We want a custom vesting contract that will allow users to be an update_authority on the vesting so they can extend the vesting and lockup.

struct VestingContract {
	/// The destination for the tokens when they are vested
	pub *destination_address*: Pubkey,
	/// Optional authority that can extend the vesting date
	pub update_authority: Pubkey,
	/// The mint address of the SPL Token being vested
	pub mint_address: Pubkey,
	/// PDA for TokenAccount that holds the total vesting SPLs
	pub token_vault: Pubkey,
	/// The vesting schedule
	pub schedule: Vec<Vest>
}

struct Vest {
	/// The amount that unlocks at the date
	pub amount: u64,
	/// The current unlock date
	pub unlock_date: i64,
}

Instruction Set

CreateVestingSchedule

Create a new TokenAccount for the mint_address, store this TokenAccount as the token_vault. Validate that the Mint on the destination_address is the mint_address. Order the VestDate array. Sum the total amount from the array of VestDates and transfer that amount from the signer's account to the token_vault.

UpdateVestingSchedule

Validate that the update_authority is the signer. Order the new VestDate array by unlock. Loop through the new array of vest dates, for each item check that the unlock_date is greater than or equal to the current unlock_date AND the current unlock_date has not passed AND check that the amounts are the same. Return error if those checks fail. If they pass, store the new VestDate array on the VestingContract.

TransferVestedTokens

Loop through the VestDates, for those that the unlock_date has passed, sum the amount. After the loop transfer the total_amount to the destination_address. Amounts will be set to 0.

CloseVestingContract

Validate that token_vault is empty. Validate that all VestDate's have been claimed. Pull the lamports from the TokenAccount and the VestingContract account and flag for close.

Additional Items For Discussion

• Should there be a revoke_authority that has the ability to cancel a VestingContract?