//! Login redirect and return-to-page handling.
use gloo_timers::callback::Timeout;
use sycamore_router::navigate_replace;

const RETURN_TO_KEY: &str = "kca.login.return_to";

fn storage() -> Option<web_sys::Storage> {
    web_sys::window()?.session_storage().ok().flatten()
}

fn current_path() -> String {
    match web_sys::window() {
        Some(window) => {
            let location = window.location();
            let path = location.pathname().unwrap_or_default();
            let search = location.search().unwrap_or_default();
            format!("{path}{search}")
        }
        None => "/".to_string(),
    }
}

fn is_restorable(path: &str) -> bool {
    !path.is_empty()
        && path.starts_with('/')
        && !path.starts_with("/api/")
        && !path.starts_with("/auth/")
        && path != "/login"
}

pub fn redirect_to_login() {
    let path = current_path();
    if is_restorable(&path) {
        if let Some(storage) = storage() {
            let _ = storage.set_item(RETURN_TO_KEY, &path);
        }
    }
    Timeout::new(0, move || {
        if current_path() != "/login" {
            navigate_replace("/login");
        }
    })
    .forget();
}

pub fn saved_return_to() -> Option<String> {
    storage()?.get_item(RETURN_TO_KEY).ok().flatten()
}

pub fn clear_return_to() {
    if let Some(storage) = storage() {
        let _ = storage.remove_item(RETURN_TO_KEY);
    }
}

pub const LOGOUT_URL: &str = "/auth/logout";