//! Contextual one-time tips (Phase I of the 2026-07 UI redesign).
//!
//! Everything the first-run onboarding doesn't cover is invisible until
//! stumbled upon: hint cycling, the radial quick-action menu. These
//! tips fire **from the situation, not a tour** — each exactly once,
//! recorded in `Settings` like `shown_achievement_onboarding`:
//!
//! - **Stall tip** — after [`STALL_TIP_SECS`] with no board change in an
//!   active game, an info toast points at Hint. A player staring at a
//!   stuck board is the one moment the tip is welcome.
//! - **Radial tip** — once a game reaches [`RADIAL_TIP_MIN_MOVES`] moves
//!   (an engaged player) and the radial menu has never been opened, an
//!   info toast teaches the long-press / right-click gesture. Opening
//!   the radial organically marks the tip as unnecessary — it is never
//!   shown to someone who already knows.
//!
//! Tips render through the queued [`InfoToastEvent`] path, so they share
//! the unified toast stack and never interrupt play.

use bevy::prelude::*;

use solitaire_data::save_settings_to;

use crate::events::{InfoToastEvent, StateChangedEvent};
use crate::game_plugin::GameMutation;
use crate::pause_plugin::PausedResource;
use crate::platform::SHOW_KEYBOARD_ACCELERATORS;
use crate::radial_menu::RightClickRadialState;
use crate::resources::GameStateResource;
use crate::settings_plugin::{SettingsResource, SettingsStoragePath};
use crate::ui_modal::ModalScrim;

/// Seconds without any board change before the stall tip fires.
/// Long enough that normal thinking never triggers it; short enough to
/// reach a genuinely stuck player before they quit.
const STALL_TIP_SECS: f32 = 45.0;

/// Move count at which an engaged player earns the radial-menu teach.
const RADIAL_TIP_MIN_MOVES: u32 = 15;

/// Stall-tip copy per platform input vocabulary.
const STALL_TIP: &str = if SHOW_KEYBOARD_ACCELERATORS {
    "Stuck? Press H for a hint."
} else {
    "Stuck? Tap Hint in the bottom bar for a suggested move."
};

/// Radial-tip copy per platform input vocabulary.
const RADIAL_TIP: &str = if SHOW_KEYBOARD_ACCELERATORS {
    "Tip: right-click a card for quick actions."
} else {
    "Tip: long-press a card for quick actions."
};

/// Seconds of board inactivity, frozen while paused / a modal is open,
/// reset by every [`StateChangedEvent`].
#[derive(Resource, Debug, Default)]
pub struct StallClock(pub f32);

/// Registers the stall clock and the two tip triggers.
pub struct ContextualTipsPlugin;

impl Plugin for ContextualTipsPlugin {
    fn build(&self, app: &mut App) {
        app.init_resource::<StallClock>()
            .add_message::<InfoToastEvent>()
            .add_message::<StateChangedEvent>()
            .add_systems(
                Update,
                (
                    tick_stall_clock,
                    fire_stall_hint_tip
                        .in_set(crate::game_plugin::InfoToastWriters)
                        .ambiguous_with(crate::game_plugin::InfoToastWriters),
                    observe_radial_menu_use,
                    fire_radial_menu_tip
                        .in_set(crate::game_plugin::InfoToastWriters)
                        .ambiguous_with(crate::game_plugin::InfoToastWriters),
                )
                    .chain()
                    .after(GameMutation),
            );
    }
}

/// Advances the stall clock; resets on any board change; freezes while
/// paused, while a modal owns the screen, or when the game is over.
fn tick_stall_clock(
    time: Res<Time>,
    mut state_events: MessageReader<StateChangedEvent>,
    paused: Option<Res<PausedResource>>,
    scrims: Query<(), With<ModalScrim>>,
    game: Option<Res<GameStateResource>>,
    mut clock: ResMut<StallClock>,
) {
    if state_events.read().next().is_some() {
        clock.0 = 0.0;
        return;
    }
    if paused.is_some_and(|p| p.0)
        || !scrims.is_empty()
        || game.as_ref().is_none_or(|g| g.0.is_won())
    {
        // Frozen, not reset: backgrounding into a menu mid-stall
        // shouldn't restart the wait.
        return;
    }
    clock.0 += time.delta_secs();
}

/// Fires the one-shot stall tip once the clock passes the threshold in
/// a game the player has actually started (at least one move).
fn fire_stall_hint_tip(
    clock: Res<StallClock>,
    game: Option<Res<GameStateResource>>,
    mut settings: Option<ResMut<SettingsResource>>,
    storage_path: Option<Res<SettingsStoragePath>>,
    mut toast: MessageWriter<InfoToastEvent>,
) {
    let Some(s) = settings.as_mut() else { return };
    if s.0.shown_stall_hint_tip || clock.0 < STALL_TIP_SECS {
        return;
    }
    if game
        .as_ref()
        .is_none_or(|g| g.0.move_count() == 0 || g.0.is_won())
    {
        return;
    }
    toast.write(InfoToastEvent(STALL_TIP.to_string()));
    s.0.shown_stall_hint_tip = true;
    persist(storage_path.as_deref(), &s.0);
}

/// A player who opens the radial menu on their own doesn't need the
/// teach — mark the tip done silently.
fn observe_radial_menu_use(
    radial: Option<Res<RightClickRadialState>>,
    mut settings: Option<ResMut<SettingsResource>>,
    storage_path: Option<Res<SettingsStoragePath>>,
) {
    let Some(radial) = radial else { return };
    if !radial.is_active() {
        return;
    }
    let Some(s) = settings.as_mut() else { return };
    if s.0.shown_radial_menu_tip {
        return;
    }
    s.0.shown_radial_menu_tip = true;
    persist(storage_path.as_deref(), &s.0);
}

/// Fires the one-shot radial teach for an engaged player who has never
/// opened the menu themselves.
fn fire_radial_menu_tip(
    game: Option<Res<GameStateResource>>,
    mut settings: Option<ResMut<SettingsResource>>,
    storage_path: Option<Res<SettingsStoragePath>>,
    mut toast: MessageWriter<InfoToastEvent>,
) {
    let Some(s) = settings.as_mut() else { return };
    if s.0.shown_radial_menu_tip {
        return;
    }
    if game
        .as_ref()
        .is_none_or(|g| g.0.move_count() < RADIAL_TIP_MIN_MOVES || g.0.is_won())
    {
        return;
    }
    toast.write(InfoToastEvent(RADIAL_TIP.to_string()));
    s.0.shown_radial_menu_tip = true;
    persist(storage_path.as_deref(), &s.0);
}

fn persist(storage_path: Option<&SettingsStoragePath>, settings: &solitaire_data::Settings) {
    if let Some(p) = storage_path
        && let Some(path) = p.0.as_deref()
        && let Err(e) = save_settings_to(path, settings)
    {
        warn!("contextual tips: failed to persist tip flag: {e}");
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use bevy::ecs::message::Messages;
    use solitaire_core::{DrawStockConfig, game_state::GameState};
    use solitaire_data::Settings;

    fn app_with(settings: Settings, game: GameState) -> App {
        let mut app = App::new();
        app.add_plugins(MinimalPlugins)
            .add_plugins(ContextualTipsPlugin);
        app.insert_resource(SettingsResource(settings));
        app.insert_resource(GameStateResource(game));
        app.update();
        app
    }

    fn info_toast_count(app: &App) -> usize {
        let events = app.world().resource::<Messages<InfoToastEvent>>();
        let mut cursor = events.get_cursor();
        cursor.read(events).count()
    }

    fn started_game() -> GameState {
        let mut game = GameState::new(7, DrawStockConfig::DrawOne);
        game.draw().expect("draw from fresh deal");
        game
    }

    #[test]
    fn stall_tip_fires_once_past_threshold() {
        let mut app = app_with(Settings::default(), started_game());
        app.world_mut().resource_mut::<StallClock>().0 = STALL_TIP_SECS + 1.0;
        app.update();

        assert_eq!(info_toast_count(&app), 1, "stall tip must fire");
        assert!(
            app.world()
                .resource::<SettingsResource>()
                .0
                .shown_stall_hint_tip,
            "the tip flag must set so it never repeats"
        );

        app.world_mut().resource_mut::<StallClock>().0 = STALL_TIP_SECS + 30.0;
        app.world_mut()
            .resource_mut::<Messages<InfoToastEvent>>()
            .clear();
        app.update();
        assert_eq!(info_toast_count(&app), 0, "the tip is one-shot");
    }

    #[test]
    fn stall_tip_needs_a_started_unwon_game() {
        // Untouched deal: staring at the launch screen is not a stall.
        let mut app = app_with(
            Settings::default(),
            GameState::new(7, DrawStockConfig::DrawOne),
        );
        app.world_mut().resource_mut::<StallClock>().0 = STALL_TIP_SECS + 1.0;
        app.update();
        assert_eq!(info_toast_count(&app), 0, "no tip on an untouched deal");

        // Won game: nothing to hint at.
        let mut won = started_game();
        won.set_test_won(true);
        let mut app = app_with(Settings::default(), won);
        app.world_mut().resource_mut::<StallClock>().0 = STALL_TIP_SECS + 1.0;
        app.update();
        assert_eq!(info_toast_count(&app), 0, "no tip on a won game");
    }

    #[test]
    fn stall_clock_resets_on_state_change() {
        let mut app = app_with(Settings::default(), started_game());
        app.world_mut().resource_mut::<StallClock>().0 = 30.0;
        app.world_mut().write_message(StateChangedEvent);
        app.update();
        assert_eq!(
            app.world().resource::<StallClock>().0,
            0.0,
            "any board change must reset the stall clock"
        );
    }

    #[test]
    fn radial_tip_fires_for_engaged_player() {
        let mut game = started_game();
        game.set_test_move_count(RADIAL_TIP_MIN_MOVES);
        let mut app = app_with(Settings::default(), game);
        app.update();

        assert_eq!(
            info_toast_count(&app),
            1,
            "radial tip must fire at the move threshold"
        );
        assert!(
            app.world()
                .resource::<SettingsResource>()
                .0
                .shown_radial_menu_tip
        );
    }

    #[test]
    fn radial_tip_suppressed_after_organic_use() {
        let mut game = started_game();
        game.set_test_move_count(RADIAL_TIP_MIN_MOVES);
        let mut app = app_with(
            Settings {
                shown_radial_menu_tip: true,
                ..Settings::default()
            },
            game,
        );
        app.update();
        assert_eq!(
            info_toast_count(&app),
            0,
            "a player who used the radial menu never sees the teach"
        );
    }
}