# coding: utf-8

from __future__ import unicode_literals, division
from custodian.custodian import ErrorHandler
import re
from custodian.utils import backup
from pymatgen.io.feff.sets import FEFFDictSet
from custodian.feff.interpreter import FeffModder
import logging

""" This module implements specific error handler for FEFF runs. """

__author__ = "Chen Zheng"
__copyright__ = "Copyright 2012, The Materials Project"
__version__ = "0.1"
__maintainer__ = "Chen Zheng"
__email__ = "chz022@ucsd.edu"
__date__ = "Oct 18, 2017"

FEFF_BACKUP_FILES = ["ATOMS", "HEADER", "PARAMETERS", "POTENTIALS", "feff.inp", "*.cif", "pot.bin"]

logger = logging.getLogger(__name__)


class UnconvergedErrorHandler(ErrorHandler):
    """
    Correct the unconverged error of FEFF's SCF calculation.
    """

    is_monitor = False

    def __init__(self, output_filename='log1.dat'):
        """
        Initializes the handler with the output file to check

        Args:
            output_filename (str): Filename for the log1.dat file. log1.dat file
                contains the SCF calculation convergence information. Change this only
                if it is different from the default (unlikely).
        """
        self.output_filename = output_filename

    def check(self):
        """
        If the FEFF run does not converge, the check will return
        "TRUE"
        """
        return self._notconverge_check()

    def _notconverge_check(self):

        # Process the output file and get converge information
        not_converge_pattern = re.compile("Convergence not reached.*")
        converge_pattern = re.compile('Convergence reached.*')
        for _, line in enumerate(open(self.output_filename)):
            if len(not_converge_pattern.findall(line)) > 0:
                return True

            elif len(converge_pattern.findall(line)) > 0:
                return False

    def correct(self):
        backup(FEFF_BACKUP_FILES)
        feff_input = FEFFDictSet.from_directory(".")
        scf_values = feff_input.tags.get("SCF")
        nscmt = scf_values[2]
        ca = scf_values[3]
        nmix = scf_values[4]
        actions = []

        #Add RESTART card to PARAMETERS
        if not "RESTART" in feff_input.tags:
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"RESTART": []}}})

        if nscmt < 100 and ca == 0.2:
            scf_values[2] = 100
            scf_values[4] = 3  # Set nmix = 3
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"SCF": scf_values}}})
            FeffModder().apply_actions(actions)
            return {"errors": ["Non-converging job"], "actions": actions}

        elif nscmt == 100 and nmix == 3 and ca > 0.01:
            # Reduce the convergence accelerator factor
            scf_values[3] = round(ca / 2, 2)
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"SCF": scf_values}}})
            FeffModder().apply_actions(actions)
            return {"errors": ["Non-converging job"], "actions": actions}

        elif nmix == 3 and ca == 0.01:
            # Set ca = 0.05 and set nmix
            scf_values[3] = 0.05
            scf_values[4] = 5
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"SCF": scf_values}}})
            FeffModder().apply_actions(actions)
            return {"errors": ["Non-converging job"], "actions": actions}

        elif nmix == 5 and ca == 0.05:
            # Set ca = 0.05 and set nmix
            scf_values[3] = 0.05
            scf_values[4] = 10
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"SCF": scf_values}}})
            FeffModder().apply_actions(actions)
            return {"errors": ["Non-converging job"], "actions": actions}

        elif nmix == 10 and ca < 0.2:
            # loop through ca with nmix = 10
            scf_values[3] = round(ca * 2, 2)
            actions.append({"dict": "PARAMETERS",
                            "action": {"_set": {"SCF": scf_values}}})
            FeffModder().apply_actions(actions)
            return {"errors": ["Non-converging job"], "actions": actions}

        # Unfixable error. Just return None for actions.
        else:
            return {"errors": ["Non-converging job"], "actions": None}
