# Copyright (c) 2008 Duncan Fordyce
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import sys
import time
import ssl
import socket
import select
import logging
import datetime
import traceback

from oyoyo.parse import parse_raw_irc_command
from oyoyo import helpers
from oyoyo.cmdhandler import CommandError

PchumLog = logging.getLogger("pchumLogger")

try:
    import certifi
except ImportError:
    if sys.platform == "darwin":
        # Certifi is required to validate certificates on MacOS with pyinstaller builds.
        PchumLog.warning(
            "Failed to import certifi, which is recommended on MacOS. "
            "Pesterchum might not be able to validate certificates unless "
            "Python's root certs are installed."
        )
    else:
        PchumLog.info(
            "Failed to import certifi, Pesterchum will not be able to validate "
            "certificates if the system-provided root certificates are invalid."
        )


class IRCClientError(Exception):
    pass


class IRCClient:
    """IRC Client class. This handles one connection to a server.
    This can be used either with or without IRCApp ( see connect() docs )
    """

    def __init__(self, cmd_handler, **kwargs):
        """the first argument should be an object with attributes/methods named
        as the irc commands. You may subclass from one of the classes in
        oyoyo.cmdhandler for convenience but it is not required. The
        methods should have arguments (prefix, args). prefix is
        normally the sender of the command. args is a list of arguments.
        Its recommened you subclass oyoyo.cmdhandler.DefaultCommandHandler,
        this class provides defaults for callbacks that are required for
        normal IRC operation.

        all other arguments should be keyword arguments. The most commonly
        used will be nick, host and port. You can also specify an "on connect"
        callback. ( check the source for others )

        Warning: By default this class will not block on socket operations, this
        means if you use a plain while loop your app will consume 100% cpu.
        To enable blocking pass blocking=True.

        >>> class My_Handler(DefaultCommandHandler):
        ...     def privmsg(self, prefix, command, args):
        ...         print "%s said %s" % (prefix, args[1])
        ...
        >>> def connect_callback(c):
        ...     helpers.join(c, '#myroom')
        ...
        >>> cli = IRCClient(My_Handler,
        ...     host="irc.freenode.net",
        ...     port=6667,
        ...     nick="myname",
        ...     connect_cb=connect_callback)
        ...
        >>> cli_con = cli.connect()
        >>> while 1:
        ...     cli_con.next()
        ...
        """

        self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

        self.nick = None
        self.realname = None
        self.username = None
        self.host = None
        self.port = None
        self.connect_cb = None
        self.timeout = None
        self.blocking = None
        self.ssl = None

        self.__dict__.update(kwargs)
        self.command_handler = cmd_handler(self)

        self._end = False

    def send(self, *args, **kwargs):
        """send a message to the connected server. all arguments are joined
        with a space for convenience, for example the following are identical

        >>> cli.send("JOIN %s" % some_room)
        >>> cli.send("JOIN", some_room)

        In python 2, all args must be of type str or unicode, *BUT* if they are
          unicode they will be converted to str with the encoding specified by
          the 'encoding' keyword argument (default 'utf8').
        In python 3, all args must be of type str or bytes, *BUT* if they are
          str they will be converted to bytes with the encoding specified by the
          'encoding' keyword argument (default 'utf8').
        """
        if self._end == True:
            return
        # Convert all args to bytes if not already
        encoding = kwargs.get("encoding") or "utf8"
        bargs = []
        for arg in args:
            if isinstance(arg, str):
                bargs.append(bytes(arg, encoding))
            elif isinstance(arg, bytes):
                bargs.append(arg)
            elif type(arg).__name__ == "unicode":
                bargs.append(arg.encode(encoding))
            else:
                PchumLog.warning(
                    "Refusing to send one of the args from provided: %s"
                    % repr([(type(arg), arg) for arg in args])
                )
                raise IRCClientError(
                    "Refusing to send one of the args from provided: %s"
                    % repr([(type(arg), arg) for arg in args])
                )

        msg = bytes(" ", "UTF-8").join(bargs)
        PchumLog.info('---> send "%s"' % msg)
        try:
            tries = 1
            while tries < 10:
                # Check if alive
                if self._end == True:
                    break
                if self.socket.fileno() == -1:
                    self._end = True
                    break
                try:
                    ready_to_read, ready_to_write, in_error = select.select(
                        [], [self.socket], []
                    )
                    for x in ready_to_write:
                        x.sendall(msg + bytes("\r\n", "UTF-8"))
                    break
                except ssl.SSLWantReadError as e:
                    PchumLog.warning("ssl.SSLWantReadError on send, " + str(e))
                    select.select([self.socket], [], [])
                    if tries >= 9:
                        raise e
                except ssl.SSLWantWriteError as e:
                    PchumLog.warning("ssl.SSLWantWriteError on send, " + str(e))
                    select.select([], [self.socket], [])
                    if tries >= 9:
                        raise e
                except ssl.SSLEOFError as e:
                    # ssl.SSLEOFError guarantees a broken connection.
                    PchumLog.warning("ssl.SSLEOFError in on send, " + str(e))
                    raise ssl.SSLEOFError
                except (socket.timeout, TimeoutError) as e:
                    # socket.timeout is deprecated in 3.10
                    PchumLog.warning("TimeoutError in on send, " + str(e))
                    raise socket.timeout
                except (OSError, IndexError, ValueError, Exception) as e:
                    PchumLog.warning("Unkown error on send, " + str(e))
                    if tries >= 9:
                        raise e
                tries += 1
                PchumLog.warning("Retrying send. (attempt %s)" % str(tries))
                time.sleep(0.1)

            PchumLog.debug(
                "ready_to_write (len %s): " % str(len(ready_to_write))
                + str(ready_to_write)
            )
        except Exception as se:
            PchumLog.warning("Send Exception %s" % str(se))
            try:
                if not self.blocking and se.errno == 11:
                    pass
                else:
                    # raise se
                    self._end = True  # This ok?
            except AttributeError:
                # raise se
                self._end = True  # This ok?

    def get_ssl_context(self):
        """Returns an SSL context for connecting over SSL/TLS.
        Loads the certifi root certificate bundle if the certifi module is less
        than a year old or if the system certificate store is empty.

        The cert store on Windows also seems to have issues, so it's better
        to use the certifi provided bundle assuming it's a recent version.

        On MacOS the system cert store is usually empty, as Python does not use
        the system provided ones, instead relying on a bundle installed with the
        python installer."""
        default_context = ssl.create_default_context()
        if "certifi" not in sys.modules:
            return default_context

        # Get age of certifi module
        certifi_date = datetime.datetime.strptime(certifi.__version__, "%Y.%m.%d")
        current_date = datetime.datetime.now()
        certifi_age = current_date - certifi_date

        empty_cert_store = (
            list(default_context.cert_store_stats().values()).count(0) == 3
        )
        # 31557600 seconds is approximately 1 year
        if empty_cert_store or certifi_age.total_seconds() <= 31557600:
            PchumLog.info(
                "Using SSL/TLS context with certifi-provided root certificates."
            )
            return ssl.create_default_context(cafile=certifi.where())
        PchumLog.info("Using SSL/TLS context with system-provided root certificates.")
        return default_context

    def connect(self, verify_hostname=True):
        """initiates the connection to the server set in self.host:self.port
        self.ssl decides whether the connection uses ssl.

        Certificate validation when using SSL/TLS may be disabled by
        passing the 'verify_hostname' parameter. The user is asked if they
        want to disable it if this functions raises a certificate validation error,
        in which case the function may be called again with 'verify_hostname'."""
        PchumLog.info("connecting to %s:%s" % (self.host, self.port))

        # Open connection
        plaintext_socket = socket.create_connection((self.host, self.port))

        if self.ssl:
            # Upgrade connection to use SSL/TLS if enabled
            context = self.get_ssl_context()
            context.check_hostname = verify_hostname
            self.socket = context.wrap_socket(
                plaintext_socket, server_hostname=self.host
            )
        else:
            # SSL/TLS is disabled, connection is plaintext
            self.socket = plaintext_socket

        # setblocking is a shorthand for timeout,
        # we shouldn't use both.
        if self.timeout:
            self.socket.settimeout(self.timeout)
        elif not self.blocking:
            self.socket.setblocking(False)
        elif self.blocking:
            self.socket.setblocking(True)

        helpers.nick(self, self.nick)
        helpers.user(self, self.username, self.realname)
        if self.connect_cb:
            self.connect_cb(self)

    def conn(self):
        """returns a generator object."""
        try:
            buffer = bytes()
            while not self._end:
                # Block for connection-killing exceptions
                try:
                    tries = 1
                    while tries < 10:
                        # Check if alive
                        if self._end == True:
                            break
                        if self.socket.fileno() == -1:
                            self._end = True
                            break
                        try:
                            ready_to_read, ready_to_write, in_error = select.select(
                                [self.socket], [], []
                            )
                            for x in ready_to_read:
                                buffer += x.recv(1024)
                            break
                        except ssl.SSLWantReadError as e:
                            PchumLog.warning("ssl.SSLWantReadError on send, " + str(e))
                            select.select([self.socket], [], [])
                            if tries >= 9:
                                raise e
                        except ssl.SSLWantWriteError as e:
                            PchumLog.warning("ssl.SSLWantWriteError on send, " + str(e))
                            select.select([], [self.socket], [])
                            if tries >= 9:
                                raise e
                        except ssl.SSLEOFError as e:
                            # ssl.SSLEOFError guarantees a broken connection.
                            PchumLog.warning("ssl.SSLEOFError in on send, " + str(e))
                            raise e
                        except (socket.timeout, TimeoutError) as e:
                            # socket.timeout is deprecated in 3.10
                            PchumLog.warning("TimeoutError in on send, " + str(e))
                            raise socket.timeout
                        except (OSError, IndexError, ValueError, Exception) as e:
                            PchumLog.debug("Miscellaneous exception in conn, " + str(e))
                            if tries >= 9:
                                raise e
                        tries += 1
                        PchumLog.debug(
                            "Possibly retrying recv. (attempt %s)" % str(tries)
                        )
                        time.sleep(0.1)

                except socket.timeout as e:
                    PchumLog.warning("timeout in client.py, " + str(e))
                    if self._end:
                        break
                    raise e
                except ssl.SSLEOFError as e:
                    raise e
                except OSError as e:
                    PchumLog.warning("conn exception %s in %s" % (e, self))
                    if self._end:
                        break
                    try:  # a little dance of compatibility to get the errno
                        errno = e.errno
                    except AttributeError:
                        errno = e[0]
                    if not self.blocking and errno == 11:
                        pass
                    else:
                        raise e
                else:
                    if self._end:
                        break
                    if len(buffer) == 0 and self.blocking:
                        PchumLog.debug("len(buffer) = 0")
                        raise OSError("Connection closed")

                    data = buffer.split(bytes("\n", "UTF-8"))
                    buffer = data.pop()

                    PchumLog.debug("data = " + str(data))

                    for el in data:
                        tags, prefix, command, args = parse_raw_irc_command(el)
                        # print(tags, prefix, command, args)
                        try:
                            # Only need tags with tagmsg
                            if command.upper() == "TAGMSG":
                                self.command_handler.run(command, prefix, tags, *args)
                            else:
                                self.command_handler.run(command, prefix, *args)
                        except CommandError as e:
                            PchumLog.warning("CommandError %s" % str(e))

                yield True
        except socket.timeout as se:
            PchumLog.debug("passing timeout")
            raise se
        except (OSError, ssl.SSLEOFError) as se:
            PchumLog.debug("problem: %s" % (str(se)))
            if self.socket:
                PchumLog.info("error: closing socket")
                self.socket.close()
            raise se
        except Exception as e:
            PchumLog.debug("other exception: %s" % str(e))
            raise e
        else:
            PchumLog.debug("ending while, end is %s" % self._end)
            if self.socket:
                PchumLog.info("finished: closing socket")
                self.socket.close()
            yield False

    def close(self):
        # with extreme prejudice
        if self.socket:
            PchumLog.info("shutdown socket")
            # print("shutdown socket")
            self._end = True
            try:
                self.socket.shutdown(socket.SHUT_RDWR)
            except OSError as e:
                PchumLog.debug(
                    "Error while shutting down socket, already broken? %s" % str(e)
                )
            try:
                self.socket.close()
            except OSError as e:
                PchumLog.debug(
                    "Error while closing socket, already broken? %s" % str(e)
                )


class IRCApp:
    """This class manages several IRCClient instances without the use of threads.
    (Non-threaded) Timer functionality is also included.
    """

    class _ClientDesc:
        def __init__(self, **kwargs):
            self.con = None
            self.autoreconnect = False
            self.__dict__.update(kwargs)

    def __init__(self):
        self._clients = {}
        self._timers = []
        self.running = False
        self.sleep_time = 0.5

    def addClient(self, client, autoreconnect=False):
        """add a client object to the application. setting autoreconnect
        to true will mean the application will attempt to reconnect the client
        after every disconnect. you can also set autoreconnect to a number
        to specify how many reconnects should happen.

        warning: if you add a client that has blocking set to true,
        timers will no longer function properly"""
        PchumLog.info("added client %s (ar=%s)" % (client, autoreconnect))
        self._clients[client] = self._ClientDesc(autoreconnect=autoreconnect)

    def addTimer(self, seconds, cb):
        """add a timed callback. accuracy is not specified, you can only
        garuntee the callback will be called after seconds has passed.
        ( the only advantage to these timers is they dont use threads )
        """
        assert callable(cb)
        PchumLog.info("added timer to call %s in %ss" % (cb, seconds))
        self._timers.append((time.time() + seconds, cb))

    def run(self):
        """run the application. this will block until stop() is called"""
        # TODO: convert this to use generators too?
        self.running = True
        while self.running:
            found_one_alive = False

            for client, clientdesc in self._clients.items():
                if clientdesc.con is None:
                    clientdesc.con = client.connect()

                try:
                    next(clientdesc.con)
                except Exception as e:
                    PchumLog.error("client error %s" % str(e))
                    PchumLog.error(traceback.format_exc())
                    if clientdesc.autoreconnect:
                        clientdesc.con = None
                        if isinstance(clientdesc.autoreconnect, (int, float)):
                            clientdesc.autoreconnect -= 1
                        found_one_alive = True
                    else:
                        clientdesc.con = False
                else:
                    found_one_alive = True

            if not found_one_alive:
                PchumLog.info("nothing left alive... quiting")
                self.stop()

            now = time.time()
            timers = self._timers[:]
            self._timers = []
            for target_time, cb in timers:
                if now > target_time:
                    PchumLog.info("calling timer cb %s" % cb)
                    cb()
                else:
                    self._timers.append((target_time, cb))

            time.sleep(self.sleep_time)

    def stop(self):
        """stop the application"""
        self.running = False