# Development Manual

package contracts.examples;

import io.nuls.contract.sdk.Contract;
import io.nuls.contract.sdk.annotation.Payable;
import io.nuls.contract.sdk.annotation.Required;
import io.nuls.contract.sdk.annotation.View;

public class SimpleStorage implements Contract {

    private String storedData;

    /**
     * Only when `@View` is added, the contract status will remain and it can be researched by such means
     */
    @View
    public String getStoredData() {
        return storedData;
    }

    /**
     * Only when `@Payable` is added, the amount can be transferred in
     */
    @Payable
    public void setStoredData(@Required String storedData) {
        this.storedData = storedData;
    }
    
    /**
     * The return value is automatically serialized by the VM in JSON format and returned as a JSON string.
     * Note: The object level must not exceed 3 layers. The more than 3 layers will call the object's toString method, and will not continue serialization.
     */
    @JSONSerializable
    public Map vJsonSerializableMap() {
        Map map = new HashMap();
        map.put("name", "nuls");
        map.put("url", "https://nuls.io");
        return map;
    }

}

public class Address {

    private final String address;

    public Address(String address) {
        valid(address);
        this.address = address;
    }
    
    /**
     * Get the available balance of the address
     *
     * @return BigInteger
     */
    public native BigInteger balance();

    /**
     * Get the total balance of the address
     *
     * @return BigInteger
     */
    public native BigInteger totalBalance();

    /**
     * 合约向该地址转账(NULS, 可锁定)
     *
     * @param value         转账金额（多少Na）
     * @param lockedTime    锁定时间（单位秒，若锁定1分钟，则填入60）
     */
    public native void transferLocked(BigInteger value, long lockedTime);

    /**
     * 合约向该地址转账(NULS)
     *
     * @param value
     */
    public void transfer(BigInteger value) {
        this.transferLocked(value, 0);
    }

    /**
     * 合约向该地址转账指定的资产(可锁定)
     *
     * @param value          转账金额
     * @param assetChainId   资产链ID
     * @param assetId        资产ID
     * @param lockedTime     锁定时间（单位秒，若锁定1分钟，则填入60）
     */
    public native void transferLocked(BigInteger value, int assetChainId, int assetId, long lockedTime);

    /**
     * 合约向该地址转账指定的资产
     *
     * @param value          转账金额
     * @param assetChainId   资产链ID
     * @param assetId        资产ID
     */
    public void transfer(BigInteger value, int assetChainId, int assetId) {
        this.transferLocked(value, assetChainId, assetId, 0);
    }

    /**
     * 获取该地址指定资产的可用余额
     *
     * @param assetChainId   资产链ID
     * @param assetId        资产ID
     * @return
     */
    public native BigInteger balance(int assetChainId, int assetId);

    /**
     * 获取该地址指定资产的总余额
     *
     * @param assetChainId   资产链ID
     * @param assetId        资产ID
     * @return
     */
    public native BigInteger totalBalance(int assetChainId, int assetId);

    /**
     * Contract method to call the address
     *
     * @param Method name
     * @param Method signature
     * @param Parameters       
     * @param value  Incidental currency (in Na)
     */
    public native void call(String methodName, String methodDesc, String[][] args, BigInteger value);

	/**
     * Call the contract method of this address with a return value(String)
     *
     * @param Method name
     * @param Method signature
     * @param Parameters       
     * @param value  Incidental currency (in Na)
     * @return return value after calling the contract
     */
    public native String callWithReturnValue(String methodName, String methodDesc, String[][] args, BigInteger value);
    
    /**
     * 调用该地址的合约方法并带有返回值(String)
     *
     * @param methodName        方法名
     * @param methodDesc        方法签名
     * @param args              参数
     * @param value             转入资产数量
     * @param multyAssetValues  转入的其他资产
     * @return 调用合约后的返回值
     */
    public native String callWithReturnValue(String methodName, String methodDesc, String[][] args, BigInteger value, MultyAssetValue[] multyAssetValues);

    /**
     * Verify the address 
     *
     * @param address
     * @see io.nuls.kernel.utils.AddressTool#validAddress(String)
     */
    private native void valid(String address);

    /**
     * Verify that the address is a contract address
     *
     */
    public native boolean isContract();
    
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Address address1 = (Address) o;
        return address != null ? address.equals(address1.address) : address1.address == null;
    }

    @Override
    public int hashCode() {
        return address != null ? address.hashCode() : 0;
    }

    @Override
    public String toString() {
        return address;
    }

}

public class Block {

    /**
     * Given block’s head
     *
     * @param blockNumber
     * @return
     */
    public static native BlockHeader getBlockHeader(long blockNumber);

    /**
     * Current block’s head
     *
     * @return
     */
    public static native BlockHeader currentBlockHeader();
    
    /**
     * Newest block’s head
     *
     * @return 
     */
    public static native BlockHeader newestBlockHeader();

    /**
     * Given block’s hash
     *
     * @param blockNumber
     * @return
     */
    public static String blockhash(long blockNumber) {
        return getBlockHeader(blockNumber).getHash();
    }

    /**
     * 
     * CCurrent block’s miner address
     *
     * @return
     */
    public static Address coinbase() {
        return currentBlockHeader().getPackingAddress();
    }

    /**
     * 
     * Current block’s No.
     *
     * @return
     */
    public static long number() {
        return currentBlockHeader().getHeight();
    }

    /**
     * 
     * Current block’s time stamp
     *
     * @return
     */
    public static long timestamp() {
        return currentBlockHeader().getTime();
    }
    
}

public class BlockHeader {

    private String hash;
    private long time;
    private long height;
    private long txCount;
    private Address packingAddress;
    private String stateRoot;

    public String getHash() {
        return hash;
    }

    public long getTime() {
        return time;
    }

    public long getHeight() {
        return height;
    }

    public long getTxCount() {
        return txCount;
    }

    public Address getPackingAddress() {
        return packingAddress;
    }

    public String getStateRoot() {
        return stateRoot;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        BlockHeader that = (BlockHeader) o;

        if (time != that.time) return false;
        if (height != that.height) return false;
        if (txCount != that.txCount) return false;
        if (hash != null ? !hash.equals(that.hash) : that.hash != null) return false;
        if (packingAddress != null ? !packingAddress.equals(that.packingAddress) : that.packingAddress != null)
            return false;
        return stateRoot != null ? stateRoot.equals(that.stateRoot) : that.stateRoot == null;
    }

    @Override
    public int hashCode() {
        int result = hash != null ? hash.hashCode() : 0;
        result = 31 * result + (int) (time ^ (time >>> 32));
        result = 31 * result + (int) (height ^ (height >>> 32));
        result = 31 * result + (int) (txCount ^ (txCount >>> 32));
        result = 31 * result + (packingAddress != null ? packingAddress.hashCode() : 0);
        result = 31 * result + (stateRoot != null ? stateRoot.hashCode() : 0);
        return result;
    }

    @Override
    public String toString() {
        return "BlockHeader{" +
                "hash='" + hash + '\'' +
                ", time=" + time +
                ", height=" + height +
                ", txCount=" + txCount +
                ", packingAddress=" + packingAddress +
                ", stateRoot='" + stateRoot + '\'' +
                '}';
    }

}

/**
 *  Contract interface, implemented by contract class
 */
public interface Contract {
    
    /**
     * Directly transfer to the contract, this method will be called, no action is done by default. 
     * Prerequisite: you need override this method and mark the `@Payable` annotation.
     */
    default void _payable() {
    }
    
    /**
     * 直接向合约转账其他资产，会触发这个方法，默认不做任何操作
     * 前提: 若合约地址支持直接转账其他资产，需重载这个方法，并且标记`@PayableMultyAsset`注解
     */
    default void _payableMultyAsset() {
    }

    /**
     * 1. This method is triggered when the consensus node reward address is the contract address, and the parameter is the block reward address detail two-dimensional array data. eg. [[address, amount], [address, amount], ...]
     * 2. This method is triggered when the deposit address is a contract address. The parameters are the contract address and the reward amount two-dimensional array data. eg. [[address, amount]]
     * Prerequisite: you need override this method and mark the `@Payable` annotation.
     */
    default void _payable(String[][] args) {
    }

}

/**
* Event interface, implemented by event class
*/
public interface Event {
}

public class Msg {

    /**
     * Remaining gas
     *
     * @return
     */
    public static native long gasleft();

    /**
     * sender of the contract
     *
     * @return
     */
    public static native Address sender();
    
    /**
     * sender public key of the contract
     *
     * @return sender public key of the contract
     */
    public static native String senderPublicKey();

    /**
     * The number of Nuls transferred by the contract sender to the contract address, the unit is Na, 1Nuls = 1 billion Na
     *
     * @return
     */
    public static native BigInteger value();

    /**
     * 合约发送者转入合约地址的其他资产列表
     *
     */
    public static native MultyAssetValue[] multyAssetValues();
    
    /**
     * Gas price
     *
     * @return
     */
    public static native long gasprice();

    /**
     * Contract address
     *
     * @return
     */
    public static native Address address();

}

public class MultyAssetValue {

    private BigInteger value;
    private int assetChainId;
    private int assetId;

    public MultyAssetValue() {
    }

    public MultyAssetValue(BigInteger value, int assetChainId, int assetId) {
        this.value = value;
        this.assetChainId = assetChainId;
        this.assetId = assetId;
    }

    public BigInteger getValue() {
        return value;
    }

    public void setValue(BigInteger value) {
        this.value = value;
    }

    public int getAssetChainId() {
        return assetChainId;
    }

    public void setAssetChainId(int assetChainId) {
        this.assetChainId = assetChainId;
    }

    public int getAssetId() {
        return assetId;
    }

    public void setAssetId(int assetId) {
        this.assetId = assetId;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        MultyAssetValue that = (MultyAssetValue) o;

        if (assetChainId != that.assetChainId) return false;
        if (assetId != that.assetId) return false;
        if (!value.equals(that.value)) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = value.hashCode();
        result = 31 * result + assetChainId;
        result = 31 * result + assetId;
        return result;
    }
}

public class Utils {

    private Utils() {
    }

    /**
     *  Check conditions; if conditions are not met, it will roll back.
     *
     * @param expression
     */
    public static void require(boolean expression) {
        if (!expression) {
            revert();
        }
    }

    /**
     * Check conditions; if conditions are not met, it will roll back
     *
     * @param expression
     * @param errorMessage
     */
    public static void require(boolean expression, String errorMessage) {
        if (!expression) {
            revert(errorMessage);
        }
    }

    /**
     * Terminate implementation and restore status
     */
    public static void revert() {
        revert(null);
    }

    /**
     * Terminate implementation and restore status
     *
     * @param errorMessage
     */
    public static native void revert(String errorMessage);

    /**
     * Send events
     *
     * @param event
     */
    public static native void emit(Event event);

	/**
     * @param seed a private seed
     * @return pseudo random number (0 ~ 1)
     */
    public static float pseudoRandom(long seed) {
        int hash1 = Block.currentBlockHeader().getPackingAddress().toString().substring(2).hashCode();
        int hash2 = Msg.address().toString().substring(2).hashCode();
        int hash3 = Msg.sender() != null ? Msg.sender().toString().substring(2).hashCode() : 0;
        int hash4 = Long.valueOf(Block.timestamp()).toString().hashCode();

        long hash = seed ^ hash1 ^ hash2 ^ hash3 ^ hash4;

        seed = (hash * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1);
        return ((int) (seed >>> 24) / (float) (1 << 24));
    }

    /**
     * @return pseudo random number (0 ~ 1)
     */
    public static float pseudoRandom() {
        return pseudoRandom(0x5DEECE66DL);
    }

    /**
     *
     * Please note that this is the SHA-3 FIPS 202 standard, not Keccak-256.
     *
     * @param src source string (hex encoding string)
     * @return sha3-256 hash (hex encoding string)
     */
    public static native String sha3(String hexString);

    /**
     *
     * Please note that this is the SHA-3 FIPS 202 standard, not Keccak-256.
     *
     * @param bytes source byte array
     * @return sha3-256 hash (hex encoding string)
     */
    public static native String sha3(byte[] bytes);
    
    /**
     * [Testnet]verify signature data(ECDSA)
     *
     * @param data(hex encoding string)
     * @param signature(hex encoding string)
     * @param pubkey(hex encoding string)
     * @return verify result
     */
    public static native boolean verifySignatureData(String data, String signature, String pubkey);

    /**
     * [Testnet]Generate a random seed with a specific algorithm based on the cutoff block height and the number of original seeds
     *
     * @param endHeight the cutoff block height
     * @param seedCount the number of original seeds
     * @param algorithm Hash algorithm identifier
     * @return After the original seed byte array is merged, the hash algorithm is used to get a 32-bit hash byte array, which is then converted into BigInteger(new BigInteger(byte[] bytes)).
     */
    public static native BigInteger getRandomSeed(long endHeight, int seedCount, String algorithm);

    /**
     * [Testnet]Generate a random seed using the `SHA3-256`hash algorithm based on the cutoff block height and the number of original seeds.
     *
     * @param endHeight the cutoff block height
     * @param seedCount the number of original seeds
     * @return After the original seed byte array is merged, the `SHA3-256` hash algorithm is used to get the 32-bit hash byte array, which is then converted into BigInteger(new BigInteger(byte[] bytes)).
     */
    public static BigInteger getRandomSeed(long endHeight, int seedCount) {
        return getRandomSeed(endHeight, seedCount, "SHA3");
    }

    /**
     * [Testnet]Generate a random seed with a specific algorithm based on the block height range
     *
     * @param startHeight the starting block height
     * @param endHeight   the cutoff block height
     * @param algorithm   Hash algorithm identifier
     * @return After the original seed byte array is merged, the hash algorithm is used to get a 32-bit hash byte array, which is then converted into BigInteger(new BigInteger(byte[] bytes)).
     */
    public static native BigInteger getRandomSeed(long startHeight, long endHeight, String algorithm);

    /**
     * [Testnet]Generate a random seed with the `SHA3-256` hash algorithm based on the block height range
     *
     * @param startHeight the starting block height
     * @param endHeight   the cutoff block height
     * @return After the original seed byte array is merged, the `SHA3-256` hash algorithm is used to get the 32-bit hash byte array, which is then converted into BigInteger(new BigInteger(byte[] bytes)).
     */
    public static BigInteger getRandomSeed(long startHeight, long endHeight){
        return getRandomSeed(startHeight, endHeight, "SHA3");
    }

    /**
     * [Testnet]Get a collection of raw seeds based on the cutoff block height and the number of original seeds
     *
     * @param endHeight the cutoff block height
     * @param seedCount the number of original seeds
     * @return returns a collection of original seeds, the element is a BigInteger (new BigInteger(byte[] bytes)))
     */
    public static native List<BigInteger> getRandomSeedList(long endHeight, int seedCount);

    /**
     * [Testnet]Get a collection of raw seeds based on the block height range
     *
     * @param startHeight the starting block height
     * @param endHeight   the cutoff block height
     * @return returns a collection of original seeds, the element is a BigInteger (new BigInteger(byte[] bytes)))
     */
    public static native List<BigInteger> getRandomSeedList(long startHeight, long endHeight);
    
    /**
     * command to call other modules on the chain
     *
     * @see <a href="https://docs.nuls.io/zh/NULS2.0/vm-sdk.html">Detailed documentation for calling the command</a>
     * @param cmdName 
     * @param args 
     * @return depending on the return type of the registration command, it can return a string, an array of strings, a two-dimensional array of strings
     */
    public static native Object invokeExternalCmd(String cmdName, String[] args);
    
    /**
     * Convert an object to a json string
     * Note: If the object contains complex objects, the serialization depth must not exceed level 3
     *
     * @param obj
     * @return Json string
     */
    public static native String obj2Json(Object obj);
    
    /**
      * Create contract internally
      * @param salt The factors involved in calculating the new contract address
      * @param codeCopy specifies the contract template
      * @param args deployment parameters
      * @return the deployed contract address
      */
    public static String deploy(String[] salt, Address codeCopy, String[] args) {
        require(codeCopy.isContract(), "not contract address");
        String finalSalt = encodePacked(salt);
        int argsLength = 0;
        if (args != null) {
            argsLength = args.length;
        }
        String[] arr = new String[args.length + 2];
        arr[0] = codeCopy.toString();
        arr[1] = finalSalt;
        for (int i = 0; i < argsLength; i++) {
            arr[2 + i] = args[i];
        }
        return (String) Utils.invokeExternalCmd("createContract", arr);
    }

    /**
     * String array encoding
     */
    public static String encodePacked(String[] args) {
        return (String) Utils.invokeExternalCmd("encodePacked", args);
    }

    /**
      * Calculate the contract address
      * @param salt The factors involved in calculating the new contract address
      * @param codeHash the hash value of the contract code
      * @param sender contract deployer
      * @return contract address
      */
    public static String computeAddress(String[] salt, String codeHash, Address sender) {
        String finalSalt = encodePacked(salt);
        return (String) Utils.invokeExternalCmd("computeAddress", new String[]{finalSalt, codeHash, sender.toString()});
    }

    /**
      * Get the hash value of the contract code
      * @param codeAddress contract address
      * @return the hash value of the contract code
      */
    public static String getCodeHash(Address codeAddress) {
        require(codeAddress.isContract(), "not contract address");
        return (String) Utils.invokeExternalCmd("getCodeHash", new String[]{codeAddress.toString()});
    }
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Payable {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface PayableMultyAsset {
}

@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Required {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface View {
}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface JSONSerializable {
}