from flask import Flask, Blueprint, request
from flask_security import (SQLAlchemyUserDatastore, login_required,
                            current_user, Security)
from flask_security.utils import verify_and_update_password, login_user
from flask_restless import APIManager, ProcessingException
from models import (db, User, Role, Gradeclass, Student, AttendanceUpdate,
                    Presence)
from sqlalchemy import func
import json
from datetime import datetime, date
from dateutil import parser

app = Flask(__name__)
app.config['DEBUG'] = True
app.config['PORT'] = 5001
app.config['SECRET_KEY'] = 'super-secret'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/db.sqlite'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['DEFAULT_MAIL_SENDER'] = 'info@example.com'
app.config['SECURITY_PASSWORD_SALT'] = 'uaisfyasiduyaisiuf'

db.init_app(app)
user_datastore = SQLAlchemyUserDatastore(db, User, Role)
security = Security(app, user_datastore)


def auth_func(*args, **kwargs):
    # if not current_user.is_authenticated:
    #     raise ProcessingException(description='Not authenticated', code=401)
    return True


verify_logged_id = dict(GET_SINGLE=[auth_func], GET_MANY=[auth_func])

manager = APIManager(app, flask_sqlalchemy_db=db)
manager.create_api(
    Student,
    methods=['GET', 'PUT'],
    results_per_page=5,
    preprocessors=verify_logged_id)
manager.create_api(
    Gradeclass,
    methods=['GET', 'PUT'],
    results_per_page=5,
    preprocessors=verify_logged_id)


json_cont = {'Content-Type': 'application/json'}
resp = lambda val,code: (json.dumps({'status': val}), code, json_cont)
presense_map = {i:str(i).replace('Presence.', '').upper() for i in Presence}

@app.before_first_request
def create_test_data():
    try:
        db.drop_all()
        db.create_all()
        for i in range(3):
            g_cls = Gradeclass("Class {}".format(i))
            db.session.add(g_cls)
            db.session.commit()
            for s in range(5):
                stu = Student("TestStudent#{}-Class{}".format(s,g_cls.id), g_cls.id)
                db.session.add(stu)
        user_datastore.create_user(
            email='user@example.com', password='password')
        db.session.commit()
    except:
        pass


def parse_time(time_str):
    utc_now = (time_str and time_str == 'now') or not time_str
    time = datetime.utcnow() if utc_now else None
    try:
        time = parser.parse(attend_date)
    except:
        pass
    return time


def compute_attendance(request_type,object_id, start_time, end_time):
    def get_record(req_type,obj_id):
        attend = AttendanceUpdate.query.filter(
            AttendanceUpdate.update_type == req_type
        ).filter(
            AttendanceUpdate.value_identifier == obj_id
        ).filter(
            func.date(AttendanceUpdate.time) >= start_time.date()
        ).filter(
            func.date(AttendanceUpdate.time) >= end_time.date()
        ).first()
        return attend
    pres_rec = None
    if request_type == 'student':
        stud_rec = get_record('student',object_id)
        stud = Student.query.get(object_id)
        pres_rec = stud_rec if stud_rec else get_record('class',stud.gradeclass_id)
    if request_type == 'class':
        pres_rec = get_record(request_type,object_id)
    return presense_map[pres_rec.presence].lower() if pres_rec else 'no_records'

def upsert_attendance(update_type, object_id, attend_time, pres_enum):
    existing = AttendanceUpdate.query.filter(
        AttendanceUpdate.update_type == update_type).filter(
            AttendanceUpdate.value_identifier == object_id).filter(
                func.date(
                    AttendanceUpdate.time) == attend_time.date()).first()
    if existing:
        existing.presence = pres_enum
    else:
        new_entry = AttendanceUpdate(update_type, object_id, attend_time,
                                     pres_enum)
        db.session.add(new_entry)
    db.session.commit()


def validate_attend(update_type, object_id):
    # return True
    if update_type in ['class', 'student'] and object_id:
        g_cls_found = update_type == 'class' and Gradeclass.query.get(
            object_id)
        stud_found = update_type == 'student' and Student.query.get(object_id)
        return g_cls_found or stud_found
    else:
        return False


def get_attendance(update_type, request):
    object_id = request.args.get('identifier', None)
    start_timestr = request.args.get('start_time', None)
    end_timestr = request.args.get('end_time', None)
    start_time, end_time = parse_time(start_timestr), parse_time(end_timestr)
    ret_data = resp('invalid',400)
    if validate_attend(update_type, object_id) and start_time and end_time:
        pres = compute_attendance(update_type,object_id,start_time,end_time)
        ret_data = resp(pres,200)
    return ret_data


def update_attendance(update_type, request):
    object_id = request.form.get('identifier', None)
    presence = request.form.get('presence', None)
    attend_str = request.form.get('time', None)
    attend_time = parse_time(attend_str)
    ret_data = resp('invalid',400)
    if validate_attend(
            update_type, object_id
    ) and presence and attend_time and presence.upper() in presense_map.values():
        pres_enum = Presence[presence.upper()]
        upsert_attendance(update_type, object_id, attend_time, pres_enum)
        ret_data = resp('updated',200)
    return ret_data


@app.route('/api/attendance/<update_type>', methods=['GET', 'POST'])
@login_required
def attendance(update_type):
    if request.method == 'GET':
        return get_attendance(update_type, request)
    elif request.method == 'POST':
        return update_attendance(update_type, request)


@app.route('/api/login', methods=['POST'])
def login():
    username = request.form.get('username', None)
    password = request.form.get('password', None)
    ret_data = (json.dumps({'status': 'failed'}), 401, json_cont)
    if username and password:
        user = User.query.filter(User.email == username).first()
        if not user:
            ret_data = resp('notfound',401)
        elif verify_and_update_password(password, user):
            login_user(user)
            ret_data = resp('success',200)
    return ret_data


@app.route('/')
def home():
    return 'hello'


if __name__ == '__main__':
    app.run()