#!/usr/bin/env python3
"""
Co-routines for handling various forms in Buckler.
"""
from passlib.hash import argon2

import tools


async def invite_user(request):
	"""Allows an admin to invite a new user."""
	if not request['session']['admin']:
		return {'main': "You do not have permission to do that."}

	data = await request.post()
	email = data.get('email')

	if not email:
		return {'invite_user': "This field is required."}
	# TODO: validate email address

	await tools.send_invite(request, email)
	return {}


async def change_user_perms(request):
	"""Allows an admin to change user permissions."""
	data = await request.post()
	pluses = []
	for key, value in data.items():
		if key == 'form_name':
			continue
		username, _, app_name = key.partition('-')
		pluses.append((username, app_name))

	async with request.app['pool'].acquire() as conn:
		apps = await conn.fetch(
			"SELECT id, name FROM app_info")
		users = {p[0] for p in pluses}
		minuses = []
		for user in users:
			for app in apps:
				minuses.append((user, app['name']))
		minuses = [m for m in minuses if m not in pluses]

		await conn.executemany(
			"INSERT INTO app_user (user_id, app_id) "
			"VALUES ((SELECT id FROM user_info WHERE username = $1), "
			"(SELECT id FROM app_info WHERE name = $2)) "
			"ON CONFLICT ON CONSTRAINT app_user_pkey DO NOTHING",
			pluses)
		await conn.executemany(
			"DELETE FROM app_user "
			"WHERE user_id = (SELECT id FROM user_info WHERE username = $1) "
			"AND app_id = (SELECT id FROM app_info WHERE name = $2)",
			minuses)
	return {}


async def new_app(request):
	"""Allows an admin to add a new app to be managed by Buckler."""
	data = await request.post()
	app_name = data.get('app_name')
	app_url = data.get('app_url')
	app_key = data.get('app_key')
	key_hash = argon2.hash(app_key)

	async with request.app['pool'].acquire() as conn:
		await conn.execute(
			"INSERT INTO app_info (name, url, key_hash) "
			"VALUES ($1, $2, $3)",
			app_name, app_url, key_hash)
	return {}


async def change_password(request):
	"""Allows a user to change their password."""
	errors = {}
	data = await request.post()
	current_pw = data.get('current_password')
	new_pw = data.get('new_password')
	verify_pw = data.get('verify_password')

	if not all((current_pw, new_pw, verify_pw)):
		errors['change_password'] = "All fields are required."
		return errors
	if not new_pw == verify_pw:
		errors['change_password'] = "Passwords do not match."
		return errors

	async with request.app['pool'].acquire() as conn:
		pw_hash = await conn.fetchrow(
			"SELECT password_hash FROM user_info WHERE id = $1",
			request['session']['id'])
		if not argon2.verify(current_pw, pw_hash['password_hash']):
			errors['change_password'] = "Invalid password."
			return errors
		h = argon2.hash(new_pw)
		await conn.execute(
			"UPDATE user_info SET password_hash = $1 WHERE id = $2",
			h, request['session']['id'])
	return errors


async def delete_key(request):
	"""Allows a user to delete a security key."""
	data = await request.post()
	async with request.app['pool'].acquire() as conn:
		for key, value in data.items():
			key_id = key.replace('fido-', '')
			if not key_id:
				continue
			try:
				key_id = int(key_id)
			except ValueError:
				continue
			if value != 'on':
				continue
			await conn.execute(
				"DELETE FROM user_credential "
				"WHERE id = $1 AND user_id = $2",
				key_id, request['session']['id'])
	return {}


async def delete_session(request):
	"""Allows a user to delete a session ."""
	data = await request.post()
	async with request.app['pool'].acquire() as conn:
		for key, value in data.items():
			session_id = key.replace('session-', '', 1)
			if not session_id:
				continue
			if value != 'on':
				continue
			await conn.execute(
				"DELETE FROM user_session "
				"WHERE id = $1 AND user_id = $2",
				session_id, request['session']['id'])
	return {}