from tinydb import TinyDB, Query
from datetime import datetime
import csv

DATE_FORMAT = '%Y-%m-%d %H:%M:%S'


class Server:
    db = TinyDB('db.json')
    terminals = db.table('terminals')
    employees = db.table('employees')
    cards = db.table('cards')
    readings_unknown = db.table('readings_unknown')
    readings_emp = db.table('readings_employees')

    def add_emp(self, name, surname):
        emp_id = self.employees.insert({'name': name, 'surname': surname})
        return emp_id

    def add_card(self, card_id):
        if self.cards.search(Query().id == card_id):
            print("Karta już istnieje!")
            return
        self.cards.insert({'id': card_id, 'emp_id': None})

    def add_terminal(self, terminal_id):
        if self.terminals.search(Query().id == terminal_id):
            print("Terminal już istnieje!")
            return
        self.terminals.insert({'id': terminal_id})

    def remove_terminal(self, terminal_id):
        removed = self.terminals.remove(Query().id == terminal_id)
        if not removed:
            print("Terminal nie istnieje!")

    def assign_emp(self, card_id, emp_id):
        updated = self.cards.update({'emp_id': emp_id}, Query().id == card_id)
        if not updated:
            print("Karty nie ma w systemie!")

    def unassign_emp(self, card_id):
        updated = self.cards.update({'emp_id': None}, Query().id == card_id)
        if not updated:
            print("Karty nie ma w systemie!")

    def register(self, terminal_id, card_id):
        current_time = datetime.now()
        if not self.terminals.search(Query().id == terminal_id):
            print("Nieobsługiwany terminal!")
            return

        card = self.cards.search(Query().id == card_id)
        if card and card[0]['emp_id'] is not None:
            emp_id = card[0]['emp_id']
            self.readings_emp.insert(
                {'terminal_id': terminal_id, 'emp_id': emp_id, 'time': current_time.strftime(DATE_FORMAT)})
        else:
            self.readings_unknown.insert(
                {'terminal_id': terminal_id, 'card_id': card_id, 'time': current_time.strftime(DATE_FORMAT)})

    def work_time_csv(self, emp_id):
        if self.employees.get(doc_id=emp_id) is None:
            print("Pracownik nie istnieje!")
            return

        readings_emp = self.readings_emp.search(Query().emp_id == emp_id)
        readings_emp.sort(key=lambda read: read['time'])

        emp = self.employees.get(doc_id=emp_id)
        file = open(str(emp_id) + "_" + emp['name'] + "_" + emp['surname'] + ".csv", "w+")
        writer = csv.writer(file)

        writer.writerow(["Rozpoczęcie pracy", "Zakończenie pracy", "Czas"])

        for enter, leave in zip(readings_emp[0::2], readings_emp[1::2]):
            diff = datetime.strptime(leave['time'], DATE_FORMAT) - datetime.strptime(enter['time'], DATE_FORMAT)
            writer.writerow([enter['time'], leave['time'], diff.__str__()])

        if len(readings_emp) % 2 == 1:
            writer.writerow([readings_emp[-1]['time']])

        file.close()

    def purge_database(self):
        self.terminals.purge()
        self.employees.purge()
        self.readings_unknown.purge()
        self.readings_emp.purge()
        self.cards.purge()