try:
    from sage_lib.ForceFieldManager import ForceFieldManager
except ImportError as e:
    import sys
    sys.stderr.write(f"An error occurred while importing ForceFieldManager: {str(e)}\n")
    del sys

class FF_GAP(ForceFieldManager):
    """
    Represents an individual force field model.
    This class can be extended to support various types of force fields,
    including those based on machine learning.
    """

    def __init__(self, parameters):
        """
        Initialize the force field model with given parameters.
        
        :param parameters: A dictionary or other structure containing the parameters for the model.
        """
        super().__init__(name=name, file_location=file_location)
        self.default_sigma = default_sigma
        self.gap_kwargs = gap_kwargs

    def train(self, at_file, gp_file='gp_new.xml', **teach_kwargs):
        """
        Train the GAP model using the provided atomic configuration file.

        :param at_file: XYZ file with teaching configurations.
        :param gp_file: Output XML file for the GAP model.
        :param teach_kwargs: Additional parameters for the GAP teaching process.
        """
        command = f"gap_fit energy_parameter_name={teach_kwargs.get('energy_parameter_name', 'energy')} " \
                  f"force_parameter_name={teach_kwargs.get('force_parameter_name', 'force')} " \
                  f"sparse_separate_file={str(teach_kwargs.get('sparse_separate_file', True))} " \
                  f"gp_file={gp_file} at_file={at_file} " \
                  f"default_sigma={self.default_sigma} gap={self._format_gap_args()}"


        # Execute the command
        subprocess.run(shlex.split(command), check=True)


    def _format_gap_args(self):
        """
        Format the GAP specific arguments for the command line.
        """
        return " ".join([f"{key}={value}" for key, value in self.gap_kwargs.items()])

    def apply(self, data):
        """
        Apply the force field model to the given data.

        :param data: The data on which the force field model is to be applied.
        :return: The result of applying the model.
        """
        # Implement the application of the force field here
        pass

'''
 gap_fit 

 energy_parameter_name=E_dftbplus_d4 
 force_parameter_name=F_dftbplus_d4 
 do_copy_at_file=F 
 sparse_separate_file=T 
 gp_file=GAP.xml 
 at_file=train.xyz 
 default_sigma={0.008 0.04 0 0} 
 gap={distance_2b cutoff=4.0 covariance_type=ard_se delta=0.5 theta_uniform=1.0 sparse_method=uniform add_species=T n_sparse=10}
'''