"""
ZK Applications Router - Privacy-preserving features for AITBC
"""

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, Field
from typing import Optional, Dict, Any, List
import hashlib
import secrets
from datetime import datetime
import json

from ..schemas import UserProfile
from ..storage import SessionDep

router = APIRouter(tags=["zk-applications"])


class ZKProofRequest(BaseModel):
    """Request for ZK proof generation"""
    commitment: str = Field(..., description="Commitment to private data")
    public_inputs: Dict[str, Any] = Field(default_factory=dict)
    proof_type: str = Field(default="membership", description="Type of proof")


class ZKMembershipRequest(BaseModel):
    """Request to prove group membership privately"""
    group_id: str = Field(..., description="Group to prove membership in")
    nullifier: str = Field(..., description="Unique nullifier to prevent double-spending")
    proof: str = Field(..., description="ZK-SNARK proof")


class PrivateBidRequest(BaseModel):
    """Submit a bid without revealing amount"""
    auction_id: str = Field(..., description="Auction identifier")
    bid_commitment: str = Field(..., description="Hash of bid amount + salt")
    proof: str = Field(..., description="Proof that bid is within valid range")


class ZKComputationRequest(BaseModel):
    """Request to verify AI computation with privacy"""
    job_id: str = Field(..., description="Job identifier")
    result_hash: str = Field(..., description="Hash of computation result")
    proof_of_execution: str = Field(..., description="ZK proof of correct execution")
    public_inputs: Dict[str, Any] = Field(default_factory=dict)


@router.post("/zk/identity/commit")
async def create_identity_commitment(
    user: UserProfile,
    session: SessionDep,
    salt: Optional[str] = None
) -> Dict[str, str]:
    """Create a privacy-preserving identity commitment"""
    
    # Generate salt if not provided
    if not salt:
        salt = secrets.token_hex(16)
    
    # Create commitment: H(email || salt)
    commitment_input = f"{user.email}:{salt}"
    commitment = hashlib.sha256(commitment_input.encode()).hexdigest()
    
    return {
        "commitment": commitment,
        "salt": salt,
        "user_id": user.user_id,
        "created_at": datetime.utcnow().isoformat()
    }


@router.post("/zk/membership/verify")
async def verify_group_membership(
    request: ZKMembershipRequest,
    session: SessionDep
) -> Dict[str, Any]:
    """
    Verify that a user is a member of a group without revealing which user
    Demo implementation - in production would use actual ZK-SNARKs
    """
    
    # In a real implementation, this would:
    # 1. Verify the ZK-SNARK proof
    # 2. Check the nullifier hasn't been used before
    # 3. Confirm membership in the group's Merkle tree
    
    # For demo, we'll simulate verification
    group_members = {
        "miners": ["user1", "user2", "user3"],
        "clients": ["user4", "user5", "user6"],
        "developers": ["user7", "user8", "user9"]
    }
    
    if request.group_id not in group_members:
        raise HTTPException(status_code=404, detail="Group not found")
    
    # Simulate proof verification
    is_valid = len(request.proof) > 10 and len(request.nullifier) == 64
    
    if not is_valid:
        raise HTTPException(status_code=400, detail="Invalid proof")
    
    return {
        "group_id": request.group_id,
        "verified": True,
        "nullifier": request.nullifier,
        "timestamp": datetime.utcnow().isoformat()
    }


@router.post("/zk/marketplace/private-bid")
async def submit_private_bid(
    request: PrivateBidRequest,
    session: SessionDep
) -> Dict[str, str]:
    """
    Submit a bid to the marketplace without revealing the amount
    Uses commitment scheme to hide bid amount while allowing verification
    """
    
    # In production, would verify:
    # 1. The ZK proof shows the bid is within valid range
    # 2. The commitment matches the hidden bid amount
    # 3. User has sufficient funds
    
    bid_id = f"bid_{secrets.token_hex(8)}"
    
    return {
        "bid_id": bid_id,
        "auction_id": request.auction_id,
        "commitment": request.bid_commitment,
        "status": "submitted",
        "timestamp": datetime.utcnow().isoformat()
    }


@router.get("/zk/marketplace/auctions/{auction_id}/bids")
async def get_auction_bids(
    auction_id: str,
    session: SessionDep,
    reveal: bool = False
) -> Dict[str, Any]:
    """
    Get bids for an auction
    If reveal=False, returns only commitments (privacy-preserving)
    If reveal=True, reveals actual bid amounts (after auction ends)
    """
    
    # Mock data - in production would query database
    mock_bids = [
        {
            "bid_id": "bid_12345678",
            "commitment": "0x1a2b3c4d5e6f...",
            "timestamp": "2025-12-28T10:00:00Z"
        },
        {
            "bid_id": "bid_87654321", 
            "commitment": "0x9f8e7d6c5b4a...",
            "timestamp": "2025-12-28T10:05:00Z"
        }
    ]
    
    if reveal:
        # In production, would use pre-images to reveal amounts
        for bid in mock_bids:
            bid["amount"] = 100.0 if bid["bid_id"] == "bid_12345678" else 150.0
    
    return {
        "auction_id": auction_id,
        "bids": mock_bids,
        "revealed": reveal,
        "total_bids": len(mock_bids)
    }


@router.post("/zk/computation/verify")
async def verify_computation_proof(
    request: ZKComputationRequest,
    session: SessionDep
) -> Dict[str, Any]:
    """
    Verify that an AI computation was performed correctly without revealing inputs
    """
    
    # In production, would verify actual ZK-SNARK proof
    # For demo, simulate verification
    
    verification_result = {
        "job_id": request.job_id,
        "verified": len(request.proof_of_execution) > 20,
        "result_hash": request.result_hash,
        "public_inputs": request.public_inputs,
        "verification_key": "demo_vk_12345",
        "timestamp": datetime.utcnow().isoformat()
    }
    
    return verification_result


@router.post("/zk/receipt/attest")
async def create_private_receipt(
    job_id: str,
    user_address: str,
    computation_result: str,
    privacy_level: str = "basic"
) -> Dict[str, Any]:
    """
    Create a privacy-preserving receipt attestation
    """
    
    # Generate commitment for private data
    salt = secrets.token_hex(16)
    private_data = f"{job_id}:{computation_result}:{salt}"
    commitment = hashlib.sha256(private_data.encode()).hexdigest()
    
    # Create public receipt
    receipt = {
        "job_id": job_id,
        "user_address": user_address,
        "commitment": commitment,
        "privacy_level": privacy_level,
        "timestamp": datetime.utcnow().isoformat(),
        "verified": True
    }
    
    return receipt


@router.get("/zk/anonymity/sets")
async def get_anonymity_sets() -> Dict[str, Any]:
    """Get available anonymity sets for privacy operations"""
    
    return {
        "sets": {
            "miners": {
                "size": 100,
                "description": "Registered GPU miners",
                "type": "merkle_tree"
            },
            "clients": {
                "size": 500,
                "description": "Active clients",
                "type": "merkle_tree"
            },
            "transactions": {
                "size": 1000,
                "description": "Recent transactions",
                "type": "ring_signature"
            }
        },
        "min_anonymity": 3,
        "recommended_sets": ["miners", "clients"]
    }


@router.post("/zk/stealth/address")
async def generate_stealth_address(
    recipient_public_key: str,
    sender_random: Optional[str] = None
) -> Dict[str, str]:
    """
    Generate a stealth address for private payments
    Demo implementation
    """
    
    if not sender_random:
        sender_random = secrets.token_hex(16)
    
    # In production, use elliptic curve diffie-hellman
    shared_secret = hashlib.sha256(
        f"{recipient_public_key}:{sender_random}".encode()
    ).hexdigest()
    
    stealth_address = hashlib.sha256(
        f"{shared_secret}:{recipient_public_key}".encode()
    ).hexdigest()[:40]
    
    return {
        "stealth_address": f"0x{stealth_address}",
        "shared_secret_hash": shared_secret,
        "ephemeral_key": sender_random,
        "view_key": f"0x{hashlib.sha256(shared_secret.encode()).hexdigest()[:40]}"
    }


@router.get("/zk/status")
async def get_zk_status() -> Dict[str, Any]:
    """Get the status of ZK features in AITBC"""
    
    # Check if ZK service is enabled
    from ..services.zk_proofs import ZKProofService
    zk_service = ZKProofService()
    
    return {
        "zk_features": {
            "identity_commitments": "active",
            "group_membership": "demo",
            "private_bidding": "demo",
            "computation_proofs": "demo",
            "stealth_addresses": "demo",
            "receipt_attestation": "active",
            "circuits_compiled": zk_service.enabled,
            "trusted_setup": "completed"
        },
        "supported_proof_types": [
            "membership",
            "bid_range",
            "computation",
            "identity",
            "receipt"
        ],
        "privacy_levels": [
            "basic",      # Hash-based commitments
            "medium",     # Simple ZK proofs
            "maximum"     # Full ZK-SNARKs (when circuits are compiled)
        ],
        "circuit_status": {
            "receipt": "compiled",
            "membership": "not_compiled",
            "bid": "not_compiled"
        },
        "next_steps": [
            "Compile additional circuits (membership, bid)",
            "Deploy verification contracts",
            "Integrate with marketplace",
            "Enable recursive proofs"
        ],
        "zkey_files": {
            "receipt_simple_0001.zkey": "available",
            "receipt_simple.wasm": "available",
            "verification_key.json": "available"
        }
    }
