FormatException) {
               throw new FormatException("Format_GuidUnrecognized");
            }

            //If we didn't parse enough characters, there's clearly an error.
            if (parsePos[0] - currStart != requiredLength) {
                throw new FormatException("Format_GuidUnrecognized");
            }
            return retVal;
        }

        private static String EatAllWhitespace(String str)
        {
            int newLength = 0;
            char[] chArr = new char[str.Length];
            char curChar;

            // Now get each char from str and if it is not whitespace add it to chArr
            for (int i = 0; i < str.Length; i++) {
                curChar = str[i];
                if (!Char.IsWhiteSpace(curChar)) {
                    chArr[newLength++] = curChar;
                }
            }

            // Return a new string based on chArr
            return new String(chArr, 0, newLength);
        }

        private static bool IsHexPrefix(String str, int i)
        {
            if (str[i] == '0' && (Char.ToLower(str[i + 1]) == 'x'))
                return true;
            else
                return false;
        }


        // Returns an unsigned byte array containing the GUID.
        //| <include path='docs/doc[@for="Guid.ToByteArray"]/*' />
        public byte[] ToByteArray()
        {
            byte[] g = new byte[16];
            byte[] tmp = BitConverter.GetBytes(_a);
            for (int i = 0; i < 4; i++)
                g[i] = tmp[i];
            tmp = BitConverter.GetBytes(_b);
            for (int i = 0; i < 2; i++)
                g[i+4] = tmp[i];
            tmp = BitConverter.GetBytes(_c);
            for (int i = 0; i < 2; i++)
                g[i+6] = tmp[i];

            g[8] = _d;
            g[9] = _e;
            g[10] = _f;
            g[11] = _g;
            g[12] = _h;
            g[13] = _i;
            g[14] = _j;
            g[15] = _k;

            return g;
        }


        // Returns the guid in "registry" format.
        //| <include path='docs/doc[@for="Guid.ToString"]/*' />
        public override String ToString()
        {
            return ToString("D");
        }

        //| <include path='docs/doc[@for="Guid.GetHashCode"]/*' />
        public override int GetHashCode()
        {
            return _a ^ (((int)_b << 16) | (int)(ushort)_c) ^ (((int)_f << 24) | _k);
        }

        // Returns true if and only if the guid represented
        //  by o is the same as this instance.
        //| <include path='docs/doc[@for="Guid.Equals"]/*' />
        public override bool Equals(Object o)
        {
            Guid g;
            // Check that o is a Guid first
            if (o == null || !(o is Guid))
                return false;
            else g = (Guid) o;

            // Now compare each of the elements
            if (g._a != _a)
                return false;
            if (g._b != _b)
                return false;
            if (g._c != _c)
                return false;
            if (g._d != _d)
                return false;
            if (g._e != _e)
                return false;
            if (g._f != _f)
                return false;
            if (g._g != _g)
                return false;
            if (g._h != _h)
                return false;
            if (g._i != _i)
                return false;
            if (g._j != _j)
                return false;
            if (g._k != _k)
                return false;

            return true;
        }

        private int GetResult(uint me, uint them) {
            if (me < them) {
                return -1;
            }
            return 1;
        }

        //| <include path='docs/doc[@for="Guid.CompareTo"]/*' />
        public int CompareTo(Object value) {
            if (value == null) {
                return 1;
            }
            if (!(value is Guid)) {
                throw new ArgumentException("Arg_MustBeGuid");
            }
            Guid g = (Guid)value;

            if (g._a != this._a) {
                return GetResult((uint)this._a, (uint)g._a);
            }

            if (g._b != this._b) {
                return GetResult((uint)this._b, (uint)g._b);
            }

            if (g._c != this._c) {
                return GetResult((uint)this._c, (uint)g._c);
            }

            if (g._d != this._d) {
                return GetResult((uint)this._d, (uint)g._d);
            }

            if (g._e != this._e) {
                return GetResult((uint)this._e, (uint)g._e);
            }

            if (g._f != this._f) {
                return GetResult((uint)this._f, (uint)g._f);
            }

            if (g._g != this._g) {
                return GetResult((uint)this._g, (uint)g._g);
            }

            if (g._h != this._h) {
                return GetResult((uint)this._h, (uint)g._h);
            }

            if (g._i != this._i) {
                return GetResult((uint)this._i, (uint)g._i);
            }

            if (g._j != this._j) {
                return GetResult((uint)this._j, (uint)g._j);
            }

            if (g._k != this._k) {
                return GetResult((uint)this._k, (uint)g._k);
            }

            return 0;
        }

        // Compares two Guids by calling Guid.Equals(Guid).
    //  private static bool operator equals(Guid a, Guid b)
    //  {
    //      return a.Equals(b);
    //  }  

        //| <include path='docs/doc[@for="Guid.operatorEQ"]/*' />
        public static bool operator ==(Guid a, Guid b)
        {
            return a.Equals(b);
        }

        //| <include path='docs/doc[@for="Guid.operatorNE"]/*' />
        public static bool operator !=(Guid a, Guid b)
        {
            return !a.Equals(b);
        }

        // This will create a new guid.  Since we've now decided that constructors should 0-init,
        // we need a method that allows users to create a guid.
        //| <include path='docs/doc[@for="Guid.NewGuid"]/*' />
        public static Guid NewGuid() {
            return new Guid(false);
        }

        private char HexToChar(int a)
        {
            Debug.Assert(a <= 0xf,"argument must be less than 0xf");
            return (char) ((a > 9) ? a - 10 + 0x61 : a + 0x30);
        }

        // IFormattable interface
        // We currently ignore provider
        //| <include path='docs/doc[@for="Guid.ToString2"]/*' />
        public String ToString(String format)
        {
            if (format == null || format.Length == 0)
                format = "D";

            char[] guidChars;
            int offset = 0;
            byte[] tmp;
            int i;

            if (format.Equals("N") || format.Equals("n")) {
                guidChars = new char[32];
                tmp = BitConverter.GetBytes(_a);
                for (i = 3; i >= 0; i--) {
                    guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                    guidChars[offset++] = HexToChar(tmp[i] & 0xf);
                }

                tmp = BitConverter.GetBytes(_b);
                for (i = 1; i >= 0; i--) {
                    guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                    guidChars[offset++] = HexToChar(tmp[i] & 0xf);

                }

                tmp = BitConverter.GetBytes(_c);
                for (i = 1; i >= 0; i--) {
                    guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                    guidChars[offset++] = HexToChar(tmp[i] & 0xf);
                }

                guidChars[offset++] = HexToChar((_d>>4) & 0xf);
                guidChars[offset++] = HexToChar(_d & 0xf);

                guidChars[offset++] = HexToChar((_e>>4) & 0xf);
                guidChars[offset++] = HexToChar(_e & 0xf);

                guidChars[offset++] = HexToChar((_f>>4) & 0xf);
                guidChars[offset++] = HexToChar(_f & 0xf);

                guidChars[offset++] = HexToChar((_g>>4) & 0xf);
                guidChars[offset++] = HexToChar(_g & 0xf);

                guidChars[offset++] = HexToChar((_h>>4) & 0xf);
                guidChars[offset++] = HexToChar(_h & 0xf);

                guidChars[offset++] = HexToChar((_i>>4) & 0xf);
                guidChars[offset++] = HexToChar(_i & 0xf);

                guidChars[offset++] = HexToChar((_j>>4) & 0xf);
                guidChars[offset++] = HexToChar(_j & 0xf);

                guidChars[offset++] = HexToChar((_k>>4) & 0xf);
                guidChars[offset++] = HexToChar(_k & 0xf);
                return new string(guidChars, 0, 32);
            }

            int strLength = 38;
            if (format.Equals("B") || format.Equals("b")) {
                guidChars = new char[38];
                guidChars[offset++] = '{';
                guidChars[37] = '}';
            }
            if (format.Equals("P") || format.Equals("p")) {
                guidChars = new char[38];
                guidChars[offset++] = '(';
                guidChars[37] = ')';
            }
            if (format.Equals("D") || format.Equals("d")) {
                guidChars = new char[36];
                strLength = 36;
            }
            else {
                throw new FormatException("Format_InvalidGuidFormatSpecification");
            }

            tmp = BitConverter.GetBytes(_a);
            for (i = 3; i >= 0; i--) {
                guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                guidChars[offset++] = HexToChar(tmp[i] & 0xf);
            }

            guidChars[offset++] = '-';

            tmp = BitConverter.GetBytes(_b);
            for (i = 1; i >= 0; i--) {
                guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                guidChars[offset++] = HexToChar(tmp[i] & 0xf);

            }

            guidChars[offset++] = '-';

            tmp = BitConverter.GetBytes(_c);
            for (i = 1; i >= 0; i--) {
                guidChars[offset++] = HexToChar((tmp[i]>>4) & 0xf);
                guidChars[offset++] = HexToChar(tmp[i] & 0xf);
            }

            guidChars[offset++] = '-';

            guidChars[offset++] = HexToChar((_d>>4) & 0xf);
            guidChars[offset++] = HexToChar(_d & 0xf);

            guidChars[offset++] = HexToChar((_e>>4) & 0xf);
            guidChars[offset++] = HexToChar(_e & 0xf);

            guidChars[offset++] = '-';

            guidChars[offset++] = HexToChar((_f>>4) & 0xf);
            guidChars[offset++] = HexToChar(_f & 0xf);

            guidChars[offset++] = HexToChar((_g>>4) & 0xf);
            guidChars[offset++] = HexToChar(_g & 0xf);

            guidChars[offset++] = HexToChar((_h>>4) & 0xf);
            guidChars[offset++] = HexToChar(_h & 0xf);

            guidChars[offset++] = HexToChar((_i>>4) & 0xf);
            guidChars[offset++] = HexToChar(_i & 0xf);

            guidChars[offset++] = HexToChar((_j>>4) & 0xf);
            guidChars[offset++] = HexToChar(_j & 0xf);

            guidChars[offset++] = HexToChar((_k>>4) & 0xf);
            guidChars[offset++] = HexToChar(_k & 0xf);

            return String.StringCTOR(guidChars, 0, strLength);
        }
    }
}