fix: Add restrictions when depositing rewards.

[Skyge]

Fix #16

[keyvank]

This will break the BETH contract. what if we deposit all the BETH to the next epoch in case there is no staker in current epoch?

[keyvank]

Or imagine smth like this:

if(epochTotalLocked[epoch - 1] == 0) {
   if(epochReward[epoch - 1] > 0) {
      epochReward[epoch] += epochReward[epoch - 1];
      epochReward[epoch - 1] = 0;
   }
}

[Skyge]

This will break the BETH contract.

I see.

Or imagine smth like this

Make sense.

But how about rewards that are deposited at epoch 0.

[keyvank]

i guess this is fixed in your PR right?

[keyvank]

Should we report total-amount or _amount here?

[Skyge]

Yes, we can use _amount, it is clear match with what depositor actually sent.

And for the line 115:

epochReward[epoch - 1] = 0;

Should we add a separate event for accumulated rewards, like:
emit RewardAccumulated(epoch - 1, epoch, previousEpochReward);

[Skyge]

There is another scenario:

Epoch Timeline:
Epoch n-1: No lockers, no rewards deposited      → epochReward[n-1] = 0
Epoch n:   No lockers, rewards deposited (> 0)  → epochReward[n] > 0
Epoch n+1: No lockers, no rewards deposited     → No depositReward() calls
Epoch n+2: Lockers present, rewards deposited   → Checks only epoch n+1

Rewards for Epoch n become permanently stuck because:

1. Distribution for epoch n only triggers when someone deposits rewards for epoch n+1

2. No one deposits rewards for epoch n+1

3. When rewards are later deposited for epoch n+2, the system only checks epoch n+1 (which has no rewards)

4. The system never skips empty epochs to check epoch n