from socket import *
from ftp_utils import *
from enum import Enum
from time import sleep
from pathlib import Path
import os
import sys
import traceback

HOST = '127.0.0.1'

PORT = 12000
if len(sys.argv) > 1:
	PORT = int(sys.argv[1])

DEBUG = True
MAX_FILE_SIZE = 65536	# 64 KiB

# set up the tcp sockets
sock = socket(AF_INET, SOCK_STREAM)
conn = None # for now...

if DEBUG:
	# Allows for quicker debugging at risk of stray
	# packets messing with the byte stream
	sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)

sock.bind((HOST, PORT))
sock.listen()

def ftp_GET(*args):
	global conn
	file_name = get_argument(args, "file name", 0)

	with open(os.path.join("./server", file_name), "rb") as fetched_file:
		file_bytes = fetched_file.read()
		conn.sendall(file_bytes)

def ftp_PUT(*args):
	file_name = get_argument(args, "file name", 0)
	size = int(get_argument(args, "file size", 1))

	if size > MAX_FILE_SIZE:
		throw_error(conn, 3884, f"File exceeds maximum file size: {MAX_FILE_SIZE}")
		return

	conn.sendall("OK".encode("utf-8"))
	file_bytes = conn.recv(size)

	parent_path = os.path.join("./server", str(Path(file_name).parent))

	if not os.path.exists(parent_path):
		os.makedirs(parent_path)

	with open(os.path.join("server", file_name), "wb") as new_file:
		new_file.write(file_bytes)

	print(f"File '{file_name}' uploaded")

def ftp_CLOSE(*args):
	global conn
	send_message(conn, "bye<3")
	conn.close()
	conn, addr = sock.accept()

def ftp_SIZE(*args):
	global conn
	file_name = get_argument(args, "file name", 0)

	try:
		send_message(conn, str(os.path.getsize(os.path.join("./server", file_name))))
	except FileNotFoundError:
		raise FTPError(f"File '{file_name}' not found", 9283)

COMMANDS = {
	"GET": ftp_GET,
	"PUT": ftp_PUT,
	"CLOSE": ftp_CLOSE,
	"SIZE": ftp_SIZE,
}

def throw_error(conn, code, msg):
	conn.sendall(f"Error {code}: {msg}".encode("utf-8"))

def send_message(conn, msg):
	conn.sendall(msg.encode("utf-8"))

# listen for a connection
conn, addr = sock.accept()
print("Connected to " , addr)

try:
	while (True):
		data = conn.recv(1024).decode("utf-8")

		command_name, arguments = parse_ftp_command(data)

		# Let's allow for case insensitivity in the command name
		command_name = command_name.upper()

		try:
			result = COMMANDS[command_name](*arguments)
		except KeyError:
			throw_error(conn, 2, f"Unknown command '{command_name}'")
			continue
		except FTPError as err:
			throw_error(conn, err.code, err.message)
		except Exception as err:
			print(f"Error: {err}")
			traceback.print_exc()
			throw_error(conn, -1, f"Unknown error while executing {command_name}")
except BrokenPipeError:
	print("Broken Pipe. Awaitng new connections...")
	conn, addr = sock.accept()
except Exception as e:
	print(f"Error: {e}")
	traceback.print_exc()
finally:
	conn.close()
	sock.close()