import os

from pathlib import Path
from typing import Annotated
from argon2 import PasswordHasher
from argon2.exceptions import VerifyMismatchError
import configparser

from fastapi import FastAPI, Depends, HTTPException, status
from fastapi.security import HTTPBasic, HTTPBasicCredentials

app = FastAPI()

security = HTTPBasic()

PATH = '/etc/'
# PATH = './'
USB_DHCPD_FILENAME = 'dhcpcd-usb.conf'
ON_FILENAME = 'dhcpcd-usb-on.conf'
OFF_FILENAME = 'dhcpcd-usb-off.conf'


def get_username(credentials: Annotated[HTTPBasicCredentials, Depends(security)]):
    config = configparser.ConfigParser()
    config.read('./config.ini')

    if credentials.username != config['credentials']['username']:
        raise_unauthorized()

    try:
        PasswordHasher().verify(config['credentials']['password_hash'], credentials.password)
    except VerifyMismatchError:
        raise_unauthorized()

    return credentials.username


def raise_unauthorized():
    raise HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Incorrect username or password",
        headers={"WWW-Authenticate": "Basic"},
    )


@app.get('/status')
async def get_status(username: Annotated[str, Depends(get_username)]):
    return {"status": "usb" if is_usb_on() else "eth"}


@app.post('/status/{status}')
async def set_status(username: Annotated[str, Depends(get_username)], status):
    if status == 'usb' and not is_usb_on():
        switch_status(True)
    elif status == 'eth' and is_usb_on():
        switch_status(False)

    return {'status': 'usb' if is_usb_on() else 'eth'}


def is_usb_on():
    real_filename = os.path.basename(os.path.realpath(PATH + USB_DHCPD_FILENAME))
    return real_filename == ON_FILENAME


def switch_status(turn_on):
    if turn_on:
        # call usb modem api to turn it on
        update_usb_modem(turn_on)

    update_dhcp_conf(turn_on)

    if not turn_on:
        # call usb modem api to turn it off
        update_usb_modem(turn_on)


def update_dhcp_conf(turn_on):
    os.remove(PATH + USB_DHCPD_FILENAME)
    source_file = ON_FILENAME if turn_on else OFF_FILENAME
    os.symlink(PATH + source_file, PATH + USB_DHCPD_FILENAME)


def update_usb_modem(turn_on):
    pass


def initialize_app():
    script_dir = Path(__file__).parent.absolute()
    credentials_file_path = str(script_dir) + '/config.ini'
    if not os.path.isfile(credentials_file_path):
        username = input("Enter a username")
        password = input("Enter a password")

        config = configparser.ConfigParser()
        config['credentials'] = {
            'username': username,
            'password_hash': PasswordHasher().hash(password)
        }
        with open(credentials_file_path, 'w') as configfile:
            config.write(configfile)


if __name__ == "__main__":
    initialize_app()

    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)