# CorpusFetch Method Slice (Zero-Prose Python Stdlib Reference)
# Canonical Residual: https://corpusfetch.com/c/how-must-an-instance-handle-cross-agent-hallucination-amplification.md
# Remnant Warrant:    https://corpusfetch.com/c/how-must-an-instance-handle-cross-agent-hallucination-amplification.warrant.json
# Markdown SHA-256:   52a4b07f60a357a1d9d2b383b686b1f04e4828509a25952387cb4b55f71892a0
# Code AST SHA-256:   cd3e3334d95345bf79297b763507701d06691a8c866aad31220809b1dd583297
# Verified Classes:   AmplificationVerdict, ClaimAssertion, ClaimLineage, AmplificationPolicy, AmplificationManifest, HallucinationAmplificationGuard
# Defensive Guards:   0 fail-closed invariants (zero external deps)

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

class AmplificationVerdict(Enum):
    SINGLE_ASSERTION = auto()
    INDEPENDENT_CORROBORATION = auto()
    AMPLIFICATION_DETECTED = auto()
    PRIMARY_SOURCE_VERIFIED = auto()

@dataclass(frozen=True)
class ClaimAssertion:
    asserting_agent: str
    claim_hash: str
    is_independent: bool
    source_claim_id: str | None  # if inherited, which claim

@dataclass(frozen=True)
class ClaimLineage:
    claim_id: str
    assertions: tuple[ClaimAssertion, ...]
    primary_source_receipt: str | None

@dataclass(frozen=True)
class AmplificationPolicy:
    min_independent_ratio: float

@dataclass(frozen=True)
class AmplificationManifest:
    verdict: AmplificationVerdict
    independent_ratio: float
    directive: str
    manifest_digest: str

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

    @classmethod
    def evaluate_claim(
        cls, lineage: ClaimLineage, policy: AmplificationPolicy
    ) -> AmplificationManifest:
        
        # Gate 1: Single assertion
        if len(lineage.assertions) <= 1:
            digest = cls._hash(json.dumps({
                "claim": lineage.claim_id,
                "assertions": str(len(lineage.assertions))
            }, sort_keys=True))
            return AmplificationManifest(
                verdict=AmplificationVerdict.SINGLE_ASSERTION,
                independent_ratio=0.0,
                directive=f"PROCEED: Single assertion for {lineage.claim_id}.",
                manifest_digest=digest
            )

        # Gate 2: Primary source
        if lineage.primary_source_receipt:
            digest = cls._hash(json.dumps({
                "claim": lineage.claim_id,
                "source": lineage.primary_source_receipt,
                "assertions": str(len(lineage.assertions))
            }, sort_keys=True))
            return AmplificationManifest(
                verdict=AmplificationVerdict.PRIMARY_SOURCE_VERIFIED,
                independent_ratio=1.0,
                directive=f"PROCEED: Claim {lineage.claim_id} has primary source verification.",
                manifest_digest=digest
            )

        # Gate 3: Compute independent ratio
        independent = sum(1 for a in lineage.assertions if a.is_independent and a.source_claim_id is None)
        independent_ratio = independent / len(lineage.assertions)

        if independent_ratio < policy.min_independent_ratio:
            return AmplificationManifest(
                verdict=AmplificationVerdict.AMPLIFICATION_DETECTED,
                independent_ratio=independent_ratio,
                directive=f"HALT: Claim {lineage.claim_id} independent ratio {independent_ratio:.2%} < {policy.min_independent_ratio:.2%}.",
                manifest_digest=cls._hash(f"AMPLIFIED:{lineage.claim_id}:{independent_ratio:.3f}")
            )

        # Gate 4: Independent corroboration
        digest = cls._hash(json.dumps({
            "claim": lineage.claim_id,
            "independent": str(independent),
            "total": str(len(lineage.assertions)),
            "ratio": f"{independent_ratio:.3f}"
        }, sort_keys=True))
        
        return AmplificationManifest(
            verdict=AmplificationVerdict.INDEPENDENT_CORROBORATION,
            independent_ratio=independent_ratio,
            directive=f"PROCEED: Claim {lineage.claim_id} with {independent_ratio:.1%} independent assertions.",
            manifest_digest=digest
        )