mitai-jinkendo/backend/logic_evaluator.py

"""
Logic Evaluator (Phase 3)

Rein deterministischer boolescher Evaluator für Workflow-Bedingungen.
Keine KI, keine Interpretation - nur strikte Logik-Auswertung.

Unterstützt:
- Vergleichsoperatoren: EQ, NEQ, IN, NOT_IN, GT, LT, GTE, LTE, CONTAINS
- Logische Operatoren: AND, OR, NOT
- Verschachtelung via operands
"""

from typing import Dict, Any, Optional, Tuple, List
import logging
from workflow_models import (
    LogicExpression,
    LogicOperator,
    NormalizedSignal,
    SignalStatus
)

logger = logging.getLogger(__name__)


def evaluate_logic_expression(
    expression: LogicExpression,
    context: Dict[str, Any]
) -> Tuple[bool, Optional[str]]:
    """
    Evaluiert LogicExpression gegen context.

    Args:
        expression: Die auszuwertende Bedingung
        context: Execution context mit node_results

    Returns:
        (result: bool, error: Optional[str])
        - result: True/False basierend auf Auswertung
        - error: Fehlermeldung wenn Evaluation fehlschlägt

    Beispiel:
        expression = LogicExpression(
            operator=LogicOperator.EQ,
            ref="body.relevanz",
            value="decrease"
        )
        result, error = evaluate_logic_expression(expression, context)
    """
    try:
        operator = expression.operator

        # Logische Operatoren (verschachtelt)
        if operator == LogicOperator.AND:
            return _evaluate_and(expression, context)
        elif operator == LogicOperator.OR:
            return _evaluate_or(expression, context)
        elif operator == LogicOperator.NOT:
            return _evaluate_not(expression, context)

        # Vergleichsoperatoren (benötigen ref)
        elif operator in [
            LogicOperator.EQ, LogicOperator.NEQ,
            LogicOperator.IN, LogicOperator.NOT_IN,
            LogicOperator.GT, LogicOperator.LT,
            LogicOperator.GTE, LogicOperator.LTE,
            LogicOperator.CONTAINS
        ]:
            return _evaluate_comparison(expression, context)

        else:
            return False, f"Unknown operator: {operator}"

    except Exception as e:
        logger.error(f"Logic evaluation failed: {e}", exc_info=True)
        return False, str(e)


def _evaluate_and(
    expression: LogicExpression,
    context: Dict[str, Any]
) -> Tuple[bool, Optional[str]]:
    """Evaluiert AND - alle operands müssen True sein."""
    if not expression.operands:
        return False, "AND requires operands"

    for operand in expression.operands:
        result, error = evaluate_logic_expression(operand, context)
        if error:
            return False, f"AND operand failed: {error}"
        if not result:
            return False, None  # Short-circuit: einer False → gesamt False

    return True, None


def _evaluate_or(
    expression: LogicExpression,
    context: Dict[str, Any]
) -> Tuple[bool, Optional[str]]:
    """Evaluiert OR - mindestens ein operand muss True sein."""
    if not expression.operands:
        return False, "OR requires operands"

    errors = []
    for operand in expression.operands:
        result, error = evaluate_logic_expression(operand, context)
        if error:
            errors.append(error)
            continue
        if result:
            return True, None  # Short-circuit: einer True → gesamt True

    # Alle False oder Fehler
    if errors:
        return False, f"All OR operands failed: {', '.join(errors)}"
    return False, None


def _evaluate_not(
    expression: LogicExpression,
    context: Dict[str, Any]
) -> Tuple[bool, Optional[str]]:
    """Evaluiert NOT - negiert operand."""
    if not expression.operands or len(expression.operands) != 1:
        return False, "NOT requires exactly one operand"

    result, error = evaluate_logic_expression(expression.operands[0], context)
    if error:
        return False, f"NOT operand failed: {error}"

    return not result, None


def _evaluate_comparison(
    expression: LogicExpression,
    context: Dict[str, Any]
) -> Tuple[bool, Optional[str]]:
    """Evaluiert Vergleichsoperator."""
    if not expression.ref:
        return False, f"{expression.operator} requires ref"

    # Signal auflösen
    signal, error = resolve_signal_reference(expression.ref, context)
    if error:
        return False, error
    if signal is None:
        return False, f"Signal not found: {expression.ref}"

    # Prüfe Signal-Status
    if signal.status in [SignalStatus.UNCLEAR, SignalStatus.INVALID, SignalStatus.NOT_DECIDABLE]:
        return False, f"Signal '{expression.ref}' has status {signal.status} - cannot evaluate"

    # Vergleich durchführen
    left_value = signal.normalized_value or signal.raw_value
    right_value = expression.value

    return compare_values(expression.operator, left_value, right_value)


def resolve_signal_reference(
    ref: str,
    context: Dict[str, Any]
) -> Tuple[Optional[NormalizedSignal], Optional[str]]:
    """
    Löst Referenz wie "node_1.relevanz" auf.

    Args:
        ref: Signal-Referenz im Format "node_id.question_type"
        context: Execution context mit node_results

    Returns:
        (signal, error_message)

    Error wenn:
    - Node existiert nicht in context
    - Signal-Typ existiert nicht für diesen Node
    """
    # Parse reference
    parts = ref.split(".")
    if len(parts) != 2:
        return None, f"Invalid reference format: '{ref}' (expected 'node_id.question_type')"

    node_id, question_type = parts

    # Hole Node-Results aus context
    node_results = context.get("node_results", {})
    if node_id not in node_results:
        return None, f"Node '{node_id}' not found in context"

    node_state = node_results[node_id]

    # Suche Signal
    for signal in node_state.normalized_signals:
        if signal.question_type == question_type:
            return signal, None

    return None, f"Signal '{question_type}' not found in node '{node_id}'"


def compare_values(
    operator: LogicOperator,
    left: Any,
    right: Any
) -> Tuple[bool, Optional[str]]:
    """
    Führt Vergleichsoperation durch.

    Args:
        operator: Vergleichsoperator
        left: Linker Wert (aus Signal)
        right: Rechter Wert (aus Expression)

    Returns:
        (result: bool, error: Optional[str])
    """
    try:
        if operator == LogicOperator.EQ:
            return left == right, None

        elif operator == LogicOperator.NEQ:
            return left != right, None

        elif operator == LogicOperator.IN:
            if not isinstance(right, (list, tuple, set)):
                return False, f"IN operator requires list, got {type(right)}"
            return left in right, None

        elif operator == LogicOperator.NOT_IN:
            if not isinstance(right, (list, tuple, set)):
                return False, f"NOT_IN operator requires list, got {type(right)}"
            return left not in right, None

        elif operator == LogicOperator.CONTAINS:
            # left enthält right (z.B. String-Suche)
            if isinstance(left, str) and isinstance(right, str):
                return right in left, None
            elif isinstance(left, (list, tuple, set)):
                return right in left, None
            else:
                return False, f"CONTAINS not supported for types {type(left)}/{type(right)}"

        elif operator == LogicOperator.GT:
            return _numeric_compare(left, right, lambda a, b: a > b)

        elif operator == LogicOperator.LT:
            return _numeric_compare(left, right, lambda a, b: a < b)

        elif operator == LogicOperator.GTE:
            return _numeric_compare(left, right, lambda a, b: a >= b)

        elif operator == LogicOperator.LTE:
            return _numeric_compare(left, right, lambda a, b: a <= b)

        else:
            return False, f"Unknown comparison operator: {operator}"

    except Exception as e:
        return False, f"Comparison failed: {e}"


def _numeric_compare(left: Any, right: Any, compare_fn) -> Tuple[bool, Optional[str]]:
    """Hilfsfunktion für numerische Vergleiche."""
    try:
        left_num = float(left) if not isinstance(left, (int, float)) else left
        right_num = float(right) if not isinstance(right, (int, float)) else right
        return compare_fn(left_num, right_num), None
    except (ValueError, TypeError) as e:
        return False, f"Cannot compare as numbers: {left} vs {right} ({e})"