import json
import os
from collections import OrderedDict

import numpy as np

import chisurf


class AvPotential(object):
    """
    A class for calculating accessible volume potentials.
    
    This class is used to calculate the potential energy of a structure based on
    accessible volume calculations.
    """
    name = 'Av'

    def __init__(self, distances=None, positions=None, av_samples=10000, min_av=150, verbose=False):
        """
        Initialize the AvPotential class.
        
        Parameters
        ----------
        distances : dict, optional
            Dictionary of distance measurements
        positions : dict, optional
            Dictionary of positions for accessible volume calculations
        av_samples : int, optional
            Number of samples for accessible volume calculations
        min_av : int, optional
            Minimum number of points in accessible volume
        verbose : bool, optional
            Whether to print verbose output
        """
        self.verbose = verbose
        self.distances = distances
        self.positions = positions
        self.n_av_samples = av_samples
        self.min_av = min_av
        self.avs = OrderedDict()

    @property
    def structure(self):
        return self._structure

    @structure.setter
    def structure(self, structure):
        self._structure = structure
        self.calc_avs()

    def calc_avs(self):
        """
        Calculate accessible volumes for all positions.
        """
        if self.positions is None:
            raise ValueError("Positions not set unable to calculate AVs")
        
        # This method would need to be implemented with chisurf's AV calculation
        # For now, we'll leave it as a placeholder
        pass

    def calc_distances(self, structure=None, verbose=False):
        """
        Calculate distances between accessible volumes.
        
        Parameters
        ----------
        structure : Structure, optional
            Structure to calculate distances for
        verbose : bool, optional
            Whether to print verbose output
        """
        verbose = verbose or self.verbose
        if structure is not None:
            self.structure = structure
            
        # This method would need to be implemented with chisurf's distance calculation
        # For now, we'll leave it as a placeholder
        pass

    def getChi2(self, structure=None, reduced=False, verbose=False):
        """
        Calculate chi-squared value for the structure.
        
        Parameters
        ----------
        structure : Structure, optional
            Structure to calculate chi-squared for
        reduced : bool, optional
            Whether to return reduced chi-squared
        verbose : bool, optional
            Whether to print verbose output
            
        Returns
        -------
        float
            Chi-squared value
        """
        verbose = self.verbose or verbose
        if structure is not None:
            self.structure = structure

        chi2 = 0.0
        self.calc_distances(verbose=verbose)
        
        # This method would need to be implemented with actual chi-squared calculation
        # For now, we'll return a placeholder value
        return chi2

    def getEnergy(self, structure=None):
        """
        Calculate energy for the structure.
        
        Parameters
        ----------
        structure : Structure, optional
            Structure to calculate energy for
            
        Returns
        -------
        float
            Energy value
        """
        if structure is not None:
            self.structure = structure
        return self.getChi2()