import { type ActionFunctionArgs, json, type LoaderFunctionArgs, redirect } from '@remix-run/node'
import { Form, useActionData, useLoaderData } from '@remix-run/react'
import { useMemo } from 'react'

import Button from '~/components/Button'
import Card from '~/components/Card'
import Code from '~/components/Code'
import TextField from '~/components/TextField'
import { type Key } from '~/types'
import { getContext } from '~/utils/config'
import { pull } from '~/utils/headscale'
import { startOidc } from '~/utils/oidc'
import { commitSession, getSession } from '~/utils/sessions'

export async function loader({ request }: LoaderFunctionArgs) {
	const session = await getSession(request.headers.get('Cookie'))
	if (session.has('hsApiKey')) {
		return redirect('/machines', {
			headers: {
				// eslint-disable-next-line @typescript-eslint/naming-convention
				'Set-Cookie': await commitSession(session),
			},
		})
	}

	const context = await getContext()
	const issuer = context.oidcConfig?.issuer
	const id = context.oidcConfig?.client
	const secret = context.oidcConfig?.secret
	const normal = process.env.DISABLE_API_KEY_LOGIN

	if (issuer && (!id || !secret)) {
		throw new Error('An invalid OIDC configuration was provided')
	}

	const data = {
		oidc: issuer,
		apiKey: normal !== 'true',
	}

	if (!data.oidc && !data.apiKey) {
		throw new Error('No authentication method is enabled')
	}

	if (data.oidc && !data.apiKey) {
		// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
		return startOidc(data.oidc, id!, request)
	}

	return data
}

export async function action({ request }: ActionFunctionArgs) {
	const formData = await request.formData()
	const oidcStart = formData.get('oidc-start')

	if (oidcStart) {
		const context = await getContext()
		const issuer = context.oidcConfig?.issuer
		const id = context.oidcConfig?.client

		// We know it exists here because this action only happens on OIDC
		// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
		return startOidc(issuer!, id!, request)
	}

	const apiKey = String(formData.get('api-key'))
	const session = await getSession(request.headers.get('Cookie'))

	// Test the API key
	try {
		const apiKeys = await pull<{ apiKeys: Key[] }>('v1/apikey', apiKey)
		const key = apiKeys.apiKeys.find(k => apiKey.startsWith(k.prefix))
		if (!key) {
			throw new Error('Invalid API key')
		}

		const expiry = new Date(key.expiration)
		const expiresIn = expiry.getTime() - Date.now()
		const expiresDays = Math.round(expiresIn / 1000 / 60 / 60 / 24)

		session.set('hsApiKey', apiKey)
		session.set('user', {
			name: key.prefix,
			email: `${expiresDays.toString()} days`,
		})

		return redirect('/machines', {
			headers: {
				// eslint-disable-next-line @typescript-eslint/naming-convention
				'Set-Cookie': await commitSession(session, {
					maxAge: expiresIn,
				}),
			},
		})
	} catch (error) {
		console.error(error)
		return json({
			error: 'Invalid API key',
		})
	}
}

export default function Page() {
	const data = useLoaderData<typeof loader>()
	const actionData = useActionData<typeof action>()
	const showOr = useMemo(() => data.oidc && data.apiKey, [data])

	return (
		<div className="flex min-h-screen items-center justify-center">
			<Card className="max-w-sm m-4 sm:m-0 rounded-2xl">
				<Card.Title>
					Welcome to Headplane
				</Card.Title>
				{data.apiKey
					? (
						<Form method="post">
							<Card.Text className="mb-8 text-sm">
								Enter an API key to authenticate with Headplane. You can generate
								one by running
								{' '}
								<Code>
									headscale apikeys create
								</Code>
								{' '}
								in your terminal.
							</Card.Text>

							{actionData?.error
								? (
									<p className="text-red-500 text-sm mb-2">{actionData.error}</p>
									)
								: undefined}
							<TextField
								isRequired
								label="API Key"
								name="api-key"
								placeholder="API Key"
							/>
							<Button
								className="w-full mt-2.5"
								variant="heavy"
								type="submit"
							>
								Login
							</Button>
						</Form>
						)
					: undefined}
				{showOr
					? (
						<div className="flex items-center gap-x-1.5 py-1">
							<hr className="flex-1 border-ui-300 dark:border-ui-800" />
							<span className="text-gray-500 text-sm">or</span>
							<hr className="flex-1 border-ui-300 dark:border-ui-800" />
						</div>
						)
					: undefined}
				{data.oidc
					? (
						<Form method="POST">
							<input type="hidden" name="oidc-start" value="true" />
							<Button
								className="w-full"
								variant="heavy"
								type="submit"
							>
								Login with SSO
							</Button>
						</Form>
						)
					: undefined}
			</Card>
		</div>
	)
}