const val REDIRECT_LOCATION = "redirectLocation"

@KtorExperimentalLocationsAPI
@Location("/login/{provider?}/{redirectLocation?}")
class Login(val provider: String = "google", val redirectLocation: String = "")

@KtorExperimentalLocationsAPI
fun Route.login(client: HttpClient) {
    authenticate(GOOGLE_OAUTH) {
        get<Login> { params ->
            val principal = call.authentication.principal<OAuthAccessTokenResponse>()
            if (principal != null) {
                val oauth = call.authentication.principal<OAuthAccessTokenResponse.OAuth2>()!!
                val response = client.get<UserInfo>("<https://www.googleapis.com/oauth2/v1/userinfo>") {
                    header(HttpHeaders.Authorization, "Bearer ${oauth.accessToken}")
                }
                call.sessions.set(Session(response, oauth.accessToken, oauth.refreshToken ?: ""))
                val to: Any = when(params.redirectLocation) {
                    AuthenticationRedirect.Reservations.toString() -> Reservations()
                    else -> Home()
                }
                call.redirect(to)
            } else {
                call.respond(status = HttpStatusCode.Unauthorized, "Unauthorized, no token issued")
            }
        }.param("error") {
            handle {
                call.respond(status = HttpStatusCode.Unauthorized, call.parameters.getAll("error").orEmpty().joinToString(", "))
            }
        }
    }
}

@Location

sealed class AuthenticationRedirect {
    object Home : AuthenticationRedirect() {
        override fun toString(): String = "home"
    }

    object Reservations : AuthenticationRedirect() {
        override fun toString(): String = "reservations"
    }
}

urlProvider = { p -> redirectUrl(Login(p.name, request.call.parameters[REDIRECT_LOCATION] ?: ""), false) }