--- id: tezos-taco-shop-payout title: Paying out profits from the Taco Shop --- In the [previous tutorial](tutorials/get-started/tezos-taco-shop-smart-contract.md) we've learned how to setup & interact with the LIGO CLI. Followed by implementation of a simple Taco Shop smart contract for our entepreneur Pedro. In this tutorial we'll make sure Pedro has access to tokens that people have spent at his shop when buying tacos.
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## Analyzing the current contract ### **`taco-shop.ligo`** ``` type taco_supply is record current_stock : nat; max_price : tez; end type taco_shop_storage is map(nat, taco_supply); function buy_taco (const taco_kind_index: nat ; var taco_shop_storage : taco_shop_storage) : (list(operation) * taco_shop_storage) is begin // Retrieve the taco_kind from the contract's storage const taco_kind : taco_supply = get_force(taco_kind_index, taco_shop_storage); const current_purchase_price : tez = taco_kind.max_price / taco_kind.current_stock; if amount =/= current_purchase_price then // we won't sell tacos if the amount isn't correct fail("Sorry, the taco you're trying to purchase has a different price"); else // Decrease the stock by 1n, because we've just sold one taco_kind.current_stock := abs(taco_kind.current_stock - 1n); // Update the storage with the refreshed taco_kind taco_shop_storage[taco_kind_index] := taco_kind; end with ((nil : list(operation)), taco_shop_storage) ``` ### Purchase price formula Pedro's Taco Shop contract currently enables customers to buy tacos, at a computed price based on a simple formula. ``` const current_purchase_price : tez = taco_kind.max_price / taco_kind.current_stock; ``` ### Replacing *spendable* smart contracts However, due to the [recent protocol upgrade](http://tezos.gitlab.io/mainnet/protocols/004_Pt24m4xi.html) of the Tezos mainnet, Pedro can't access the tokens stored in his Shop's contract directly. This was previously possible via `spendable` smart contracts, which are no longer available in the new protocol. We will have to implement a solution to access tokens from the contract programatically. --- ## Designing a payout scheme Pedro is a standalone bussines owner, and in our case, he doesn't have to split profits / earnings of the taco shop with anyone. So for the sake of simplicity, we'll payout all the earned XTZ directly to Pedro right after a succesful taco purchase. This means that after all the *purchase conditions* of our contract are met - e.g. correct amount is sent to the contract - we'll not only decrease the supply of the individual purchased *taco kind*, but we'll also transfer this amount in a *subsequent transaction* to Pedro's personal address. ## Forging a payout transaction ### Defining the recipient In order to send tokens, we will need a receiver address - which in our case will be Pedro's personal account. Additionally we'll wrap the given address as a *`contract(unit)`* - which represents either a contract with no parameters, or an implicit account. ``` const ownerAddress : address = "tz1TGu6TN5GSez2ndXXeDX6LgUDvLzPLqgYV"; const receiver : contract(unit) = get_contract(ownerAddress); ``` > Would you like to learn more about addresses, contracts and operations in LIGO? Check out the [LIGO cheat sheet](language-basics/cheat-sheet.md) ### Adding the transaction to the list of output operations Now we can transfer the `amount` received by `buy_taco` to Pedro's `ownerAddress`. We will do so by forging a `transaction(unit, amount, receiver)` within a list of operations returned at the end of our contract. ``` const payoutOperation : operation = transaction(unit, amount, receiver) ; const operations : list(operation) = list payoutOperation end; ``` --- ## Finalizing the contract ### **`taco-shop.ligo`** ``` type taco_supply is record current_stock : nat; max_price : tez; end type taco_shop_storage is map(nat, taco_supply); const ownerAddress: address = "tz1TGu6TN5GSez2ndXXeDX6LgUDvLzPLqgYV"; function buy_taco (const taco_kind_index: nat ; var taco_shop_storage : taco_shop_storage) : (list(operation) * taco_shop_storage) is begin // Retrieve the taco_kind from the contract's storage const taco_kind : taco_supply = get_force(taco_kind_index, taco_shop_storage); const current_purchase_price : tez = taco_kind.max_price / taco_kind.current_stock; if amount =/= current_purchase_price then // we won't sell tacos if the amount isn't correct fail("Sorry, the taco you're trying to purchase has a different price"); else // Decrease the stock by 1n, because we've just sold one taco_kind.current_stock := abs(taco_kind.current_stock - 1n); // Update the storage with the refreshed taco_kind taco_shop_storage[taco_kind_index] := taco_kind; const receiver : contract(unit) = get_contract(ownerAddress); const payoutOperation : operation = transaction(unit, amount, receiver); const operations : list(operation) = list payoutOperation end; end with (operations, taco_shop_storage) ``` ### Dry-run the contract To confirm that our contract is valid, we can dry run it. As a result we see a *new operation* in the list of returned operations to be executed subsequently. ``` ligo dry-run taco-shop.ligo --syntax pascaligo --amount 1 buy_taco 1n "map 1n -> record current_stock = 50n; max_price = 50000000mtz; end; 2n -> record current_stock = 20n; max_price = 75000000mtz; end; end" ```
Operation(...bytes) included in the output

**Done! Our tokens are no longer locked in the contract, and instead they are sent to Pedro's personal account/wallet.** --- ## 👼 Bonus: donating part of the profits Because Pedro is a member of the (STA) Specialty Taco Association, he has decided to donate **10%** of the earnings to the STA. We'll just add a `donationAddress` to the contract, and compute a 10% donation sum from each taco purchase. ``` const ownerAddress: address = "tz1TGu6TN5GSez2ndXXeDX6LgUDvLzPLqgYV"; const donationAddress: address = "tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx"; ``` ``` const receiver : contract(unit) = get_contract(ownerAddress); const donationReceiver : contract(unit) = get_contract(donationAddress); const donationAmount: tez = amount / 10n; const operations : list(operation) = list // Pedro will get 90% of the amount transaction(unit, amount - donationAmount, receiver); transaction(unit, donationAmount, donationReceiver); end; ``` This will result into two operations being subsequently executed on the blockchain: - Donation transfer (10%) - Pedro's profits (90%)