import telnetlib
import urllib
import select

from screen import Screen


class Server(object):
    
    """ LCDproc Server Object """
    
    def __init__(self, hostname="localhost", port=13666, debug=False):
        
        """ Constructor """
        
        self.debug = debug
        self.hostname = hostname
        self.port = port
        self.tn = telnetlib.Telnet(self.hostname, self.port)
        self.server_info = dict()
        self.screens = dict()
        self.keys = list()
                
    def start_session(self):
        
        """ Start Session """
        
        response = self.request("hello") 
	print(response)
        bits = response.split(" ")
        self.server_info.update({
            "server_version": bits[2],
            "protocol_version": bits[4],
            "screen_width": int(bits[7]),
            "screen_height": int(bits[9]),
            "cell_width": int(bits[11]),
            "cell_height": int(bits[13])            
        })                
        return response  
        
                
    def request(self, command_string):
        
        """ Request """
        
        #self.tn.write((command_string + "\n").encode())
        self.tn.write((command_string + "\n"))
        if self.debug: print "Telnet Request:  %s" % (command_string)
        while True:
            response = urllib.unquote(self.tn.read_until(b"\n").decode())
            if "success" in response:   # Normal successful reply
                break
            if "huh" in response:       # Something went wrong
                break
            if "connect" in response:   # Special reply to "hello"
                break
            # TODO Keep track of which screen is displayed
            # Try again if response was key, menu or visibility notification.
        if "huh" in response or self.debug: print "Telnet Response: %s" % (response[:-1])
        return response


    def poll(self):
        """
        Poll
        
        Check for a non-response string generated by LCDd and return any string read.
        LCDd generates strings for key presses, menu events & screen visibility changes.
        """
        if select.select([self.tn], [], [], 0) == ([self.tn], [], []):
            response = urllib.unquote(self.tn.read_until(b"\n").decode())
            if self.debug: print "Telnet Poll: %s" % (response[:-1])
            # TODO Keep track of which screen is displayed
            return response
        else:
            return None


    def add_screen(self, ref):     
        
        """ Add Screen """
        
        if ref not in self.screens:   
            screen = Screen(self, ref)
            screen.clear()              # TODO Check this is needed, new screens should be clear.
            self.screens[ref] = screen
            return self.screens[ref]
    	return self.screens[ref]
     

    def del_screen(self, ref):
        """ Delete/Remove Screen """
        self.request("screen_del %s" % (ref))
        del(self.screens[ref])

        
    def add_key(self, ref, mode = "shared"):
        """
        Add a key.
        
        (ref)
        Return key name or None on error
        """
        if ref not in self.keys:   
            response = self.request("client_add_key %s -%s" % (ref, mode))
            if "success" not in response: return None
            self.keys.append(ref)
            return ref


    def del_key(self, ref):
        """
        Delete a key.
        
        (ref)
        Return None or LCDd response on error
        """
        if ref not in self.keys:   
            response = self.request("client_del_key %s" % (ref))
            self.keys.remove(ref)
            if "success" in response:
                return None
            else:
                return response
            

    def output(self, value):
        """
        Sets the client's output (on, off, int)
        
        Sets the general purpose output on some display modules to this value.
        Use on to set all outputs to high state, and off to set all to low state.
        The meaning of the integer value depends on your specific device, usually
        it is a bit pattern describing the state of each output line.
        
        Return None or LCDd response on error
        """
        response = self.request(("output %s" % (value)).encode())
        if "success" in response:
            return None
        else:
            return response

    def get_server_info(self):
        """
        Returns information about the server and the connected
        LCD as a dictionary with the following keys:

            "server_version", "protocol_version",
            "screen_width", "screen_height",
            "cell_width", "cell_height"
        """
        return self.server_info