aiogram/examples/finite_state_machine.py

import asyncio
import logging
import sys
from os import getenv
from typing import Any

from aiogram import Bot, Dispatcher, F, Router, html
from aiogram.client.default import DefaultBotProperties
from aiogram.enums import ParseMode
from aiogram.filters import Command, CommandStart
from aiogram.fsm.context import FSMContext
from aiogram.fsm.state import State, StatesGroup
from aiogram.types import (
    KeyboardButton,
    Message,
    ReplyKeyboardMarkup,
    ReplyKeyboardRemove,
)

TOKEN = getenv("BOT_TOKEN")

form_router = Router()


class Form(StatesGroup):
    name = State()
    like_bots = State()
    language = State()


@form_router.message(CommandStart())
async def command_start(message: Message, state: FSMContext) -> None:
    await state.set_state(Form.name)
    await message.answer(
        "Hi there! What's your name?",
        reply_markup=ReplyKeyboardRemove(),
    )


@form_router.message(Command("cancel"))
@form_router.message(F.text.casefold() == "cancel")
async def cancel_handler(message: Message, state: FSMContext) -> None:
    """
    Allow user to cancel any action
    """
    current_state = await state.get_state()
    if current_state is None:
        return

    logging.info("Cancelling state %r", current_state)
    await state.clear()
    await message.answer(
        "Cancelled.",
        reply_markup=ReplyKeyboardRemove(),
    )


@form_router.message(Form.name)
async def process_name(message: Message, state: FSMContext) -> None:
    await state.update_data(name=message.text)
    await state.set_state(Form.like_bots)
    await message.answer(
        f"Nice to meet you, {html.quote(message.text)}!\nDid you like to write bots?",
        reply_markup=ReplyKeyboardMarkup(
            keyboard=[
                [
                    KeyboardButton(text="Yes"),
                    KeyboardButton(text="No"),
                ],
            ],
            resize_keyboard=True,
        ),
    )


@form_router.message(Form.like_bots, F.text.casefold() == "no")
async def process_dont_like_write_bots(message: Message, state: FSMContext) -> None:
    data = await state.get_data()
    await state.clear()
    await message.answer(
        "Not bad not terrible.\nSee you soon.",
        reply_markup=ReplyKeyboardRemove(),
    )
    await show_summary(message=message, data=data, positive=False)


@form_router.message(Form.like_bots, F.text.casefold() == "yes")
async def process_like_write_bots(message: Message, state: FSMContext) -> None:
    await state.set_state(Form.language)

    await message.reply(
        "Cool! I'm too!\nWhat programming language did you use for it?",
        reply_markup=ReplyKeyboardRemove(),
    )


@form_router.message(Form.like_bots)
async def process_unknown_write_bots(message: Message) -> None:
    await message.reply("I don't understand you :(")


@form_router.message(Form.language)
async def process_language(message: Message, state: FSMContext) -> None:
    data = await state.update_data(language=message.text)
    await state.clear()

    if message.text.casefold() == "python":
        await message.reply(
            "Python, you say? That's the language that makes my circuits light up! 😉",
        )

    await show_summary(message=message, data=data)


async def show_summary(message: Message, data: dict[str, Any], positive: bool = True) -> None:
    name = data["name"]
    language = data.get("language", "<something unexpected>")
    text = f"I'll keep in mind that, {html.quote(name)}, "
    text += (
        f"you like to write bots with {html.quote(language)}."
        if positive
        else "you don't like to write bots, so sad..."
    )
    await message.answer(text=text, reply_markup=ReplyKeyboardRemove())


async def main() -> None:
    # Initialize Bot instance with default bot properties which will be passed to all API calls
    bot = Bot(token=TOKEN, default=DefaultBotProperties(parse_mode=ParseMode.HTML))

    dp = Dispatcher()

    dp.include_router(form_router)

    # Start event dispatching
    await dp.start_polling(bot)


if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO, stream=sys.stdout)
    asyncio.run(main())