from __future__ import annotations

import json
from enum import Enum
from pathlib import Path
from typing import Optional

from fastapi import Depends
from jose.constants import ALGORITHMS
from passlib.context import CryptContext
from pydantic import BaseModel, Field
from sqlalchemy import create_engine
from sqlalchemy.orm import Session, sessionmaker

from .db.models import ORMBaseModel

PRODUCTION_MODE = False

# to get a string like this run:
# openssl rand -hex 32
SECRET_KEY = "2f7875b0d2be8a76eba8077ab4d9f8b1c749e02647e9ac9e0f909c3acbfc9856"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

CRYPT_CONTEXT = CryptContext(schemes=["bcrypt"], deprecated="auto")

SESSION_LOCAL = None


class DBType(Enum):
    sqlite = "sqlite"
    mysql = "mysql"


class DBConfig(BaseModel):
    db_type: DBType = DBType.sqlite


class JWTConfig(BaseModel):
    secret: Optional[str] = None
    hash_algorithm: str = ALGORITHMS.HS256
    expiry_minutes: int = 30


class CryptoConfig(BaseModel):
    schemes: list[str] = ["bcrypt"]


class BaseConfig(BaseModel):
    db: DBConfig = Field(default_factory=DBConfig)
    jwt: JWTConfig = Field(default_factory=JWTConfig)
    crypto: CryptoConfig = Field(default_factory=CryptoConfig)


CONFIG_FILE = "tmp/config.json"


async def has_config() -> bool:
    return Path(CONFIG_FILE).is_file()


async def load_config() -> BaseConfig:
    try:
        with open(CONFIG_FILE, "r") as kv:
            return BaseConfig.parse_obj(json.load(kv))

    except FileNotFoundError:
        return BaseConfig()


async def connect_db(config: BaseConfig = Depends(load_config)) -> None:
    global SESSION_LOCAL

    engine = create_engine(
        "sqlite:///./tmp/vpn.db",
        connect_args={"check_same_thread": False},
    )
    SESSION_LOCAL = sessionmaker(
        autocommit=False, autoflush=False, bind=engine)

    ORMBaseModel.metadata.create_all(bind=engine)


async def get_db() -> Session:
    global SESSION_LOCAL

    db = SESSION_LOCAL()
    try:
        yield db
    finally:
        db.close()