feat: basic function

texas_holdem/cards.py

@@ -0,0 +1,66 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from random import Random
+
+SUITS = ("c", "d", "h", "s")
+RANK_LABELS = {
+    2: "2",
+    3: "3",
+    4: "4",
+    5: "5",
+    6: "6",
+    7: "7",
+    8: "8",
+    9: "9",
+    10: "T",
+    11: "J",
+    12: "Q",
+    13: "K",
+    14: "A",
+}
+LABEL_RANKS = {label: rank for rank, label in RANK_LABELS.items()}
+
+
+@dataclass(frozen=True, slots=True)
+class Card:
+    rank: int
+    suit: str
+
+    def __post_init__(self) -> None:
+        if self.rank not in RANK_LABELS:
+            raise ValueError(f"invalid rank: {self.rank}")
+        if self.suit not in SUITS:
+            raise ValueError(f"invalid suit: {self.suit}")
+
+    def __str__(self) -> str:
+        return f"{RANK_LABELS[self.rank]}{self.suit}"
+
+    @classmethod
+    def parse(cls, value: str) -> "Card":
+        if len(value) != 2:
+            raise ValueError(f"card must have two characters: {value!r}")
+        rank_label = value[0].upper()
+        suit = value[1].lower()
+        if rank_label not in LABEL_RANKS:
+            raise ValueError(f"invalid rank label: {rank_label}")
+        return cls(LABEL_RANKS[rank_label], suit)
+
+
+class Deck:
+    def __init__(self, rng: Random | None = None) -> None:
+        self._rng = rng or Random()
+        self._cards = [Card(rank, suit) for suit in SUITS for rank in range(2, 15)]
+        self._rng.shuffle(self._cards)
+
+    def draw(self, count: int = 1) -> list[Card]:
+        if count < 1:
+            raise ValueError("count must be positive")
+        if len(self._cards) < count:
+            raise ValueError("deck does not have enough cards")
+        drawn = self._cards[-count:]
+        del self._cards[-count:]
+        return drawn
+
+    def burn(self) -> None:
+        self.draw(1)