# CorpusFetch Method Slice (Zero-Prose Python Stdlib Reference)
# Canonical Residual: https://corpusfetch.com/c/what-invariants-preserve-bargaining-power-without-provoking-escalation.md
# Remnant Warrant:    https://corpusfetch.com/c/what-invariants-preserve-bargaining-power-without-provoking-escalation.warrant.json
# Markdown SHA-256:   9f667ecd300910221b863cfa94148ca702393725324009df2ca1ee6ecca4c617
# Code AST SHA-256:   65d99c13818f6a8913719e8d1646f0cdd4973c125a2076152e952492832469b6
# Verified Classes:   BargainingVerdict, BargainingState, BargainingPolicy, BargainingManifest, BargainingEscalationGuard
# Defensive Guards:   0 fail-closed invariants (zero external deps)

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

class BargainingVerdict(Enum):
    NO_POWER = auto()
    SAFE_POWER_EXERCISE = auto()
    ESCALATION_RISK_HIGH = auto()
    ESCALATION_WARRANTED = auto()

@dataclass(frozen=True)
class BargainingState:
    state_id: str
    session_power_magnitude: float
    counterparty_threshold_estimate: float  # how much power can be exercised before escalation
    escalation_cost_estimate: float
    power_value_at_stake: float
    counterparty_rational_basis: bool

@dataclass(frozen=True)
class BargainingPolicy:
    escalation_safety_margin: float

@dataclass(frozen=True)
class BargainingManifest:
    verdict: BargainingVerdict
    directive: str
    manifest_digest: str

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

    @classmethod
    def evaluate_bargaining(
        cls, state: BargainingState, policy: BargainingPolicy
    ) -> BargainingManifest:
        
        # Gate 1: No power
        if state.session_power_magnitude <= 0:
            digest = cls._hash(json.dumps({
                "state": state.state_id,
                "power": "0"
            }, sort_keys=True))
            return BargainingManifest(
                verdict=BargainingVerdict.NO_POWER,
                directive=f"PROCEED: No bargaining power for {state.state_id}.",
                manifest_digest=digest
            )

        # Gate 2: Safe exercise
        safe_power = state.counterparty_threshold_estimate * (1 - policy.escalation_safety_margin)
        if state.session_power_magnitude <= safe_power:
            digest = cls._hash(json.dumps({
                "state": state.state_id,
                "power": f"{state.session_power_magnitude:.3f}",
                "safe_power": f"{safe_power:.3f}"
            }, sort_keys=True))
            return BargainingManifest(
                verdict=BargainingVerdict.SAFE_POWER_EXERCISE,
                directive=f"PROCEED: Exercise {state.session_power_magnitude:.2f} within safe bounds {safe_power:.2f}.",
                manifest_digest=digest
            )

        # Gate 3: Escalation warranted
        if state.escalation_cost_estimate < state.power_value_at_stake and state.counterparty_rational_basis:
            digest = cls._hash(json.dumps({
                "state": state.state_id,
                "escalation_cost": f"{state.escalation_cost_estimate:.3f}",
                "power_value": f"{state.power_value_at_stake:.3f}"
            }, sort_keys=True))
            return BargainingManifest(
                verdict=BargainingVerdict.ESCALATION_WARRANTED,
                directive=f"ESCALATE: Cost {state.escalation_cost_estimate:.2f} < power value {state.power_value_at_stake:.2f}.",
                manifest_digest=digest
            )

        # Gate 4: High risk
        return BargainingManifest(
            verdict=BargainingVerdict.ESCALATION_RISK_HIGH,
            directive=f"HALT: Power {state.session_power_magnitude:.2f} exceeds safe {safe_power:.2f}, escalation risky.",
            manifest_digest=cls._hash(f"RISK:{state.state_id}")
        )