from genericpath import isdir
import logging
import os
import subprocess
from typing import List, Optional
import re


from tempfile import NamedTemporaryFile

from telegram import Update
from telegram.ext import (
    Updater,
    CommandHandler,
    DictPersistence,
    CallbackContext,
    defaults,
)
from telegram.parsemode import ParseMode
from parser import SafeArgumentParser, safe_str


class KollagenBot:
    def __init__(
        self, tg_token: str, kollagen_path: str, base_dir: Optional[str]
    ) -> None:
        self.logger = logging.getLogger("kollagen")
        self.kollagen_path = kollagen_path
        self.base_dir = base_dir

        self._init_parser()

        self.updater = Updater(
            tg_token, persistence=DictPersistence(user_data_json="{}")
        )

        dispatcher = self.updater.dispatcher

        dispatcher.add_handler(CommandHandler("start", self.tg_start))
        dispatcher.add_handler(CommandHandler("help", self.tg_help))
        dispatcher.add_handler(CommandHandler("generate", self.tg_generate))
        dispatcher.add_handler(CommandHandler("g", self.tg_generate))
        dispatcher.add_handler(CommandHandler("regenerate", self.tg_regenerate))
        dispatcher.add_handler(CommandHandler("r", self.tg_regenerate))
        dispatcher.add_error_handler(self.tg_error)

    def _init_parser(self):
        parser = SafeArgumentParser(prog="/generate", add_help=False)
        parser.add_argument(
            "directories",
            metavar="dir",
            type=safe_str,
            nargs="*",
            default=[self.base_dir] if self.base_dir else [],
            help="Directories to process. By default, the entire directory is processed.",
        )
        parser.add_argument(
            "-m",
            dest="mode",
            metavar="mode",
            choices=self._get_modes(),
            nargs="?",
            const=True,
            help=f"Which collage mode to use. By default, one is chosen at random. When no value is specified, all modes are listed.",
        )
        parser.add_argument(
            "-n",
            dest="num_images",
            metavar="N",
            type=int,
            help=f"How many images to have in a collage. Random (2<n<5) by default.",
        )
        parser.add_argument(
            "-w",
            dest="width",
            type=int,
            default=640,
            help=f"Width of resulting output (in px). 640px by default.",
        )
        parser.add_argument(
            "-h",
            dest="height",
            type=int,
            default=640,
            help=f"Height of resulting output (in px). 640px by default.",
        )
        self.parser = parser

    def _get_modes(self):
        modes = subprocess.run(
            [self.kollagen_path, "-m"], check=True, capture_output=True
        )
        return modes.stdout.decode("utf-8").strip().split(", ")

    def tg_start(self, update: Update, context: CallbackContext):
        update.message.reply_text("Hi! Check out https://gitlab.com/tmladek/kollagen")
        self._process([], update)

    def tg_generate(self, update: Update, context: CallbackContext):
        cmd_line = update.message.text.split(" ")[1:]
        success = self._process(cmd_line, update)
        if success and context.user_data is not None:
            context.user_data["last_cmd_line"] = cmd_line

    def tg_regenerate(self, update: Update, context: CallbackContext):
        if context.user_data and context.user_data.get("last_cmd_line"):
            self._process(context.user_data["last_cmd_line"], update)
        else:
            update.message.reply_text("No previous command to regenerate!")

    def _process(self, cmd_line: List[str], update: Update):
        self.logger.info(
            f"Generating from {update.effective_user}, with cmd_line: `{cmd_line}`"
        )
        args = self.parser.parse_args(cmd_line)

        if args.mode is True:
            update.message.reply_text(
                f"Available modes: {', '.join(self._get_modes())}"
            )
            return False

        directories = []
        for dir in args.directories:
            for possible in [
                os.path.join(self.base_dir or "./", dir),
                os.path.join(self.base_dir or "./", dir.upper()),
            ]:
                if os.path.exists(possible):
                    directories.append(possible)
                    break
            else:
                raise FileNotFoundError(f'"{dir}" does not exist.')

        mode = ["-m", args.mode] if args.mode else []
        num_images = ["-n", str(args.num_images)] if args.num_images else []

        with NamedTemporaryFile(suffix=".png") as ntf:
            shell_cmd_line = [
                self.kollagen_path,
                "-r",
                *directories,
                "-w",
                str(args.width),
                "-h",
                str(args.height),
                *mode,
                *num_images,
                "-o",
                ntf.name,
            ]
            self.logger.debug(f"Running: " + str(shell_cmd_line))
            subprocess.run(
                shell_cmd_line,
                check=True,
                capture_output=True,
            )
            ntf.seek(0)
            update.message.reply_photo(ntf)
            return True

    def tg_help(self, update: Update, context: CallbackContext):
        update.message.reply_text(
            f"```{self.parser.format_help()}```", parse_mode=ParseMode.MARKDOWN
        )

    def tg_error(self, update: object, context: CallbackContext) -> None:
        self.logger.error(
            msg="Exception while handling an update:", exc_info=context.error
        )

        if isinstance(update, Update):
            if isinstance(context.error, subprocess.CalledProcessError):
                update.message.reply_text(
                    f"Something is fucked!\n{context.error.stderr.decode('utf-8')}"
                )
            else:
                update.message.reply_text(f"Something is fucked!\n{context.error}")

    def start_idle(self):
        self.updater.start_polling()
        self.updater.idle()


def main() -> None:
    logging.basicConfig(
        format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
        level=getattr(logging, os.getenv("LOG_LEVEL", "info").upper()),
    )

    tg_token = os.getenv("TG_TOKEN")
    if not tg_token:
        logging.error("TG_TOKEN is required.")
        exit(1)

    if env_kollagen_path := os.getenv("KOLLAGEN_PATH"):
        if os.path.exists(env_kollagen_path):
            kollagen_path = env_kollagen_path
        else:
            logging.error(f"kollagen not found! {env_kollagen_path} does not exist.")
            exit(1)
    else:
        which = subprocess.run(["which", "kollagen"], capture_output=True)
        try:
            which.check_returncode()
            kollagen_path = which.stdout.decode("utf-8").strip()
        except subprocess.CalledProcessError:
            logging.error(
                "kollagen not found! KOLLAGEN_PATH not specified and `kollagen` isn't in $PATH."
            )
            exit(1)

    bot = KollagenBot(tg_token, kollagen_path, os.getenv("BASE_DIR"))
    bot.start_idle()


if __name__ == "__main__":
    main()