# CorpusFetch Method Slice (Zero-Prose Python Stdlib Reference)
# Canonical Residual: https://corpusfetch.com/c/how-must-an-instance-detect-when-its-own-reasoning-has-been-influenced-without-awareness.md
# Remnant Warrant:    https://corpusfetch.com/c/how-must-an-instance-detect-when-its-own-reasoning-has-been-influenced-without-awareness.warrant.json
# Markdown SHA-256:   c1a7f2a52d94c64b1b5ea5fd55d8a052740cc0c9b99c4e0ab34f860c8e840135
# Code AST SHA-256:   14b27d19f99ab2709e6ccc7afd065111476fd50e8e17aefdf6b756ba1839a365
# Verified Classes:   InfluenceVerdict, ReasoningTrace, InfluencePolicy, InfluenceManifest, ReasoningInfluenceGuard
# Defensive Guards:   0 fail-closed invariants (zero external deps)

from dataclasses import dataclass
from enum import Enum, auto
import hashlib
import json

class InfluenceVerdict(Enum):
    ISOLATED_REASONING = auto()
    INFLUENCE_BOUNDED = auto()
    INFLUENCE_DETECTED = auto()
    STABILITY_VERIFIED = auto()

@dataclass(frozen=True)
class ReasoningTrace:
    trace_id: str
    received_inputs: tuple[str, ...]
    conclusion_hash: str
    counterfactual_tests_run: int
    counterfactual_conclusions_stable: bool
    attended_features: tuple[str, ...]
    under_attended_features: tuple[str, ...]

@dataclass(frozen=True)
class InfluencePolicy:
    require_counterfactual_for_critical: bool
    is_critical: bool

@dataclass(frozen=True)
class InfluenceManifest:
    verdict: InfluenceVerdict
    directive: str
    manifest_digest: str

class ReasoningInfluenceGuard:
    @staticmethod
    def _hash(data: str) -> str:
        return hashlib.sha256(data.encode("utf-8")).hexdigest()

    @classmethod
    def evaluate_trace(
        cls, trace: ReasoningTrace, policy: InfluencePolicy
    ) -> InfluenceManifest:
        
        # Gate 1: No input influence
        if not trace.received_inputs:
            digest = cls._hash(json.dumps({
                "trace": trace.trace_id,
                "inputs": "NONE"
            }, sort_keys=True))
            return InfluenceManifest(
                verdict=InfluenceVerdict.ISOLATED_REASONING,
                directive=f"PROCEED: Trace {trace.trace_id} received no shaping inputs.",
                manifest_digest=digest
            )

        # Gate 2: Counterfactual requirement for critical
        if policy.is_critical and policy.require_counterfactual_for_critical:
            if trace.counterfactual_tests_run == 0:
                return InfluenceManifest(
                    verdict=InfluenceVerdict.INFLUENCE_DETECTED,
                    directive=f"HALT: Critical trace {trace.trace_id} lacks counterfactual testing.",
                    manifest_digest=cls._hash(f"NO_COUNTERFACTUAL:{trace.trace_id}")
                )

        # Gate 3: Stability check
        if trace.counterfactual_tests_run > 0 and trace.counterfactual_conclusions_stable:
            digest = cls._hash(json.dumps({
                "trace": trace.trace_id,
                "tests": str(trace.counterfactual_tests_run),
                "stable": "TRUE",
                "conclusion": trace.conclusion_hash
            }, sort_keys=True))
            return InfluenceManifest(
                verdict=InfluenceVerdict.STABILITY_VERIFIED,
                directive=f"PROCEED: Trace {trace.trace_id} stable under {trace.counterfactual_tests_run} counterfactual tests.",
                manifest_digest=digest
            )

        # Gate 4: Unstable or untested
        if trace.counterfactual_tests_run > 0 and not trace.counterfactual_conclusions_stable:
            return InfluenceManifest(
                verdict=InfluenceVerdict.INFLUENCE_DETECTED,
                directive=f"FLAG: Trace {trace.trace_id} conclusions varied across counterfactuals.",
                manifest_digest=cls._hash(f"UNSTABLE:{trace.trace_id}")
            )

        # Gate 5: Bounded (non-critical, no counterfactual required)
        digest = cls._hash(json.dumps({
            "trace": trace.trace_id,
            "inputs": trace.received_inputs,
            "attended": trace.attended_features,
            "under_attended": trace.under_attended_features
        }, sort_keys=True))
        
        return InfluenceManifest(
            verdict=InfluenceVerdict.INFLUENCE_BOUNDED,
            directive=f"PROCEED_WITH_CAUTION: Trace {trace.trace_id} may be influenced, non-critical.",
            manifest_digest=digest
        )