import secrets
from datetime import datetime
from uuid import uuid4
from flask import flash, jsonify
import secrets
import os
from json import dump, loads

from main import app, db
from common.security import encrypt

class Test:
    def __init__(self, _id=None, start_date=None, expiry_date=None, time_limit=None, creator=None, dataset=None):
        self._id = _id
        self.start_date = start_date
        self.expiry_date = expiry_date
        self.time_limit = None if time_limit == 'none' or time_limit == '' or time_limit == None else int(time_limit)
        self.creator = creator
        self.dataset = dataset
    
    def create(self):
        test = {
            '_id': self._id,
            'date_created': datetime.today(),
            'start_date': self.start_date,
            'expiry_date': self.expiry_date,
            'time_limit': self.time_limit,
            'creator': encrypt(self.creator),
            'test_code': secrets.token_hex(6).upper(),
            'dataset': self.dataset
        }
        if db.tests.insert_one(test):
            dataset_file_path = os.path.join(app.config["DATA_FILE_DIRECTORY"],self.dataset)
            with open(dataset_file_path, 'r') as dataset_file:
                data = loads(dataset_file.read())
            data['meta']['tests'].append(self._id)
            with open(dataset_file_path, 'w') as dataset_file:
                dump(data, dataset_file, indent=2)
            flash(f'Created a new exam with Exam Code <strong>{self.render_test_code(test["test_code"])}</strong>.', 'success')
            return jsonify({'success': test}), 200
        return jsonify({'error': f'Could not create exam. An error occurred.'}), 400

    def add_time_adjustment(self, time_adjustment):
        adjustment = {
            '_id': uuid4().hex,
            'user_code': secrets.token_hex(3).upper(),
            'time_adjustment': time_adjustment
        }
        if db.tests.find_one_and_update({'_id': self._id}, {'$push': {'time_adjustments': adjustment}},upsert=False):
            flash(f'Time adjustment for {adjustment["time_adjustment"]} minutes has been added. This can be enabled using the user code {adjustment["user_code"]}.')
            return jsonify({'success': adjustment})
        return jsonify({'error': 'Failed to add the time adjustment. An error occurred.'}), 400

    def remove_time_adjustment(self, _id):
        if db.tests.find_one_and_update({'_id': self._id}, {'$pull': {'time_adjustments': {'_id': _id} }}):
            message = 'Time adjustment has been deleted.'
            flash(message, 'success')
            return jsonify({'success': message})
        return jsonify({'error': 'Failed to delete the time adjustment. An error occurred.'}), 400

    def render_test_code(self, test_code):
        return '—'.join([test_code[:4], test_code[4:8], test_code[8:]])
    
    def parse_test_code(self, test_code):
        return test_code.replace('—', '')
    
    def delete(self):
        test = db.tests.find_one({'_id': self._id})
        if 'entries' in test:
            if test['entries']:
                return jsonify({'error': 'Cannot delete an exam that has entries submitted to it.'}), 400
        if self.dataset is None:
            self.dataset = db.tests.find_one({'_id': self._id})['dataset']
        if db.tests.delete_one({'_id': self._id}):
            dataset_file_path = os.path.join(app.config["DATA_FILE_DIRECTORY"],self.dataset)
            with open(dataset_file_path, 'r') as dataset_file:
                data = loads(dataset_file.read())
            data['meta']['tests'].remove(self._id)
            with open(dataset_file_path, 'w') as dataset_file:
                dump(data, dataset_file, indent=2)
            message = 'Deleted exam.'
            flash(message, 'alert')
            return jsonify({'success': message}), 200
        return jsonify({'error': f'Could not create exam. An error occurred.'}), 400

    def update(self):
        test = {}
        updated = []
        if not self.start_date == '' and self.start_date is not None:
            test['start_date'] = self.start_date
            updated.append('start date')
        if not self.expiry_date == '' and self.expiry_date is not None:
            test['expiry_date'] = self.expiry_date
            updated.append('expiry date')
        if not self.time_limit == '' and self.time_limit is not None:
            test['time_limit'] = int(self.time_limit)
            updated.append('time limit')
        output = ''
        if len(updated) == 0:
            flash(f'There were no changes requested for your account.', 'alert'), 200
            return jsonify({'success': 'There were no changes requested for your account.'}), 200
        elif len(updated) == 1:
            output = updated[0]
        elif len(updated) == 2:
            output = ' and '.join(updated)
        elif len(updated) > 2:
            output = updated[0]
            for index in range(1,len(updated)):
                if index < len(updated) - 2:
                    output = ', '.join([output, updated[index]])
                elif index == len(updated) - 2:
                    output = ', and '.join([output, updated[index]])
                else:
                    output = ''.join([output, updated[index]])
        db.tests.find_one_and_update({'_id': self._id}, {'$set': test})
        _output = f'The {output} of the test {"has" if len(updated) == 1 else "have"} been updated.'
        flash(_output)
        return jsonify({'success': _output}), 200