/**
*  Novacoin classes library
*  Copyright (C) 2015 Alex D. (balthazar.ad@gmail.com)

*  This program is free software: you can redistribute it and/or modify
*  it under the terms of the GNU Affero General Public License as
*  published by the Free Software Foundation, either version 3 of the
*  License, or (at your option) any later version.

*  This program is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU Affero General Public License for more details.

*  You should have received a copy of the GNU Affero General Public License
*  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

using System.Collections.Generic;
using System.Linq;
using System;
using System.Diagnostics.Contracts;

namespace Novacoin
{
    /// <summary>
    /// Available address types
    /// </summary>
    public enum AddrType
    {
        PUBKEY_ADDRESS = 8,
        SCRIPT_ADDRESS = 20,
        PUBKEY_ADDRESS_TEST = 111,
        SCRIPT_ADDRESS_TEST = 196
    };

    /// <summary>
    /// Represents novacoin address
    /// </summary>
    public class CNovacoinAddress
    {
        private byte nVersion;
        private byte[] addrData = new byte[20];

        /// <summary>
        /// Initialize with custom data and version
        /// </summary>
        /// <param name="nVersionIn"></param>
        /// <param name="addrDataIn"></param>
        public CNovacoinAddress(byte nVersionIn, byte[] addrDataIn)
        {
            Contract.Requires<ArgumentException>(addrDataIn.Length == 20, "Your data doesn't look like a valid hash160 of some value.");

            nVersion = nVersionIn;
            addrDataIn.CopyTo(addrData, 0);
        }

        /// <summary>
        /// Initialize new instance of PUBKEY_ADDRESS
        /// </summary>
        /// <param name="keyID">CKeyID instance</param>
        public CNovacoinAddress(CKeyID keyID)
        {
            nVersion = (byte)AddrType.PUBKEY_ADDRESS;
            addrData = keyID;
        }

        /// <summary>
        /// Initialize new instance of SCRIPT_ADDRESS
        /// </summary>
        /// <param name="keyID">CScriptID instance</param>
        public CNovacoinAddress(CScriptID scriptID)
        {
            nVersion = (byte)AddrType.SCRIPT_ADDRESS;
            addrData = scriptID;
        }

        /// <summary>
        /// Initialize new instance from base58 string
        /// </summary>
        /// <param name="strNovacoinAddress"></param>
        public CNovacoinAddress(string strNovacoinAddress)
        {
            var RawAddrData = AddressTools.Base58DecodeCheck(strNovacoinAddress);

            if (RawAddrData.Length != 21)
            {
                throw new ArgumentException("Though you have provided a correct Base58 representation of some data, this data doesn't represent a valid Novacoin address.");
            }

            nVersion = RawAddrData[0];
            Array.Copy(RawAddrData, 1, addrData, 0, 20);
        }

        /// <summary>
        /// 20 bytes, Hash160 of script or public key
        /// </summary>
        public static implicit operator byte[](CNovacoinAddress addr)
        {
            return addr.addrData;
        }

        /// <summary>
        /// Basic sanity checking
        /// </summary>
        public bool IsValid
        {
            get
            {
                // Address data is normally generated by RIPEMD-160 hash function
                int nExpectedSize = 20;

                switch ((AddrType)nVersion)
                {
                    case AddrType.PUBKEY_ADDRESS:
                        nExpectedSize = 20; // Hash of public key
                        break;
                    case AddrType.SCRIPT_ADDRESS:
                        nExpectedSize = 20; // Hash of CScript
                        break;
                    case AddrType.PUBKEY_ADDRESS_TEST:
                        nExpectedSize = 20;
                        break;
                    case AddrType.SCRIPT_ADDRESS_TEST:
                        nExpectedSize = 20;
                        break;
                    default:
                        return false;
                }

                return addrData.Length == nExpectedSize;
            }
        }

        /// <summary>
        /// Generate base58 serialized representation of novacoin address
        /// </summary>
        /// <returns>Base58(data + checksum)</returns>
        public override string ToString()
        {
            var r = new List<byte>();

            r.Add(nVersion);
            r.AddRange(addrData);

            return AddressTools.Base58EncodeCheck(r.ToArray());
        }
    }
}