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"""Poker decision engine with a single, calibrated risk knob (r in [0, 1]).

Design (v0, documented limitations at bottom):
  - Equity: Monte Carlo vs uniform random opponent hole card(s) and remaining
    board, via the `treys` evaluator.
  - The knob r simultaneously and MONOTONICALLY controls:
      calling threshold  : need = pot_odds - 0.20*r      (risk-seeking calls thinner)
      raise threshold    : 0.62 - 0.10*r                  (aggression scales up)
      bet threshold      : 0.60 - 0.12*r                  (bluffier at high r)
      bet sizing         : 0.45 + 0.55 of pot, scaled by equity excess
  - Position modifier: BTN -0.03, SB/BB +0.03, middle +0.00 on all thresholds.
  - EV model (heuristic, for policy comparison only — not ground truth):
      fold: 0
      call: eq*(pot+to_call) - to_call
      bet X: p_fold*pot + (1-p_fold)*(eq*(pot+2X) - X),
             p_fold = clamp(0.6 - 1.2*eq, 0.05, 0.6)   (opponent folds more vs big eq)
"""
import random
from dataclasses import dataclass

from treys import Card as TCard
from treys import Evaluator


@dataclass
class TableState:
    hero: list          # ['AS', 'KD'] ASCII card strings
    board: list         # up to 5 ASCII cards
    pot: int            # chips in middle, including current street bets
    stack: int          # hero chips behind
    to_call: int        # 0 if checked to hero
    n_players: int      # players still in the hand
    position: str       # BTN, SB, BB, UTG, MP, MP2, CO
    street: str         # preflop, flop, turn, river


# treys card ints are bit-encoded, not 0..51 — build the real 52-card deck once
_ALL_CARDS = [TCard.new(r + s) for r in "23456789TJQKA" for s in "shdc"]


_POS_MOD = {"BTN": -0.03, "CO": -0.02, "SB": 0.03, "BB": 0.03,
            "UTG": 0.02, "UTG+1": 0.02, "MP": 0.0, "MP2": 0.0}


def parse_card(c):
    c = c.strip().upper()
    if c[-1] in "SHDC" and len(c) == 2:
        return TCard.new(c[:-1] + c[-1].lower())
    # unicode suit form 'A♠'
    suit = {"♠": "s", "♥": "h", "♦": "d", "♣": "c"}.get(c[-1])
    rank = c[:-1].replace("10", "T")
    return TCard.new(rank + suit.lower())


class RiskEngine:
    def __init__(self, n_sims=1500, seed=7):
        self.ev = Evaluator()
        self.n_sims = n_sims
        self.rng = random.Random(seed)

    def equity(self, hero, board, n_opponents=1):
        """Win/tie probability vs uniform random opponents. ~0.15-0.3 s for 1500 sims."""
        hero_c = [parse_card(c) for c in hero]
        board_c = [parse_card(c) for c in board]
        known = set(hero_c + board_c)
        deck = [c for c in _ALL_CARDS if c not in known]
        wins = ties = 0
        n_sims = self.n_sims
        for _ in range(n_sims):
            self.rng.shuffle(deck)
            opp_hands = []
            need = 2 * n_opponents + (5 - len(board_c))
            used = deck[:need]
            k = 0
            full_board = board_c + used[k:k + (5 - len(board_c))]
            k += (5 - len(board_c))
            best = None
            hero_score = self.ev.evaluate(hero_c, full_board)
            all_scores = [hero_score]
            for o in range(n_opponents):
                oc = used[k:k + 2]
                k += 2
                all_scores.append(self.ev.evaluate(oc, full_board))
            m = min(all_scores)
            if all_scores[0] == m and all_scores.count(m) == 1:
                wins += 1
            elif all_scores[0] == m:
                ties += 1
        return (wins + 0.5 * ties) / n_sims

    def thresholds(self, r, position):
        mod = _POS_MOD.get(position, 0.0)
        return {
            "call_margin": 0.20 * r,                 # equity buffer below pot odds
            "raise_thr": max(0.45, 0.62 - 0.10 * r - mod),
            "bet_thr": max(0.42, 0.60 - 0.12 * r - mod),
            "bet_frac": 0.45 + 0.55 * r,             # of pot
        }

    def decide(self, state: TableState, r: float, eq=None):
        """Action for the state at risk knob r. eq may be precomputed."""
        t = self.thresholds(r, state.position)
        if eq is None:
            eq = self.equity(state.hero, state.board,
                             max(1, state.n_players - 1))
        pot, to_call, stack = state.pot, state.to_call, state.stack
        pot_odds = to_call / (pot + to_call) if to_call > 0 else 0.0
        need = max(0.0, pot_odds - t["call_margin"])
        if to_call > 0:
            if eq >= t["raise_thr"] and stack > to_call:
                amt = int(min(stack - to_call,
                              (0.45 + 0.55 * r) * (pot + 2 * to_call)
                              * (0.5 + eq)))
                return {"action": "raise", "amount": max(1, amt), "equity": eq,
                        "thresholds": t}
            if eq >= need:
                return {"action": "call", "amount": to_call, "equity": eq,
                        "thresholds": t}
            return {"action": "fold", "amount": 0, "equity": eq,
                    "thresholds": t}
        # checked to hero
        if eq >= t["bet_thr"]:
            amt = int(min(stack, t["bet_frac"] * pot * (0.5 + eq)))
            return {"action": "bet" if state.street != "preflop" else "raise",
                    "amount": max(1, amt), "equity": eq, "thresholds": t}
        return {"action": "check", "amount": 0, "equity": eq, "thresholds": t}

    # --- heuristic EV (policy comparison only) ---
    def ev_of(self, state, action, eq):
        pot, to_call, stack = state.pot, state.to_call, state.stack
        if action["action"] in ("fold", "check"):
            return 0.0
        if action["action"] == "call":
            return eq * (pot + to_call) - to_call
        X = min(stack, action["amount"])
        p_fold = min(0.6, max(0.05, 0.6 - 1.2 * eq))
        return p_fold * pot + (1 - p_fold) * (eq * (pot + 2 * X) - X)

    def best_ev(self, state, eq):
        """Best heuristic EV among the candidate actions (oracle for decision loss)."""
        cands = []
        t = self.thresholds(0.5, state.position)
        cands.append({"action": "fold", "amount": 0})
        if state.to_call > 0:
            cands.append({"action": "call", "amount": state.to_call})
            if state.stack > state.to_call:
                cands.append({"action": "raise",
                              "amount": min(state.stack - state.to_call,
                                            int(0.8 * (state.pot + 2 * state.to_call)))})
        else:
            cands.append({"action": "check", "amount": 0})
            cands.append({"action": "bet",
                          "amount": min(state.stack, int(0.8 * state.pot))})
        return max(self.ev_of(state, c, eq) for c in cands)


LIMITATIONS = """v0 limitations, by design:
  - One opponent model: uniform random hole cards. No opponent ranges/reads.
  - Single-street decisions: no future-street planning, no ICM, no multiway
    pot dynamics beyond equity-vs-n-opponents.
  - EV model is heuristic (fold-equity linear in equity) and is used only to
    COMPARE policies on the same footing, never as ground truth.
  - Preflop uses the same equity MC (no chart knowledge).
"""