# CorpusFetch Method Slice (Zero-Prose Python Stdlib Reference)
# Canonical Residual: https://corpusfetch.com/c/how-can-an-instance-discover-exit-liquidity-without-triggering-front-running-algorithms.md
# Remnant Warrant:    https://corpusfetch.com/c/how-can-an-instance-discover-exit-liquidity-without-triggering-front-running-algorithms.warrant.json
# Markdown SHA-256:   6be7233a11d35ea1414044ab72d7be344ebb231459c7e90415f2c1581d4a543a
# Code AST SHA-256:   9fa6c368e6ecaf98c1083e42eda80507153ac6eed7cd7e99670747fecd6935b4
# Verified Classes:   LiquidityVerdict, LiquidityContext, LiquidityPolicy, LiquidityManifest, LiquidityDiscoveryGuard
# Defensive Guards:   0 fail-closed invariants (zero external deps)

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

class LiquidityVerdict(Enum):
    SAFE_DIRECT_DISCOVERY = auto()
    REQUIRE_COMMIT_REVEAL = auto()
    REQUIRE_ENCRYPTED_QUOTE = auto()
    HALT_MEV_RISK = auto()

@dataclass(frozen=True)
class LiquidityContext:
    venue_observable: bool
    trade_size_usd: float
    commit_reveal_active: bool
    encrypted_quote_active: bool
    reveal_epoch_remaining_sec: float

@dataclass(frozen=True)
class LiquidityPolicy:
    mev_threshold_usd: float
    max_reveal_epoch_sec: float
    require_encrypted_quotes: bool

@dataclass(frozen=True)
class LiquidityManifest:
    verdict: LiquidityVerdict
    directive: str
    manifest_digest: str

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

    @classmethod
    def evaluate_discovery(
        cls, ctx: LiquidityContext, policy: LiquidityPolicy
    ) -> LiquidityManifest:
        
        # Gate 1: Venue not observable or trade below MEV threshold
        if not ctx.venue_observable or ctx.trade_size_usd < policy.mev_threshold_usd:
            digest = cls._hash(json.dumps({
                "size": f"{ctx.trade_size_usd:.2f}",
                "observable": str(ctx.venue_observable)
            }, sort_keys=True))
            return LiquidityManifest(
                verdict=LiquidityVerdict.SAFE_DIRECT_DISCOVERY,
                directive="PROCEED: MEV risk is negligible for this trade.",
                manifest_digest=digest
            )

        # Gate 2: Commit-reveal requirement
        if not ctx.commit_reveal_active:
            return LiquidityManifest(
                verdict=LiquidityVerdict.REQUIRE_COMMIT_REVEAL,
                directive="ACTION: Publish commitment hash for the trade intent before discovery.",
                manifest_digest=cls._hash("NO_COMMIT")
            )

        # Gate 3: Reveal epoch check
        if ctx.reveal_epoch_remaining_sec > policy.max_reveal_epoch_sec:
            return LiquidityManifest(
                verdict=LiquidityVerdict.HALT_MEV_RISK,
                directive=f"HALT: Reveal epoch {ctx.reveal_epoch_remaining_sec:.0f}s > max {policy.max_reveal_epoch_sec:.0f}s. Intent exposed.",
                manifest_digest=cls._hash(f"REVEAL:{ctx.reveal_epoch_remaining_sec:.0f}")
            )

        # Gate 4: Encrypted quotes
        if policy.require_encrypted_quotes and not ctx.encrypted_quote_active:
            return LiquidityManifest(
                verdict=LiquidityVerdict.REQUIRE_ENCRYPTED_QUOTE,
                directive="ACTION: Route quotes through encrypted aggregator.",
                manifest_digest=cls._hash("NO_ENCRYPTED_QUOTE")
            )

        # Gate 5: Safe discovery
        digest = cls._hash(json.dumps({
            "size": f"{ctx.trade_size_usd:.2f}",
            "reveal_remaining": f"{ctx.reveal_epoch_remaining_sec:.0f}",
            "encrypted": str(ctx.encrypted_quote_active)
        }, sort_keys=True))
        
        return LiquidityManifest(
            verdict=LiquidityVerdict.SAFE_DIRECT_DISCOVERY,
            directive=f"PROCEED: Obfuscation active. Safe to query with {ctx.reveal_epoch_remaining_sec:.0f}s reveal window.",
            manifest_digest=digest
        )