import os
import pickle
import time
import datetime
import copy
from textattack.shared import logger, utils
from textattack.attack_results import SuccessfulAttackResult, FailedAttackResult, SkippedAttackResult

class Checkpoint:
    """ An object that stores necessary information for saving and loading checkpoints
    
        Args:
            args: command line arguments of the original attack
            log_manager (AttackLogManager)
            chkpt_time (float): epoch time representing when checkpoint was made
    """
    def __init__(self, args, log_manager, chkpt_time=None):
        self.args = copy.deepcopy(args)
        self.log_manager = log_manager
        if chkpt_time:
            self.time = chkpt_time
        else:
            self.time = time.time()

    def __repr__(self):
        main_str = 'Checkpoint('
        lines = []
        lines.append(
            utils.add_indent(f'(Time):  {self.datetime}', 2)
        )

        args_lines = []
        recipe_set = True if 'recipe' in self.args.__dict__ and self.args.__dict__['recipe'] else False
        mutually_exclusive_args = ['search', 'transformation', 'constraints', 'recipe']
        if recipe_set:
            args_lines.append(utils.add_indent(f'(recipe): {self.args.__dict__["recipe"]}', 2))
        else:
            args_lines.append(utils.add_indent(f'(search): {self.args.__dict__["search"]}', 2))
            args_lines.append(utils.add_indent(f'(transformation): {self.args.__dict__["transformation"]}', 2))
            args_lines.append(utils.add_indent(f'(constraints): {self.args.__dict__["constraints"]}', 2))
    
        for key in self.args.__dict__:
            if key not in mutually_exclusive_args:
                args_lines.append(utils.add_indent(f'({key}): {self.args.__dict__[key]}', 2))

        args_str = utils.add_indent('\n' + '\n'.join(args_lines), 2)
        lines.append(utils.add_indent(f'(Args):  {args_str}', 2))

        attack_logger_lines = []
        attack_logger_lines.append(utils.add_indent(
            f'(Total number of examples to attack): {self.args.num_examples}', 2
        ))
        attack_logger_lines.append(utils.add_indent(
            f'(Number of attacks performed): {self.results_count}', 2
        ))
        attack_logger_lines.append(utils.add_indent(
            f'(Number of remaining attacks): {self.num_remaining_attacks}', 2
        ))
        breakdown_lines = []
        breakdown_lines.append(utils.add_indent(
            f'(Number of successful attacks): {self.num_successful_attacks}', 2
        ))
        breakdown_lines.append(utils.add_indent(
            f'(Number of failed attacks): {self.num_failed_attacks}', 2
        ))
        breakdown_lines.append(utils.add_indent(
            f'(Number of skipped attacks): {self.num_skipped_attacks}', 2
        ))
        breakdown_str = utils.add_indent('\n' + '\n'.join(breakdown_lines), 2)
        attack_logger_lines.append(utils.add_indent(f'(Latest result breakdown): {breakdown_str}', 2))
        attack_logger_str = utils.add_indent('\n' + '\n'.join(attack_logger_lines), 2)
        lines.append(utils.add_indent(f'(Previous attack summary):  {attack_logger_str}', 2))

        main_str += '\n  ' + '\n  '.join(lines) + '\n'
        main_str += ')'
        return main_str
    
    __str__ = __repr__
    
    @property
    def results_count(self):
        """ Return number of attacks made so far """
        return len(self.log_manager.results)
    
    @property
    def num_skipped_attacks(self):
        return sum(isinstance(r, SkippedAttackResult) for r in self.log_manager.results)

    @property
    def num_failed_attacks(self):
        return sum(isinstance(r, FailedAttackResult) for r in self.log_manager.results)

    @property
    def num_successful_attacks(self):
       return sum(isinstance(r, SuccessfulAttackResult) for r in self.log_manager.results)

    @property
    def num_remaining_attacks(self):
        if self.args.attack_n:
            non_skipped_attacks = self.num_successful_attacks + self.num_failed_attacks 
            count = self.args.num_examples - non_skipped_attacks
        else:
            count = self.args.num_examples - self.results_count
        return count

    @property
    def dataset_offset(self):
        """ Calculate offset into the dataset to start from """
        # Original offset + # of results processed so far
        return self.args.num_examples_offset + self.results_count

    @property
    def datetime(self):
        return datetime.datetime.fromtimestamp(self.time).strftime('%Y-%m-%d %H:%M:%S')

    def save(self, quiet=False):
        file_name = "{}.ta.chkpt".format(int(self.time*1000))
        if not os.path.exists(self.args.checkpoint_dir):
            os.makedirs(self.args.checkpoint_dir)
        path = os.path.join(self.args.checkpoint_dir, file_name)
        if not quiet:
            print('\n\n' + '=' * 125)
            logger.info('Saving checkpoint under "{}" at {} after {} attacks.'.format(path, self.datetime, self.results_count))
            print('=' * 125 + '\n')
        with open(path, 'wb') as f:
            pickle.dump(self, f, protocol=pickle.HIGHEST_PROTOCOL)

    @classmethod
    def load(self, path):
        with open(path, 'rb') as f:
            checkpoint = pickle.load(f)
        assert isinstance(checkpoint, Checkpoint)

        return checkpoint