"""XMPP bots for humans."""

import re
from argparse import ArgumentParser
from configparser import ConfigParser
from datetime import datetime as dt
from getpass import getpass
from imghdr import what
from inspect import cleandoc
from json import dumps, loads
from logging import DEBUG, INFO, basicConfig, getLogger
from os import environ, mkdir
from os.path import exists
from pathlib import Path
from sys import exit, stdout

from humanize import naturaldelta
from slixmpp import ClientXMPP


class SimpleDatabase(dict):
    """A simple database.

    It is a dictionary which saves to disk on all writes. It is optimised for
    ease of hacking and accessibility and not for performance or efficiency.
    """

    def __init__(self, filename, log, *args, **kwargs):
        """Initialise the object."""
        self.filename = Path(filename).absolute()
        self.log = log

        self._loads()
        self.update(*args, **kwargs)

    def _loads(self):
        """Load the database."""
        if not exists(self.filename):
            return

        try:
            with open(self.filename, "r") as handle:
                self.update(loads(handle.read()))
        except Exception as exception:
            message = f"Loading file storage failed: {exception}"
            self.log.error(message, exc_info=exception)
            exit(1)

    def _dumps(self):
        """Save the databse to disk."""
        try:
            with open(self.filename, "w") as handle:
                handle.write(dumps(self, indent=2, sort_keys=True))
        except Exception as exception:
            message = f"Saving file storage failed: {exception}"
            self.log.error(message, exc_info=exception)
            exit(1)

    def __setitem__(self, key, val):
        """Write data to the database."""
        super().__setitem__(key, val)
        self._dumps()

    def __delitem__(self, key):
        """Remove data from the database."""
        super().__delitem__(key)
        self._dumps()

    def update(self, *args, **kwargs):
        """Update the database."""
        for k, v in dict(*args, **kwargs).items():
            self[k] = v
        self._dumps()


class SimpleMessage:
    """A simple message interface."""

    def __init__(self, message, nick, log):
        """Initialise the object."""
        self.message = message
        self._nick = nick
        self.log = log

    @property
    def text(self):
        """The entire message text."""
        return self.message["body"]

    @property
    def content(self):
        """The content of the message received.

        This implementation aims to match and extract the content of the
        messages directed at bots in group chats. So, for example, when sending
        messages like so.

        echobot: hi
        echobot, hi
        echobot  hi

        The result produced by `message.content` will always be "hi". This
        makes it easier to work with various commands and avoid messy parsing
        logic in end-user implementations.
        """
        body = self.message["body"]

        try:
            match = fr"^{self._nick}.?(\s)"
            split = re.split(match, body)
            filtered = list(filter(None, split))
            return filtered[-1].strip()
        except Exception as exception:
            message = f"Couldn't parse {body}: {exception}"
            self.log.error(message, exc_info=exception)
            return None

    @property
    def sender(self):
        """The sender of the message."""
        return self.message["from"]

    @property
    def room(self):
        """The room from which the message originated."""
        return self.message["from"].bare

    @property
    def receiver(self):
        """The receiver of the message."""
        return self.message["to"]

    @property
    def type(self):
        """The type of the message."""
        return self.message["type"]

    @property
    def nick(self):
        """The nick of the message."""
        return self.message["mucnick"]

    @property
    def url(self):
        """The URL of a sent file."""
        return self.message["oob"]["url"]


class Config:
    """Bot file configuration."""

    def __init__(self, name, config):
        """Initialise the object."""
        self.name = name
        self.config = config
        self.section = config[self.name] if self.name in config else {}

    @property
    def account(self):
        """The account of the bot."""
        return self.section.get("account", None)

    @property
    def password(self):
        """The password of the bot account."""
        return self.section.get("password", None)

    @property
    def nick(self):
        """The nickname of the bot."""
        return self.section.get("nick", None)

    @property
    def avatar(self):
        """The avatar of the bot."""
        return self.section.get("avatar", None)

    @property
    def redis_url(self):
        """The Redis connection URL."""
        return self.section.get("redis_url", None)

    @property
    def rooms(self):
        """A list of rooms to automatically join."""
        rooms = self.section.get("rooms", None)

        if rooms is None:
            return None

        return [room.strip() for room in rooms.split(",")]

    @property
    def no_auto_join(self):
        """Disable auto-join when invited."""
        return self.section.get("no_auto_join", None)

    @property
    def port(self):
        """The port to serve from."""
        return self.section.get("port", None)

    @property
    def template(self):
        """The Jinja template to render."""
        return self.section.get("template", None)

    @property
    def serve(self):
        """Turn on the web server."""
        return self.section.get("serve", None)

    @property
    def storage(self):
        """Choice of storage back-end."""
        return self.section.get("storage", None)

    @property
    def output(self):
        """Path to the output directory."""
        return self.section.get("output", None)


class Bot(ClientXMPP):
    """XMPP bots for humans."""

    DIRECT_MESSAGE_TYPES = ("chat", "normal")
    GROUP_MESSAGE_TYPES = ("groupchat", "normal")

    def __init__(self):
        """Initialise the object."""
        self.name = type(self).__name__.lower()
        self.start = dt.now()
        self.CONFIG_FILE = f"{self.name}.conf"

        self.parse_arguments()
        self.setup_logging()
        self.read_config()
        self.init_bot()
        self.register_xmpp_event_handlers()
        self.register_xmpp_plugins()
        self.init_storage()
        self.init_data()
        self.run()

    def parse_arguments(self):
        """Parse command-line arguments."""
        self.parser = ArgumentParser(description="XMPP bots for humans")

        self.parser.add_argument(
            "-d",
            "--debug",
            help="enable verbose debug logs",
            action="store_const",
            dest="log_level",
            const=DEBUG,
            default=INFO,
        )
        self.parser.add_argument(
            "-a",
            "--account",
            dest="account",
            help="account for the bot account",
        )
        self.parser.add_argument(
            "-p",
            "--password",
            dest="password",
            help="password for the bot account",
        )
        self.parser.add_argument(
            "-n",
            "--nick",
            dest="nick",
            help="nickname for the bot account",
        )
        self.parser.add_argument(
            "-av", "--avatar", dest="avatar", help="avatar for the bot account"
        )
        self.parser.add_argument(
            "-ru",
            "--redis-url",
            dest="redis_url",
            help="redis storage connection URL",
        )
        self.parser.add_argument(
            "-r",
            "--rooms",
            dest="rooms",
            nargs="+",
            help="rooms to automatically join",
        )
        self.parser.add_argument(
            "-naj",
            "--no-auto-join",
            default=False,
            action="store_true",
            dest="no_auto_join",
            help="disable automatically joining rooms when invited",
        )
        self.parser.add_argument(
            "-pt",
            "--port",
            dest="port",
            help="the port to serve from",
        )
        self.parser.add_argument(
            "-t",
            "--template",
            dest="template",
            help="the template to render",
        )
        self.parser.add_argument(
            "-s",
            "--serve",
            default=False,
            action="store_true",
            dest="serve",
            help="turn on the web server",
        )
        self.parser.add_argument(
            "-st",
            "--storage",
            dest="storage",
            help="choice of storage back-end",
            choices=("file", "redis"),
        )
        self.parser.add_argument(
            "-o",
            "--output",
            dest="output",
            help="path to output directory",
        )

        self.args = self.parser.parse_args()

    def setup_logging(self):
        """Arrange logging for the bot."""
        basicConfig(
            level=self.args.log_level, format="%(levelname)-8s %(message)s"
        )
        self.log = getLogger(__name__)

    def read_config(self):
        """Read configuration for running bot."""
        config = ConfigParser()

        config_file_path = Path(self.CONFIG_FILE).absolute()

        if not exists(config_file_path) and stdout.isatty():
            self.log.info(f"Did not find {config_file_path}")
            self.generate_config_interactively()

        if exists(config_file_path):
            config.read(config_file_path)

        self.config = Config(self.name, config)

    def generate_config_interactively(self):
        """Generate bot configuration."""
        print(
            "Please enter the XMPP user account of your bot",
            "This is often referred to as the JID (Jabber ID)",
            "An example: echobot@vvvvvvaria.org",
            "See https://xmpp-servers.404.city to make an account",
            sep="\n",
        )
        account = input("Account: ")

        print("Please enter the password for your bot account")
        password = getpass("Password: ")

        print(
            "Please enter the nickname for your bot",
            "Others will use this name to refer to the bot",
            sep="\n",
        )
        nick = input("Nickname: ")

        print(
            "Please list the rooms you want your bot to automatically join",
            "An example: room1@muc.example.com, room2@muc.example.com",
            "If your bot only responds to direct messages, leave it blank",
            sep="\n",
        )
        rooms = input("Rooms: ")

        inputs = {
            "account": account,
            "password": password,
            "nick": nick,
        }

        if rooms:
            inputs["rooms"] = rooms

        self.log.debug(f"Received {inputs} as input")

        config = ConfigParser()
        config[self.name] = inputs

        with open(self.CONFIG_FILE, "w") as file_handle:
            config.write(file_handle)
            self.log.info(f"Generated {self.CONFIG_FILE}")

    def init_bot(self):
        """Initialise bot with connection details."""
        account = (
            self.args.account
            or self.config.account
            or environ.get("XBOT_ACCOUNT", None)
        )
        password = (
            self.args.password
            or self.config.password
            or environ.get("XBOT_PASSWORD", None)
        )
        nick = (
            self.args.nick or self.config.nick or environ.get("XBOT_NICK", None)
        )
        avatar = (
            self.args.avatar
            or self.config.avatar
            or environ.get("XBOT_AVATAR", None)
            or "avatar.png"
        )
        redis_url = (
            self.args.redis_url
            or self.config.redis_url
            or environ.get("XBOT_REDIS_URL", None)
        )
        rooms = (
            self.args.rooms
            or self.config.rooms
            or environ.get("XBOT_ROOMS", None)
        )
        no_auto_join = (
            self.args.no_auto_join
            or self.config.no_auto_join
            or environ.get("XBOT_NO_AUTO_JOIN", None)
        )
        port = (
            self.args.port
            or self.config.port
            or environ.get("XBOT_PORT", None)
            or "8080"
        )
        template = (
            self.args.template
            or self.config.template
            or environ.get("XBOT_TEMPLATE", None)
            or "index.html.j2"
        )
        serve_web = (
            self.args.serve
            or self.config.serve
            or environ.get("XBOT_SERVE", None)
        )
        storage = (
            self.args.storage
            or self.config.storage
            or environ.get("XBOT_STORAGE", None)
            or "file"
        )
        output = (
            self.args.output
            or self.config.output
            or environ.get("XBOT_OUTPUT", None)
            or "."
        )

        if not account:
            self.log.error("Unable to discover account")
            exit(1)
        if not password:
            self.log.error("Unable to discover password")
            exit(1)
        if not nick:
            self.log.error("Unable to discover nick")
            exit(1)

        ClientXMPP.__init__(self, account, password)

        self.account = account
        self.password = password
        self.nick = nick
        self.avatar = avatar
        self.redis_url = redis_url
        self.rooms = rooms
        self.no_auto_join = no_auto_join
        self.port = port
        self.serve_web = serve_web
        self.template = self.load_template(template)
        self.storage = storage
        self.output = Path(output).absolute()

    def load_template(self, template):
        """Load template via Jinja."""
        if not exists(Path(template).absolute()):
            return None

        try:
            from jinja2 import Environment, FileSystemLoader
        except ModuleNotFoundError as exception:
            self.log.error(
                "Missing required dependency jinja2, ",
                "have you tried `pip install xbotlib[web]`",
                exc_info=exception,
            )
            exit(1)

        try:
            loader = FileSystemLoader(searchpath="./")
            env = Environment(loader=loader)
            return env.get_template(template)
        except Exception as exception:
            message = f"Unable to load {template}"
            self.log.error(message, exc_info=exception)
            exit(1)

    def register_xmpp_event_handlers(self):
        """Register functions against specific XMPP event handlers."""
        self.add_event_handler("session_start", self.session_start)
        self.add_event_handler("groupchat_invite", self.group_invite)
        self.add_event_handler("message", self.direct_message)
        self.add_event_handler("groupchat_message", self.group_message)
        self.add_event_handler("message_error", self.error_message)

    def error_message(self, message):
        message = SimpleMessage(message, self.nick, self.log)
        self.log.error(f"Received error message: {message.text}")

    def direct_message(self, message):
        """Handle direct message events."""
        message = SimpleMessage(message, self.nick, self.log)

        if message.type not in self.DIRECT_MESSAGE_TYPES:
            return

        if message.text.startswith("@"):
            if self.command(message, to=message.sender):
                return

        if not hasattr(self, "direct"):
            self.log.info(f"Bot.direct not implemented for {self.nick}")
            return

        try:
            self.direct(message)
        except Exception as exception:
            message = f"Bot.direct threw exception: {exception}"
            self.log.error(message, exc_info=exception)

        if self.storage == "file":
            self.db._dumps()

    def session_start(self, message):
        """Handle session_start event."""
        self.send_presence()
        self.get_roster()
        self.publish_avatar()
        self.join_rooms()

    def publish_avatar(self):
        """Publish bot avatar."""
        abspath = Path(self.avatar).absolute()

        if not exists(abspath):
            self.log.info(f"No avatar discovered (tried '{abspath})'")
            return

        try:
            with open(abspath, "rb") as handle:
                contents = handle.read()
        except Exception as exception:
            message = f"Failed to load avatar: {exception}"
            self.log.error(message, exc_info=exception)
            return

        id = self.plugin["xep_0084"].generate_id(contents)
        info = {
            "id": id,
            "type": f"image/{what('', contents)}",
            "bytes": len(contents),
        }

        self.plugin["xep_0084"].publish_avatar(contents)
        self.plugin["xep_0084"].publish_avatar_metadata(items=[info])

    def join_rooms(self):
        """Automatically join rooms if specified."""
        if self.rooms is None:
            return

        for room in self.rooms:
            self.plugin["xep_0045"].join_muc(room, self.config.nick)
            self.log.info(f"Joining {room} automatically")

        for room in self._data["invited"]:
            self.plugin["xep_0045"].join_muc(room, self.config.nick)
            self.log.info(f"Re-joining {room} (invited previously)")

    def group_invite(self, message):
        """Accept invites to group chats."""
        room = message["from"]

        if self.no_auto_join:
            return self.log.info(f"Not joining {room} (disabled)")

        self.plugin["xep_0045"].join_muc(room, self.config.nick)
        self.log.info(f"Joining {room} as invited")

        if room not in self._data["invited"]:
            self._data["invited"].append(str(room))
            self._data._dumps()

    def group_message(self, message):
        """Handle group chat message events."""
        message = SimpleMessage(message, self.nick, self.log)

        if "@" in message.text:
            if self.meta(message, room=message.room):
                return

        miss = message.type not in self.GROUP_MESSAGE_TYPES
        loop = message.nick == self.nick
        other = self.nick not in message.text and not message.url

        if miss or other or loop:
            return

        if "@" in message.content:
            if self.command(message, room=message.room):
                return

        if not hasattr(self, "group"):
            self.log.info(f"Bot.group not implemented for {self.nick}")
            return

        try:
            self.group(message)
        except Exception as exception:
            message = f"Bot.group threw exception: {exception}"
            self.log.error(message, exc_info=exception)

        if self.storage == "file":
            self.db._dumps()

    def register_xmpp_plugins(self):
        """Register XMPP plugins that the bot supports."""
        self.register_plugin("xep_0030")  # Service Discovery
        self.register_plugin("xep_0045")  # Multi-User Chat
        self.register_plugin("xep_0199")  # XMPP Ping
        self.register_plugin("xep_0084")  # User Avatar
        self.register_plugin("xep_0066")  # Proces URIs (files, images)

        if not hasattr(self, "plugins"):
            self.log.info("No additional plugins loaded")
            return

        try:
            for plugin in self.plugins:
                self.register_plugin(plugin)
                self.log.info(f"Loaded {plugin}")
        except Exception as exception:
            message = f"Loading additional plugins failed: {exception}"
            self.log.error(message, exc_info=exception)

    def init_storage(self):
        """Initialise the storage back-end."""
        file_storage_path = f"{self.output}/{self.nick}.json"

        if self.storage == "file":
            try:
                self.db = SimpleDatabase(file_storage_path, self.log)
                self.log.info("Successfully loaded file storage")
            except Exception as exception:
                message = f"Failed to load {file_storage_path}: {exception}"
                self.log.error(message, exc_info=exception)
                exit(1)
        else:
            try:
                from redis import Redis

                self.db = Redis.from_url(self.redis_url, decode_responses=True)
                return self.log.info("Successfully connected to Redis storage")
            except ValueError as exception:
                message = f"Failed to connect to Redis storage: {exception}"
                self.log.error(message, exc_info=exception)
                exit(1)
            except ModuleNotFoundError as exception:
                self.log.error(
                    "Missing required dependency using Redis, ",
                    "have you tried `pip install xbotlib[redis]`",
                    exc_info=exception,
                )
                exit(1)

    def init_data(self):
        """Initialise internal data storage."""
        try:
            internal_dir = Path(".xbotlib").absolute()
            if not exists(internal_dir):
                mkdir(internal_dir)
                self.log.info("Successfully initialised internal directory")
        except Exception as exception:
            message = f"Failed to create {internal_dir}: {exception}"
            self.log.error(message, exc_info=exception)
            exit(1)

        try:
            internal_storage_path = f"{internal_dir}/data.json"
            self._data = SimpleDatabase(internal_storage_path, self.log)
            self.log.info("Successfully loaded internal storage")
        except Exception as exception:
            message = f"Failed to load {internal_storage_path}: {exception}"
            self.log.error(message, exc_info=exception)
            exit(1)

        if "invited" not in self._data:
            self._data["invited"] = []

    def run(self):
        """Run the bot."""
        self.connect()

        try:
            if self.serve_web:
                self.log.info("Running the web server")
                self.run_web_server()

            if hasattr(self, "setup"):
                try:
                    self.setup()
                    self.log.info("Finished running setup")
                except Exception as exception:
                    message = f"Bot.setup failed: {exception}"
                    self.log.error(message, exc_info=exception)

            self.process(forever=False)
        except (KeyboardInterrupt, RuntimeError):
            pass

    def run_web_server(self):
        """Run the web server."""
        try:
            from aiohttp.web import Application, get, run_app
        except ModuleNotFoundError as exception:
            self.log.error(
                "Missing required dependency aiohttp, ",
                "have you tried `pip install xbotlib[web]`",
                exc_info=exception,
            )
            exit(1)

        self.web = Application()

        if hasattr(self, "serve"):
            self.web.add_routes([get("/", self.serve)])
        else:
            self.web.add_routes([get("/", self.default_serve)])

        try:
            self.routes()
            self.log.info("Registered additional web routes")
        except Exception:
            pass

        self.log.info(f"Serving on http://0.0.0.0:{self.port}")
        run_app(self.web, port=self.port, print=None)

    async def default_serve(self, request):
        """Default placeholder text for HTML serving."""
        try:
            from aiohttp.web import Response
        except ModuleNotFoundError as exception:
            self.log.error(
                "Missing required dependency aiohttp, ",
                "have you tried `pip install xbotlib[web]`",
                exc_info=exception,
            )
            exit(1)

        return Response(text=f"{self.nick} is alive and well")

    def reply(self, text, to=None, room=None):
        """Send back a reply."""
        if to is None and room is None:
            self.log.error("`to` or `room` arguments required for `reply`")
            exit(1)

        if to is not None and room is not None:
            self.log.error("Cannot send to both `to` and `room` for `reply`")
            exit(1)

        kwargs = {"mbody": text}
        if to is not None:
            kwargs["mto"] = to
            kwargs["mtype"] = "chat"
        else:
            kwargs["mto"] = room
            kwargs["mtype"] = "groupchat"

        self.send_message(**kwargs)
        return True

    @property
    def uptime(self):
        """Time since the bot came up."""
        return naturaldelta(self.start - dt.now())

    def meta(self, message, **kwargs):
        """Handle meta command invocations."""
        if "@bots" in message.text:
            return self.reply("🖐️", **kwargs)

    def command(self, message, **kwargs):
        """Handle command invocations."""
        if "@uptime" in message.content:
            return self.reply(self.uptime, **kwargs)
        elif "@help" in message.content:
            try:
                return self.reply(cleandoc(self.help), **kwargs)
            except AttributeError:
                return self.reply("No help found 🤔️", **kwargs)

    def respond(self, response, content_type="text/html"):
        """Send this response back with the web server."""
        try:
            from aiohttp.web import Response
        except ModuleNotFoundError as exception:
            self.log.error(
                "Missing required dependency aiohttp, ",
                "have you tried `pip install xbotlib[web]`",
                exc_info=exception,
            )
            exit(1)

        return Response(text=response, content_type=content_type)