//! HUD bell for desktop notifications about the other players' moves.
use std::cell::Cell;
use std::rc::Rc;

use sycamore::prelude::*;
use wasm_bindgen_futures::spawn_local;

use crate::notify::{self, Permission};

/// Notification state shared by the game page and its table views: the
/// opt-in flag and the browser permission, both page-scoped so a
/// permission prompt that resolves after a table re-render still lands
/// somewhere safe. `alive` mirrors the game page's unmount flag.
#[derive(Clone)]
pub struct NotifyCtx {
    pub enabled: Signal<bool>,
    pub permission: Signal<Permission>,
    pub alive: Rc<Cell<bool>>,
}

/// The caption for the current (enabled, permission) state, and whether
/// the button is a dead end (the user must change browser settings).
fn face(enabled: bool, permission: Permission) -> (&'static str, bool) {
    match (enabled, permission) {
        (true, _) => ("🔔 Notifications on", false),
        (false, Permission::Granted | Permission::Default) => ("🔔 Notify me", false),
        (false, Permission::Denied | Permission::Unsupported) => {
            ("🔔 Notifications blocked", true)
        }
    }
}

/// The move-notification bell, rendered in the HUD of seated players.
///
/// The preference is global (all games) and persisted per device. The
/// permission prompt fires on the first click: browsers require a user
/// gesture, and asking on page load would be ignored.
pub fn notify_toggle(ctx: NotifyCtx) -> View {
    let NotifyCtx { enabled, permission, alive } = ctx;
    let on_click = move |_| {
        if enabled.get() {
            enabled.set(false);
            notify::set_enabled(false);
            return;
        }
        match permission.get() {
            Permission::Default => {
                let alive = alive.clone();
                spawn_local(async move {
                    let granted = notify::request_permission().await;
                    if !alive.get() {
                        return;
                    }
                    permission.set(granted);
                    if granted == Permission::Granted {
                        enabled.set(true);
                        notify::set_enabled(true);
                    }
                })
            }
            Permission::Granted => {
                enabled.set(true);
                notify::set_enabled(true);
            }
            Permission::Denied | Permission::Unsupported => {}
        }
    };

    view! {
        button(
            class="btn btn-outline-light",
            disabled=move || face(enabled.get(), permission.get()).1,
            title="Desktop notification when another player plays a card, \
                   while this tab is in the background",
            on:click=on_click,
        ) {
            (move || face(enabled.get(), permission.get()).0)
        }
    }
}