use dioxus::prelude::*;
use dioxus_free_icons::icons::bs_icons::BsBook;
use dioxus_free_icons::icons::fa_solid_icons::{FaChartLine, FaCubes, FaGears};
use dioxus_free_icons::Icon;

use crate::components::DashboardCard;
use crate::Route;

/// Overview dashboard page rendered inside the `AppShell` layout.
///
/// Displays a welcome heading and a grid of quick-access cards
/// for the main GenAI platform tools.
#[component]
pub fn OverviewPage() -> Element {
    // Check authentication status on mount via a server function.
    let auth_check = use_resource(check_auth);
    let navigator = use_navigator();

    // Once the server responds, redirect unauthenticated users to /auth.
    use_effect(move || {
        if let Some(Ok(false)) = auth_check() {
            navigator.push(NavigationTarget::<Route>::External(
                "/auth?redirect_url=/".into(),
            ));
        }
    });

    match auth_check() {
        // Still waiting for the server to respond.
        None => rsx! {},
        // Not authenticated -- render nothing while the redirect fires.
        Some(Ok(false)) => rsx! {},
        // Authenticated -- render the overview dashboard.
        Some(Ok(true)) => rsx! {
            section { class: "overview-page",
                h1 { class: "overview-heading", "GenAI Dashboard" }
                div { class: "dashboard-grid",
                    DashboardCard {
                        title: "Documentation".to_string(),
                        description: "Guides & API Reference".to_string(),
                        href: "#".to_string(),
                        icon: rsx! {
                            Icon { icon: BsBook, width: 28, height: 28 }
                        },
                    }
                    DashboardCard {
                        title: "Langfuse".to_string(),
                        description: "Observability & Analytics".to_string(),
                        href: "#".to_string(),
                        icon: rsx! {
                            Icon { icon: FaChartLine, width: 28, height: 28 }
                        },
                    }
                    DashboardCard {
                        title: "Langchain".to_string(),
                        description: "Agent Framework".to_string(),
                        href: "#".to_string(),
                        icon: rsx! {
                            Icon { icon: FaGears, width: 28, height: 28 }
                        },
                    }
                    DashboardCard {
                        title: "Hugging Face".to_string(),
                        description: "Browse Models".to_string(),
                        href: "#".to_string(),
                        icon: rsx! {
                            Icon { icon: FaCubes, width: 28, height: 28 }
                        },
                    }
                }
            }
        },
        // Server error -- surface it so it is not silently swallowed.
        Some(Err(err)) => rsx! {
            p { "Error: {err}" }
        },
    }
}

/// Check whether the current request has an active logged-in session.
///
/// # Returns
///
/// `true` if the session contains a logged-in user, `false` otherwise.
///
/// # Errors
///
/// Returns `ServerFnError` if the session cannot be extracted from the request.
#[server]
async fn check_auth() -> Result<bool, ServerFnError> {
    use crate::infrastructure::{UserStateInner, LOGGED_IN_USER_SESS_KEY};
    use tower_sessions::Session;

    // Extract the tower_sessions::Session from the Axum request.
    let session: Session = FullstackContext::extract().await?;
    let user: Option<UserStateInner> = session
        .get(LOGGED_IN_USER_SESS_KEY)
        .await
        .map_err(|e| ServerFnError::new(format!("session read failed: {e}")))?;

    Ok(user.is_some())
}