Alarm Contract - Or how to incentivise people to wake you up!

Use Case

(Based on the escrow contract)

Let's imagine you set up an alarm clock that links to the blockchain. You want to incentivise people to wake you up in the morning! We need to do this:

1. Have an oracle setup the alarm when the time is right (don't want people to call this every waking moment!)
2. Let people bid on the wake-up time (people send Stacks and the winner gets all!)
3. Allow me to click the snooze button, or click the I am Awake button. Snooze gives 10% of the bounty to the person who triggered it, and I am Awake gives the full bounty and resets the timer

Lets get started

Checkout this repository:

git clone https://github.com/sprect8/morning-clarity
cd morning-clarity
npm install

Run the test:

npm run test

Note that I have hard-coded the keys into the smart contract; and generated 5 users (owner, oracle, and 3 bidders). (keys[2,3,4,5].json)

Inspect the source code:

cd contracts
vscode alarm-clock.clar

Inspect the test case:

cd tests
vscode alarm-clock.ts

Key bits of the code are the oracle (which controls when an alarm can be active) - this is similar to isOwner of Solidity:

;; time oracle set up the alarm; only when this is called can others begin to try and wake up the owner 
(define-public (activateAlarm)
  (begin
    (if (is-eq tx-sender timeOracle)
      (begin
         (var-set alarmActive true)
         (ok 1)
      )
      (ok 0)
    )
  )
)

Alarms can trigger only when the oracle says so. (alarmActive set to true). However we don't stop people from bidding.

When the user calls "iamAwake" we actually disburse the amount from the escrow itself:

;; send the bounty to the person who woke me up!
(define-private (payout-bounty)
   (begin
      (as-contract (stx-transfer? (var-get bounty) escrow (var-get lastSubmitted)))
      (var-set alarmActive false) ;; turn off alarm, oracle will call this to set alarm again later
      (var-set bounty u0) ;; reset the bounty once payout has been claimed
   )
)
...
;; owner hits the stop alarm button, wakes up and the last submitted transaction gets the bounty

(define-public (iamAwake)
  (begin
    (if-not-owner-then-panic)
    (if (is-eq (var-get bounty) u0)
        (ok true) ;; no bounty, no need to payout
      (if (> (var-get bounty) u0)
         (ok (payout-bounty))
         (ok true)
      )
    )
  )
)

Some challenges

• The Provider code is still very much alpha, and I couldn't find good documentation online
• There are some weird nuances in the language, especially the Provider/Client interface
  1. Why do I specify uint and int differently and as a string?!
  2. How come the transactions don't unwrap nicely and I ended up having to use text to compare
  3. Tuples, transactions don't work very well
  4. Compiler output can be challenging!

Overall a decent language once you get the hang of it. Great stuff!