using Neo.SmartContract.Framework;
using Neo.SmartContract.Framework.Services.Neo;
using Neo.SmartContract.Framework.Services.System;
using System;
using System.ComponentModel;
using System.Numerics;

namespace Nep5Template
{
    public class Nep5Template : SmartContract
    {
        //Token Settings
        public static string Name() => "Nep5Template Token";
        public static string Symbol() => "TMP";
        public static readonly byte[] community = "AXK2KtCfcJnSMyRzSwTuwTKgNrtx5aXfFX".ToScriptHash();
        public static byte Decimals() => 8;
        private const ulong factor = 100000000; //decided by Decimals()

        //ICO Settings
        private const ulong totalAmount = 1000000000 * factor;
        private const ulong communityCap = 1000000000 * factor;

        [DisplayName("transfer")]
        public static event Action<byte[], byte[], BigInteger> Transferred;

        public static Object Main(string operation, params object[] args)
        {
            if (Runtime.Trigger == TriggerType.Application)
            {
                if (operation == "init") return Init();
                if (operation == "totalSupply") return TotalSupply();
                if (operation == "name") return Name();
                if (operation == "symbol") return Symbol();
                if (operation == "transfer")
                {
                    if (args.Length != 3) return false;
                    byte[] from = (byte[])args[0];
                    byte[] to = (byte[])args[1];
                    BigInteger value = (BigInteger)args[2];
                    return Transfer(from, to, value);
                }
                if (operation == "balanceOf")
                {
                    if (args.Length != 1) return 0;
                    byte[] account = (byte[])args[0];
                    return BalanceOf(account);
                }
                if (operation == "decimals") return Decimals();
            }
            return false;
        }

        // 초기화 파라미터
        public static bool Init()
        {
            byte[] total_supply = Storage.Get(Storage.CurrentContext, "totalSupply");
            if (total_supply.Length != 0) return false;

            Storage.Put(Storage.CurrentContext, community, communityCap);
            Transferred(null, community, communityCap);

            Storage.Put(Storage.CurrentContext, "totalSupply", totalAmount);
            return true;
        }

        // get the total token supply
        // 이미 발행된 token총량 획득
        public static BigInteger TotalSupply()
        {
            Runtime.CheckSig(new byte[1]{ 1 },  new byte[]{2},new byte[]{ 3});
            return Storage.Get(Storage.CurrentContext, "totalSupply").AsBigInteger();
        }

        // function that is always called when someone wants to transfer tokens.
        // 트랜잭션Token 호출
        public static bool Transfer(byte[] from, byte[] to, BigInteger value)
        {
            if (value <= 0) return false;
            if (!Runtime.CheckWitness(from)) return false;
            if (from == to) return true;
            BigInteger from_value = Storage.Get(Storage.CurrentContext, from).AsBigInteger();
            if (from_value < value) return false;
            if (from_value == value)
                Storage.Delete(Storage.CurrentContext, from);
            else
                Storage.Put(Storage.CurrentContext, from, from_value - value);
            BigInteger to_value = Storage.Get(Storage.CurrentContext, to).AsBigInteger();
            Storage.Put(Storage.CurrentContext, to, to_value + value);
            Transferred(from, to, value);
            return true;
        }

        // get the account balance of another account with address
        // 주소에 따라 token잔액 획득
        public static BigInteger BalanceOf(byte[] address)
        {
            return Storage.Get(Storage.CurrentContext, address).AsBigInteger();
        }
    }
}