import socket
import random
import threading
import json
import os
import string



"""
users, odnosno oni koji imaju nalog ce takodje imati opciju da uploaduju
fajlove. Oni koji nemaju nalog mogu samo da downloaduju.
Svi users ce se cuvati u vidu recnika ciji primer imamo dole
"""
# users = {
#     "user1":{
#         "password":"fon123",
#         "files":[
#         "Gq37zTq432",
#         "mX6A1njGxZ",
#         ]
#     },


"""
Ucitavanje baze podataka svih korisnika radi koriscenja
recnika users
"""
def database_load(path):
    if os.path.isfile(path):
        with open(path, 'r') as database:
            data = database.read()
        return json.loads(data)
    else:
        return {}

users = database_load('database/users.json')
active_users = []

""" Upisivanje recnika "users" u JSON fajl """

def database_save(recnik):
    with open("database/users.json", 'w') as f:
        f.write(json.dumps(recnik, indent=2))

""" Funkcije za logovanje i registraciju, kao i cuvanje baze korisnika """


""" Funkcija omogucava log in za klijente """

def login(sock):
    username = sock.recv(1024).decode()

    while username not in users.keys():
        sock.send("ERR".encode())
        username = sock.recv(1024).decode()
    sock.send("OK".encode())

    password = sock.recv(1024).decode()
    while password != users[username]['password']:
        sock.send("ERR".encode())
        password = sock.recv(1024).decode()
    sock.send("OK".encode())
    active_users.append(username)
    print('Upravo se ulogovao ' + username)

"""Registracija novih korisnika"""

def register(sock):
    username = sock.recv(1024)

    while username.decode() in users.keys():
        sock.send("ERR".encode())
        username = sock.recv(1024)
    sock.send("OK".encode())

    p = sock.recv(1024)

    while p.decode() == "":
        sock.send("ERR".encode())
        p = sock.recv(1024)

    sock.send("OK".encode())
    username = username.decode()
    password = p.decode()
    new_dic = {'password': password, 'files': []}
    users[username] = new_dic
    active_users.append(username)
    database_save(users)

"""Generator jedinstvenog kljuca od 10 karaktera"""

def unique_key_generator():
    chars = string.ascii_letters + string.digits
    check = 0
    key = ''
    while check == 0:
        check = 1
        for i in range(10):
            key += random.choice(chars)

        for x in os.listdir('database/files/'):
            if x == key:
                check = 0
                key = ''
                break
    return key

"""Upisivanje recnika "users" u JSON fajl"""

def database_save(recnik):
    with open("database/users.json", 'w') as f:
        f.write(json.dumps(recnik, indent=2))

"""Download fajlova"""

def download(sock):
    code = sock.recv(1024).decode()
    print(code)
    if code == 'q':
        print('izasao iz downloada')
        return
    status = False
    for file in os.listdir('database/files'):
        if os.path.basename(file) == code:
            with open('database/files/' + code,'rb') as f:
                text = f.read()
            sock.send(text)
            status = True
            break
    if not status:
        sock.send("ERR".encode())


"""Funkcija za upload novog fajla"""

def upload(sock):
    text = sock.recv(1024).decode()
    while not text:
        sock.send("ERR".encode())
        text = sock.recv(1024).decode()
    sock.send("OK".encode())
    code = unique_key_generator()

    sock.send(code.encode())
    with open('database/files/' + code,'wb') as f:
        f.write(text.encode())
    username = sock.recv(1024).decode()
    users[username]['files'].append(code)
    database_save(users)

"""Funkcija koja vrsi navigaciju kroz aplikaciju za ne ulogovane korisnike{navigator_main}"""

def navigator_main(sock,address):
    try:
        while True:
            userInput = sock.recv(1024)
            if userInput.decode() == '1':
                login(sock)
                navigator_logged_in(sock)
            elif userInput.decode() == '2':
                register(sock)
                navigator_logged_in(sock)
            elif userInput.decode() == '3':
                download(sock)
            elif userInput.decode() == 'q':
                print("zatvorio konekciju")
                sock.close()
                return
    except:
        print('Izgubila se veza sa {} klijentom'.format(address))

"""Funkcija koja vrsi navigaciju kroz aplikaciju za ulogovane korisnike{navigator_logged_in}"""

def navigator_logged_in(sock):
    while True:
        userInput = sock.recv(1024)
        if userInput.decode() == '1':
            username = sock.recv(1024).decode()
            if not users[username]['files']:
                sock.send('Niste uploadovali ni jedan fajl'.encode())
            else:
                poruka = "Vasi uploadovani fajlovi su: " + ", ".join(users[username]['files'])
                sock.send(poruka.encode())
        elif userInput.decode() == '2':
            upload(sock)
        elif userInput.decode() == '3':
            download(sock)
        elif userInput.decode() == 'q':
            return

def main():
    host = socket.gethostname()
    port = 9000

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    try:
        sock.bind((host, port))
    except:
        print("Port je zauzet!")
        sock.close()
        main()

    sock.listen(10)
    print("Server ceka konekciju")
    while True:
        c, address = sock.accept()
        print("{} se konektovao".format(address))
        t = threading.Thread(target=navigator_main, args=(c,address))
        t.start()

    sock.close()

if __name__ == '__main__':
    main()