#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
#  main.py
#
#  Copyright 2014 Fanir <projects@mail.fanir.de>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#
#


# SETTINGS CAN BE FOUND AT THE BOTTOM OF THE FILE


import sys, string, socket, re, signal
from random import choice
from time import sleep
from select import poll, POLLIN, POLLPRI, POLLOUT,\
                        POLLERR, POLLHUP, POLLNVAL
from threading import Thread, Event

bot = None


class log():
    DEBUG, INFO, WARNING, ERROR, FATAL, SILENT =\
        0,    1,       2,     3,     4,      5
    
    levels = {
        0: "[DEBUG]   ", 1: "[INFO]    ", 2: "[WARNING] ",
        3: "[ERROR]   ", 4: "[FATAL]   ", 5: "[SILENT]  "
    }
    
    def show(level, msg):
        if level in range(log.DEBUG, log.SILENT):
            if LOGLEVEL <= level: print("".join((log.levels[level], msg)))
        else:
            raise ValueError("That's not a loglevel!")



class pircbot():
    def __init__(self, nicknames, server, port=6667,
                 ident="pircbot", realname="pircbot", serverpasswd="",
                 encodings=("utf-8", "latin-1"), users="",
                 query_type="", command_prefix=".",
                 parser_wait_time=0.1):
        self.server = server
        self.port = port
        self.serverpasswd = serverpasswd
        self.encodings = encodings
        
        self.nicknames = nicknames
        self.ident = ident
        self.realname = realname
        
        self.users = users
        self.cmdprefix = command_prefix
        self.query_type = query_type.upper()
        
        self.parser_wait_time=parser_wait_time
        
        self.user = {}
        
        self.socket = None
        self.recvbuffer = bytearray(1024)
        
        self.recvloop = None
        self.parseloop = None
        
        self.die_event = Event()
        self.ready = False
        
        self.mode_reply = {}
    
    def connect(self):
        # connect
        self.socket = socket.socket()
        log.show(log.DEBUG, "--- SOCKET OPENING ---")
        try:
            self.socket.connect((self.server, self.port))
        except socket.error as e:
            log.show(log.FATAL, "Fehler: %s" % e)
            return
        
        # start getting data
        self.recvloop = Thread(target=self.recv, name="recvloop")
        self.recvloop.start()
        
        # optionally send a server password
        if self.serverpasswd != "": self.send("PASS %s" % self.serverpasswd)
        # get a nick
        self.send("NICK %s" % self.nicknames.pop(0))
        # set user data
        self.send("USER %s 0 * :%s" % (self.ident, self.realname))
    
    # implements irc command QUIT and (more or less) clean exiting
    def disconnect(self, reason="", send_quit=True):
        if send_quit:
            try:
                self.send("QUIT :%s" % reason)
                sleep(1)
            except: pass
        self.die_event.set()
        ctr = 0
        while self.recvloop.is_alive() and self.parseloop.is_alive() and ctr < 15:
            ctr += 1
            sleep(1)
        log.show(log.DEBUG, "--- SOCKET CLOSING ---")
        try:
            self.socket.shutdown(socket.SHUT_RDWR)
            self.socket.close()
        except: pass
    
    
    ### threaded functions ###
    
    # loop for recieving data from irc
    def recv(self):
        """
        Loop for reciving data
        """
        log.show(log.DEBUG, "--- RECVLOOP STARTING ---")
        self.parseloop = Thread(target=self.parser, name="parser")
        p = poll()
        p.register(self.socket.fileno(), POLLIN)
        while not self.die_event.is_set():
            ap = p.poll(1000)
            if (self.socket.fileno(), POLLIN) in ap:
                self.recvbuffer.extend(self.socket.recv(1024))
                if not self.parseloop.is_alive():
                    self.parseloop = Thread(target=self.parser, name="parser")
                    self.parseloop.start()
        log.show(log.DEBUG, "--- RECVLOOP EXITING ---")
    
    # loop for parsing incoming data
    def parser(self):
        """
        Loop for parsing incoming data
        """
        log.show(log.DEBUG, "--- PARSELOOP STARTING ---")
        while not self.die_event.is_set():# and self.recvbuffer.endswith(b"\r\n"):# != b"":
            if self.recvbuffer.endswith(b"\r\n"):
                # get and decode line from buffer
                rawline, _, self.recvbuffer = self.recvbuffer.partition(b"\r\n")
                rawline = self.decode(rawline)
                # prepare line
                line = rawline.split(" :", 1)
                head = line[0].lstrip("\x00").split(" ")
                larg = line[1] if len(line)>1 else ""
                # parse prefix
                origin = {}
                if head[0].startswith(":"):
                    prefix = head.pop(0)[1:]
                    if "@" in prefix:
                        origin["nick"], origin["ident"], origin["host"] = re.match(r"(\S+)!(\S+)@(\S+)", prefix).groups()
                        origin["mask"] = prefix
                    else:
                        origin["server"] = prefix
                else:
                    prefix = ""
                # parse command
                command = head.pop(0)
                # parse params
                params = head
                params.append(larg.strip())
                
                log.show(log.DEBUG, " > %s" % rawline)
                
                # PING
                if command == "PING":
                    self.send("PONG %s" % params[0])
                # PRIVMSG and NOTICE
                elif command == "PRIVMSG" or command == "NOTICE":
                    if params[1][0] == self.cmdprefix:
                        args = []
                        for v in params[1][1:].split(" "):
                            if v!="": args.append(v)
                        rp = self.on_command(command, prefix, origin, params[0], args[0].lower(), args[1:])
                        if rp not in (None, ""):
                            self.reply(origin, params[0], rp, command)
                # 221 (RPL_UMODEIS)
                elif command == "221" and self.mode_reply is not {}:
                        self.query(self.mode_reply["to"], "Modes are %s" % params[1], self.mode_reply["type"])
                        self.mode_reply = {}
                # INVITE
                elif command == "INVITE":
                    if self.check_privileges(origin["mask"], command):
                        self.join(params[1])
                    else:
                        self.query(origin["nick"], "You can not force me to do that!", "NOTICE")
                # 001 (RPL_WELCOME)
                elif command == "001":
                    self.user["mask"] = re.search(r" (\S+!\S+@\S+)$", rawline.split(" :", 1)[1]).groups()[0]
                    self.user["nick"], self.user["ident"], self.user["host"] = re.match(r"(\S+)!(\S+)@(\S+)", self.user["mask"]).groups()
                    self.ready = True
                # 433 (ERR_NICKNAMEINUSE)
                elif command == "433":
                    self.send("NICK %s" % self.nicknames.pop(0))
                # KILL
                elif command == "KILL":
                    log.show(log.WARNING, "Got killed by %s: %s" % (params[0], params[1:]))
                    self.disconnect(send_quit=False)
            else:
                sleep(self.parser_wait_time)
        log.show(log.DEBUG, "--- PARSELOOP EXITING ---")
    
    
    ### helper functions ###
    
    # encodes data for irc
    def encode(self, textstring):
        for codec in self.encodings:
            try: return textstring.encode(codec)
            except UnicodeDecodeError: continue
        return textstring.encode(self.encodings[0], 'ignore')
    
    # decodes data from irc
    def decode(self, textstring):
        for codec in self.encodings:
            try: return textstring.decode(codec)
            except UnicodeDecodeError: continue
        return textstring.decode(self.encodings[0], 'ignore')
    
    
    # checks if a given user may execute a given command
    def check_privileges(self, usermask, command):
        for user, privs in self.users.items():
            if re.search(user, usermask, re.IGNORECASE) != None:
                if command.lower() in privs or "*" in privs:
                    return True
        return False
    
    
    # checks if s is a valid channel name
    def is_channel(self, s):
        return (True if s[0] in ('&', '#', '!') else False)
    
    
    def exec_on_ready(self, command, retry_times=-1, interval=1):
        if command.startswith("self."):
            if retry_times == -1:
                while not self.ready: sleep(interval)
            else:
                cnt = 0
                while not self.ready and cnt<retry_times: sleep(interval)
                if not self.ready:
                    log.show(log.WARNING, "Connection did not get ready in time (%sx %s seconds), \"%s\" not executed" % (retry_times, interval, command))
                    return True
            exec("ret = %s" % command)
            return False
        else:
            log.show(log.FATAL, "exec_on_ready() called with an invalid command: %s" % command)
            return True
    
    def exec_retry(self, command, times=5, interval=1, wait_for_ready=True):
        if command.startswith("self."):
            if wait_for_ready:
                while not self.ready: sleep(interval)
            cnt = 0
            exec("while %s and cnt<times: sleep(interval)" % command)
        else: log.show(log.FATAL, "exec_retry() called with an invalid command.")
    
    
    def send(self, data):
        log.show(log.DEBUG, "<  %s" % data)
        try: self.socket.send(self.encode("".join((data, "\r\n"))))
        except BrokenPipeError as e:
            log.show(log.FATAL, e)
            self.disconnect(send_quit=False)
    
    # decides whether to reply to user or to channel
    def reply(self, origin, source, msg, in_query_type):
        if self.is_channel(source):
            self.chanmsg(source, msg)
        else:
            self.query(origin["nick"], msg, in_query_type)
    
    
    ### irc command wrapper ###
    
    # replies to channel by PRIVMSG
    def chanmsg(self, channel, msg):
        self.send("".join(("PRIVMSG ", channel, " :", msg)))
    
    # replies to user by NOTICE or PRIVMSG
    def query(self, nick, msg, in_query_type):
        self.send("".join((self.query_type if self.query_type!="" else in_query_type, " ", nick, " :", msg)))
    
    def nick(self, nick):
        self.exec_on_ready("".join(('self.send("JOIN %s" % "', channel, '")')))
    
    def join(self, channel):
        self.exec_on_ready("".join(('self.send("JOIN %s" % "', channel, '")')))
    
    def part(self, channel):
        self.exec_on_ready("".join(('self.send("PART %s" % "', channel, '")')))
    
    def set_mode(self, modes, target=""):
        self.exec_on_ready("".join(('self.send("MODE %s :%s" % (', ''.join(('"', target, '"')) if target != "" else 'self.user["nick"]', ', "', modes, '"))')))
        
    def get_modes(self, target=""):
        self.exec_on_ready("".join(('self.send("MODE %s" % ', ''.join(('"', target, '"')) if target != "" else 'self.user["nick"]', ')')))
    
    ### handler ###
    
    # bot-command handler
    def on_command(self, in_query_type, prefix, origin, source, command, params):
        """
        Executed when getting a PRIVMSG starting with self.cmdprefix
        Prefix contains the optional prefix of the raw line.
        Origin is a map holding the parsed prefix, containing
            "nick", "ident" and "host" for users and "server" for servers.
        Source is the first parameter after the irc-command, specifying
            the channel or user, from where the line comes.
        Command is the command for the bot.
        Params contains a list of originally space separated parameters.
        """
        # hello
        if command == "hello":
            greeting = "".join(("Hi " + origin["nick"] +"!"))
            return greeting
        # say
        if command == "say":
            return " ".join(params)
        # join <channel>
        elif command == "join":
            if len(params)>0:
                if self.check_privileges(origin["mask"], command): self.join(params[0])
                else: self.query(origin["nick"], "You cannot do that!", in_query_type)
        # part <channel>
        elif command == "part":
            if len(params)>0:
                if self.check_privileges(origin["mask"], command): self.part(params[0])
                else: self.query(origin["nick"], "You cannot do that!", in_query_type)
        # mode ±<modes>
        elif command == "mode":
            if self.check_privileges(origin["mask"], command):
                if len(params)==0:
                    self.mode_reply["to"] = origin["nick"]
                    self.mode_reply["type"] = in_query_type
                    self.get_modes()
                else:
                    self.set_mode(" ".join(params) if len(params)>0 else params)
            else: self.query(origin["nick"], "You cannot do that!", in_query_type)
        # die [<quitmsg>]
        elif command == "die":
            if self.check_privileges(origin["mask"], command):
                self.disconnect("".join(params) if len(params)>0 else "".join((origin["nick"], " shot me, dying now... Bye...")))
            else: self.query(origin["nick"], "Go die yourself!", in_query_type)
        else:
            replies = [
                ("What? \"%s\" is not a command!", 15),
                ("%s? What's that?", 3),
                ("Sorry, I don't know how to %s...", 1)
            ]
            self.query(origin["nick"], choice([val for val, cnt in replies for i in range(cnt)]) % (command), in_query_type)



def parseargs():
    import argparse
    p = argparse.ArgumentParser(
        description = "i think my desc is missing")
    p.add_argument("action", default="help", choices = ["start", "stop"], help="What to do?")
    #p.add_argument("--daemon", "-d", type = bool, choices = [1, 0], default=1, help="Daemonize, Default: 1")
    return p.parse_args()

def main():
    global bot
    args = parseargs()
    if args.action == "start":
        try:
            bot = pircbot(nicknames=NICKNAMES, ident=IDENT, realname=REALNAME,
                          server=SERVER, port=PORT, serverpasswd=SERVERPASSWD,
                          encodings=ENCODINGS, users=USERS,
                          query_type=QUERY_TYPE, command_prefix=COMMAND_PREFIX,
                          parser_wait_time=PARSER_WAIT_TIME)
            bot.connect()
            # wait for the bot to become ready
            while bot.ready and not bot.die_event.is_set() == False:
                sleep(1)
            
            if not bot.die_event.is_set():
                # set modes and join channels
                bot.set_mode(MODES)
                for channel in CHANNELS:
                    bot.join(channel)
            
            # while bot is active, do nothing
            while not bot.die_event.is_set():
                sleep(1)
        except KeyboardInterrupt:
            log.show(log.INFO, "Got Ctrl-C, dying now...")
            bot.disconnect("Ouch! Got shot by Ctrl-C, dying now... See you!")
    
    elif args.action == "stop": print("nope!")
    log.show(log.DEBUG, "--- MAIN EXITING ---")
    return 0


if __name__ == '__main__':
    
    ################
    ### SETTINGS ###
    ################
    
    # Also known as username. Some IRC-internal.
    # By default, the nickname will be used as ident.
    IDENT = "chalkbot"
    
    # The list of nicknames to try. If the first one is not aviable, it will
    # try the second, and so on...
    # You should specfy at least two nicks.
    NICKNAMES = ["chalkbot", "chalkbot_", "chalkbot__"]
    
    REALNAME = "A ChalkBot Instance"
    
    # Command for registering with nickserv, without leading slash.
    NICKSERVCMD = ""
    
    MODES = "+iB"
    
    
    # The Server name to connect to. Duh!
    SERVER = "fanir.de"
    #SERVER = "localhost"
    
    # "Default" is 6667. An often used port for SSL would be 6697, if SSL would be
    # supported. Maybe in a future, far far away...
    PORT = 6667
    
    # Serverpassword. Empty in most cases.
    SERVERPASSWD = ""
    
    # A comma-seperated list of channels to join, enclosed by braces.
    CHANNELS = ["#bots"]
    
    # The encodings to try when getting messages from IRC. Will be tried in the given order.
    # The first one is used to encode data when sending stuff.
    # The list given shoud do just fine in most networks, I assume.
    # Also comma seperated and enclosed by braces.
    ENCODINGS = ['utf-8', 'latin-1', 'iso-8859-1', 'cp1252']
    
    
    # List of users (hostmasks as regex) and the commands they are allowed to execute.
    # "*" Can be used instead of commands to allow every command.
    # All command names should be lowercase.
    USERS = {
        "Fanir\!fanir@.*": ["*"],
        "\!@some weird user that cannot exist": ["join", "part", "invite"],
    }
    
    # The prefix for commands for the bot.
    COMMAND_PREFIX = "."
    
    # Which way should be used to speak to users?
    # "" means the type of the incoming message should be used.
    # One of: "NOTICE", "PRIVMSG", ""
    QUERY_TYPE = ""
    
    
    # With how much information do you want to be annoyed?
    # DEBUG spams most, FATAL least. WARNING should be a good tradeoff.
    # One of: log.DEBUG, log.INFO, log.WARNING, log.ERROR, log.FATAL
    LOGLEVEL = log.DEBUG
    
    # The time the parser for incoming data should wait between each attempt to read new data in seconds.
    # High values will certainly make the bot reply slowly while very low values increads cpu load and therefore will perform badly on slow machines.
    # You should keep it between 1 and 0.001 seconds.
    # For gods sake, don't set it to 0!
    PARSER_WAIT_TIME = 0.05
    
    #######################
    ### END OF SETTINGS ###
    #######################
    
    
    main()