Project Setup

We setup Python virtual environment. The following commands will install and activate the virtual environment and then install dependencies.

Installing with Virtual environment

pip install virtualenv
virtualenv venv
source venv/bin/activate
pip install pyteal

deactivate to deactivate the virtual environment.

source venv/bin/activate to activate virtualenv once again. Replace bin with Scripts on Windows.

PyTeal AMM Smart Contract

PyTeal contracts are written in Python using any editor of your choice. compileProgram method produces the TEAL code which is then compiled into bytecode and deployed to the blockchain.

The PyTeal smart contract consists of two programs. These are called the approval program and the clear programs. In PyTeal both of these programs are generally created in the same Python file.

The approval_program is responsible for processing all application calls to the contract, with the exception of the clear call. The program is responsible for implementing most of the logic of an application.

The clear_program is used to handle accounts using the clear call to remove the smart contract from their balance record.

To write PyTeal code we create a new directory and amm.py config.py helpers.py __init__.py files:

mkdir contracts
cd contracts
touch amm.py config.py helpers.py __init__.py

In amm.py we keep the high-level logic of the contract, helpers.py contains lower level methods and config.py keeps track of global variable and key configuration variables.

PyTeal Contract Configuration File

In config.py we contain the global variables, except for TOKEN_DEFAULT_AMOUNT, to congifure the smart contract.

from pyteal import Bytes, Int

CREATOR_KEY = Bytes("creator_key")

RESULT = Bytes("result")

TOKEN_FUNDING_KEY = Bytes("token_funding_key")
TOKEN_FUNDING_RESERVES = Bytes("token_funding_reserves")

POOL_FUNDING_RESERVES = Bytes("pool_funding_reserves")

POOL_TOKEN_KEY = Bytes("pool_token_key")
POOL_TOKENS_OUTSTANDING_KEY = Bytes("pool_tokens_outstanding_key")

YES_TOKEN_KEY = Bytes("yes_token_key")
YES_TOKENS_OUTSTANDING_KEY = Bytes("yes_tokens_outstanding_key")
YES_TOKENS_RESERVES = Bytes("yes_tokens_reserves")

NO_TOKEN_KEY = Bytes("no_token_key")
NO_TOKENS_OUTSTANDING_KEY = Bytes("no_tokens_outstanding_key")
NO_TOKENS_RESERVES = Bytes("no_tokens_reserves")

MIN_INCREMENT_KEY = Bytes("min_increment_key")

TOKEN_DEFAULT_AMOUNT = Int(10 ** 13)

These variables can be imported as:

from contracts.config import (
    CREATOR_KEY, TOKEN_FUNDING_KEY,
    POOL_TOKEN_KEY, MIN_INCREMENT_KEY,
    POOL_TOKENS_OUTSTANDING_KEY, TOKEN_DEFAULT_AMOUNT,
    YES_TOKEN_KEY, NO_TOKEN_KEY,
    TOKEN_FUNDING_RESERVES, POOL_FUNDING_RESERVES,
    RESULT
)

Main Conditional

    on_call_method = Txn.application_args[0]

    on_call = Cond(
        [on_call_method == Bytes("setup"), on_setup],
        [on_call_method == Bytes("supply"), on_supply],
        [on_call_method == Bytes("withdraw"), on_withdraw],
        [on_call_method == Bytes("redeem"), on_redemption],
        [on_call_method == Bytes("result"), on_result],
        [on_call_method == Bytes("swap"), on_swap],
    )

    program = Cond(
        [Txn.application_id() == Int(0), on_create],
        [Txn.on_completion() == OnComplete.NoOp, on_call],
        [Txn.on_completion() == OnComplete.DeleteApplication, on_delete],
        [
            Or(
                Txn.on_completion() == OnComplete.OptIn,
                Txn.on_completion() == OnComplete.CloseOut,
                Txn.on_completion() == OnComplete.UpdateApplication,
            ),
            Reject(),
        ],
    )

This statement is the heart of the smart contract. Based on how the contract is called, it chooses which operation to run. For example, if Txn.application_id() is 0, then the code from on_create runs. If Txn.on_completion() is OnComplete.NoOp, then on_call runs. If Txn.application_args[0] is "setup", then on_setup runs. If either Txn.on_completion() are OnComplete.OptIn,OnComplete.CloseOut,OnComplete.UpdateApplication or none of the described cases are true, the program will exit an with error. Let’s look at each of these cases below.

On create

    on_create = Seq(
        App.globalPut(CREATOR_KEY, Txn.application_args[0]),
        App.globalPut(TOKEN_FUNDING_KEY, Btoi(Txn.application_args[1])),
        App.globalPut(MIN_INCREMENT_KEY, Btoi(Txn.application_args[2])),
        App.globalPut(TOKEN_FUNDING_RESERVES, Int(0)),
        App.globalPut(POOL_FUNDING_RESERVES, Int(0)),
        App.globalPut(RESULT, Int(0)),
        Approve(),
    )

This part of the program is responsible for setting up the initial state of the smart contract. It writes the keys to its global state.

The values of CREATOR_KEY,TOKEN_FUNDING_KEY and MIN_INCREMENT_KEY keys are determined by the application call arguments from the Txn.application_args list. Meanhwile, TOKEN_FUNDING_RESERVES, POOL_FUNDING_RESERVES and RESULT are initialised as 0 integer values.

On setup

def get_setup():
    pool_token_id = App.globalGetEx(Global.current_application_id(), POOL_TOKEN_KEY)
    pool_tokens_outstanding = App.globalGetEx(
        Global.current_application_id(), POOL_TOKENS_OUTSTANDING_KEY
    )

    on_setup = Seq(
        pool_token_id,
        pool_tokens_outstanding,
        Assert(Not(pool_token_id.hasValue())),
        Assert(Not(pool_tokens_outstanding.hasValue())),
        createPoolToken(TOKEN_DEFAULT_AMOUNT),
        optIn(TOKEN_FUNDING_KEY),
        createNoToken(TOKEN_DEFAULT_AMOUNT),
        optIn(NO_TOKEN_KEY),
        createYesToken(TOKEN_DEFAULT_AMOUNT),
        optIn(YES_TOKEN_KEY),
        Approve(),
    )
    return on_setup

This code runs when an account calls Txn.application_args[0] that equals to Bytes("setup") into the smart contract. It returns true if the current pool token has not been created and there are no outstanding tokens, meaning that the smart contract can only be set up once.

The methods create pool token, yes and no tokens, which the contract opts in the application.

def createPoolToken(pool_token_amount: TealType.uint64) -> Expr:
    return Seq(
        InnerTxnBuilder.Begin(),
        InnerTxnBuilder.SetFields(
            {
                TxnField.type_enum: TxnType.AssetConfig,
                TxnField.config_asset_total: pool_token_amount,
                TxnField.config_asset_name: Bytes("PoolToken"),
                TxnField.config_asset_default_frozen: Int(0),
                TxnField.config_asset_decimals: Int(0),
                TxnField.config_asset_reserve: Global.current_application_address(),
            }
        ),
        InnerTxnBuilder.Submit(),
        App.globalPut(POOL_TOKEN_KEY, InnerTxn.created_asset_id()),
        App.globalPut(POOL_TOKENS_OUTSTANDING_KEY, Int(0)),
    )

def optIn(token_key: TealType.bytes) -> Expr:
    return sendToken(token_key, Global.current_application_address(), Int(0))

def sendToken(
    token_key: TealType.bytes, receiver: TealType.bytes, amount: TealType.uint64
) -> Expr:
    return Seq(
        InnerTxnBuilder.Begin(),
        InnerTxnBuilder.SetFields(
            {
                TxnField.type_enum: TxnType.AssetTransfer,
                TxnField.xfer_asset: App.globalGet(token_key),
                TxnField.asset_receiver: receiver,
                TxnField.asset_amount: amount,
            }
        ),
        InnerTxnBuilder.Submit(),
    )

def createNoToken(token_amount: TealType.uint64) -> Expr:
    return Seq(
        InnerTxnBuilder.Begin(),
        InnerTxnBuilder.SetFields(
            {
                TxnField.type_enum: TxnType.AssetConfig,
                TxnField.config_asset_total: token_amount,
                TxnField.config_asset_name: Bytes("NoToken"),
                TxnField.config_asset_unit_name: Bytes("No"),
                TxnField.config_asset_default_frozen: Int(0),
                TxnField.config_asset_decimals: Int(0),
                TxnField.config_asset_reserve: Global.current_application_address(),
            }
        ),
        InnerTxnBuilder.Submit(),
        App.globalPut(NO_TOKEN_KEY, InnerTxn.created_asset_id()),
        App.globalPut(NO_TOKENS_OUTSTANDING_KEY, Int(0)),
        App.globalPut(NO_TOKENS_RESERVES, Int(0)),
    )

def createYesToken(token_amount: TealType.uint64) -> Expr:
    return Seq(
        InnerTxnBuilder.Begin(),
        InnerTxnBuilder.SetFields(
            {
                TxnField.type_enum: TxnType.AssetConfig,
                TxnField.config_asset_total: token_amount,
                TxnField.config_asset_name: Bytes("YesToken"),
                TxnField.config_asset_unit_name: Bytes("Yes"),
                TxnField.config_asset_default_frozen: Int(0),
                TxnField.config_asset_decimals: Int(0),
                TxnField.config_asset_reserve: Global.current_application_address(),
            }
        ),
        InnerTxnBuilder.Submit(),
        App.globalPut(YES_TOKEN_KEY, InnerTxn.created_asset_id()),
        App.globalPut(YES_TOKENS_OUTSTANDING_KEY, Int(0)),
        App.globalPut(YES_TOKENS_RESERVES, Int(0)),
    )

On supply

def get_supply():
    token_txn_index = Txn.group_index() - Int(1)

    on_supply = Seq(
        Assert(
            And(
                validateTokenReceived(token_txn_index, TOKEN_FUNDING_KEY),
                Gtxn[token_txn_index].asset_amount()
                >= App.globalGet(MIN_INCREMENT_KEY),
           )
        ),
        mintAndSendPoolToken(
            Txn.sender(),
            Gtxn[token_txn_index].asset_amount(),
        ),
        Approve(),
    )
    return on_supply

This code runs when an account calls Txn.application_args[0] that equals to Bytes("supply") into the smart contract. It returns true if the token received by the smart contract is the same funding (reserve) token declared in the on_create part of the program and is larger in quantity than the minimum value.

validateTokenReceived validates the transfer of the tokens. mintAndSendPoolToken keeps track of the pool funding reserves and disburses the pool token based on the proportion of the provided to the exisitng funds.

def validateTokenReceived(
    transaction_index: TealType.uint64, token_key: TealType.bytes
) -> Expr:
    return And(
        Gtxn[transaction_index].type_enum() == TxnType.AssetTransfer,
        Gtxn[transaction_index].sender() == Txn.sender(),
        Gtxn[transaction_index].asset_receiver()
        == Global.current_application_address(),
        Gtxn[transaction_index].xfer_asset() == App.globalGet(token_key),
        Gtxn[transaction_index].asset_amount() > Int(0),
    )

def mintAndSendPoolToken(receiver: TealType.bytes, amount: TealType.uint64) -> Expr:
    ratio: ScratchVar = ScratchVar(TealType.uint64)
    return Seq(
        ratio.store(
            (Int(1) + App.globalGet(NO_TOKENS_RESERVES)) / (Int(1)  + App.globalGet(YES_TOKENS_RESERVES))
        ),
        If(App.globalGet(POOL_FUNDING_RESERVES) > Int(0))
        .Then(
            Seq(
                sendToken(POOL_TOKEN_KEY, receiver, amount * App.globalGet(POOL_TOKENS_OUTSTANDING_KEY) / App.globalGet(POOL_FUNDING_RESERVES) ),
                App.globalPut(
                    POOL_TOKENS_OUTSTANDING_KEY,
                App.globalGet(POOL_TOKENS_OUTSTANDING_KEY) + amount * App.globalGet(POOL_TOKENS_OUTSTANDING_KEY) / App.globalGet(POOL_FUNDING_RESERVES)
            ))
        )
        .ElseIf(App.globalGet(POOL_FUNDING_RESERVES) == Int(0))
        .Then(
            Seq(
                sendToken(POOL_TOKEN_KEY, receiver, amount ),
                App.globalPut(
                    POOL_TOKENS_OUTSTANDING_KEY,
                    App.globalGet(POOL_TOKENS_OUTSTANDING_KEY) + amount,
                ),
            )
        ),
        App.globalPut(NO_TOKENS_RESERVES, ratio.load()  * (amount / Int(4)) + App.globalGet(NO_TOKENS_RESERVES) ),
        App.globalPut(YES_TOKENS_RESERVES, ( Int(1) / ratio.load() )* (amount / Int(4)) + App.globalGet(YES_TOKENS_RESERVES) ),
        App.globalPut(
            POOL_FUNDING_RESERVES, App.globalGet(POOL_FUNDING_RESERVES) + amount
        ),
    )

On Withdraw

def get_withdraw():
    pool_token_txn_index = Txn.group_index() - Int(1)

    on_withdraw = Seq(
        Assert(
            validateTokenReceived(pool_token_txn_index, POOL_TOKEN_KEY)
        ),
        withdrawLPToken(
            Txn.sender(),
            Gtxn[pool_token_txn_index].asset_amount(),
        ),
        Approve(),
    )

    return on_withdraw

The code runs when an account calls Txn.application_args[0] that equals to Bytes("withdraw") into the smart contract. It returns true if the token received by the smart contract is the same pool token created in the on_create part of the program.

withdrawLPToken sends the proportional amount of funding (reserve) token to outstanding pool token, supplied pool tokens and funding reserves.

def withdrawLPToken(
    receiver: TealType.bytes,
    pool_token_amount: TealType.uint64,
) -> Expr:
    ratio: ScratchVar = ScratchVar(TealType.uint64)
    return Seq(
        sendToken(
            TOKEN_FUNDING_KEY,
            receiver,
            App.globalGet(POOL_FUNDING_RESERVES) * pool_token_amount / App.globalGet(POOL_TOKENS_OUTSTANDING_KEY),
        ),
        App.globalPut(
            POOL_FUNDING_RESERVES, App.globalGet(POOL_FUNDING_RESERVES) - (App.globalGet(POOL_FUNDING_RESERVES) * pool_token_amount / App.globalGet(POOL_TOKENS_OUTSTANDING_KEY)),
        ),
        App.globalPut(
            POOL_TOKENS_OUTSTANDING_KEY,
            App.globalGet(POOL_TOKENS_OUTSTANDING_KEY) - pool_token_amount,
        ),
        If(App.globalGet(RESULT)==Int(0)).Then(
            Seq(
                ratio.store(
                    (Int(1) + App.globalGet(NO_TOKENS_RESERVES)) / (Int(1) + App.globalGet(YES_TOKENS_RESERVES))
                ),
                App.globalPut(NO_TOKENS_RESERVES,  App.globalGet(NO_TOKENS_RESERVES) - (App.globalGet(POOL_FUNDING_RESERVES) * pool_token_amount / App.globalGet(POOL_TOKENS_OUTSTANDING_KEY)) / Int(4) * ratio.load() ),
                App.globalPut(YES_TOKENS_RESERVES, App.globalGet(YES_TOKENS_RESERVES) - (App.globalGet(POOL_FUNDING_RESERVES) * pool_token_amount / App.globalGet(POOL_TOKENS_OUTSTANDING_KEY)) / Int(4) * (Int(1)/ratio.load()) ),
            )),
    )

On Swap

def get_swap():
    token_txn_index = Txn.group_index() - Int(1)
    option = Txn.application_args[1]

    on_swap = Seq(
        Assert(
            validateTokenReceived(token_txn_index, TOKEN_FUNDING_KEY),
        ),
        If(option == Bytes("buy_yes"))
        .Then(
            Seq(
                mintAndSendYesToken(
                    Txn.sender(),
                    Gtxn[token_txn_index].asset_amount(),
                ),
                Approve()
            ),
        )
        .ElseIf(option == Bytes("buy_no"))
        .Then(
            Seq(
                mintAndSendNoToken(
                    Txn.sender(),
                    Gtxn[token_txn_index].asset_amount(),
                ),
                Approve()
            ),
        ),
        Reject()
        )

    return on_swap

The code runs when an account calls Txn.application_args[0] that equals to Bytes("swap") into the smart contract. It returns true if the token received by the smart contract is the same funding (reserve) token declared in on_create part of the program.

Depending on the argument in Txn.application_args[1], the user either can choose a yes or no option token. The price of each token is explicitly determined by the existing liquidity, reserves of yes and no tokens and the size of the trade.

def mintAndSendNoToken(
    receiver: TealType.bytes, amount: TealType.uint64
) -> Expr:
    funding = AssetHolding.balance(
        Global.current_application_address(), App.globalGet(TOKEN_FUNDING_KEY)
    )
    tokensOut: ScratchVar = ScratchVar(TealType.uint64)
    return Seq(
        tokensOut.store(
            App.globalGet(YES_TOKENS_RESERVES) * amount / (App.globalGet(NO_TOKENS_RESERVES) + amount )
        ),
        App.globalPut(NO_TOKENS_OUTSTANDING_KEY, App.globalGet(NO_TOKENS_OUTSTANDING_KEY) + tokensOut.load()),
        App.globalPut(NO_TOKENS_RESERVES, App.globalGet(NO_TOKENS_RESERVES) - tokensOut.load()),
        sendToken(NO_TOKEN_KEY, receiver, tokensOut.load()),
        If(App.globalGet(NO_TOKENS_OUTSTANDING_KEY) > App.globalGet(YES_TOKENS_OUTSTANDING_KEY))
        .Then(
            App.globalPut(TOKEN_FUNDING_RESERVES, App.globalGet(NO_TOKENS_OUTSTANDING_KEY) * Int(2))
        ),
        funding,
        App.globalPut(
            POOL_FUNDING_RESERVES,
            funding.value() - App.globalGet(TOKEN_FUNDING_RESERVES)
        ),
    )


def mintAndSendYesToken(
    receiver: TealType.bytes, amount: TealType.uint64
) -> Expr:
    funding = AssetHolding.balance(
        Global.current_application_address(), App.globalGet(TOKEN_FUNDING_KEY)
    )
    tokensOut: ScratchVar = ScratchVar(TealType.uint64)
    return Seq(
        tokensOut.store(
            (App.globalGet(NO_TOKENS_RESERVES) * amount / (App.globalGet(YES_TOKENS_RESERVES) + amount ))
        ),
        App.globalPut(YES_TOKENS_OUTSTANDING_KEY, App.globalGet(YES_TOKENS_OUTSTANDING_KEY) + tokensOut.load()),
        App.globalPut(YES_TOKENS_RESERVES, App.globalGet(YES_TOKENS_RESERVES) - tokensOut.load()),
        sendToken(YES_TOKEN_KEY, receiver, tokensOut.load()),
        If(App.globalGet(YES_TOKENS_OUTSTANDING_KEY) > App.globalGet(NO_TOKENS_OUTSTANDING_KEY))
        .Then(
            App.globalPut(TOKEN_FUNDING_RESERVES, App.globalGet(YES_TOKENS_OUTSTANDING_KEY) * Int(2))
        ),
        funding,
        App.globalPut(
            POOL_FUNDING_RESERVES,
            funding.value() - App.globalGet(TOKEN_FUNDING_RESERVES)
        ),
    )

On Result

def get_result():
    result = Txn.application_args[1]
    on_result = Seq(
        Assert(
            Txn.sender() == App.globalGet(CREATOR_KEY)
        ),
        If(result == Bytes("yes"))
        .Then(
            Seq(
                App.globalPut(RESULT, App.globalGet(YES_TOKEN_KEY)),
                Approve()
            )
        )
        .ElseIf(
                result == Bytes("no"),
            )
        .Then(
            Seq(
                App.globalPut(RESULT, App.globalGet(NO_TOKEN_KEY)),
                Approve()
            )
        ),
        Reject(),
    )

    return on_result

The code runs when an account calls Txn.application_args[0] that equals to Bytes("result") into the smart contract. It returns true if the token received by the smart contract is the creator account declared in on_create part of the program.

Depending on the argument in Txn.application_args[1], the creator should choose a yes or no result of the event to declare the winning option.

On Redemption

def get_redemption():
    token_txn_index = Txn.group_index() - Int(1)

    on_redemption = Seq(
        Assert(
            And(
                validateTokenReceived(token_txn_index, RESULT),
            )
        ),
        redeemToken(
            Txn.sender(),
            Gtxn[token_txn_index].asset_amount(),
        ),
        Approve(),
    )

    return on_redemption

The code runs when an account calls Txn.application_args[0] that equals to Bytes("redeem") into the smart contract. It returns true if the token received by the smart contract is the winner decided in on_result part of the program.

redeemToken tracks the withdrawal of Yes/No Tokens. Since the initial distribution of liquidity provided was distribtued in 50%/50% towards each token, after the deadline the winning token should be worth double its initial price.

def redeemToken(
    receiver: TealType.bytes,
    result_token_amount: TealType.uint64,
) -> Expr:

    return Seq(
        sendToken(
            TOKEN_FUNDING_KEY,
            receiver,
            result_token_amount * Int(2)
        ),
        App.globalPut(
            TOKEN_FUNDING_RESERVES, App.globalGet(TOKEN_FUNDING_RESERVES) - result_token_amount * Int(2)
        ),
        If( App.globalGet(RESULT) == App.globalGet(YES_TOKEN_KEY) )
        .Then(
            App.globalPut(
                YES_TOKENS_OUTSTANDING_KEY, App.globalGet(YES_TOKENS_OUTSTANDING_KEY) - result_token_amount
            ),
        )
        .ElseIf(App.globalGet(RESULT) == App.globalGet(NO_TOKEN_KEY) )
        .Then(
            App.globalPut(
                NO_TOKENS_OUTSTANDING_KEY, App.globalGet(NO_TOKENS_OUTSTANDING_KEY) - result_token_amount
            ),
        ),
    )

Contract Demo

Create Account

To deploy a smart contract we create an account and fund it using Testnet Dispensary.

from algosdk import account

# generate an account
private_key, address = account.generate_account()
print("Private key:", private_key)
print("Address:", address)

Connect to AlgodClient

We register on the purestake.com to obtain the api key and initialize the Algorand Client.

algod_token = "Enter Yout token here"
algod_address = "https://testnet-algorand.api.purestake.io/ps2"

headers = {
   "X-API-Key": algod_token,
}

# initialize an algodClient
client = algod.AlgodClient(algod_token, algod_address, headers)

Create Reserve Asset

We create an asset that will be used for reserves in the contract and return the asset index.

from algosdk import account
from algosdk.future import transaction

def wait_for_confirmation(client, txid):
    last_round = client.status().get("last-round")
    txinfo = client.pending_transaction_info(txid)
    while not (txinfo.get("confirmed-round") and txinfo.get("confirmed-round") > 0):
        print("Waiting for confirmation...")
        last_round += 1
        client.status_after_block(last_round)
        txinfo = client.pending_transaction_info(txid)
    print(
        "Transaction {} confirmed in round {}.".format(
            txid, txinfo.get("confirmed-round")
        )
    )
    return txinfo


def create_asset(client, private_key):
    # declare sender
    sender = account.address_from_private_key(private_key)

    params = client.suggested_params()

    txn = transaction.AssetConfigTxn(
        sender=sender,
        sp=params,
        total=1_000_000_000,
        default_frozen=False,
        unit_name="Copio",
        asset_name="coin",
        manager=sender,
        reserve=sender,
        freeze=sender,
        clawback=sender,
        strict_empty_address_check=False,
        url=None,
        decimals=0)

    # Sign with secret key of creator
    stxn = txn.sign(private_key)

    # Send the transaction to the network and retrieve the txid.

    txid = client.send_transaction(stxn)
    print("Signed transaction with txID: {}".format(txid))
    # Wait for the transaction to be confirmed
    response = wait_for_confirmation(client, txid)
    print("TXID: ", txid)
    print("Result confirmed in round: {}".format(response['confirmed-round']))
    return response['asset-index']

Deploy Contract

First, to interact with the smart contract we need to compile and deploy it. createAmmApp function requires client, reserve token id, minimum increment of the reserve token, creator address and private_key to sign the transaction.

def waitForTransaction(
    client: AlgodClient, txID: str, timeout: int = 10
):

    lastStatus = client.status()
    lastRound = lastStatus["last-round"]
    startRound = lastRound

    while lastRound < startRound + timeout:
        pending_txn = client.pending_transaction_info(txID)

        if pending_txn.get("confirmed-round", 0) > 0:
            return pending_txn

        if pending_txn["pool-error"]:
            raise Exception("Pool error: {}".format(pending_txn["pool-error"]))

        lastStatus = client.status_after_block(lastRound + 1)

        lastRound += 1

    raise Exception(
        "Transaction {} not confirmed after {} rounds".format(txID, timeout)
    )

def fullyCompileContract(
    client: AlgodClient, contract: Expr
) -> bytes:

    teal = compileTeal(contract, mode=Mode.Application, version=6)
    response = client.compile(teal)

    return b64decode(response["result"])

def getContracts(client: AlgodClient) -> Tuple[bytes, bytes]:
    """Get the compiled TEAL contracts for the amm.
    Args:q
        client: An algod client that has the ability to compile TEAL programs.
    Returns:
        A tuple of 2 byte strings. The first is the approval program, and the
        second is the clear state program.
    """

    APPROVAL_PROGRAM = fullyCompileContract(client, approval_program())
    CLEAR_STATE_PROGRAM = fullyCompileContract(client, clear_program())

    return APPROVAL_PROGRAM, CLEAR_STATE_PROGRAM

def createAmmApp(
    client: AlgodClient,
    token: int,
    minIncrement: int,
    creator: str,
    private_key: str
) -> int:
    """Creates a new amm.
    Args:
        client: An algod client.
        creator: The account that will create the amm application.
        token: The id of token A in the liquidity pool,
    Returns:
        The ID of the newly created amm app.
    """
    approval, clear = getContracts(client)

    globalSchema = transaction.StateSchema(num_uints=13, num_byte_slices=1)
    localSchema = transaction.StateSchema(num_uints=0, num_byte_slices=0)

    app_args = [
        encoding.decode_address(creator),
        token.to_bytes(8, "big"),
        minIncrement.to_bytes(8, "big"),
    ]

    txn = transaction.ApplicationCreateTxn(
        sender=creator,
        on_complete=transaction.OnComplete.NoOpOC,
        approval_program=approval,
        clear_program=clear,
        global_schema=globalSchema,
        local_schema=localSchema,
        app_args=app_args,
        sp=client.suggested_params(),
    )

    signedTxn = txn.sign(private_key)

    client.send_transaction(signedTxn)

    response = waitForTransaction(client, signedTxn.get_txid())
    assert response["application-index"] is not None and response["application-index"] > 0
    return response["application-index"]

Setting up the AMM

MIN_BALANCE_REQUIREMENT = (
    # min account balance
    110_000
    # additional min balance for 4 assets
    + 100_000 * 4
)


def setupAmmApp(
    client: AlgodClient,
    appID: int,
    token: int,
    funder: str,
    private_key: str
) -> int:
    """Finish setting up an amm.
    This operation funds the pool account, creates pool token,
    and opts app into tokens A and B, all in one atomic transaction group.
    Args:
        client: An algod client.
        appID: The app ID of the amm.
        funder: The account providing the funding for the escrow account.
        token: Token id.
        private_key
    Return: pool token id
    """
    appAddr = get_application_address(appID)

    suggestedParams = client.suggested_params()

    fundAppTxn = transaction.PaymentTxn(
        sender=funder,
        receiver=appAddr,
        amt=MIN_BALANCE_REQUIREMENT,
        sp=suggestedParams,
    )

    setupTxn = transaction.ApplicationCallTxn(
        sender=funder,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[b"setup"],
        foreign_assets=[token],
        sp=suggestedParams,
    )

    transaction.assign_group_id([fundAppTxn, setupTxn])

    signedFundAppTxn = fundAppTxn.sign(private_key)
    signedSetupTxn = setupTxn.sign(private_key)

    client.send_transactions([signedFundAppTxn, signedSetupTxn])

    waitForTransaction(client, signedFundAppTxn.get_txid())
    glob_state = client.application_info(appID)['params']['global-state']

    ids = {}

    for i in range(len(glob_state)):
        if b64decode(glob_state[i]['key']) == b"pool_token_key":
            ids['pool_token_key'] = glob_state[i]['value']['uint']
        elif b64decode(glob_state[i]['key']) == b"yes_token_key":
            ids['yes_token_key'] = glob_state[i]['value']['uint']
        elif b64decode(glob_state[i]['key']) == b"no_token_key":
            ids['no_token_key'] = glob_state[i]['value']['uint']

    return ids

setupAmmApp method requires an appID as one of the arguments. It funds the app and calls the smart contract with the given arguments all in one atomic transaction group. The method returns the dictionary with ids of created pool and option tokens.

Further we need to opt in to the created new assets:

def optInToPoolToken(
    client: AlgodClient,
    poolToken: int,
    account: str,
    private_key: str
) -> None:
    """Opts into Pool Token
    Args:
        client: An algod client.
        account: The account opting into the token.
        poolToken: Token id.
        private_key: to sign the tx.
    """
    suggestedParams = client.suggested_params()

    optInTxn = transaction.AssetOptInTxn(
        sender=account, index=poolToken, sp=suggestedParams
    )

    signedOptInTxn = optInTxn.sign(private_key)

    client.send_transaction(signedOptInTxn)
    waitForTransaction(client, signedOptInTxn.get_txid())

Supplying AMM with Liquidity

def supply(
    client: AlgodClient, appID: int, q: int, supplier: str, private_key: str, \
    token: int, poolToken: int, yesToken: int, noToken: int
) -> None:
    """Supply liquidity to the pool.
    """
    appAddr = get_application_address(appID)
    suggestedParams = client.suggested_params()

    # pay for the fee incurred by AMM for sending back the pool token
    feeTxn = transaction.PaymentTxn(
        sender=supplier,
        receiver=appAddr,
        amt=MIN_BALANCE_REQUIREMENT,
        sp=suggestedParams,
    )

    tokenTxn = transaction.AssetTransferTxn(
        sender=supplier,
        receiver=appAddr,
        index=token,
        amt=q,
        sp=suggestedParams,
    )

    appCallTxn = transaction.ApplicationCallTxn(
        sender=supplier,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[b"supply"],
        foreign_assets=[token, poolToken, yesToken, noToken],
        sp=suggestedParams,
    )

    transaction.assign_group_id([feeTxn, tokenTxn, appCallTxn])
    signedFeeTxn = feeTxn.sign(private_key)
    signedTokenTxn = tokenTxn.sign(private_key)
    signedAppCallTxn = appCallTxn.sign(private_key)

    client.send_transactions(
        [signedFeeTxn, signedTokenTxn, signedAppCallTxn]
    )
    waitForTransaction(client, signedAppCallTxn.get_txid())

Swap stablecoin for Option

def swap(
    client: AlgodClient,
    appID: int,
    option: str,
    q: int,
    supplier: int,
    private_key: str,
    token: int,
    poolToken: int,
    yesToken: int,
    noToken: int
) -> None:

    if option == 'yes':
        second_argument = b"buy_yes"
    elif option =='no':
        second_argument = b"buy_no"
    else:
        return

    appAddr = get_application_address(appID)
    suggestedParams = client.suggested_params()

    # pay for the fee incurred by AMM for sending back the pool token
    feeTxn = transaction.PaymentTxn(
        sender=supplier,
        receiver=appAddr,
        amt=2_000,
        sp=suggestedParams,
    )

    tokenTxn = transaction.AssetTransferTxn(
        sender=supplier,
        receiver=appAddr,
        index=token,
        amt=q,
        sp=suggestedParams,
    )

    appCallTxn = transaction.ApplicationCallTxn(
        sender=supplier,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[ b"swap", second_argument],
        foreign_assets=[token, poolToken, yesToken, noToken],
        sp=suggestedParams,
    )

    transaction.assign_group_id([feeTxn, tokenTxn, appCallTxn])
    signedFeeTxn = feeTxn.sign(private_key)
    signedTokenTxn = tokenTxn.sign(private_key)
    signedAppCallTxn = appCallTxn.sign(private_key)

    client.send_transactions(
        [signedFeeTxn, signedTokenTxn, signedAppCallTxn]
    )
    waitForTransaction(client, signedAppCallTxn.get_txid())

Withdraw LP tokens

def withdraw(
    client: AlgodClient,
    appID: int,
    poolToken: int,
    poolTokenAmount: int,
    withdrawAccount: str,
    token: int,
    private_key: str
) -> None:
    """Withdraw liquidity  + rewards from the pool back to supplier.
    Supplier should receive stablecoin + fees proportional to the liquidity share in the pool they choose to withdraw.
    """
    appAddr = get_application_address(appID)
    suggestedParams = client.suggested_params()

    # pay for the fee incurred by AMM for sending back tokens A and B
    feeTxn = transaction.PaymentTxn(
        sender=withdrawAccount,
        receiver=appAddr,
        amt=2_000,
        sp=suggestedParams,
    )


    poolTokenTxn = transaction.AssetTransferTxn(
        sender=withdrawAccount,
        receiver=appAddr,
        index=poolToken,
        amt=poolTokenAmount,
        sp=suggestedParams,
    )

    appCallTxn = transaction.ApplicationCallTxn(
        sender=withdrawAccount,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[b"withdraw"],
        foreign_assets=[token, poolToken],
        sp=suggestedParams,
    )

    transaction.assign_group_id([feeTxn, poolTokenTxn, appCallTxn])
    signedFeeTxn = feeTxn.sign(private_key)
    signedPoolTokenTxn = poolTokenTxn.sign(private_key)
    signedAppCallTxn = appCallTxn.sign(private_key)

    client.send_transactions([signedFeeTxn, signedPoolTokenTxn, signedAppCallTxn])
    waitForTransaction(client, signedAppCallTxn.get_txid())

Set result

def set_result(
    client: AlgodClient,
    appID: int,
    funder: str,
    private_key: str,
    second_argument
):
    """ Set the winning token key
    """
    appAddr = get_application_address(appID)

    suggestedParams = client.suggested_params()

    feeTxn = transaction.PaymentTxn(
        sender=funder,
        receiver=appAddr,
        amt=2_000,
        sp=suggestedParams,
    )

    callTxn = transaction.ApplicationCallTxn(
        sender=funder,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[b"result", second_argument],
        sp=suggestedParams,
    )

    transaction.assign_group_id([feeTxn, callTxn])
    signedFeeTxn = feeTxn.sign(private_key)
    signedAppCallTxn = callTxn.sign(private_key)

    client.send_transactions([signedFeeTxn, signedAppCallTxn])
    waitForTransaction(client, signedAppCallTxn.get_txid())

Redeem Resolved Option for Stablecoin

def redeem(
    client: AlgodClient, appID: int, Token:int, TokenAmount: int,
    withdrawAccount: str, token: int, private_key: str
) -> None:

    appAddr = get_application_address(appID)
    suggestedParams = client.suggested_params()

    # pay for the fee incurred by AMM for sending back tokens A and B
    feeTxn = transaction.PaymentTxn(
        sender=withdrawAccount,
        receiver=appAddr,
        amt=2_000,
        sp=suggestedParams,
    )


    TokenTxn = transaction.AssetTransferTxn(
        sender=withdrawAccount,
        receiver=appAddr,
        index=Token,
        amt=TokenAmount,
        sp=suggestedParams,
    )

    appCallTxn = transaction.ApplicationCallTxn(
        sender=withdrawAccount,
        index=appID,
        on_complete=transaction.OnComplete.NoOpOC,
        app_args=[b"redeem"],
        foreign_assets=[token, Token],
        sp=suggestedParams,
    )

    transaction.assign_group_id([feeTxn, TokenTxn, appCallTxn])
    signedFeeTxn = feeTxn.sign(private_key)
    signedPoolTokenTxn = TokenTxn.sign(private_key)
    signedAppCallTxn = appCallTxn.sign(private_key)

    client.send_transactions([signedFeeTxn, signedPoolTokenTxn, signedAppCallTxn])
    waitForTransaction(client, signedAppCallTxn.get_txid())

Close out the AMM

def closeAmm(
    client: AlgodClient, appID: int, closer: str, private_key: str
)-> None:
    """Close an AMM.
    Args:
        client: An Algod client.
        appID: The app ID of the amm.
        closer: closer account public address. Must be the original creator of the pool.
        private_key: closer account private key to sign the transactions.
    """

    deleteTxn = transaction.ApplicationDeleteTxn(
        sender=closer,
        index=appID,
        sp=client.suggested_params(),
    )
    signedDeleteTxn = deleteTxn.sign(private_key)

    client.send_transaction(signedDeleteTxn)

    waitForTransaction(client, signedDeleteTxn.get_txid())

Example Script

import os
from dotenv import load_dotenv
from algosdk import account
from algosdk.v2client import algod

from create_asset import create_asset
from amm_api import createAmmApp, setupAmmApp, optInToPoolToken, \
    supply, withdraw, swap, set_result, closeAmm, redeem


load_dotenv()

private_key = os.getenv('key')
creator = account.address_from_private_key(private_key)

algod_token = os.getenv('algod_token')

algod_address = "https://testnet-algorand.api.purestake.io/ps2"

headers = {
   "X-API-Key": algod_token,
}

# initialize an algodClient
client = algod.AlgodClient(algod_token, algod_address, headers)

# create (stable) asset
token = create_asset(client, private_key)

appID = createAmmApp(
    client=client,
    creator=creator,
    private_key=private_key,
    token=token,
    minIncrement=1000,
)

print(f"Alice is setting up and funding amm {appID}")

Tokens = setupAmmApp(
    client=client,
    appID=appID,
    funder=creator,
    private_key=private_key,
    token=token,
)

poolToken = Tokens['pool_token_key']
yesToken = Tokens['yes_token_key']
noToken = Tokens['no_token_key']

print(Tokens['pool_token_key'], Tokens['yes_token_key'], Tokens['no_token_key'])

optInToPoolToken(client, creator, private_key, poolToken)
optInToPoolToken(client, creator, private_key, yesToken)
optInToPoolToken(client, creator, private_key, noToken)


print("Supplying AMM with initial token")

poolTokenFirstAmount = 500_000

supply(
    client=client,
    appID=appID,
    q=poolTokenFirstAmount,
    supplier=creator,
    private_key=private_key,
    token=token,
    poolToken=poolToken,
    yesToken=yesToken, noToken=noToken
)

print("Supplying AMM with more tokens")

poolTokenSecondAmount = 1_500_000

supply(
    client=client,
    appID=appID,
    q=poolTokenSecondAmount,
    supplier=creator,
    private_key=private_key,
    token=token,
    poolToken=poolToken,
    yesToken=yesToken, noToken=noToken
)

print("Swapping")

yesTokenAmount = 100_000

# buy yes token
swap(
    client=client,
    appID=appID,
    option="yes",
    q=yesTokenAmount,
    supplier=creator,
    private_key=private_key,
    token=token,
    poolToken=poolToken,
    yesToken=yesToken,
    noToken=noToken
)

#buy no token
swap(
    client=client,
    appID=appID,
    option="no",
    q=yesTokenAmount,
    supplier=creator,
    private_key=private_key,
    token=token,
    poolToken=poolToken,
    yesToken=yesToken,
    noToken=noToken
)

print("Withdrawing")

AllTokens = 2_000_000

withdraw(
    client = client,
    appID = appID,
    poolTokenAmount = AllTokens,
    poolToken = poolToken,
    withdrawAccount = creator,
    private_key = private_key,
    token = token
)

print("Result")
#set winner

set_result(
    client = client,
    appID = appID,
    second_argument=b"yes",
    funder=creator,
    private_key = private_key
)


# redemption for for yes/no

print("Redeeming")

YesTokensAmount = 95_238

redeem(
    client = client,
    appID = appID,
    TokenAmount = YesTokensAmount,
    Token = yesToken,
    withdrawAccount = creator,
    private_key = private_key,
    token = token
)

# Delete

print("Deleting")

closeAmm(
    client = client,
    appID = appID,
    closer=creator,
    private_key = private_key
)

Useful Resources

Algorand: Build with Python

Alogrand: Smart contract details

Amm Demo contract

Creating Stateful Algorand Smart Contracts in Python with PyTeal

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contract.md

contract.md

Project Setup

Installing with Virtual environment

PyTeal AMM Smart Contract

PyTeal Contract Configuration File

Main Conditional

On create

On setup

On supply

On Withdraw

On Swap

On Result

On Redemption

Contract Demo

Create Account

Connect to AlgodClient

Create Reserve Asset

Deploy Contract

Setting up the AMM

Supplying AMM with Liquidity

Swap stablecoin for Option

Withdraw LP tokens

Set result

Redeem Resolved Option for Stablecoin

Close out the AMM

Example Script

Useful Resources

Files

contract.md

Latest commit

History

contract.md

File metadata and controls

Project Setup

Installing with Virtual environment

PyTeal AMM Smart Contract

PyTeal Contract Configuration File

Main Conditional

On create

On setup

On supply

On Withdraw

On Swap

On Result

On Redemption

Contract Demo

Create Account

Connect to AlgodClient

Create Reserve Asset

Deploy Contract

Setting up the AMM

Supplying AMM with Liquidity

Swap stablecoin for Option

Withdraw LP tokens

Set result

Redeem Resolved Option for Stablecoin

Close out the AMM

Example Script

Useful Resources