feat: Implement payment notification system and API structure

- Added notifications for successful payments in `api/core/notifications.py`.
- Created main API entry point in `api/main.py` with FastAPI integration.
- Established routing structure in `api/routes/__init__.py` and `api/routes/pally.py` for handling payment callbacks.
- Developed billing handlers in `bot/handlers/billing.py` and `bot/handlers/buy.py` for subscription management.
- Introduced state management for user interactions in `bot/states/`.
- Created user interface elements in `bot/keyboards/` for navigation and payment processing.
- Set up middleware for dependency injection in `bot/middlewares/di.py`.
- Added support for user commands and interactions in `bot/handlers/common.py` and `bot/handlers/support.py`.
- Implemented logging and error handling throughout the bot's functionality.
- Created entry point script for API server in `entrypoints/api.sh`.

api/core/deps.py

@@ -0,0 +1,18 @@
+from aiogram import Bot
+from fastapi import Request
+
+from db.session import async_session
+from schemas.di import APIDependenciesDTO
+
+
+def get_bot(request: Request) -> Bot:
+    return request.app.state.bot
+
+
+async def get_db():
+    async with async_session() as db:
+        yield db
+
+
+def get_deps(request: Request) -> APIDependenciesDTO:
+    return request.app.state.deps

api/core/notifications.py

@@ -0,0 +1,13 @@
+from aiogram import Bot
+from aiogram.types import InlineKeyboardButton, InlineKeyboardMarkup
+from aiogram.utils.keyboard import InlineKeyboardBuilder
+
+SUCCESSFUL_PAYMENT = "<b>💸 Зачислен платёж на {amount}₽</b>"
+
+close_kb: InlineKeyboardMarkup = InlineKeyboardBuilder(
+    [[InlineKeyboardButton(text="❌", callback_data="delete")]]
+).as_markup()
+
+
+async def successful_payment_notification(bot: Bot, user_id: int, amount: int):
+    await bot.send_message(user_id, SUCCESSFUL_PAYMENT.format(amount=amount), reply_markup=close_kb)

api/main.py

@@ -0,0 +1,52 @@
+from collections.abc import AsyncGenerator
+from contextlib import asynccontextmanager
+
+from aiogram import Bot
+from fastapi import FastAPI
+
+from api.routes import routers
+from config import settings
+from repositories.bills import BillsRepository
+from repositories.users import UserRepository
+from schemas.di import APIDependenciesDTO
+from services.billing_service import BillingService
+from services.user_service import UserService
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI) -> AsyncGenerator:
+    # Bot Init
+    bot = Bot(token=settings.bot_token)
+    app.state.bot = bot
+
+    user_repository = UserRepository()
+    user_service = UserService(user_repository)
+
+    bills_repository = BillsRepository()
+    bills_service = BillingService(
+        user_repository=user_repository, bills_repository=bills_repository
+    )
+
+    deps_dto = APIDependenciesDTO(
+        user_repository=user_repository,
+        user_service=user_service,
+        bills_repository=bills_repository,
+        billing_service=bills_service,
+    )
+    app.state.deps = deps_dto
+
+    for r in routers:
+        app.include_router(r)
+
+    yield  # App's lifespan
+
+    await bot.session.close()  # D IE!!!!!!!!
+
+
+app = FastAPI(
+    title="Malenia API",
+    description="Payment webhook handler and user balance management",
+    version="1.0.0",
+    lifespan=lifespan,
+    docs_url="",
+)

api/routes/__init__.py

@@ -0,0 +1,3 @@
+from .pally import router as pally_router
+
+routers = [pally_router]

api/routes/pally.py

@@ -0,0 +1,78 @@
+import hashlib
+import logging
+import math
+
+from aiogram import Bot
+from fastapi import Depends, Form, HTTPException
+from fastapi.routing import APIRouter
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from api.core.deps import get_bot, get_db, get_deps
+from api.core.notifications import successful_payment_notification
+from config import settings
+from misc.pally import BillStatus
+from schemas.di import APIDependenciesDTO
+
+router = APIRouter(prefix="/checkout/pally")
+
+logger = logging.getLogger(__name__)
+
+
+@router.post("/callback")
+async def pally_callback(
+    id: str = Form(...),
+    bill_id: str = Form(...),
+    status: str = Form(...),
+    req_amount: str = Form(...),
+    currency: str = Form(...),
+    order_id: str | None = Form(None),
+    signature: str = Form(...),
+    session: AsyncSession = Depends(get_db),
+    bot: Bot = Depends(get_bot),
+    deps: APIDependenciesDTO = Depends(get_deps),
+):
+    oid = order_id or ""
+    raw_string = f"{id}{status}{req_amount}{currency}{oid}{settings.pally_token}"
+    md5_hash = hashlib.md5(raw_string.encode("utf-8")).hexdigest()
+    expected_signature = hashlib.sha1(md5_hash.encode("utf-8")).hexdigest()
+
+    if signature != expected_signature:
+        logger.critical("Invalid signature for bill %s", bill_id)
+        raise HTTPException(403, detail="Invalid signature.")
+
+    if status != BillStatus.SUCCESS or not req_amount.isdigit():
+        logger.info("Bill %s skipped: status=%s, req_amount=%s", bill_id, status, req_amount)
+        return "OK"
+
+    logger.info("Received successfully paid bill %s", bill_id)
+
+    if not oid.isdigit():
+        logger.critical("Invalid order_id format for bill %s", bill_id)
+        return "OK"
+
+    bill = await deps.bills_repository.get_bill_by_id(session, int(oid))
+
+    if not bill:
+        logger.critical("Bill %s is not found in db", bill_id)
+        return "OK"
+
+    try:
+        amount = int(req_amount)
+
+        await deps.user_repository.increase_user_balance(session, bill.creator_id, amount=amount)
+        await successful_payment_notification(bot, bill.creator_id, amount)
+
+        referal = bill.user.referal_id
+        if referal is not None:
+            referal_amount = math.floor(amount * (settings.referal_bonus / 100))
+            await deps.user_repository.increase_user_balance(session, referal, referal_amount)
+            await successful_payment_notification(bot, referal, referal_amount)
+
+    except Exception:
+        logger.exception(
+            "Exception caught while processing balances for bill %s (Creator: %s)",
+            bill_id,
+            bill.creator_id,
+        )
+
+    return "OK"