CIA/e-voting-system/backend/routes/votes.py

"""
Routes pour le vote et les bulletins.
"""

import logging
from fastapi import APIRouter, HTTPException, status, Depends, Request, Query
from sqlalchemy.orm import Session
from datetime import datetime, timezone
import base64
import uuid
from typing import Dict, Any, List
from .. import schemas, services
from ..dependencies import get_db, get_current_voter
from ..models import Voter
from ..crypto.hashing import SecureHash
from ..blockchain import BlockchainManager
from ..blockchain_client import BlockchainClient, get_blockchain_client_sync
import asyncio

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/votes", tags=["votes"])

# Global blockchain manager instance (fallback for in-memory blockchain)
blockchain_manager = BlockchainManager()

# Global blockchain client instance for PoA validators
blockchain_client: BlockchainClient = None


def normalize_poa_blockchain_to_election_format(poa_data: Dict[str, Any], election_id: int) -> Dict[str, Any]:
    """
    Normalize PoA blockchain format to election blockchain format.
    
    PoA format has nested transactions in each block.
    Election format has flat structure with transaction_id and encrypted_vote fields.
    
    Args:
        poa_data: Blockchain data from PoA validators
        election_id: Election ID for logging
        
    Returns:
        Blockchain data in election format
    """
    logger.info(f"Normalizing PoA blockchain data for election {election_id}")
    
    normalized_blocks = []
    
    # Convert each PoA block to election format
    for block in poa_data.get("blocks", []):
        logger.debug(f"Processing block {block.get('index')}: {len(block.get('transactions', []))} transactions")
        
        # If block has transactions (PoA format), convert each to a separate entry
        transactions = block.get("transactions", [])
        
        if len(transactions) == 0:
            # Genesis block or empty block - convert directly
            normalized_blocks.append({
                "index": block.get("index"),
                "prev_hash": block.get("prev_hash", "0" * 64),
                "timestamp": block.get("timestamp", 0),
                "encrypted_vote": "",
                "transaction_id": "",
                "block_hash": block.get("block_hash", ""),
                "signature": block.get("signature", "")
            })
        else:
            # Block with transactions - create one entry per transaction
            for tx in transactions:
                normalized_blocks.append({
                    "index": block.get("index"),
                    "prev_hash": block.get("prev_hash", "0" * 64),
                    "timestamp": block.get("timestamp", tx.get("timestamp", 0)),
                    "encrypted_vote": tx.get("encrypted_vote", ""),
                    "transaction_id": tx.get("voter_id", ""),  # Use voter_id as transaction_id
                    "block_hash": block.get("block_hash", ""),
                    "signature": block.get("signature", "")
                })
    
    logger.info(f"Normalized {len(poa_data.get('blocks', []))} PoA blocks to {len(normalized_blocks)} election format blocks")
    
    # Return in election format
    return {
        "blocks": normalized_blocks,
        "verification": poa_data.get("verification", {
            "chain_valid": True,
            "total_blocks": len(normalized_blocks),
            "total_votes": len(normalized_blocks) - 1  # Exclude genesis
        })
    }


async def init_blockchain_client():
    """Initialize the blockchain client on startup"""
    global blockchain_client
    if blockchain_client is None:
        blockchain_client = BlockchainClient()
        await blockchain_client.refresh_validator_status()


def get_blockchain_client() -> BlockchainClient:
    """Get the blockchain client instance"""
    global blockchain_client
    if blockchain_client is None:
        blockchain_client = BlockchainClient()
    return blockchain_client


@router.post("")
async def submit_simple_vote(
    vote_data: dict,
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db),
    request: Request = None
):
    """
    Soumettre un vote simple avec just élection_id et nom du candidat.
    Interface simplifiée pour l'application web.
    """
    from .. import models
    
    election_id = vote_data.get('election_id')
    candidate_name = vote_data.get('choix')
    
    if not election_id or not candidate_name:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="election_id and choix are required"
        )
    
    # Vérifier que l'électeur n'a pas déjà voté
    if services.VoteService.has_voter_voted(db, current_voter.id, election_id):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Voter has already voted in this election"
        )
    
    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(db, election_id)
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )
    
    # Trouver le candidat par nom
    candidate = db.query(models.Candidate).filter(
        models.Candidate.name == candidate_name,
        models.Candidate.election_id == election_id
    ).first()
    
    if not candidate:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Candidate not found"
        )
    
    # Enregistrer le vote (sans chiffrement pour l'MVP)
    import time
    from ..crypto.hashing import SecureHash
    
    ballot_hash = SecureHash.hash_bulletin(
        vote_id=current_voter.id,
        candidate_id=candidate.id,
        timestamp=int(time.time())
    )
    
    vote = services.VoteService.record_vote(
        db=db,
        voter_id=current_voter.id,
        election_id=election_id,
        candidate_id=candidate.id,
        encrypted_vote=b"",  # Empty for MVP
        ballot_hash=ballot_hash,
        ip_address=request.client.host if request else None
    )

    # Generate transaction ID for blockchain
    import uuid
    transaction_id = f"tx-{uuid.uuid4().hex[:12]}"

    # Submit vote to PoA blockchain
    blockchain_client = get_blockchain_client()
    await blockchain_client.refresh_validator_status()

    blockchain_response = {
        "status": "pending"
    }

    try:
        async with BlockchainClient() as poa_client:
            # Submit vote to PoA network
            submission_result = await poa_client.submit_vote(
                voter_id=current_voter.id,
                election_id=election_id,
                encrypted_vote="",  # Empty for MVP (not encrypted)
                ballot_hash=ballot_hash,
                transaction_id=transaction_id
            )
            blockchain_response = {
                "status": "submitted",
                "transaction_id": transaction_id,
                "block_hash": submission_result.get("block_hash"),
                "validator": submission_result.get("validator")
            }
            logger.info(
                f"Vote submitted to PoA: voter={current_voter.id}, "
                f"election={election_id}, tx={transaction_id}"
            )
    except Exception as e:
        # Fallback: Record in local blockchain
        import traceback
        logger.warning(f"PoA submission failed: {e}")
        logger.warning(f"Exception type: {type(e).__name__}")
        logger.warning(f"Traceback: {traceback.format_exc()}")
        logger.warning("Falling back to local blockchain.")
        try:
            blockchain = blockchain_manager.get_or_create_blockchain(election_id)
            block = blockchain.add_block(
                encrypted_vote=ballot_hash,
                transaction_id=transaction_id
            )
            blockchain_response = {
                "status": "submitted_fallback",
                "transaction_id": transaction_id,
                "block_index": block.index,
                "warning": "Vote recorded in local blockchain (PoA validators unreachable)"
            }
        except Exception as fallback_error:
            logger.error(f"Fallback blockchain also failed: {fallback_error}")
            blockchain_response = {
                "status": "database_only",
                "transaction_id": transaction_id,
                "warning": "Vote recorded in database but blockchain submission failed"
            }

    # Mark voter as having voted (only after confirming vote is recorded)
    # This ensures transactional consistency between database and marked status
    try:
        services.VoterService.mark_as_voted(db, current_voter.id)
        marked_as_voted = True
    except Exception as mark_error:
        logger.error(f"Failed to mark voter as voted: {mark_error}")
        # Note: Vote is already recorded, this is a secondary operation
        marked_as_voted = False

    return {
        "message": "Vote recorded successfully",
        "id": vote.id,
        "ballot_hash": ballot_hash,
        "timestamp": vote.timestamp,
        "blockchain": blockchain_response,
        "voter_marked_voted": marked_as_voted
    }



@router.post("/submit")
async def submit_vote(
    vote_bulletin: schemas.VoteBulletin,
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db),
    request: Request = None
):
    """
    Soumettre un vote chiffré via PoA blockchain.

    Le vote doit être:
    - Chiffré avec ElGamal
    - Accompagné d'une preuve ZK de validité

    Le vote est enregistré dans la PoA blockchain pour l'immuabilité.
    """

    # Vérifier que l'électeur n'a pas déjà voté
    if services.VoteService.has_voter_voted(
        db,
        current_voter.id,
        vote_bulletin.election_id
    ):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Voter has already voted in this election"
        )

    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(
        db,
        vote_bulletin.election_id
    )
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Vérifier que le candidat existe
    from ..models import Candidate
    candidate = db.query(Candidate).filter(
        Candidate.id == vote_bulletin.candidate_id,
        Candidate.election_id == vote_bulletin.election_id
    ).first()
    if not candidate:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Candidate not found"
        )

    # Décoder le vote chiffré
    try:
        encrypted_vote_bytes = base64.b64decode(vote_bulletin.encrypted_vote)
    except Exception:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Invalid encrypted vote format"
        )

    # Générer le hash du bulletin
    import time
    ballot_hash = SecureHash.hash_bulletin(
        vote_id=current_voter.id,
        candidate_id=vote_bulletin.candidate_id,
        timestamp=int(time.time())
    )

    # Générer ID unique pour la blockchain (anonyme)
    transaction_id = f"tx-{uuid.uuid4().hex[:12]}"

    # Enregistrer le vote en base de données
    vote = services.VoteService.record_vote(
        db=db,
        voter_id=current_voter.id,
        election_id=vote_bulletin.election_id,
        candidate_id=vote_bulletin.candidate_id,
        encrypted_vote=encrypted_vote_bytes,
        ballot_hash=ballot_hash,
        ip_address=request.client.host if request else None
    )

    # Soumettre le vote aux validateurs PoA
    blockchain_client = get_blockchain_client()
    await blockchain_client.refresh_validator_status()

    blockchain_status = "pending"
    marked_as_voted = False

    try:
        async with BlockchainClient() as poa_client:
            # Soumettre le vote au réseau PoA
            submission_result = await poa_client.submit_vote(
                voter_id=current_voter.id,
                election_id=vote_bulletin.election_id,
                encrypted_vote=vote_bulletin.encrypted_vote,
                ballot_hash=ballot_hash,
                transaction_id=transaction_id
            )
            blockchain_status = "submitted"

            logger.info(
                f"Vote submitted to PoA: voter={current_voter.id}, "
                f"election={vote_bulletin.election_id}, tx={transaction_id}"
            )

    except Exception as e:
        # Fallback: Try to record in local blockchain
        logger.warning(f"PoA submission failed: {e}. Falling back to local blockchain.")

        try:
            blockchain = blockchain_manager.get_or_create_blockchain(vote_bulletin.election_id)
            block = blockchain.add_block(
                encrypted_vote=vote_bulletin.encrypted_vote,
                transaction_id=transaction_id
            )
            blockchain_status = "submitted_fallback"
        except Exception as fallback_error:
            logger.error(f"Fallback blockchain also failed: {fallback_error}")
            blockchain_status = "database_only"

    # Mark voter as having voted (only after vote is confirmed recorded)
    # This ensures consistency regardless of blockchain status
    try:
        services.VoterService.mark_as_voted(db, current_voter.id)
        marked_as_voted = True
    except Exception as mark_error:
        logger.error(f"Failed to mark voter as voted: {mark_error}")
        # Note: Vote is already recorded, this is a secondary operation
        marked_as_voted = False

    return {
        "id": vote.id,
        "transaction_id": transaction_id,
        "ballot_hash": ballot_hash,
        "timestamp": vote.timestamp,
        "status": blockchain_status,
        "voter_marked_voted": marked_as_voted
    }


@router.get("/status")
def get_vote_status(
    election_id: int,
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db)
):
    """Vérifier si l'électeur a déjà voté pour une élection"""
    
    has_voted = services.VoteService.has_voter_voted(
        db,
        current_voter.id,
        election_id
    )
    
    return {"has_voted": has_voted}


@router.get("/history", response_model=list)
def get_voter_history(
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db)
):
    """Récupérer l'historique des votes de l'électeur actuel"""
    from .. import models
    from datetime import datetime, timezone

    votes = db.query(models.Vote).filter(
        models.Vote.voter_id == current_voter.id
    ).all()

    # Retourner la structure avec infos des élections
    history = []
    now = datetime.now(timezone.utc)
    
    for vote in votes:
        election = db.query(models.Election).filter(
            models.Election.id == vote.election_id
        ).first()
        candidate = db.query(models.Candidate).filter(
            models.Candidate.id == vote.candidate_id
        ).first()

        if election:
            # Ensure dates are timezone-aware for comparison
            start_date = election.start_date
            end_date = election.end_date
            
            # Make naive datetimes aware if needed
            if start_date and start_date.tzinfo is None:
                start_date = start_date.replace(tzinfo=timezone.utc)
            if end_date and end_date.tzinfo is None:
                end_date = end_date.replace(tzinfo=timezone.utc)
            
            # Déterminer le statut de l'élection
            if start_date and start_date > now:
                status_val = "upcoming"
            elif end_date and end_date < now:
                status_val = "closed"
            else:
                status_val = "active"

            history.append({
                "vote_id": vote.id,
                "election_id": election.id,
                "election_name": election.name,
                "candidate_name": candidate.name if candidate else "Unknown",
                "candidate_id": vote.candidate_id,
                "candidate_id": candidate.id if candidate else None,
                "vote_date": vote.timestamp,
                "election_status": status_val
            })

    return history


@router.post("/setup")
async def setup_election(
    election_id: int,
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db)
):
    """
    Initialiser une élection avec les clés cryptographiques.

    Crée une blockchain pour l'élection et génère les clés publiques
    pour le chiffrement ElGamal côté client.
    """
    from .. import models
    from ..crypto.encryption import ElGamalEncryption

    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(db, election_id)
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Générer ou récupérer la blockchain pour cette élection
    blockchain = blockchain_manager.get_or_create_blockchain(election_id)

    # Générer les clés ElGamal si nécessaire
    if not election.public_key:
        elgamal = ElGamal()
        # Store as base64-encoded bytes (database column is LargeBinary)
        # public_key_bytes returns UTF-8 "p:g:h", then encode to base64
        election.public_key = base64.b64encode(elgamal.public_key_bytes)
        db.add(election)
        db.commit()

    return {
        "status": "initialized",
        "election_id": election_id,
        "public_keys": {
            "elgamal_pubkey": election.public_key.decode('utf-8') if election.public_key else None
        },
        "blockchain_blocks": blockchain.get_block_count()
    }


@router.get("/public-keys")
async def get_public_keys(
    election_id: int = Query(...),
    db: Session = Depends(get_db)
):
    """
    Récupérer les clés publiques pour le chiffrement côté client.

    Accessible sans authentification pour permettre le chiffrement avant
    la connexion (si applicable).
    """
    from .. import models

    # Vérifier que l'élection existe
    election = db.query(models.Election).filter(
        models.Election.id == election_id
    ).first()

    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    if not election.public_key:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Election keys not initialized. Call /setup first."
        )

    return {
        "elgamal_pubkey": election.public_key.decode('utf-8') if election.public_key else None
    }


@router.get("/blockchain")
async def get_blockchain(
    election_id: int = Query(...),
    db: Session = Depends(get_db)
):
    """
    Récupérer l'état complet de la blockchain pour une élection.

    Retourne tous les blocs et l'état de vérification.
    Requête d'abord aux validateurs PoA, puis fallback sur blockchain locale.
    """
    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(db, election_id)
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Try to get blockchain state from PoA validators first
    try:
        async with BlockchainClient() as poa_client:
            blockchain_data = await poa_client.get_blockchain_state(election_id)
            if blockchain_data:
                logger.info(f"Got blockchain state from PoA for election {election_id}")
                # Normalize PoA format to election blockchain format
                return normalize_poa_blockchain_to_election_format(blockchain_data, election_id)
    except Exception as e:
        logger.warning(f"Failed to get blockchain from PoA: {e}")

    # Fallback to local blockchain manager
    logger.info(f"Falling back to local blockchain for election {election_id}")
    blockchain = blockchain_manager.get_or_create_blockchain(election_id)
    return blockchain.get_blockchain_data()


@router.get("/results")
async def get_results(
    election_id: int = Query(...),
    db: Session = Depends(get_db)
):
    """
    Obtenir les résultats comptabilisés d'une élection.

    Requête d'abord aux validateurs PoA, puis fallback sur blockchain locale.
    """
    from .. import models

    # Vérifier que l'élection existe
    election = db.query(models.Election).filter(
        models.Election.id == election_id
    ).first()

    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Essayer d'obtenir les résultats du réseau PoA en premier
    try:
        async with BlockchainClient() as poa_client:
            poa_results = await poa_client.get_election_results(election_id)

            if poa_results:
                logger.info(f"Retrieved results from PoA validators for election {election_id}")
                return poa_results

    except Exception as e:
        logger.warning(f"Failed to get results from PoA: {e}")

    # Fallback: Utiliser la blockchain locale
    logger.info(f"Falling back to local blockchain for election {election_id}")

    # Compter les votes par candidat (simple pour MVP)
    votes = db.query(models.Vote).filter(
        models.Vote.election_id == election_id
    ).all()

    # Grouper par candidat
    vote_counts = {}
    for vote in votes:
        candidate = db.query(models.Candidate).filter(
            models.Candidate.id == vote.candidate_id
        ).first()

        if candidate:
            if candidate.name not in vote_counts:
                vote_counts[candidate.name] = 0
            vote_counts[candidate.name] += 1

    # Obtenir la blockchain
    blockchain = blockchain_manager.get_or_create_blockchain(election_id)

    total_votes = blockchain.get_vote_count()

    results = []
    for candidate_name, count in vote_counts.items():
        percentage = (count / total_votes * 100) if total_votes > 0 else 0
        results.append({
            "candidate_name": candidate_name,
            "vote_count": count,
            "percentage": round(percentage, 2)
        })

    return {
        "election_id": election_id,
        "election_name": election.name,
        "total_votes": total_votes,
        "results": sorted(results, key=lambda x: x["vote_count"], reverse=True),
        "verification": {
            "chain_valid": blockchain.verify_chain_integrity(),
            "timestamp": datetime.now(timezone.utc).isoformat()
        }
    }


@router.post("/verify-blockchain")
async def verify_blockchain(
    election_id: int,
    db: Session = Depends(get_db)
):
    """
    Vérifier l'intégrité de la blockchain pour une élection.

    Requête d'abord aux validateurs PoA, puis fallback sur blockchain locale.
    Vérifie:
    - La chaîne de hachage (chaque bloc lie au précédent)
    - Les signatures des blocs
    - L'absence de modification
    """
    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(db, election_id)
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Essayer de vérifier sur les validateurs PoA en premier
    try:
        async with BlockchainClient() as poa_client:
            is_valid = await poa_client.verify_blockchain_integrity(election_id)

            if is_valid is not None:
                blockchain_state = await poa_client.get_blockchain_state(election_id)

                logger.info(f"Blockchain verification from PoA validators for election {election_id}: {is_valid}")

                return {
                    "election_id": election_id,
                    "chain_valid": is_valid,
                    "total_blocks": blockchain_state.get("verification", {}).get("total_blocks", 0) if blockchain_state else 0,
                    "total_votes": blockchain_state.get("verification", {}).get("total_votes", 0) if blockchain_state else 0,
                    "status": "valid" if is_valid else "invalid",
                    "source": "poa_validators"
                }

    except Exception as e:
        logger.warning(f"Failed to verify blockchain on PoA: {e}")

    # Fallback: Vérifier sur la blockchain locale
    logger.info(f"Falling back to local blockchain verification for election {election_id}")

    blockchain = blockchain_manager.get_or_create_blockchain(election_id)
    is_valid = blockchain.verify_chain_integrity()

    return {
        "election_id": election_id,
        "chain_valid": is_valid,
        "total_blocks": blockchain.get_block_count(),
        "total_votes": blockchain.get_vote_count(),
        "status": "valid" if is_valid else "invalid",
        "source": "local_blockchain"
    }


@router.get("/transaction-status")
async def get_transaction_status(
    transaction_id: str = Query(...),
    election_id: int = Query(...),
    db: Session = Depends(get_db)
):
    """
    Check the confirmation status of a vote on the PoA blockchain.

    Returns:
    - status: "pending" or "confirmed"
    - confirmed: boolean
    - block_number: block where vote is confirmed (if confirmed)
    - block_hash: hash of the block (if confirmed)
    """
    # Vérifier que l'élection existe
    election = services.ElectionService.get_election(db, election_id)
    if not election:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Election not found"
        )

    # Essayer de vérifier le statut sur PoA en premier
    try:
        async with BlockchainClient() as poa_client:
            status_info = await poa_client.get_vote_confirmation_status(
                transaction_id,
                election_id
            )

            if status_info:
                logger.info(f"Transaction status from PoA: {transaction_id} = {status_info['status']}")
                return {
                    **status_info,
                    "source": "poa_validators"
                }

    except Exception as e:
        logger.warning(f"Failed to get transaction status from PoA: {e}")

    # Fallback: Check local blockchain
    logger.debug(f"Falling back to local blockchain for transaction {transaction_id}")

    return {
        "status": "unknown",
        "confirmed": False,
        "transaction_id": transaction_id,
        "source": "local_fallback"
    }


@router.get("/check")
async def check_voter_vote(
    election_id: int = Query(...),
    current_voter: Voter = Depends(get_current_voter),
    db: Session = Depends(get_db)
):
    """
    Vérifier si le votant a déjà voté dans une élection spécifique.
    """
    from .. import models
    
    # Vérifier si le votant a voté dans cette élection
    vote_exists = db.query(models.Vote).filter(
        models.Vote.voter_id == current_voter.id,
        models.Vote.election_id == election_id
    ).first() is not None
    
    return {
        "has_voted": vote_exists,
        "election_id": election_id,
        "voter_id": current_voter.id
    }


from datetime import datetime