lockdrop

A fair-launch lockdrop (Astroport-style).

During the lock window, participants lock lockToken for a duration of their choosing. Their reward allocation is weighted by amount × lock duration, so committing more, for longer, earns a larger slice of the reward pool. The operator funds the rewardToken pool and finalizes it; after a participant's chosen unlock time they reclaim their locked tokens, and once finalized they claim their pro-rata reward. It bootstraps a new token's distribution by rewarding genuine, time-weighted commitment rather than mercenary capital.

• lock(amount, unlockTime) — during the window; unlockTime must be lockWindowEnd + [minDuration, maxDuration]. Weight = amount × (unlockTime − lockWindowEnd). One lock per address.
• fundRewards(amount) — operator tops up the reward pool (only before finalization).
• finalize() — operator freezes the pool and opens claims (only after the lock window). Once.
• withdraw() — reclaim locked tokens once your unlock time passes.
• claim() — claim rewardPool × yourWeight / totalWeight once finalized. Once.
• Views: pendingReward(user), isLockOpen(), locks(user).

• ReentrancyGuard + SafeERC20; all pulls credit the actual amount received (fee-on-transfer safe).
• Rewards are frozen at finalize() before any claim, so allocations can't shift under claimants; pro-rata uses floored mulDiv, so the pool is never over-distributed.
• Locked principal is never at risk — it is always returned in full at unlock, independent of the reward math.
• Fully tested: unit tests for the amount×duration weighting, pro-rata rewards, unlock/withdraw, and every phase/access guard, plus two stateful invariants (fail_on_revert = true):
  • lock-token conservation — the lock-token balance always equals the un-withdrawn locked total;
  • reward conservation — the reward-token balance always equals the reward pool minus rewards claimed.

forge test
FOUNDRY_INVARIANT_FAIL_ON_REVERT=true forge test --match-path "test/Lockdrop.invariant.t.sol"

LOCK_TOKEN=0x... REWARD_TOKEN=0x... LOCK_WINDOW_END=1750000000 \
MIN_DURATION=2592000 MAX_DURATION=31536000 \
  forge script script/Deploy.s.sol --rpc-url "$RPC_URL" --broadcast

Not audited. Reference implementation — review before any real deployment.