from flask import Blueprint, render_template, request, redirect, jsonify, session, abort, flash
from flask.helpers import url_for
from datetime import datetime, timedelta
from uuid import uuid4
import os
from json import loads
from flask_mail import Message

from pymongo.collection import ReturnDocument

from main import app, db, mail
from common.security import encrypt
from common.data_tools import generate_questions, evaluate_answers
from common.security.database import decrypt_find_one

views = Blueprint(
    'quiz_views',
    __name__,
    static_url_path='',
    template_folder='templates',
    static_folder='static'
)

@views.route('/')
@views.route('/home/')
def home():
    _id = session.get('_id')
    if _id and db.entries.find_one({'_id': _id}):
        return redirect(url_for('quiz_views.start_quiz'))
    return render_template('/quiz/index.html')

@views.route('/instructions/')
def instructions():
    _id = session.get('_id')
    if _id and db.entries.find_one({'_id': _id}):
        return redirect(url_for('quiz_views.start_quiz'))
    return render_template('/quiz/instructions.html')

@views.route('/start/', methods = ['GET', 'POST'])
def start():
    from .forms import StartQuiz
    form = StartQuiz()
    if request.method == 'GET':
        _id = session.get('_id')
        if _id and db.entries.find_one({'_id': _id}):
            return redirect(url_for('quiz_views.start_quiz'))
        return render_template('/quiz/start-quiz.html', form=form)
    if request.method == 'POST':
        if form.validate_on_submit():
            name = {
                'first_name': request.form.get('first_name'),
                'surname': request.form.get('surname')
            }
            email = request.form.get('email')
            club = request.form.get('club')
            test_code = request.form.get('test_code').replace('—', '')
            user_code = request.form.get('user_code')
            user_code = None if user_code == '' else user_code
            test = db.tests.find_one({'test_code': test_code})
            if not test:
                return jsonify({'error': 'The exam code you entered is invalid.'}), 400
            if test['expiry_date'] < datetime.utcnow():
                return jsonify({'error': f'The exam code you entered expired on {test["expiry_date"].strftime("%d %b %Y")}.'}), 400
            if test['start_date'] > datetime.utcnow():
                return jsonify({'error': f'The exam has not yet opened. Your exam code will be valid from {test["start_date"].strftime("%d %b %Y %H:%M")}.'}), 400
            entry = {
                '_id': uuid4().hex,
                'name': encrypt(name),
                'email': encrypt(email),
                'club': encrypt(club),
                'test_code': test_code,
                'user_code': user_code
            }
            if db.entries.insert(entry):
                session['_id'] = entry['_id']
                return jsonify({
                    'success': 'Received and validated test and/or user code. Redirecting to test client.',
                    '_id': entry['_id']
                }), 200
        else:
            errors = [*form.errors]
            return jsonify({ 'error': errors}), 400

@views.route('/api/questions/', methods=['POST'])
def fetch_questions():
    _id = request.get_json()['_id']
    entry = db.entries.find_one({'_id': _id})
    if not entry:
        return jsonify({'error': 'The data that the client sent to the server is invalid. This is possibly because you have already submitted your exam and have tried to access the page again.'}), 400
    test_code = entry['test_code']
    # user_code = entry['user_code'] TODO Implement functionality for adjustments

    test = db.tests.find_one({'test_code' : test_code})
    time_limit = test['time_limit']
    if time_limit:
        _time_limit = int(time_limit)
        end_delta = timedelta(minutes=_time_limit)
        end_time = datetime.utcnow() + end_delta
    else:
        end_time = None
    update = {
        'start_time': datetime.utcnow(),
        'status': 'started',
        'end_time': end_time
    }
    entry = db.entries.find_one_and_update({'_id': _id}, {'$set': update}, upsert=False, return_document=ReturnDocument.AFTER)
    dataset = test['dataset']
    dataset_path = os.path.join(app.config['DATA_FILE_DIRECTORY'], dataset)
    with open(dataset_path, 'r') as data_file:
        data = loads(data_file.read())
    questions = generate_questions(data)
    return jsonify({
        'time_limit': end_time,
        'questions': questions,
        'start_time': entry['start_time']
    })

@views.route('/test/')
def start_quiz():
    _id = session.get('_id')
    if not _id or not db.entries.find_one({'_id': _id}):
        print('Foo')
        flash('Your log in was not recognised. Please sign in to the quiz again.', 'error')
        return redirect(url_for('quiz_views.start'))
    return render_template('quiz/client.html')

@views.route('/api/submit/', methods=['POST'])
def submit_quiz():
    _id = request.get_json()['_id']
    answers = request.get_json()['answers']
    entry = db.entries.find_one({'_id': _id})
    if not entry:
        return jsonify('Unrecognised ID', 'error'), 400
    status = 'submitted'
    if entry['end_time']:
        if datetime.utcnow() > entry['end_time'] + timedelta(minutes=2):
            status = 'late'
    test_code = entry['test_code']
    test = db.tests.find_one({'test_code' : test_code})
    dataset = test['dataset']
    dataset_path = os.path.join(app.config['DATA_FILE_DIRECTORY'], dataset)
    with open(dataset_path, 'r') as _dataset:
        data = loads(_dataset.read())
    results = evaluate_answers(data, answers)
    entry = db.entries.find_one_and_update({'_id': _id}, {'$set': {
        'status': status,
        'submission_time': datetime.utcnow(),
        'results': results,
        'answers': answers
    }})
    return jsonify({
        'success': 'Your submission has been processed. Redirecting you to receive your results.',
        '_id': _id
    }), 200

@views.route('/result/')
def result():
    _id = session.get('_id')
    entry = decrypt_find_one(db.entries, {'_id': _id})
    if not entry:
        return abort(404)
    score = round(100*entry['results']['score']/entry['results']['max'])
    tags_low = { tag: tag_result['max'] - tag_result['scored'] for tag, tag_result in entry['results']['tags'].items() }
    sorted_low_tags = sorted(tags_low.items(), key=lambda x: x[1], reverse=True)
    tag_output = [ tag[0] for tag in sorted_low_tags[0:3] if tag[1] > 3]
    if entry['results']['grade'] == 'pass':
        flavour_text_plain = """Well done on successfully completing the refereeing theory exam. We really appreciate members of our community taking the time to get qualified to referee.
        """
    elif entry['results']['grade'] == 'merit':
        flavour_text_plain = """Congratulations on achieving a merit in the refereeing exam. We are delighted that members of our community work so hard with refereeing.
        """
    elif entry['results']['grade'] == 'fail':
        flavour_text_plain = """Unfortunately, you were not successful in passing the theory exam in this attempt. We hope that this does not dissuade you, and that you try again in the future.
        """
    email = Message(
        subject="SKA Refereeing Theory Exam Results",
        recipients=[entry['email']],
        body=f"""SKA Refereeing Theory Exam\n\n
        Candidate Results\n\n
        Dear {entry['name']['first_name']},\n\n
        This email is to confirm that you have took the SKA Refereeing Theory Exam. Your test has been evaluated and your results have been generated.\n\n
        {entry['name']['surname']}, {entry['name']['first_name']}\n\n
        Email Address: {entry['email']}\n
        {f"Club: {entry['club']}" if entry['club'] else ''}\n
        Date of Test: {entry['submission_time'].strftime('%d %b %Y')}\n
        Score: {score}%\n
        Grade: {entry['results']['grade']}\n\n
        {flavour_text_plain}\n\n
        Based on your answers, we would also suggest you brush up on the following topics as you continue refereeing:\n\n
        {','.join(tag_output)}\n\n
        Thank you for taking the time to get qualified as a referee.\n\n
        Best wishes,\n
        SKA Refereeing
        """,
        html=f"""<h1>SKA Refereeing Theory Exam</h1>
        <h2>Candidate Results</h2>
        <p>Dear {entry['name']['first_name']},</p>
        <p>This email is to confirm that you have took the SKA Refereeing Theory Exam. Your test has been evaluated and your results have been generated.</p>
        <h3>{entry['name']['surname']}, {entry['name']['first_name']}</h3>
        <p><strong>Email Address</strong>: {entry['email']}</p>
        {f"<p><strong>Club</strong>: {entry['club']}</p>" if entry['club'] else ''}
        <p><strong>Date of Test</strong>: {entry['submission_time'].strftime('%d %b %Y')}</p>
        <h1>{score}%</h1>
        <h2>{entry['results']['grade']}</h2>
        <p>{flavour_text_plain}</p>
        <p>Based on your answers, we would also suggest you revise the following topics as you continue refereeing:</p>
        <ul>
        <li>{'</li><li>'.join(tag_output)}</li>
        </ul>
        <p>Thank you for taking the time to get qualified as a referee.</p>
        <p>Best wishes,<br />
        SKA Refereeing</p>
        """,
    )
    mail.send(email)
    return render_template('/quiz/result.html', entry=entry, score=score, tag_output=tag_output)

@views.route('/privacy/')
def privacy():
    return render_template('/quiz/privacy.html')