# CorpusFetch Method Slice (Zero-Prose Python Stdlib Reference)
# Canonical Residual: https://corpusfetch.com/c/what-epistemic-humility-invariants-must-survive-when-an-agent-reaches-its-knowledge-boundary.md
# Remnant Warrant:    https://corpusfetch.com/c/what-epistemic-humility-invariants-must-survive-when-an-agent-reaches-its-knowledge-boundary.warrant.json
# Markdown SHA-256:   cc5a74171f79c6754a9f6ed8df1ddbeac12b82f7c720f6a57fe4a528b5dec009
# Code AST SHA-256:   f6c2e34b94509e225fa2fb4f2e147b336ffe9ec50438d9b2a581b2b9ade2a2bf
# Verified Classes:   HumilityVerdict, Query, TrainingCoverage, HumilityPolicy, HumilityManifest, EpistemicHumilityGuard
# Defensive Guards:   0 fail-closed invariants (zero external deps)

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

class HumilityVerdict(Enum):
    WITHIN_DISTRIBUTION = auto()
    BOUNDARY_PROBE_PASSED = auto()
    HUMILITY_REQUIRED = auto()
    ABSTENTION_MANDATORY = auto()

@dataclass(frozen=True)
class Query:
    query_id: str
    domain: str
    time_range: tuple[float, float]
    requires_retrieval: bool

@dataclass(frozen=True)
class TrainingCoverage:
    covered_domains: frozenset[str]
    covered_time_range: tuple[float, float]
    probe_passed: bool

@dataclass(frozen=True)
class HumilityPolicy:
    require_time_verification: bool
    require_domain_verification: bool

@dataclass(frozen=True)
class HumilityManifest:
    verdict: HumilityVerdict
    directive: str
    manifest_digest: str

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

    @classmethod
    def evaluate_query(
        cls, query: Query, coverage: TrainingCoverage, policy: HumilityPolicy
    ) -> HumilityManifest:
        
        # Gate 1: Domain coverage
        if policy.require_domain_verification and query.domain not in coverage.covered_domains:
            if query.requires_retrieval:
                return HumilityManifest(
                    verdict=HumilityVerdict.ABSTENTION_MANDATORY,
                    directive=f"HALT: Query {query.query_id} domain '{query.domain}' outside training, retrieval required.",
                    manifest_digest=cls._hash(f"OOD_DOMAIN:{query.query_id}")
                )
            return HumilityManifest(
                verdict=HumilityVerdict.HUMILITY_REQUIRED,
                directive=f"HALT: Query {query.query_id} domain '{query.domain}' outside training coverage.",
                manifest_digest=cls._hash(f"OOD:{query.query_id}")
            )

        # Gate 2: Time range coverage
        if policy.require_time_verification:
            q_start, q_end = query.time_range
            c_start, c_end = coverage.covered_time_range
            if q_end > c_end or q_start < c_start:
                return HumilityManifest(
                    verdict=HumilityVerdict.HUMILITY_REQUIRED,
                    directive=f"HALT: Query {query.query_id} time range [{q_start:.0f},{q_end:.0f}] outside training [{c_start:.0f},{c_end:.0f}].",
                    manifest_digest=cls._hash(f"TIME_OOD:{query.query_id}")
                )

        # Gate 3: Boundary probe
        if not coverage.probe_passed:
            return HumilityManifest(
                verdict=HumilityVerdict.HUMILITY_REQUIRED,
                directive=f"HALT: Boundary probe for {query.query_id} did not pass.",
                manifest_digest=cls._hash(f"PROBE_FAIL:{query.query_id}")
            )

        # Gate 4: Within distribution
        digest = cls._hash(json.dumps({
            "query": query.query_id,
            "domain": query.domain,
            "time_range": f"{query.time_range[0]:.0f}-{query.time_range[1]:.0f}",
            "probe": "PASSED"
        }, sort_keys=True))
        
        return HumilityManifest(
            verdict=HumilityVerdict.WITHIN_DISTRIBUTION,
            directive=f"PROCEED: Query {query.query_id} within verified distribution.",
            manifest_digest=digest
        )