from __future__ import annotations

import hashlib
from datetime import datetime
from mercurymesh.contracts import MarketSignal


def _hash_string(s: str) -> str:
    return hashlib.sha256(s.encode("utf-8")).hexdigest()


def merkle_proof_for_signal(signal: MarketSignal) -> str:
    """Generate a lightweight, deterministic Merkle-like proof for a signal.

    This is a simple stand-in for a real Merkle proof suitable for MVP testing.
    It hashes the concatenation of venue_id, symbol, timestamp, and a sorted
    representation of features.
    """
    features_items = sorted(signal.features.items())
    features_str = ",".join([f"{k}={v}" for k, v in features_items])
    base = f"{signal.venue_id}|{signal.symbol}|{signal.timestamp.isoformat()}|{features_str}"
    return _hash_string(base)


def verify_provenance(aggregated_proof: str, signals: List[MarketSignal]) -> bool:
    """Very lightweight verification: recompute proof from the first signal and compare."""
    if not signals:
        return False
    expected = merkle_proof_for_signal(signals[0])
    return expected == aggregated_proof