Added support for unknown assets and special casing of AssetAmounts.

fin_defs/__init__.py

@@ -143,6 +143,8 @@ class Asset:
             return f'index:{self.ticker}'
         if isinstance(self, Commodity):
             return f'commodity:{self.alpha_vantage_id}'
+        if isinstance(self, UnknownAsset):
+            return 'unknown:XXX'
 
         msg = f'Unsupported asset type: {repr(self)}'
         raise ValueError(msg)
@@ -179,6 +181,8 @@ class Asset:
             return CryptoCurrency(ticker, **attrs)
         if prefix == 'commodity':
             return Commodity(ticker)
+        if prefix == 'unknown':
+            return UnknownAsset()
 
         msg = f'Unsupported asset format: {asset_id}'
         raise ValueError(msg)
@@ -187,6 +191,12 @@ class Asset:
         return self.to_string_id()
 
 
+@enforce_typing.enforce_types
+@dataclasses.dataclass(frozen=True)
+class UnknownAsset(Asset):
+    pass
+
+
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True)
 class Currency(Asset):
@@ -198,7 +208,7 @@ class Currency(Asset):
 class FiatCurrency(Currency):
     iso_code: str
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         if not re.match(RE_TICKER_FORMAT, self.iso_code):
             msg = f'iso_code was not in correct format: {self.iso_code}'
             raise ValueError(msg)
@@ -206,6 +216,22 @@ class FiatCurrency(Currency):
     def raw_short_name(self) -> str:
         return self.iso_code
 
+    @staticmethod
+    def from_currency_symbol(symbol: str) -> 'Currency | None':
+        for (currency, currency_symbol) in CURRENCY_SYMBOLS.items():
+            if currency_symbol == symbol:
+                return currency
+        return None
+
+    def to_currency_symbol(self) -> str:
+        return CURRENCY_SYMBOLS[self]
+
+FiatCurrency.DKK = FiatCurrency('DKK')
+FiatCurrency.NOK = FiatCurrency('NOK')
+FiatCurrency.USD = FiatCurrency('USD')
+FiatCurrency.EUR = FiatCurrency('EUR')
+FiatCurrency.GBP = FiatCurrency('GBP')
+FiatCurrency.JPY = FiatCurrency('JPY')
 
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, eq=True)
@@ -213,7 +239,7 @@ class CryptoCurrency(Currency):
     ccxt_symbol: str
     coingecko_id: str | None = None
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         """TODO
         if not re.match(RE_CRYPTO_TICKER_FORMAT, self.ccxt_symbol):
             msg = f'ccxt_symbol was not in correct format: {self.ccxt_symbol}'
@@ -231,7 +257,7 @@ class Stock(Asset):
     exchange: StockExchange
     nordnet_id: int | None = None
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         if not re.match(RE_TICKER_FORMAT_FLEXIBLE, self.ticker):
             msg = f'ticker was not in correct format: {self.ticker}'
             raise ValueError(msg)
@@ -249,7 +275,7 @@ class Stock(Asset):
 class Index(Asset):
     ticker: str
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         if not re.match(RE_TICKER_FORMAT_FLEXIBLE, self.ticker):
             msg = f'ticker was not in correct format: {self.ticker}'
             raise ValueError(msg)
@@ -263,7 +289,7 @@ class Index(Asset):
 class Commodity(Asset):
     alpha_vantage_id: str
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         if not re.match(RE_TICKER_FORMAT, self.alpha_vantage_id):
             msg = f'alpha_vantage_id was not in correct format: {self.alpha_vantage_id}'
             raise ValueError(msg)
@@ -284,11 +310,10 @@ Commodity.COFFEE = Commodity('COFFEE')
 
 # Well known
 
-DKK = FiatCurrency('DKK')
-NOK = FiatCurrency('NOK')
-USD = FiatCurrency('USD')
-EUR = FiatCurrency('EUR')
-GBP = FiatCurrency('GBP')
+DKK = FiatCurrency.DKK
+USD = FiatCurrency.USD
+EUR = FiatCurrency.EUR
+
 BTC = CryptoCurrency('BTC', coingecko_id='bitcoin')
 MPC = CryptoCurrency('MPC', coingecko_id='partisia-blockchain')
 SPX = Index('SPX')
@@ -324,36 +349,42 @@ COMMON_NAMES: dict[Asset, list[str]] = {
     USDT: ['Tether USDT'],
 }
 
+CURRENCY_CODES = {
+    sym: FiatCurrency(sym)
+    for sym in [
+        'USD',
+        'DKK',
+        'EUR',
+        'JPY',
+        'CAD',
+        'GBP',
+        'CNY',
+        'PLN',
+        'ILS',
+        'CHF',
+        'ZAR',
+        'CZK',
+    ]
+}
+
+
 WELL_KNOWN_SYMBOLS = (
-    {
-        sym: FiatCurrency(sym)
-        for sym in [
-            'USD',
-            'DKK',
-            'EUR',
-            'JPY',
-            'CAD',
-            'GBP',
-            'CNY',
-            'PLN',
-            'ILS',
-            'CHF',
-            'ZAR',
-            'CZK',
-        ]
-    }
+        CURRENCY_CODES
     | {'XXBT': BTC}
     | {k.raw_short_name(): k for k in COMMON_NAMES}
     | {'SPX500': SPX, 'SP500': SPX, 'Nasdaq 100': NDX}
 )
 
-ASSET_PREFIX: dict[Asset, str] = {
+CURRENCY_SYMBOLS: dict[Currency, str] = {
     USD: '$',
     EUR: '€',
-    GBP: '£',
+    FiatCurrency.GBP: '£',
     BTC: '₿',
+    FiatCurrency.JPY: '¥',
 }
 
+ASSET_PREFIX: dict[Asset, str] = CURRENCY_SYMBOLS # TODO: Remove at some point.
+
 NYSE = StockExchange(
     name='New York Stock Exchange',
     mic='XNYS',
@@ -467,26 +498,30 @@ class AssetAmount:
     asset: Asset
     amount: Decimal
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.human_readable_str()
 
-    def human_readable_str(self):
+    def human_readable_str(self) -> str:
         specificity = '2' if self.amount >= 0.10 else '3'
         prefix = ASSET_PREFIX.get(self.asset, '')
         return ('{}{:.' + specificity + 'f} {}').format(
             prefix, self.amount, self.asset.raw_short_name(),
         )
 
-    def __mul__(self, other: Decimal):
+    def __mul__(self, other: Decimal) -> 'AssetAmount':
         if not isinstance(other, Decimal):
             msg = f'other must be decimal, but was {type(other)}'
             raise TypeError(msg)
         return AssetAmount(self.asset, self.amount * other)
 
-    def __add__(self, other):
+    def __add__(self, other: 'AssetAmount') -> 'AssetAmount':
         if not isinstance(other, AssetAmount):
             msg = f'other must be AssetAmount, but was {type(other)}'
             raise TypeError(msg)
+        if self.is_zero():
+            return other
+        if other.is_zero():
+            return self
         if self.asset != other.asset:
             msg = (
                 f'AssetAmount must have same asset, but: {self.asset} != {other.asset}'
@@ -495,10 +530,14 @@ class AssetAmount:
 
         return AssetAmount(self.asset, self.amount + other.amount)
 
-    def __sub__(self, other):
+    def __sub__(self, other: 'AssetAmount') -> 'AssetAmount':
         if not isinstance(other, AssetAmount):
             msg = f'other must be AssetAmount, but was {type(other)}'
             raise TypeError(msg)
+        if self.is_zero():
+            return -other
+        if other.is_zero():
+            return self
         if self.asset != other.asset:
             msg = (
                 f'AssetAmount must have same asset, but: {self.asset} != {other.asset}'
@@ -506,7 +545,7 @@ class AssetAmount:
             raise ValueError(msg)
         return AssetAmount(self.asset, self.amount - other.amount)
 
-    def __truediv__(self, other):
+    def __truediv__(self, other: 'Decimal | AssetAmount') -> 'Decimal | AssetAmount':
         if isinstance(other, AssetAmount):
             if self.asset != other.asset:
                 msg = f'AssetAmount must have same asset, but: {self.asset} != {other.asset}'
@@ -514,16 +553,38 @@ class AssetAmount:
             return self.amount / other.amount
         return AssetAmount(self.asset, self.amount / other)
 
-    def __lt__(self, other):
+    def __neg__(self) -> 'AssetAmount':
+        return AssetAmount(self.asset, -self.amount)
+
+    def cmp(self, other) -> Decimal:
         if not isinstance(other, AssetAmount):
             msg = f'other must be AssetAmount, but was {type(other)}'
             raise TypeError(msg)
+        if self.is_zero() or other.is_zero():
+            return self.amount - other.amount
         if self.asset != other.asset:
             msg = (
                 f'AssetAmount must have same asset, but: {self.asset} != {other.asset}'
             )
             raise ValueError(msg)
-        return self.amount < other.amount
+        return self.amount - other.amount
+
+    def is_zero(self) -> bool:
+        return self.amount == 0
+
+    def __lt__(self, other: 'AssetAmount') -> bool:
+        return self.cmp(other) < 0
+
+    def __le__(self, other: 'AssetAmount') -> bool:
+        return self.cmp(other) <= 0
+
+    def __gt__(self, other: 'AssetAmount') -> bool:
+        return self.cmp(other) > 0
+
+    def __ge__(self, other: 'AssetAmount') -> bool:
+        return self.cmp(other) >= 0
+
+AssetAmount.ZERO = AssetAmount(UnknownAsset(), Decimal(0))
 
 
 AssetPair = tuple[Asset, Asset]
@@ -550,10 +611,10 @@ class ExchangeRateSample:
             return self._average
         return (self.high + self.low) / 2
 
-    def replace_timestamp(self, timestamp):
+    def replace_timestamp(self, timestamp: datetime.date | datetime.datetime) -> 'ExchangeRateSample':
         return dataclasses.replace(self, timestamp=timestamp)
 
-    def invert_exchange_rate(self):
+    def invert_exchange_rate(self) -> 'ExchangeRateSample':
         one = Decimal('1')
         return dataclasses.replace(
             self,