using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Novacoin
{
    /// <summary>
    /// Script opcodes
    /// </summary>
    public enum opcodetype
    {
        // push value
        OP_0 = 0x00,
        OP_FALSE = OP_0,
        OP_PUSHDATA1 = 0x4c,
        OP_PUSHDATA2 = 0x4d,
        OP_PUSHDATA4 = 0x4e,
        OP_1NEGATE = 0x4f,
        OP_RESERVED = 0x50,
        OP_1 = 0x51,
        OP_TRUE = OP_1,
        OP_2 = 0x52,
        OP_3 = 0x53,
        OP_4 = 0x54,
        OP_5 = 0x55,
        OP_6 = 0x56,
        OP_7 = 0x57,
        OP_8 = 0x58,
        OP_9 = 0x59,
        OP_10 = 0x5a,
        OP_11 = 0x5b,
        OP_12 = 0x5c,
        OP_13 = 0x5d,
        OP_14 = 0x5e,
        OP_15 = 0x5f,
        OP_16 = 0x60,

        // control
        OP_NOP = 0x61,
        OP_VER = 0x62,
        OP_IF = 0x63,
        OP_NOTIF = 0x64,
        OP_VERIF = 0x65,
        OP_VERNOTIF = 0x66,
        OP_ELSE = 0x67,
        OP_ENDIF = 0x68,
        OP_VERIFY = 0x69,
        OP_RETURN = 0x6a,

        // stack ops
        OP_TOALTSTACK = 0x6b,
        OP_FROMALTSTACK = 0x6c,
        OP_2DROP = 0x6d,
        OP_2DUP = 0x6e,
        OP_3DUP = 0x6f,
        OP_2OVER = 0x70,
        OP_2ROT = 0x71,
        OP_2SWAP = 0x72,
        OP_IFDUP = 0x73,
        OP_DEPTH = 0x74,
        OP_DROP = 0x75,
        OP_DUP = 0x76,
        OP_NIP = 0x77,
        OP_OVER = 0x78,
        OP_PICK = 0x79,
        OP_ROLL = 0x7a,
        OP_ROT = 0x7b,
        OP_SWAP = 0x7c,
        OP_TUCK = 0x7d,

        // splice ops
        OP_CAT = 0x7e,
        OP_SUBSTR = 0x7f,
        OP_LEFT = 0x80,
        OP_RIGHT = 0x81,
        OP_SIZE = 0x82,

        // bit logic
        OP_INVERT = 0x83,
        OP_AND = 0x84,
        OP_OR = 0x85,
        OP_XOR = 0x86,
        OP_EQUAL = 0x87,
        OP_EQUALVERIFY = 0x88,
        OP_RESERVED1 = 0x89,
        OP_RESERVED2 = 0x8a,

        // numeric
        OP_1ADD = 0x8b,
        OP_1SUB = 0x8c,
        OP_2MUL = 0x8d,
        OP_2DIV = 0x8e,
        OP_NEGATE = 0x8f,
        OP_ABS = 0x90,
        OP_NOT = 0x91,
        OP_0NOTEQUAL = 0x92,

        OP_ADD = 0x93,
        OP_SUB = 0x94,
        OP_MUL = 0x95,
        OP_DIV = 0x96,
        OP_MOD = 0x97,
        OP_LSHIFT = 0x98,
        OP_RSHIFT = 0x99,

        OP_BOOLAND = 0x9a,
        OP_BOOLOR = 0x9b,
        OP_NUMEQUAL = 0x9c,
        OP_NUMEQUALVERIFY = 0x9d,
        OP_NUMNOTEQUAL = 0x9e,
        OP_LESSTHAN = 0x9f,
        OP_GREATERTHAN = 0xa0,
        OP_LESSTHANOREQUAL = 0xa1,
        OP_GREATERTHANOREQUAL = 0xa2,
        OP_MIN = 0xa3,
        OP_MAX = 0xa4,

        OP_WITHIN = 0xa5,

        // crypto
        OP_RIPEMD160 = 0xa6,
        OP_SHA1 = 0xa7,
        OP_SHA256 = 0xa8,
        OP_HASH160 = 0xa9,
        OP_HASH256 = 0xaa,
        OP_CODESEPARATOR = 0xab,
        OP_CHECKSIG = 0xac,
        OP_CHECKSIGVERIFY = 0xad,
        OP_CHECKMULTISIG = 0xae,
        OP_CHECKMULTISIGVERIFY = 0xaf,

        // expansion
        OP_NOP1 = 0xb0,
        OP_NOP2 = 0xb1,
        OP_NOP3 = 0xb2,
        OP_NOP4 = 0xb3,
        OP_NOP5 = 0xb4,
        OP_NOP6 = 0xb5,
        OP_NOP7 = 0xb6,
        OP_NOP8 = 0xb7,
        OP_NOP9 = 0xb8,
        OP_NOP10 = 0xb9,

        // template matching params
        OP_SMALLDATA = 0xf9,
        OP_SMALLINTEGER = 0xfa,
        OP_PUBKEYS = 0xfb,
        OP_PUBKEYHASH = 0xfd,
        OP_PUBKEY = 0xfe,

        OP_INVALIDOPCODE = 0xff,
    };

    /// <summary>
    /// Transaction output types.
    /// </summary>
    public enum txnouttype
    {
        TX_NONSTANDARD,

        // 'standard' transaction types:
        TX_PUBKEY,
        TX_PUBKEYHASH,
        TX_SCRIPTHASH,
        TX_MULTISIG,
        TX_NULL_DATA,
    };

    public static class ScriptCode
    {

        /// <summary>
        /// Get the name of supplied opcode
        /// </summary>
        /// <param name="opcode">Opcode</param>
        /// <returns>Opcode name</returns>
        public static string GetOpName(opcodetype opcode)
        {
            switch (opcode)
            {
                // push value
                case opcodetype.OP_0:
                    return "0";
                case opcodetype.OP_PUSHDATA1:
                    return "OP_PUSHDATA1";
                case opcodetype.OP_PUSHDATA2:
                    return "OP_PUSHDATA2";
                case opcodetype.OP_PUSHDATA4:
                    return "OP_PUSHDATA4";
                case opcodetype.OP_1NEGATE:
                    return "-1";
                case opcodetype.OP_RESERVED:
                    return "OP_RESERVED";
                case opcodetype.OP_1:
                    return "1";
                case opcodetype.OP_2:
                    return "2";
                case opcodetype.OP_3:
                    return "3";
                case opcodetype.OP_4:
                    return "4";
                case opcodetype.OP_5:
                    return "5";
                case opcodetype.OP_6:
                    return "6";
                case opcodetype.OP_7:
                    return "7";
                case opcodetype.OP_8:
                    return "8";
                case opcodetype.OP_9:
                    return "9";
                case opcodetype.OP_10:
                    return "10";
                case opcodetype.OP_11:
                    return "11";
                case opcodetype.OP_12:
                    return "12";
                case opcodetype.OP_13:
                    return "13";
                case opcodetype.OP_14:
                    return "14";
                case opcodetype.OP_15:
                    return "15";
                case opcodetype.OP_16:
                    return "16";

                // control
                case opcodetype.OP_NOP:
                    return "OP_NOP";
                case opcodetype.OP_VER:
                    return "OP_VER";
                case opcodetype.OP_IF:
                    return "OP_IF";
                case opcodetype.OP_NOTIF:
                    return "OP_NOTIF";
                case opcodetype.OP_VERIF:
                    return "OP_VERIF";
                case opcodetype.OP_VERNOTIF:
                    return "OP_VERNOTIF";
                case opcodetype.OP_ELSE:
                    return "OP_ELSE";
                case opcodetype.OP_ENDIF:
                    return "OP_ENDIF";
                case opcodetype.OP_VERIFY:
                    return "OP_VERIFY";
                case opcodetype.OP_RETURN:
                    return "OP_RETURN";

                // stack ops
                case opcodetype.OP_TOALTSTACK:
                    return "OP_TOALTSTACK";
                case opcodetype.OP_FROMALTSTACK:
                    return "OP_FROMALTSTACK";
                case opcodetype.OP_2DROP:
                    return "OP_2DROP";
                case opcodetype.OP_2DUP:
                    return "OP_2DUP";
                case opcodetype.OP_3DUP:
                    return "OP_3DUP";
                case opcodetype.OP_2OVER:
                    return "OP_2OVER";
                case opcodetype.OP_2ROT:
                    return "OP_2ROT";
                case opcodetype.OP_2SWAP:
                    return "OP_2SWAP";
                case opcodetype.OP_IFDUP:
                    return "OP_IFDUP";
                case opcodetype.OP_DEPTH:
                    return "OP_DEPTH";
                case opcodetype.OP_DROP:
                    return "OP_DROP";
                case opcodetype.OP_DUP:
                    return "OP_DUP";
                case opcodetype.OP_NIP:
                    return "OP_NIP";
                case opcodetype.OP_OVER:
                    return "OP_OVER";
                case opcodetype.OP_PICK:
                    return "OP_PICK";
                case opcodetype.OP_ROLL:
                    return "OP_ROLL";
                case opcodetype.OP_ROT:
                    return "OP_ROT";
                case opcodetype.OP_SWAP:
                    return "OP_SWAP";
                case opcodetype.OP_TUCK:
                    return "OP_TUCK";

                // splice ops
                case opcodetype.OP_CAT:
                    return "OP_CAT";
                case opcodetype.OP_SUBSTR:
                    return "OP_SUBSTR";
                case opcodetype.OP_LEFT:
                    return "OP_LEFT";
                case opcodetype.OP_RIGHT:
                    return "OP_RIGHT";
                case opcodetype.OP_SIZE:
                    return "OP_SIZE";

                // bit logic
                case opcodetype.OP_INVERT:
                    return "OP_INVERT";
                case opcodetype.OP_AND:
                    return "OP_AND";
                case opcodetype.OP_OR:
                    return "OP_OR";
                case opcodetype.OP_XOR:
                    return "OP_XOR";
                case opcodetype.OP_EQUAL:
                    return "OP_EQUAL";
                case opcodetype.OP_EQUALVERIFY:
                    return "OP_EQUALVERIFY";
                case opcodetype.OP_RESERVED1:
                    return "OP_RESERVED1";
                case opcodetype.OP_RESERVED2:
                    return "OP_RESERVED2";

                // numeric
                case opcodetype.OP_1ADD:
                    return "OP_1ADD";
                case opcodetype.OP_1SUB:
                    return "OP_1SUB";
                case opcodetype.OP_2MUL:
                    return "OP_2MUL";
                case opcodetype.OP_2DIV:
                    return "OP_2DIV";
                case opcodetype.OP_NEGATE:
                    return "OP_NEGATE";
                case opcodetype.OP_ABS:
                    return "OP_ABS";
                case opcodetype.OP_NOT:
                    return "OP_NOT";
                case opcodetype.OP_0NOTEQUAL:
                    return "OP_0NOTEQUAL";
                case opcodetype.OP_ADD:
                    return "OP_ADD";
                case opcodetype.OP_SUB:
                    return "OP_SUB";
                case opcodetype.OP_MUL:
                    return "OP_MUL";
                case opcodetype.OP_DIV:
                    return "OP_DIV";
                case opcodetype.OP_MOD:
                    return "OP_MOD";
                case opcodetype.OP_LSHIFT:
                    return "OP_LSHIFT";
                case opcodetype.OP_RSHIFT:
                    return "OP_RSHIFT";
                case opcodetype.OP_BOOLAND:
                    return "OP_BOOLAND";
                case opcodetype.OP_BOOLOR:
                    return "OP_BOOLOR";
                case opcodetype.OP_NUMEQUAL:
                    return "OP_NUMEQUAL";
                case opcodetype.OP_NUMEQUALVERIFY:
                    return "OP_NUMEQUALVERIFY";
                case opcodetype.OP_NUMNOTEQUAL:
                    return "OP_NUMNOTEQUAL";
                case opcodetype.OP_LESSTHAN:
                    return "OP_LESSTHAN";
                case opcodetype.OP_GREATERTHAN:
                    return "OP_GREATERTHAN";
                case opcodetype.OP_LESSTHANOREQUAL:
                    return "OP_LESSTHANOREQUAL";
                case opcodetype.OP_GREATERTHANOREQUAL:
                    return "OP_GREATERTHANOREQUAL";
                case opcodetype.OP_MIN:
                    return "OP_MIN";
                case opcodetype.OP_MAX:
                    return "OP_MAX";
                case opcodetype.OP_WITHIN:
                    return "OP_WITHIN";

                // crypto
                case opcodetype.OP_RIPEMD160:
                    return "OP_RIPEMD160";
                case opcodetype.OP_SHA1:
                    return "OP_SHA1";
                case opcodetype.OP_SHA256:
                    return "OP_SHA256";
                case opcodetype.OP_HASH160:
                    return "OP_HASH160";
                case opcodetype.OP_HASH256:
                    return "OP_HASH256";
                case opcodetype.OP_CODESEPARATOR:
                    return "OP_CODESEPARATOR";
                case opcodetype.OP_CHECKSIG:
                    return "OP_CHECKSIG";
                case opcodetype.OP_CHECKSIGVERIFY:
                    return "OP_CHECKSIGVERIFY";
                case opcodetype.OP_CHECKMULTISIG:
                    return "OP_CHECKMULTISIG";
                case opcodetype.OP_CHECKMULTISIGVERIFY:
                    return "OP_CHECKMULTISIGVERIFY";

                // expansion
                case opcodetype.OP_NOP1:
                    return "OP_NOP1";
                case opcodetype.OP_NOP2:
                    return "OP_NOP2";
                case opcodetype.OP_NOP3:
                    return "OP_NOP3";
                case opcodetype.OP_NOP4:
                    return "OP_NOP4";
                case opcodetype.OP_NOP5:
                    return "OP_NOP5";
                case opcodetype.OP_NOP6:
                    return "OP_NOP6";
                case opcodetype.OP_NOP7:
                    return "OP_NOP7";
                case opcodetype.OP_NOP8:
                    return "OP_NOP8";
                case opcodetype.OP_NOP9:
                    return "OP_NOP9";
                case opcodetype.OP_NOP10:
                    return "OP_NOP10";

                // template matching params
                case opcodetype.OP_PUBKEYHASH:
                    return "OP_PUBKEYHASH";
                case opcodetype.OP_PUBKEY:
                    return "OP_PUBKEY";
                case opcodetype.OP_SMALLDATA:
                    return "OP_SMALLDATA";

                case opcodetype.OP_INVALIDOPCODE:
                    return "OP_INVALIDOPCODE";
                default:
                    return "OP_UNKNOWN";
            }
        }

        /// <summary>
        /// Get next opcode from passed list of bytes and extract push arguments if there are some.
        /// </summary>
        /// <param name="codeBytes">WrappedList reference.</param>
        /// <param name="opcodeRet">Found opcode.</param>
        /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
        /// <returns>Result of operation</returns>
        public static bool GetOp(ref WrappedList<byte> codeBytes, out opcodetype opcodeRet, out IEnumerable<byte> bytesRet)
        {
            bytesRet = new List<byte>();
            opcodeRet = opcodetype.OP_INVALIDOPCODE;

            opcodetype opcode;

            try
            {
                // Read instruction
                opcode = (opcodetype)codeBytes.GetItem();
            }
            catch (WrappedListException)
            {
                // No instruction found there
                return false;
            }

            // Immediate operand
            if (opcode <= opcodetype.OP_PUSHDATA4)
            {
                byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length

                try
                {
                    if (opcode < opcodetype.OP_PUSHDATA1)
                    {
                        // Zero value opcodes (OP_0, OP_FALSE)
                        szBytes[3] = (byte)opcode;
                    }
                    else if (opcode == opcodetype.OP_PUSHDATA1)
                    {
                        // The next byte contains the number of bytes to be pushed onto the stack, 
                        //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
                        szBytes[3] = (byte)codeBytes.GetItem();
                    }
                    else if (opcode == opcodetype.OP_PUSHDATA2)
                    {
                        // The next two bytes contain the number of bytes to be pushed onto the stack,
                        //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
                        codeBytes.GetItems(2).CopyTo(szBytes, 2);
                    }
                    else if (opcode == opcodetype.OP_PUSHDATA4)
                    {
                        // The next four bytes contain the number of bytes to be pushed onto the stack,
                        //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
                        szBytes = codeBytes.GetItems(4);
                    }
                }
                catch (WrappedListException)
                {
                    // Unable to read operand length
                    return false;
                }

                int nSize = (int)Interop.BEBytesToUInt32(szBytes);

                if (nSize > 0)
                {
                    // If nSize is greater than zero then there is some data available
                    try
                    {
                        // Read found number of bytes into list of OP_PUSHDATAn arguments.
                        bytesRet = codeBytes.GetEnumerableItems(nSize);
                    }
                    catch (WrappedListException)
                    {
                        // Unable to read data
                        return false;
                    }
                }
            }

            opcodeRet = opcode;

            return true;
        }

        /// <summary>
        /// Convert value bytes into readable representation.
        /// 
        /// If list lengh is equal or lesser than 4 bytes then bytes are interpreted as integer value. Otherwise you will get hex representation of supplied data.
        /// </summary>
        /// <param name="bytes">Collection of value bytes.</param>
        /// <returns>Formatted value.</returns>
        public static string ValueString(IEnumerable<byte> bytes)
        {
            StringBuilder sb = new StringBuilder();

            if (bytes.Count() <= 4)
            {
                byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
                bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());

                sb.Append(Interop.BEBytesToUInt32(valueBytes));
            }
            else
            {
                return Interop.ToHex(bytes);
            }

            return sb.ToString();
        }

        /// <summary>
        /// Convert list of stack items into human readable representation.
        /// </summary>
        /// <param name="stackList">List of stack items.</param>
        /// <returns>Formatted value.</returns>
        public static string StackString(IList<IList<byte>> stackList)
        {
            StringBuilder sb = new StringBuilder();
            foreach (IList<byte> bytesList in stackList)
            {
                sb.Append(ValueString(bytesList));
            }

            return sb.ToString();
        }

        /// <summary>
        /// Decode small integer
        /// </summary>
        /// <param name="opcode">Small integer opcode (OP_0 - OP_16)</param>
        /// <returns>Small integer</returns>
        public static int DecodeOP_N(opcodetype opcode)
        {
            if (opcode == opcodetype.OP_0)
                return 0;

            // Only OP_n opcodes are supported, throw exception otherwise.
            if (opcode < opcodetype.OP_1 || opcode > opcodetype.OP_16)
                throw new Exception("Invalid small integer opcode.");
            return (int)opcode - (int)(opcodetype.OP_1 - 1);
        }

        /// <summary>
        /// Converts small integer into opcode
        /// </summary>
        /// <param name="n">Small integer from the range of 0 up to 16.</param>
        /// <returns>Corresponding opcode.</returns>
        public static opcodetype EncodeOP_N(int n)
        {
            // The n value must be in the range of 0 to 16.
            if (n < 0 || n > 16)
                throw new Exception("Invalid small integer value.");
            if (n == 0)
                return opcodetype.OP_0;
            return (opcodetype)(opcodetype.OP_1 + n - 1);
        }

        public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
        {
            switch (t)
            {
                case txnouttype.TX_NONSTANDARD:
                    return -1;
                case txnouttype.TX_NULL_DATA:
                    return 1;
                case txnouttype.TX_PUBKEY:
                    return 1;
                case txnouttype.TX_PUBKEYHASH:
                    return 2;
                case txnouttype.TX_MULTISIG:
                    if (solutions.Count() < 1 || solutions.First().Count() < 1)
                        return -1;
                    return solutions.First().First() + 1;
                case txnouttype.TX_SCRIPTHASH:
                    return 1; // doesn't include args needed by the script
            }
            return -1;
        }


        public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
        {
            IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();

            if (!Solver(scriptPubKey, out whichType, out solutions))
            {
                // No solutions found
                return false;
            }

            if (whichType == txnouttype.TX_MULTISIG)
            {
                byte m = solutions.First().First();
                byte n = solutions.Last().First();

                // Support up to x-of-3 multisig txns as standard
                if (n < 1 || n > 3)
                {
                    return false;
                }
                if (m < 1 || m > n)
                {
                    return false;
                }
            }

            return whichType != txnouttype.TX_NONSTANDARD;
        }

        /// <summary>
        /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
        /// </summary>
        /// <param name="scriptPubKey">CScript instance</param>
        /// <param name="typeRet">Output type</param>
        /// <param name="solutions">Set of solutions</param>
        /// <returns>Result</returns>
        public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
        {
            solutions = new List<IEnumerable<byte>>();

            // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types:

            // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
            if (scriptPubKey.IsPayToScriptHash())
            {
                typeRet = txnouttype.TX_SCRIPTHASH;

                // Take 20 bytes with offset of 2 bytes
                IEnumerable<byte> hashBytes = scriptPubKey.Enumerable.Skip(2).Take(20);
                solutions.Add(hashBytes);

                return true;
            }

            // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
            if (scriptPubKey.IsPayToPubKeyHash())
            {
                typeRet = txnouttype.TX_PUBKEYHASH;

                // Take 20 bytes with offset of 3 bytes
                IEnumerable<byte> hashBytes = scriptPubKey.Enumerable.Skip(3).Take(20);
                solutions.Add(hashBytes);

                return true;
            }

            List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();

            // Sender provides pubkey, receiver adds signature
            // [ECDSA public key] OP_CHECKSIG
            templateTuples.Add(
                new Tuple<txnouttype, IEnumerable<byte>>(
                    txnouttype.TX_PUBKEY,
                    new byte[] { (byte)opcodetype.OP_PUBKEY, (byte)opcodetype.OP_CHECKSIG })
            );

            // Sender provides N pubkeys, receivers provides M signatures
            // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
            // Where N and M are small integer opcodes (OP1 ... OP_16)
            templateTuples.Add(
                new Tuple<txnouttype, IEnumerable<byte>>(
                    txnouttype.TX_MULTISIG,
                    new byte[] { (byte)opcodetype.OP_SMALLINTEGER, (byte)opcodetype.OP_PUBKEYS, (byte)opcodetype.OP_SMALLINTEGER, (byte)opcodetype.OP_CHECKMULTISIG })
            );

            // Data-carrying output
            // OP_RETURN [up to 80 bytes of data]
            templateTuples.Add(
                new Tuple<txnouttype, IEnumerable<byte>>(
                    txnouttype.TX_NULL_DATA,
                    new byte[] { (byte)opcodetype.OP_RETURN, (byte)opcodetype.OP_SMALLDATA })
            );

            // Nonstandard tx output
            typeRet = txnouttype.TX_NONSTANDARD;

            foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
            {
                CScript script1 = scriptPubKey;
                CScript script2 = new CScript(templateTuple.Item2);

                opcodetype opcode1, opcode2;

                // Compare
                WrappedList<byte> wl1 = script1.GetWrappedList();
                WrappedList<byte> wl2 = script2.GetWrappedList();

                IEnumerable<byte> args1, args2;

                byte last1 = script1.Enumerable.Last();
                byte last2 = script2.Enumerable.Last();

                while (true)
                {
                    if (wl1.GetCurrentItem() == last1 && wl2.GetCurrentItem() == last2)
                    {
                        // Found a match
                        typeRet = templateTuple.Item1;
                        if (typeRet == txnouttype.TX_MULTISIG)
                        {
                            // Additional checks for TX_MULTISIG:
                            byte m = solutions.First().First();
                            byte n = solutions.Last().First();

                            if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
                            {
                                return false;
                            }
                        }
                        return true;
                    }

                    if (!GetOp(ref wl1, out opcode1, out args1))
                    {
                        break;
                    }
                    if (!GetOp(ref wl2, out opcode2, out args2))
                    {
                        break;
                    }

                    // Template matching opcodes:
                    if (opcode2 == opcodetype.OP_PUBKEYS)
                    {
                        while (args1.Count() >= 33 && args1.Count() <= 120)
                        {
                            solutions.Add(args1);
                            if (!GetOp(ref wl1, out opcode1, out args1))
                            {
                                break;
                            }
                        }
                        if (!GetOp(ref wl2, out opcode2, out args2))
                            break;
                        // Normal situation is to fall through
                        // to other if/else statements
                    }
                    if (opcode2 == opcodetype.OP_PUBKEY)
                    {
                        if (args1.Count() < 33 || args1.Count() > 120)
                        {
                            break;
                        }
                        solutions.Add(args1);
                    }
                    else if (opcode2 == opcodetype.OP_PUBKEYHASH)
                    {
                        if (args1.Count() != 20) // hash160 size
                        {
                            break;
                        }
                        solutions.Add(args1);
                    }
                    else if (opcode2 == opcodetype.OP_SMALLINTEGER)
                    {
                        // Single-byte small integer pushed onto solutions
                        if (opcode1 == opcodetype.OP_0 || (opcode1 >= opcodetype.OP_1 && opcode1 <= opcodetype.OP_16))
                        {
                            byte n = (byte)DecodeOP_N(opcode1);
                            solutions.Add(new byte[] { n });
                        }
                        else
                        {
                            break;
                        }
                    }
                    else if (opcode2 == opcodetype.OP_SMALLDATA)
                    {
                        // small pushdata, <= 80 bytes
                        if (args1.Count() > 80)
                        {
                            break;
                        }
                    }
                    else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
                    {
                        // Others must match exactly
                        break;
                    }
                }
            }

            solutions.Clear();
            typeRet = txnouttype.TX_NONSTANDARD;

            return false;
        }
    };
}