mport os
import socket, struct

from colorOptions import *
from fontOptions import *
from renderImg import renderImg
from runImages import *

### Get IP address of gateway / router
def localGateway():
    with open("/proc/net/route") as file:
        for line in file:
            fields = line.strip().split()
            if fields[1] != '00000000' or not int(fields[3], 16) & 2:
                continue
            return socket.inet_ntoa(struct.pack("<L", int(fields[2], 16)))

### Call this module to run program
def networkCheck():
    global gatewayIP
    global hostName
    global dnsIP

    gatewayIP = localGateway()
    hostName = "connectivitycheck.gstatic.com"
    dnsIP = "172.217.4.131"

    networkTest(gatewayIP, "gateway")
    networkTest(dnsIP, "internet")
    networkTest(hostName, "dns")

### This performs a series of ping tests against the addresses and should return a result of 0
### Any non 0 result is an error and it will continue to attempt to restart the network interface
### If after 5 attempts the network does not come back up a reboot will be initiated
def networkTest(hostAddress, testName):
    testResponse = 1
    failCount = 0
    while testResponse is not 2:
        testResponse = os.system("ping -c 1 " + hostAddress)
        if testResponse is not 2:
            if failCount is 5:
                rebootSystem()
            errorMessage(testName)
            os.system('/sbin/ip link set eth0 down && /sbin/ip link set eth0 up')
            failCount = failCount + 1
    failCount = 0

### This scrolls the error message of what part of the network is not responding based on the
### results of the ping test.
def errorMessage(errorMessage):
    if errorMessage is "dns":
        errorMessage = "The DNS is down ... please check the DNS server.      "
    if errorMessage is "internet":
        errorMessage = "The Internet is down ... please check the router and modem.      "
    if errorMessage is "gateway":
        errorMessage = "The local network is down ... please check the router and modem.      "
    renderImg("networkError.png", errorMessage, newsFont, backgroundColor, 0, 0)
    scrollImgDisplay('networkError.png', 40)

### This scrolls a message twice a reboot is about to occur and then forces a reboot
def rebootSystem():
    networkError = "The network did not come back up - attempting to reboot ... please stand by          "
    renderImg("networkError.png", networkError, newsFont, backgroundColor, 0, 0)
    for x in range(0, 2):
        scrollImgDisplay('networkError.png', 40)
    os.system('/sbin/shutdown -r -f now')

### This is temporary for testing outside of the rest of the program
networkCheck()