# Source code for macop.callbacks.BasicCheckpoint

    """Basic Checkpoint class implementation
    """

    # main imports
    import os
    import logging
    import numpy as np

    # module imports
    from .Callback import Callback
    from ..utils.color import macop_text, macop_line

    class BasicCheckpoint(Callback):
        """
        BasicCheckpoint is used for loading previous computations and start again after loading checkpoint

        Attributes:
            algo: {Algorithm} -- main algorithm instance reference
            every: {int} -- checkpoint frequency used (based on number of evaluations)
            filepath: {str} -- file path where checkpoints will be saved
        """
        def run(self):
            """
            Check if necessary to do backup based on `every` variable
            """
            # get current best solution
            solution = self.algo.bestSolution

            currentEvaluation = self.algo.getGlobalEvaluation()

            # backup if necessary
            if currentEvaluation % self.every == 0:

                logging.info("Checkpoint is done into " + self.filepath)

                solutionData = ""
                solutionSize = len(solution.data)

                for index, val in enumerate(solution.data):
                    solutionData += str(val)

                    if index < solutionSize - 1:
                        solutionData += ' '

                line = str(currentEvaluation) + ';' + solutionData + ';' + str(
                    solution.fitness()) + ';\n'

                # check if file exists
                if not os.path.exists(self.filepath):
                    with open(self.filepath, 'w') as f:
                        f.write(line)
                else:
                    with open(self.filepath, 'a') as f:
                        f.write(line)

        def load(self):
            """
            Load last backup line of solution and set algorithm state (best solution and evaluations) at this backup
            """
            if os.path.exists(self.filepath):

                logging.info('Load best solution from last checkpoint')
                with open(self.filepath) as f:

                    # get last line and read data
                    lastline = f.readlines()[-1]
                    data = lastline.split(';')

                    # get evaluation  information
                    globalEvaluation = int(data[0])

                    if self.algo.parent is not None:
                        self.algo.parent.numberOfEvaluations = globalEvaluation
                    else:
                        self.algo.numberOfEvaluations = globalEvaluation

                    # get best solution data information
                    solutionData = list(map(int, data[1].split(' ')))

                    self.algo.bestSolution.data = np.array(solutionData)
                    self.algo.bestSolution.score = float(data[2])

                print(macop_line())
                print(
                    macop_text('Checkpoint found from `{}` file.'.format(
                        self.filepath)))

                print(
                    macop_text('Restart algorithm from evaluation {}.'.format(
                        self.algo.numberOfEvaluations)))

            else:
                print(
                    macop_text(
                        'No backup found... Start running algorithm from evaluation 0.'
                    ))
                logging.info(
                    "Can't load backup... Backup filepath not valid in Checkpoint")

            print(macop_line())