#!/usr/bin/env python3
"""
Session interface middlewares to integrate the fastapi app with Buckler.
"""
import json
from datetime import datetime

import httpx
from fastapi import FastAPI, Request
from fastapi.responses import RedirectResponse
from starlette.middleware.base import BaseHTTPMiddleware

import config


class BucklerSessionMiddleware(BaseHTTPMiddleware):
	"""
	Verifies the user with the configured Buckler app and retrieves any
	session data they may have. Redirects them to the login page otherwise.
	"""
	def __init__(self, app):
		super().__init__(app)

	async def dispatch(self, request: Request, call_next):
		user_id = request.cookies.get('userid', '')
		user_sid = request.cookies.get('session', '')

		url = config.buckler['url'] + '/get_session'
		params = {
			'app_id': config.buckler['app_id'],
			'app_key': config.buckler['app_key'],
			'userid': user_id,
			'session': user_sid }

		async with httpx.AsyncClient() as client:
			resp = await client.get(url, params=params)
			data = resp.json()

		if data.get('error'): # user not logged in
			response = RedirectResponse(config.buckler['login_url'])
			response.set_cookie('redirect', config.server_homepage)
			return response

		request.state.session = data.get('session_data')
		request.state.meta = data.get('meta')
		response = await call_next(request)

		if request.state.session != data['session_data']: # session data modified
			url = config.buckler['url'] + '/set_session'
			data = json.dumps(request.state.session)
			async with httpx.AsyncClient() as client:
				await client.post(url, params=params, data=data)

		last_used = datetime.fromisoformat(request.state.meta['last_used'])
		now = datetime.now(last_used.tzinfo)
		delta = now - last_used
		if delta.seconds > 600:
			response.set_cookie(
				'userid',
				user_id,
				domain=config.server_domain,
				max_age=30*24*60*60,
				secure=True,
				httponly=True,
				samesite='strict')
			response.set_cookie(
				'session',
				user_sid,
				domain=config.server_domain,
				max_age=30*24*60*60,
				secure=True,
				httponly=True,
				samesite='strict')
		return response