client.py

# client

import socket
import threading
import time
import sys

print("Welcome to the stock trading application!\n")

# create socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# get server address and create address pair
connectCmd = input("Please input a server address and port: ")
address = (connectCmd[0:connectCmd.find(":")],
           int(connectCmd[connectCmd.find(":") + 1:]))
connection = False
MSGLEN = 256

# command thread variables
message = ""
oldMessage = ""
listening = False
listenerThread = None

# try to connect to server - error if it fails and prompt again for server address
while connection == False:
    try:
        s.connect(address)
        connection = True
        print(
            f"Connection successfully established with {address[0]}:{address[1]}\n")
    except Exception as e:
        print(
            f"Connection could not be established with server on {address[0]}:{address[1]} \nException is " + str(e))
        connectCmd = input("Please input another server address and port: ")
        if connectCmd.lower() == "quit":
            break
        address = (connectCmd[0:connectCmd.find(":")],
                   int(connectCmd[connectCmd.find(":") + 1:]))

# sends input string of max length MSGLEN to the server


def sendMsg(msg):
    totalSent = 0
    while len(msg) < MSGLEN:
        msg = msg + " "
    while totalSent < MSGLEN:
        sent = s.send(msg[totalSent:].encode("utf-8"))
        if sent == 0 and msg != "":
            quitClient()
            break
        elif msg == "":
            break
        totalSent += sent
    print("msg '" + msg.strip() + "' sent with total bytes: " + str(totalSent))

# recieves string from server


def recieveMsg():
    chunks = []
    bytesRecieved = 0
    while bytesRecieved < MSGLEN:
        chunk = s.recv(min(MSGLEN - bytesRecieved, 2048))
        if chunk.decode("utf-8") == "":
            quitClient()
            break
        chunks.append(chunk)
        bytesRecieved += len(chunk)
    returnStr = ""
    for c in chunks:
        returnStr = returnStr + c.decode("utf-8")
    print("msg '" + returnStr.strip() +
          "' recieved with total bytes: " + str(bytesRecieved))
    return returnStr.strip()

# client close function


def quitClient():
    s.close()
    print("Connection broken - Program exiting...\n")
    global connection
    global listening
    connection = False
    sys.exit(0)


def isServerClose(sock: socket.socket):
    try:
        # this will try to read bytes without blocking and also without removing them from buffer (peek only)
        sock.setblocking(False)
        data = sock.recv(2048, socket.MSG_PEEK)
        if data.decode("utf-8") == "":
            return True
    except BlockingIOError:
        sock.setblocking(True)
        return False  # socket is open and reading from it would block
    except ConnectionResetError:
        return True  # socket was closed for some other reason
    except Exception as e:
        sock.setblocking(True)
        return False
    sock.setblocking(True)
    return False


# executes command
loggedIn = False
uid = None
userName = None


def executeCMD(cmd: str):
    global uid
    global userName
    # check login
    global loggedIn
    if loggedIn == False and (cmd.lower() != "quit" and cmd[0:5].lower() != "login"):
        print("Command cannot be executed. You are not logged in. \nPlease try the login command or quit the program.")
        return
    # run command
    if cmd.lower() == "shutdown".lower():
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:6] == "200 OK":
            print(response[7:])
            quitClient()
        else:
            print(response)
    elif cmd.lower() == "quit".lower():
        sendMsg("quit")
        quitClient()
    elif cmd[0:5].lower() == "login".lower():
        params = cmd.split(" ")
        if (len(params) == 0 or len(params) == 1 or params[1] == ""):
            un = input("Please enter a username: ")
            password = input("Please enter password: ")
            cmd = ("LOGIN " + un + " " + password)
        elif (len(params) == 2):
            un = params[1]
            password = input("Please enter password: ")
            cmd = ("LOGIN " + un + " " + password)
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":
            loggedIn = True
            uid = response[7:8]
            userName = cmd.split()[1]
            print(response[9:])
        elif response[0:3] == "403":
            print(response)
    elif cmd.lower() == "logout".lower():
        sendMsg(cmd)
        response = recieveMsg()
        uid = None
        userName = ""
        loggedIn = False
    elif cmd.lower()[0:7] == "balance".lower():
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":
            print(f"Balance for user {userName}: " + response[7:])
        elif response[0:3] == "400":
            print(response)
    elif cmd.lower()[0:7] == "deposit".lower():
        amount_flag = False
        params = cmd.split(" ")
        if (len(params) == 0 or len(params) == 1 or params[1] == ""):
            amount = input("Please enter deposit amount\n")
            while (amount_flag == False):
                try:
                    float(amount)
                    if float(amount) < 0:
                        raise("negative")
                    amount_flag = True
                except:
                    amount_flag = False
                    amount = input("Please enter a positive deposit amount\n")
            
            cmd = "DEPOSIT " + str(amount)
        else:
            amount = params[1]
            while (amount_flag == False):
                try:
                    float(amount)
                    if float(amount) < 0:
                        raise("negative")
                    amount_flag = True
                except:
                    amount_flag = False
                    amount = input("Please enter a positive deposit amount\n")
            cmd = "DEPOSIT " + str(amount)    
        
        sendMsg(cmd + " "+str(uid))
        response = recieveMsg()
        if response[0:3] == "200":
            print(f"Updated Balance for user {userName}: " + response[7:])
        elif response[0:3] == "400":
            print(response)
    elif cmd.lower()[0:6] == "lookup".lower():
        params = cmd.split(" ")
        if (len(params) == 0 or len(params) == 1 or params[1] == ""):
            search = input("Please enter stock to lookup\n")           
            cmd = "LOOKUP " + str(search)
        sendMsg(cmd + " " + str(uid))
        response = recieveMsg()
        if response[0:3] == "200":
            print(f"Found stock records matching you search for user {userName}: ")
            
            stocks = response[7:].split()
            stocksList = []
            for stock in stocks:
                stockTuple = stock[1:-1].split(",")
                stocksList.append(stockTuple)

            for stock in stocksList:
                print(stock[0], stock[1], stock[3])
        elif response[0:3] == "404":
            print(response)
    elif cmd.lower()[0:4] == "list".lower():
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":

            stocks = response[7:].split()
            stocksList = []
            for stock in stocks:
                stockTuple = stock[1:-1].split(",")
                stocksList.append(stockTuple)

            if userName == "root":
                print("The list of stock records for all users:")
                for stock in stocksList:
                    print(stock[0], stock[1], stock[3], stock[4])
            else:
                print(f"The list of stock records for user {userName}:")
                for stock in stocksList:
                    print(stock[0], stock[1], stock[3])
        elif response[0:3] == "400":
            print(response)
    elif cmd.lower()[0:3] == "who".lower():
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":
            print("The list of active users is: ")
            activeUsers = response[6:].split()
            for user in activeUsers:
                print(user)
        else:
            print(response)
    elif cmd.lower()[0:3] == "buy".lower():
        parameters = cmd.split(" ")
        price_flag = False  # boolean for the price per share
        stock_flag = False  # boolean for stock amount
        symbol = ""
        # "BUY" or "BUY " case we need a stock symbol, price per share, stock ammount and a user id
        if len(parameters) == 0 or len(parameters) == 1:
            symbol = str(input("Please enter stock symbol\n"))
            while stock_flag == False:
                try:
                    # Ensure that stock is a positive number
                    stock = float(
                        input("Please enter stock ammount as a float or integer\n"))
                    if stock > 0:
                        stock_flag = True
                except:
                    stock_flag = False
            while price_flag == False:
                try:
                    # Ensure that price is a positive number
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            cmd = "BUY " + symbol + " " + \
                str(stock) + " " + str(price) + " " + \
                str(uid)+"\n"  # The message to be sent
        elif len(parameters) == 2:  # "BUY symbol" case
            symbol = str(parameters[1])
            while stock_flag == False:
                try:
                    stock = float(
                        input("Please enter stock ammount as a float or integer\n"))
                    if stock > 0:
                        stock_flag = True
                except:
                    stock_flag = False
            while price_flag == False:
                try:
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            cmd = "BUY " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        elif len(parameters) == 3:  # "BUY symbol pricepershare" case
            symbol = str(parameters[1])
            try:
                stock = float(parameters[2])
                if stock < 0:
                    raise("less than 0")
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            while price_flag == False:
                try:
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            cmd = "BUY " + symbol + " " + \
                str(stock) + " " + str(price) + " " + \
                str(uid)+"\n"  # The message to be sent
        elif len(parameters) == 4:  # "BUY symbol pricepershare stockamount" case
            symbol = str(parameters[1])
            try:
                stock = float(parameters[2])
                if stock < 0:
                    raise("less than 0")
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            try:
                price = float(parameters[3])
            except:
                while price_flag == False:
                    try:
                        price = float(
                            input("Please enter stock price per share as a float or integer\n"))
                        if price > 0:
                            price_flag = True
                    except:
                        price_flag = False
            cmd = "BUY " + symbol + " " + \
                str(stock) + " " + str(price) + " " + \
                str(uid)+"\n"  # Message to be sent
        elif len(parameters) >= 5:  # "BUY symbol price per share stock amount uid" and corners case
            symbol = str(parameters[1])
            try:
                stock = float(parameters[2])
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            try:
                price = float(parameters[3])
            except:
                while price_flag == False:
                    try:
                        price = float(
                            input("Please enter stock price per share as a float or integer\n"))
                        if price > 0:
                            price_flag = True
                    except:
                        price_flag = False
            cmd = "BUY " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":
            print(response[7:])
        elif response[0:3] == "400":
            print(response)
    elif cmd.lower()[0:4] == "sell".lower():
        parameters = cmd.split(" ")
        price_flag = False
        stock_flag = False
        symbol = ""
        if len(parameters) == 0 or len(parameters) == 1:  # "SELL" and "SELL " case
            symbol = str(input("Please enter stock symbol\n"))
            # Ensure real positive numbers for price and stock amount, ensure integer for uid
            while price_flag == False:
                try:
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            while stock_flag == False:
                try:
                    stock = float(
                        input("Please enter stock ammount as a float or integer\n"))
                    if stock > 0:
                        stock_flag = True
                except:
                    stock_flag = False
            cmd = "SELL " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        elif len(parameters) == 2:  # "Sell symbol" case
            symbol = str(parameters[1])
            # Ensure real positive numbers for price and stock amount, ensure integer for uid
            while price_flag == False:
                try:
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            while stock_flag == False:
                try:
                    stock = float(
                        input("Please enter stock ammount as a float or integer\n"))
                    if stock > 0:
                        stock_flag = True
                except:
                    stock_flag = False
            cmd = "SELL " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        elif len(parameters) == 3:  # "SELL symbol stock" case
            symbol = str(parameters[1])
            # Ensure real positive numbers for price and stock amount, ensure integer for uid
            try:
                stock = float(parameters[2])
                if stock < 0:
                    raise("less than 0")
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            while price_flag == False:
                try:
                    price = float(
                        input("Please enter stock price per share as a float or integer\n"))
                    if price > 0:
                        price_flag = True
                except:
                    price_flag = False
            cmd = "SELL " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        elif len(parameters) == 4:  # "SELL symbol stock price" case
            symbol = str(parameters[1])
            # Ensure real positive numbers for price and stock amount, ensure integer for uid
            try:
                price = float(parameters[3])
            except:
                while price_flag == False:
                    try:
                        price = float(
                            input("Please enter stock price per share as a float or integer\n"))
                        if price > 0:
                            price_flag = True
                    except:
                        price_flag = False
            try:
                stock = float(parameters[2])
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            cmd = "SELL " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        elif len(parameters) >= 5:  # "SELL symbol stock price uid" and corner case
            symbol = str(parameters[1])
            # Ensure real positive numbers for price and stock amount, ensure integer for uid
            try:
                price = float(parameters[3])
            except:
                while price_flag == False:
                    try:
                        price = float(
                            input("Please enter stock price per share as a float or integer\n"))
                        if price > 0:
                            price_flag = True
                    except:
                        price_flag = False
            try:
                stock = float(parameters[2])
                if stock < 0:
                    raise("less than 0")
            except:
                while stock_flag == False:
                    try:
                        stock = float(
                            input("Please enter stock ammount as a float or integer\n"))
                        if stock > 0:
                            stock_flag = True
                    except:
                        stock_flag = False
            cmd = "SELL " + symbol + " " + \
                str(stock) + " " + str(price) + " " + str(uid)+"\n"
        sendMsg(cmd)
        response = recieveMsg()
        if response[0:3] == "200":
            print(response[7:])
        elif response[0:3] == "400" or response[0:3] == "401":
            print(response)
    else:
        print(f"command '{cmd}' not recognized... please try again")


def cmdListen():
    global listening
    global message
    listening = True
    cmd = input("CMD>> ")
    listening = False
    message = cmd


# main client command loop - "quit" to quit the program and "shutdown" to shutdown the server
while connection:
    # manage command listener
    if listening == False:
        if message != oldMessage:
            oldMessage = message
            executeThread = threading.Thread(
                target=executeCMD, args=(message,))
            executeThread.start()
            executeThread.join()
        if connection == False:
            break
        listenerThread = threading.Thread(
            target=cmdListen, daemon=True, args=())
        listenerThread.start()

    # check for message from server
    if connection == False:
        break
    try:
        s.setblocking(False)
        serverMSG = s.recv(2048, socket.MSG_PEEK)
        s.setblocking(True)
        if serverMSG.decode("utf-8") != "":
            if serverMSG.decode("utf-8").strip() == "shutdown":
                print("\nShutdown command received from server")
                quitClient()
    except BlockingIOError:  # no message recieved
        s.setblocking(True)
    except Exception as e:
        s.setblocking(True)
        print(e)
        quitClient()

    # loop delay
    time.sleep(0.1)