simulation/pitch_simulator.py

from __future__ import annotations

from math import sqrt
from typing import Any

from simulation.pa_outcome_sampler import (
    sample_contact_event,
    sample_pitch_family,
    sample_pitch_result,
    sample_zone_bucket,
)

def _safe_count_int(value: Any, default: int = 0) -> int:
    try:
        if value is None:
            return default
        text = str(value).strip().lower()
        if text in {"", "nan", "none"}:
            return default
        return int(float(value))
    except Exception:
        return default

def _clamp(value: float, low: float, high: float) -> float:
    return max(low, min(high, value))


def simulate_plate_appearance(
    game_row: dict[str, Any],
    batter_row: dict[str, Any],
    pitcher_row: dict[str, Any],
    context_adjustment: dict[str, Any],
    pitcher_adjustment: dict[str, Any],
    bullpen_adjustment: dict[str, Any],
    sequence_distribution: dict[str, Any],
    batter_baseline: dict[str, Any],
    n_sims: int = 10000,
) -> dict[str, float]:
    hit_prob = (
        batter_baseline["hit_prob_base"]
        + pitcher_adjustment["hit_adj"]
        + context_adjustment["hit_adj"]
        + bullpen_adjustment["bullpen_risk_adj_hit"]
    )
    hr_prob = (
        batter_baseline["hr_prob_base"]
        + pitcher_adjustment["hr_adj"]
        + context_adjustment["hr_adj"]
        + bullpen_adjustment["bullpen_risk_adj_hr"]
    )
    tb2p_prob = (
        batter_baseline["tb2p_prob_base"]
        + pitcher_adjustment["tb2p_adj"]
        + context_adjustment["tb2p_adj"]
        + bullpen_adjustment["bullpen_risk_adj_tb2p"]
    )

    hit_prob = _clamp(hit_prob, 0.05, 0.55)
    hr_prob = _clamp(hr_prob, 0.005, 0.25)
    tb2p_prob = _clamp(tb2p_prob, 0.03, 0.45)

    start_balls = _safe_count_int(game_row.get("balls"), 0)
    start_strikes = _safe_count_int(game_row.get("strikes"), 0)

    hit_total = 0
    hr_total = 0
    tb2p_total = 0

    zone_probs = sequence_distribution.get("zone_probs", {}) or {}

    # I1: Compute pitch movement magnitude from pitcher_row for movement adjustment
    movement_magnitude = None
    try:
        pfx_x = pitcher_row.get("avg_pfx_x")
        pfx_z = pitcher_row.get("avg_pfx_z")
        if pfx_x is not None and pfx_z is not None:
            movement_magnitude = sqrt(float(pfx_x) ** 2 + float(pfx_z) ** 2)
    except Exception:
        movement_magnitude = None

    for _ in range(n_sims):
        balls = _clamp(start_balls, 0, 3)
        strikes = _clamp(start_strikes, 0, 2)

        resolved = False

        # simulate remainder of PA pitch-by-pitch
        for _pitch_num in range(8):
            pitch_family = sample_pitch_family(sequence_distribution)
            zone_bucket = sample_zone_bucket(zone_probs)
            pitch_result = sample_pitch_result(
                balls=int(balls),
                strikes=int(strikes),
                zone_bucket=zone_bucket,
                pitch_family=pitch_family,
                movement_magnitude=movement_magnitude,
            )["pitch_result"]

            if pitch_result == "ball":
                balls += 1
                if balls >= 4:
                    resolved = True
                    break

            elif pitch_result in {"called_strike", "whiff"}:
                strikes += 1
                if strikes >= 3:
                    resolved = True
                    break

            elif pitch_result == "foul":
                if strikes < 2:
                    strikes += 1

            elif pitch_result == "ball_in_play":
                event = sample_contact_event(
                    hit_prob=hit_prob,
                    hr_prob=hr_prob,
                    tb2p_prob=tb2p_prob,
                    zone_bucket=zone_bucket,
                    pitch_family=pitch_family,
                )

                hit_total += int(event["hit"])
                hr_total += int(event["hr"])
                tb2p_total += int(event["tb2p"])
                resolved = True
                break

        # unresolved long PA fallback
        if not resolved:
            event = sample_contact_event(
                hit_prob=hit_prob * 0.95,
                hr_prob=hr_prob * 0.95,
                tb2p_prob=tb2p_prob * 0.95,
                zone_bucket="shadow",
                pitch_family="breaking",
            )
            hit_total += int(event["hit"])
            hr_total += int(event["hr"])
            tb2p_total += int(event["tb2p"])

    return {
        "hit_prob": hit_total / n_sims,
        "hr_prob": hr_total / n_sims,
        "tb2p_prob": tb2p_total / n_sims,
    }


def simulate_upcoming_hitter(
    game_row: dict[str, Any],
    batter_row: dict[str, Any],
    pitcher_row: dict[str, Any],
    context_adjustment: dict[str, Any],
    pitcher_adjustment: dict[str, Any],
    bullpen_adjustment: dict[str, Any],
    sequence_distribution: dict[str, Any],
    batter_baseline: dict[str, Any],
    n_sims: int = 10000,
) -> dict[str, float]:
    return simulate_plate_appearance(
        game_row=game_row,
        batter_row=batter_row,
        pitcher_row=pitcher_row,
        context_adjustment=context_adjustment,
        pitcher_adjustment=pitcher_adjustment,
        bullpen_adjustment=bullpen_adjustment,
        sequence_distribution=sequence_distribution,
        batter_baseline=batter_baseline,
        n_sims=n_sims,
    )