Merge pull request crypto-org-chain#35 from macong-cdc/coin-class

Problem: Coin protobuf message is exposed to user directly(fix crypto-org-chain#28)

README.md

@@ -24,7 +24,7 @@
 
 ## Installing<a name="installing"></a>
 
-Require Python >= 3.7, installing from PyPI repository (https://pypi.org/project/chainlibpy):
+Require Python >= 3.8, installing from [PyPI repository](https://pypi.org/project/chainlibpy):
 
 ```bash
 pip install chainlibpy
@@ -84,32 +84,36 @@ Please refer to `example/secure_channel_example.py` on how to use secure gRPC ch
 
 ## Acknowledgement<a name="acknowledgement"></a>
 
-Thanks [cosmospy](https://github.com/hukkinj1/cosmospy) for the following:
+Thanks to [cosmospy](https://github.com/hukkinj1/cosmospy) for the following:
 
 - referenced the packages to sign transaction and create hd wallet
 - python lint config file
 - use same sign method
 
+Thanks to [eth-utils](https://github.com/ethereum/eth-utils) for the following:
+
+- Conversion of different units without facing precision issues in Python
+
 ## Development<a name="development"></a>
 
 ### Set up development environment<a name="set-up-development-environment"></a>
 
 More about [poetry](https://python-poetry.org/docs/).
 
-```
+```bash
 poetry install
 ```
 
 ### Generate gRPC code<a name="generate-grpc-code"></a>
 
-```
+```bash
 poetry shell
 ./generated_protos.sh
 ```
 
 **NOTE:** By default, `master` branch of `cosmos-sdk` is used. Use command below to download a different version:
 
-```
+```bash
 ./generated_protos.sh -COSMOS_REF=v0.44.5
 ```
 
@@ -124,7 +128,7 @@ $COSMOS_SDK_DIR/proto/cosmos/auth/v1beta1/auth.proto
 
 ### Tox<a name="tox"></a>
 
-```
+```bash
 pyenv local 3.8.a 3.9.b
 ```
 
@@ -133,7 +137,7 @@ pyenv local 3.8.a 3.9.b
 After this command, a `.python-version` file will be generated at project root directory, which means python versions inside `.python-version` are presented for this project. So running `tox` command with `py{38,39}` configuration should succeed.\
 Then run to verify. Command below is recommended to run before pushing a commit.
 
-```sh
+```bash
 poetry run tox
 # or
 poetry shell

chainlibpy/__init__.py

@@ -1,9 +1,3 @@
-from .grpc_client import CRO_NETWORK, GrpcClient, NetworkConfig
-from .wallet import Wallet
-
-__all__ = [
-    "Wallet",
-    "GrpcClient",
-    "CRO_NETWORK",
-    "NetworkConfig",
-]
+from .cro_coin import MAX_CRO_SUPPLY, CROCoin  # noqa: F401
+from .grpc_client import CRO_NETWORK, GrpcClient, NetworkConfig  # noqa: F401
+from .wallet import Wallet  # noqa: F401

chainlibpy/cro_coin.py

@@ -0,0 +1,174 @@
+import decimal
+from typing import Union
+
+from chainlibpy.generated.cosmos.base.v1beta1.coin_pb2 import Coin
+from chainlibpy.grpc_client import NetworkConfig
+
+from .utils import is_integer
+
+MAX_CRO_SUPPLY = 30_000_000_000  # max CRO supply: 30 billion
+
+
+class CROCoin:
+    def __init__(
+        self,
+        amount: "Union[int, float, str, decimal.Decimal]",
+        unit: str,
+        network_config: "NetworkConfig",
+    ) -> None:
+        """
+        Parameters
+        ----------
+            amount : int, float, str, decimal.Decimal
+                The amount of coin
+
+                To avoid precision issues in Python,
+                "str" and "decimal.Decimal" types are highly recommended
+            unit : str
+                One of coin_denom and coin_base_denom from network_config
+            network_config : NetworkConfig
+                Network configuration to interact with the chain
+        """
+        assert unit in [network_config.coin_denom, network_config.coin_base_denom], (
+            f"unit should be {network_config.coin_denom} or "
+            f"{network_config.coin_base_denom}, got {unit}"
+        )
+
+        self._denom = network_config.coin_denom
+        self._base_denom = network_config.coin_base_denom
+        self._exponent = network_config.exponent
+        self._unit = unit
+        self.amount_base = amount
+
+    @property
+    def amount_base(self) -> str:
+        """Returns Coin amount only, in base denom unit.
+
+        ("1cro" is returned as "100000000")
+        """
+        return self._amount_base
+
+    @amount_base.setter
+    def amount_base(self, amount):
+        temp_base_amount = self._to_number_in_base(amount, self._unit)
+
+        if "." in temp_base_amount:
+            raise ValueError(f"Amount is less than 1{self._base_denom}")
+        if int(temp_base_amount) > MAX_CRO_SUPPLY * 10 ** self._exponent:
+            raise ValueError(
+                "Input is more than maximum cro supply"
+                f" {MAX_CRO_SUPPLY * 10 ** self._exponent}{self._base_denom}"
+                f" got {temp_base_amount}{self._base_denom}"
+            )
+        if int(temp_base_amount) < 0:
+            raise ValueError("Amount cannot be negative")
+
+        self._amount_base = temp_base_amount
+
+    @property
+    def amount(self) -> str:
+        """Returns Coin amount only, in denom unit.
+
+        ("1cro" is returned as "1")
+        """
+        return self._from_number_in_base(self.amount_base, self._denom)
+
+    @property
+    def amount_with_unit(self) -> str:
+        """Returns converted Coin amount with denom unit.
+
+        (e.g. "10cro").
+        """
+        return f"{self.amount}{self._denom}"
+
+    @property
+    def amount_base_with_unit(self) -> str:
+        """Returns converted Coin amount with base denom unit.
+
+        (e.g. "100000basecro").
+        """
+        return f"{self.amount_base}{self._base_denom}"
+
+    def __eq__(self, __o: "CROCoin") -> bool:
+        return self.amount_base == __o.amount_base
+
+    def _cast_to_str(self, number: Union[int, float, decimal.Decimal]) -> str:
+        """Cast number to string format.
+
+        Remove trailing "0" and "." if necessary
+        """
+        s_number = "{:f}".format(number)
+
+        if "." in s_number:
+            s_number = s_number.rstrip("0").rstrip(".")
+        return s_number
+
+    def _cast_to_Decimal_obj(
+        self, number: Union[int, float, str, "decimal.Decimal"]
+    ) -> "decimal.Decimal":
+        if is_integer(number) or isinstance(number, str):
+            d_number = decimal.Decimal(value=number)
+        elif isinstance(number, float):
+            d_number = decimal.Decimal(value=str(number))
+        elif isinstance(number, decimal.Decimal):
+            d_number = number
+        else:
+            raise TypeError("Unsupported type.  Must be one of integer, float, or string")
+
+        return d_number
+
+    def _get_conversion_rate_to_base_unit(self, unit: str) -> decimal.Decimal:
+        """Takes a unit and gets its conversion rate to the base unit."""
+        if unit == self._denom:
+            return decimal.Decimal(value=10 ** self._exponent)
+        elif unit == self._base_denom:
+            return decimal.Decimal(1)
+        else:
+            raise ValueError(
+                f"Expect denom to be {self._denom} or {self._base_denom}, got ${unit}"
+            )
+
+    def _from_number_in_base(self, number: int, unit: str) -> str:
+        """Takes an amount of base denom and converts it to an amount of other
+        denom unit."""
+        if number == 0:
+            return "0"
+
+        unit_conversion = self._get_conversion_rate_to_base_unit(unit)
+
+        with decimal.localcontext() as ctx:
+            ctx.prec = 999
+            d_number = decimal.Decimal(value=number, context=ctx)
+            result_value = d_number / unit_conversion
+
+        return self._cast_to_str(result_value)
+
+    def _to_number_in_base(
+        self, number: Union[int, float, str, "decimal.Decimal"], unit: str
+    ) -> str:
+        """Takes a number of a unit and converts it to a number of the base
+        denom."""
+        d_number = self._cast_to_Decimal_obj(number)
+
+        s_number = str(number)
+        unit_conversion = self._get_conversion_rate_to_base_unit(unit)
+
+        if d_number == decimal.Decimal(0):
+            return "0"
+
+        if d_number < 1 and "." in s_number:
+            with decimal.localcontext() as ctx:
+                multiplier = len(s_number) - s_number.index(".") - 1
+                ctx.prec = multiplier
+                d_number = decimal.Decimal(value=number, context=ctx) * 10 ** multiplier
+            unit_conversion /= 10 ** multiplier
+
+        with decimal.localcontext() as ctx:
+            ctx.prec = 999
+            result_value = decimal.Decimal(value=d_number, context=ctx) * unit_conversion
+
+        return self._cast_to_str(result_value)
+
+    def to_coin_message(self) -> "Coin":
+        """Returns protobuf compatiable Coin message."""
+        return Coin(amount=self.base_amount, denom=self._base_denom)

chainlibpy/grpc_client.py

@@ -54,6 +54,7 @@ class NetworkConfig:
     address_prefix: str
     coin_denom: str
     coin_base_denom: str
+    exponent: int
     derivation_path: str
 
 
@@ -64,6 +65,7 @@ class NetworkConfig:
         address_prefix="cro",
         coin_denom="cro",
         coin_base_denom="basecro",
+        exponent=8,
         derivation_path="m/44'/394'/0'/0/0",
     ),
     "testnet_croeseid": NetworkConfig(
@@ -72,6 +74,7 @@ class NetworkConfig:
         address_prefix="tcro",
         coin_denom="tcro",
         coin_base_denom="basetcro",
+        exponent=8,
         derivation_path="m/44'/1'/0'/0/0",
     ),
 }

chainlibpy/utils/__init__.py

@@ -0,0 +1 @@
+from .types import is_integer  # noqa: F401

chainlibpy/utils/types.py

@@ -0,0 +1,5 @@
+from typing import Any
+
+
+def is_integer(value: Any) -> bool:
+    return isinstance(value, int) and not isinstance(value, bool)

pyproject.toml

@@ -37,6 +37,7 @@ pytest-env = "^0.6.2"
 pystarport = "^0.2.3"
 requests = "^2.27.1"
 toml = "^0.10.2"
+hypothesis = "^6.35.1"
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]

tests/conftest.py

@@ -70,5 +70,6 @@ def local_test_network_config(data_folder: "Path", chain_id):
         address_prefix="cro",
         coin_denom="cro",
         coin_base_denom="basecro",
+        exponent=8,
         derivation_path="m/44'/394'/0'/0/0",
     )