strat-gameplay-webapp/backend/app/core/validators.py

"""
Rule Validators - Validate game actions and state transitions.

Ensures all game actions follow baseball rules and state is valid.

Author: Claude
Date: 2025-10-24
"""
import logging
from uuid import UUID

from app.models.game_models import GameState, DefensiveDecision, OffensiveDecision

logger = logging.getLogger(f'{__name__}.GameValidator')


class ValidationError(Exception):
    """Raised when validation fails"""
    pass


class GameValidator:
    """Validates game actions and state"""

    @staticmethod
    def validate_game_active(state: GameState) -> None:
        """Ensure game is in active state"""
        if state.status != "active":
            raise ValidationError(f"Game is not active (status: {state.status})")

    @staticmethod
    def validate_outs(outs: int) -> None:
        """Ensure outs are valid"""
        if outs < 0 or outs > 2:
            raise ValidationError(f"Invalid outs: {outs} (must be 0-2)")

    @staticmethod
    def validate_inning(inning: int, half: str) -> None:
        """Ensure inning is valid"""
        if inning < 1:
            raise ValidationError(f"Invalid inning: {inning}")
        if half not in ["top", "bottom"]:
            raise ValidationError(f"Invalid half: {half}")

    @staticmethod
    def validate_defensive_decision(decision: DefensiveDecision, state: GameState) -> None:
        """Validate defensive team decision"""
        valid_alignments = ["normal", "shifted_left", "shifted_right"]
        if decision.alignment not in valid_alignments:
            raise ValidationError(f"Invalid alignment: {decision.alignment}")

        valid_depths = ["in", "normal", "back", "double_play"]  # TODO: update these to strat-specific values
        if decision.infield_depth not in valid_depths:
            raise ValidationError(f"Invalid infield depth: {decision.infield_depth}")

        # Validate hold runners - can't hold empty bases
        runner_bases = [r.on_base for r in state.runners]
        for base in decision.hold_runners:
            if base not in runner_bases:
                raise ValidationError(f"Can't hold base {base} - no runner present")

        logger.debug("Defensive decision validated")

    @staticmethod
    def validate_offensive_decision(decision: OffensiveDecision, state: GameState) -> None:
        """Validate offensive team decision"""
        valid_approaches = ["normal", "contact", "power", "patient"]  # TODO: update these to strat-specific values
        if decision.approach not in valid_approaches:
            raise ValidationError(f"Invalid approach: {decision.approach}")

        # Validate steal attempts
        runner_bases = [r.on_base for r in state.runners]
        for base in decision.steal_attempts:
            # Must have runner on base-1 to steal base
            if (base - 1) not in runner_bases:
                raise ValidationError(f"Can't steal {base} - no runner on {base-1}")
            
            # TODO: add check that base in front of stealing runner is unoccupied

        # Can't bunt with 2 outs (simplified rule)
        if decision.bunt_attempt and state.outs == 2:
            raise ValidationError("Cannot bunt with 2 outs")

        logger.debug("Offensive decision validated")

    @staticmethod
    def validate_defensive_lineup_positions(lineup: list) -> None:
        """
        Validate defensive lineup has exactly 1 active player per position.

        Args:
            lineup: List of LineupPlayerState objects

        Raises:
            ValidationError: If any position is missing or duplicated
        """
        required_positions = ['P', 'C', '1B', '2B', '3B', 'SS', 'LF', 'CF', 'RF']

        # Count active players per position
        position_counts: dict[str, int] = {}
        for player in lineup:
            if player.is_active:
                pos = player.position
                position_counts[pos] = position_counts.get(pos, 0) + 1

        # Check each required position has exactly 1 active player
        errors = []
        for pos in required_positions:
            count = position_counts.get(pos, 0)
            if count == 0:
                errors.append(f"Missing active player at {pos}")
            elif count > 1:
                errors.append(f"Multiple active players at {pos} ({count} players)")

        if errors:
            raise ValidationError(f"Invalid defensive lineup: {'; '.join(errors)}")

        logger.debug("Defensive lineup positions validated")

    @staticmethod
    def can_continue_inning(state: GameState) -> bool:
        """Check if inning can continue"""
        return state.outs < 3

    @staticmethod
    def is_game_over(state: GameState) -> bool:
        """Check if game is complete"""
        # Game over after 9 innings if score not tied
        if state.inning >= 9 and state.half == "bottom":
            if state.home_score != state.away_score:
                return True
            # Home team wins if ahead in bottom of 9th
            if state.home_score > state.away_score:
                return True
        # Also check if we're in extras and bottom team is ahead
        if state.inning > 9 and state.half == "bottom":
            if state.home_score > state.away_score:
                return True
        return False


# Singleton instance
game_validator = GameValidator()