StakeLocking.sol

contract LockManager {
    function canUnlock(bytes32 lockId, bytes lockData) public view returns (bool);
}

// ERC900 compatibility left out of this spec
contract StakeLocking /*is ERC900*/{
    struct Staker {
        // would need to be checkpointed
        uint256 amount;
        // evaluate when it makes sense to keep an updated unlockedAmount or a list of locks that gets checked
        // probably no need for checkpointing unlockedAmount
        uint256 unlockedAmount;
    }    

    mapping (address => Staker) public stakers;
    
    struct Lock {
        uint256 amount;
        uint64 createdAt;
        uint64 updatedAt;
        uint64 unlockedAt;
        address staker;
        LockManager manager; // can also be an EOA
        bytes data;
    }
    
    mapping (bytes32 => Lock) public locks;
    
    // STAKER
    
    function lock(uint256 amount, address manager, bytes data) external returns (bytes32 lockId);
    
    // Same as lock, but staker doesnt need to directly call it. Staker can provide signed message to someone else that can then lock.
    function lockFor(address staker, uint256 amount, LockManager manager, bytes data, bytes signature) external returns (bytes32 lockId);
    
    // Directly unlock if msg.sender is the lock's manager otherwise check `manager.canUnlock(lockId, data)` and msg.sender is staker
    function unlock(bytes32 lockId) external;
    
    // Staker can transfer unlocked tokens to another account or to a lock
    // If toLockId is provided, MUST not have already been unlocked
    // `toLockId` staker MUST be `to`
    function transfer(uint256 amount, address to, bytes32 toLockId);
    
    // ONLY MANAGER
    
    // Manager can transfer from a lock to another staker account, or to a lock
    // `amount` MUST be decreased from `lockId`'s amount
    // If toLockId is provided, MUST not have already been unlocked
    // `toLockId` staker MUST be `to`
    function transferFromLock(bytes32 lockId, uint256 amount, address to, bytes32 toLockId);
    
    // Manager can only decrease lock amount
    function setLockAmount(bytes32 lockId, uint256 newAmount) external;
    // Manager can set another manager for the lock
    function setLockManager(bytes32 lockId, LockManager newManager) external;
    // Manager can change lock data
    function setLockData(bytes32 lockId, bytes newData) external;
}