"""
ZKPC (Zero-Knowledge Proof of Constitutionality)

Cryptographic proofs for constitutional floors.
"""

import hashlib
import json
from dataclasses import dataclass
from typing import Dict, Any, Optional

from .state import SessionState


@dataclass
class ZKPCProof:
    """ZKPC proof structure."""
    commitment_hash: str
    merkle_root: str
    floors_validated: list[str]
    witness_signature: str
    timestamp: str


class ZKPCPreCommitment:
    """Generate ZKPC commitments for constitutional stages."""
    
    def compute_initial_root(self, state: SessionState) -> str:
        """
        Compute initial Merkle root (stage 000).
        
        For micro version: simple hash of session_id + floors
        Production: real Merkle tree with full state
        """
        data = {
            "session_id": state.session_id,
            "stage": 0,
            "floors": list(state.floor_scores.keys()),
            "timestamp": state.created_at.isoformat()
        }
        
        sorted_data = json.dumps(data, sort_keys=True, separators=(",", ":"))
        return hashlib.sha256(sorted_data.encode()).hexdigest()[:16]
    
    def generate_commitment(self, state: SessionState, 
                          merkle_root: str) -> Dict[str, Any]:
        """
        Generate ZKPC proof for a stage transition.
        
        Args:
            state: Current session state
            merkle_root: Merkle root for this stage
            
        Returns:
            ZKPC proof dictionary
        """
        # In production, this would be a real zero-knowledge proof
        # For micro version: deterministic hash
        
        commitment_data = {
            "session_id": state.session_id,
            "stage": state.current_stage,
            "merkle_root": merkle_root,
            "floors": state.floor_scores,
            "timestamp": state.last_updated.isoformat()
        }
        
        sorted_data = json.dumps(commitment_data, sort_keys=True, 
                               separators=(",", ":"))
        
        return {
            "commitment_hash": hashlib.sha256(sorted_data.encode()).hexdigest()[:16],
            "merkle_root": merkle_root,
            "floors_validated": list(state.floor_scores.keys()),
            "stage": state.current_stage
        }
