ANM20 Token Contract

# Animica vm_py smart contract — ANM20 fungible token
# Runs on the Animica VM. Deployment is prepared for Animica testnet.


class ANM20Token:
    """A standard ANM20 fungible token with owner-only minting.

    All persistent data lives in self.state, a dict that the Animica VM
    commits between calls. Balances and allowances are keyed by address
    string; missing keys read as 0.
    """

    def __init__(self, name, symbol, decimals, total_supply, owner):
        self.name = name
        self.symbol = symbol
        self.decimals = int(decimals)
        self.total_supply = int(total_supply)
        self.owner = owner
        # state["balances"][addr] -> int
        # state["allowances"][owner][spender] -> int
        self.state = {
            "balances": {owner: int(total_supply)},
            "allowances": {},
        }

    # ── Views ────────────────────────────────────────────────────────────
    def balance_of(self, addr):
        return int(self.state["balances"].get(addr, 0))

    def allowance(self, owner, spender):
        return int(self.state["allowances"].get(owner, {}).get(spender, 0))

    # ── Transfers ────────────────────────────────────────────────────────
    def transfer(self, caller, to, amount):
        amount = int(amount)
        if amount < 0:
            raise ValueError("amount must be non-negative")
        balances = self.state["balances"]
        frm = int(balances.get(caller, 0))
        if frm < amount:
            raise ValueError("insufficient balance")
        balances[caller] = frm - amount
        balances[to] = int(balances.get(to, 0)) + amount
        return True

    def approve(self, caller, spender, amount):
        amount = int(amount)
        if amount < 0:
            raise ValueError("amount must be non-negative")
        allowances = self.state["allowances"]
        if caller not in allowances:
            allowances[caller] = {}
        allowances[caller][spender] = amount
        return True

    def transfer_from(self, caller, sender, to, amount):
        amount = int(amount)
        if amount < 0:
            raise ValueError("amount must be non-negative")
        allowances = self.state["allowances"]
        allowed = int(allowances.get(sender, {}).get(caller, 0))
        if allowed < amount:
            raise ValueError("allowance exceeded")
        balances = self.state["balances"]
        frm = int(balances.get(sender, 0))
        if frm < amount:
            raise ValueError("insufficient balance")
        balances[sender] = frm - amount
        balances[to] = int(balances.get(to, 0)) + amount
        allowances[sender][caller] = allowed - amount
        return True

    # ── Supply ───────────────────────────────────────────────────────────
    def mint(self, caller, to, amount):
        if caller != self.owner:
            raise PermissionError("only owner can mint")
        amount = int(amount)
        if amount < 0:
            raise ValueError("amount must be non-negative")
        balances = self.state["balances"]
        balances[to] = int(balances.get(to, 0)) + amount
        self.total_supply += amount
        return True