tonb/sources/staking.tact

import "constants";
import "messages";

fun stakingDepositMessage(value: Int, pool: Address): SendParameters {
    return SendParameters{
        to: pool,
        value: value,
        body: beginCell().storeUint(0x7bcd1fef, 32)/*.storeSlice("Deposit".asSlice())*/.endCell()
    };
}

fun stakingWithdrawMessage(value: Int, pool: Address): SendParameters {
    return SendParameters{
        to: pool,
        value: ton("0.05"),
        body: beginCell().storeUint(3665837821, 32).storeCoins(value).endCell()
    };
}

struct WithdrawalRequests {
    addresses: map[Int]Address;
    amounts: map[Int]Int;
    n_requests: Int = 0;
}

fun withdrawalSum(requests: WithdrawalRequests): Int {
    let sum: Int = 0;
    let i: Int = 0;
    while(i < requests.n_requests) {
        sum = sum + requests.amounts.get(i)!!;
        i = i + 1;
    }
    return sum;
}

trait StakingTrait {
    staking_pool: Address?;
    withdrawal_requests: WithdrawalRequests;
    owner: Address;
    in_the_pool: Int = 0;

    fun sendStake() {
        if(self.staking_pool == null) {
            return;
        }
        let value: Int = myBalance() - tonb_floor - staking_gas;
        if(value < ton("0.05")) {
            return;
        }
        self.in_the_pool = self.in_the_pool + value;
        send(stakingDepositMessage(value, self.staking_pool!!));
    }

    fun sendWithdrawal() {
        if(self.staking_pool == null) {
            return;
        }
        let value: Int = withdrawalSum(self.withdrawal_requests);
        send(stakingWithdrawMessage(value, self.staking_pool!!));
    }

    receive("Withdraw completed") {
        let i: Int = 0;
        while(i < self.withdrawal_requests.n_requests) {
            let addr: Address = self.withdrawal_requests.addresses.get(i)!!;
            send(SendParameters{
                to: addr, 
                value: ton("0.08"), 
                bounce: false,
                body: TokenBurn{
                    amount: self.withdrawal_requests.amounts.get(i)!!,
                    queryId: 0,
                    responseAddress: myAddress(),
                    owner: addr
                }.toCell()
            });
            i = i + 1;
        }
        let ctx: Context = context();
        let val: Int = ctx.value;
        self.in_the_pool = self.in_the_pool - val;
        if (self.in_the_pool < 0) {
            let value: Int = -self.in_the_pool;
            send(SendParameters{
                to: self.owner,
                value: value,
                body: Unstake{amount: value}.toCell()
            });
            self.in_the_pool = 0;
        }
        self.withdrawal_requests = WithdrawalRequests{
            addresses: emptyMap(),
            amounts: emptyMap()
        };
    }

    receive(msg: Unstake) {
        if(self.staking_pool == null) {
            return;
        }
        let ctx: Context = context();
        require(ctx.sender == self.owner, "Only the owner can trigger un-staking");
        send(stakingWithdrawMessage(msg.amount /* 0 to unstake all */, self.staking_pool!!));
    }

    fun requestWithdrawal(address: Address, value: Int) {
        self.withdrawal_requests.addresses.set(self.withdrawal_requests.n_requests, address);
        self.withdrawal_requests.amounts.set(self.withdrawal_requests.n_requests, value);
        self.withdrawal_requests.n_requests = self.withdrawal_requests.n_requests + 1;
        send(stakingWithdrawMessage(value, self.staking_pool!!));
    }
}