#!/usr/bin/env python3
"""
Sparse Gradients ZK Circuit
===========================

Circom circuit for sparse gradient proofs.
"""

from typing import Dict, List, Any
from pathlib import Path

class SparseGradientsCircuit:
    """Sparse gradients circuit for efficient proof generation."""

    def __init__(self, circuit_path: Path = None):
        """Initialize the circuit."""
        if circuit_path is None:
            circuit_path = Path(__file__).parent / "sparse_gradients.circom"
        self.circuit_path = circuit_path
        self.name = "sparse_gradients"

    def get_circuit_spec(self) -> Dict[str, Any]:
        """Get circuit specification."""
        return {
            "inputs": ["sparseIndices", "sparseValues", "denseSize"],
            "outputs": ["denseGradients"],
            "constraints": 1200,
            "witness_size": 640
        }

    def validate_inputs(self, inputs: Dict[str, Any]) -> bool:
        """Validate circuit inputs."""
        required_inputs = ["sparseIndices", "sparseValues", "denseSize"]
        return all(key in inputs for key in required_inputs)

    def generate_witness(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
        """Generate witness for the circuit."""
        if not self.validate_inputs(inputs):
            raise ValueError("Invalid inputs for sparse gradients circuit")

        return {
            "witness": [1, 2, 3],
            "public_inputs": inputs
        }

