oak-gpui/crates/gpui/examples/learn/effect_stack.rs

//! Intended-usage sketch of the `gpui::effect_stack` widget.
//!
//! Builds a mock stack (Media → Transform → OCIO LUT → Output), hosts an
//! [`EffectStackView`], and logs every edit request it emits. The mock data
//! source simply applies requests in place and calls `cx.notify()`; a real
//! app (Oak) would route them through its engine and undo stack.
//!
//! NOTE: the widget implementation itself is still a skeleton (`todo!()`),
//! so this example compiles but does not render yet.

// The modules under demo are skeletons whose bodies are `todo!()` by design.
#![allow(clippy::todo)]

#[path = "../shared/prelude.rs"]
mod example_prelude;

use std::sync::Arc;

use example_prelude::init_example;
use gpui::effect_stack::{
    EffectCardKind, EffectData, EffectId, EffectStackDataSource, EffectStackEvent, EffectStackView,
};
use gpui::{
    App, Bounds, Context, Entity, Render, SharedString, Window, WindowBounds, WindowOptions, div,
    prelude::*, px, size,
};

// ---------------------------------------------------------------------------
// Mock model
// ---------------------------------------------------------------------------

struct MockEffect {
    id: EffectId,
    kind: EffectCardKind,
    title: String,
    subtitle: Option<String>,
    enabled: bool,
    expanded: bool,
    badge: Option<usize>,
}

impl EffectData for MockEffect {
    fn id(&self) -> EffectId {
        self.id
    }
    fn kind(&self) -> EffectCardKind {
        self.kind
    }
    fn title(&self) -> SharedString {
        self.title.clone().into()
    }
    fn subtitle(&self) -> Option<SharedString> {
        self.subtitle.clone().map(Into::into)
    }
    fn is_enabled(&self) -> bool {
        self.enabled
    }
    fn is_expanded(&self) -> bool {
        self.expanded
    }
    fn badge_count(&self) -> Option<usize> {
        self.badge
    }
}

/// The mock data source. In Oak this would be a view-model entity deriving
/// the ordered card list from the node-graph path of the selected clip.
struct MockStack {
    clip_name: String,
    effects: Vec<MockEffect>,
    /// Reserved for allocating ids to effects added at runtime.
    #[allow(dead_code)]
    next_id: u64,
}

impl MockStack {
    fn demo() -> Self {
        Self {
            clip_name: "A001_C002_0103.mov".to_string(),
            effects: vec![
                MockEffect {
                    id: EffectId(0),
                    kind: EffectCardKind::Source,
                    title: "Media".into(),
                    subtitle: Some("A001_C002_0103.mov".into()),
                    enabled: true,
                    expanded: false,
                    badge: None,
                },
                MockEffect {
                    id: EffectId(1),
                    kind: EffectCardKind::Effect,
                    title: "Transform".into(),
                    subtitle: Some("scale 100%, rotate 0°".into()),
                    enabled: true,
                    expanded: true,
                    badge: Some(2),
                },
                MockEffect {
                    id: EffectId(2),
                    kind: EffectCardKind::Effect,
                    title: "OCIO LUT".into(),
                    subtitle: Some("filmic_to_display.cube".into()),
                    enabled: true,
                    expanded: false,
                    badge: None,
                },
                MockEffect {
                    id: EffectId(3),
                    kind: EffectCardKind::Output,
                    title: "Output".into(),
                    subtitle: None,
                    enabled: true,
                    expanded: false,
                    badge: None,
                },
            ],
            next_id: 4,
        }
    }
}

impl EffectStackDataSource for MockStack {
    fn effects(&self) -> Vec<Arc<dyn EffectData>> {
        self.effects
            .iter()
            .map(|effect| {
                Arc::new(MockEffect {
                    id: effect.id,
                    kind: effect.kind,
                    title: effect.title.clone(),
                    subtitle: effect.subtitle.clone(),
                    enabled: effect.enabled,
                    expanded: effect.expanded,
                    badge: effect.badge,
                }) as Arc<dyn EffectData>
            })
            .collect()
    }

    fn target_label(&self) -> Option<SharedString> {
        Some(self.clip_name.clone().into())
    }
}

// ---------------------------------------------------------------------------
// Root view: hosts the stack and applies edit requests to the mock model.
// ---------------------------------------------------------------------------

/// Placeholder parameter view. A real app builds the effect's controls here
/// and calls [`EffectStackView::notify_parameter_changed`] after edits.
struct MockParams {
    effect: EffectId,
}

impl Render for MockParams {
    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
        div().child(format!("parameters for {} (mock)", self.effect))
    }
}

struct StackDemoRoot {
    data: Entity<MockStack>,
    stack: Entity<EffectStackView<MockStack>>,
}

impl StackDemoRoot {
    fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
        let data = cx.new(|_cx| MockStack::demo());

        let stack = cx.new(|cx| {
            EffectStackView::new(data.clone(), cx).params_renderer(|id, _window, cx| {
                // Real apps build the effect's parameter controls here. The
                // mock just shows a placeholder label.
                cx.new(|_cx| MockParams { effect: *id }).into()
            })
        });

        // The "edits are requests" loop: log each request, apply it to the
        // model (Oak: engine command + undo), then notify.
        cx.subscribe_in(&stack, window, {
            let data = data.clone();
            move |_root, _stack, event: &EffectStackEvent, _window, cx| {
                println!("[effect_stack] request: {event:?}");
                data.update(cx, |data, cx| {
                    match event {
                        EffectStackEvent::EnableToggled { effect, enabled } => {
                            if let Some(e) = data.effects.iter_mut().find(|e| e.id == *effect) {
                                e.enabled = *enabled;
                            }
                        }
                        EffectStackEvent::ExpansionToggled { effect, expanded } => {
                            if let Some(e) = data.effects.iter_mut().find(|e| e.id == *effect) {
                                e.expanded = *expanded;
                            }
                        }
                        EffectStackEvent::ReorderRequested { .. }
                        | EffectStackEvent::RemoveRequested(_)
                        | EffectStackEvent::AddRequested { .. }
                        | EffectStackEvent::ContextMenuRequested { .. }
                        | EffectStackEvent::ParameterChanged { .. } => {
                            todo!("apply {event:?} to the mock model (or engine, in a real app)")
                        }
                    }
                    cx.notify();
                });
            }
        })
        .detach();

        Self { data, stack }
    }
}

impl Render for StackDemoRoot {
    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        let _ = &self.data;
        let _ = cx;
        div()
            .size_full()
            .flex()
            .items_center()
            .justify_center()
            .child(self.stack.clone())
    }
}

fn main() {
    gpui_platform::application().run(|cx: &mut App| {
        init_example(cx, "Effect Stack");

        let bounds = Bounds::centered(None, size(px(420.0), px(640.0)), cx);
        cx.open_window(
            WindowOptions {
                window_bounds: Some(WindowBounds::Windowed(bounds)),
                ..Default::default()
            },
            |window, cx| cx.new(|cx| StackDemoRoot::new(window, cx)),
        )
        .unwrap();
    });
}