cartography 0.11.1

//! Xilem / Masonry widget for cartography.
//!
//! # Architecture
//!
//! Cartography renders maps using its own `vello` 0.8 pipeline (via
//! [`crate::vello::ThreadedRenderer`]).  The Masonry/Xilem stack uses vello
//! 0.6 internally, so the two renderers cannot share a wgpu texture directly.
//!
//! The bridge follows the same strategy as the `egui` integration:
//! the cartography renderer sends rendered frames as raw RGBA CPU images over
//! a `crossbeam` channel; the Masonry widget uploads them into a
//! `peniko::Image` and paints it into the Masonry vello scene.
//!
//! # Usage (Xilem reactive layer)
//!
//! ```ignore
//! use cartography::xilem::{MapView, SharedRenderer, shared_renderer};
//!
//! // Build the renderer once (holds the background render thread).
//! let renderer = shared_renderer(map.clone(), style).unwrap();
//!
//! // Inside your app_logic closure return a MapView:
//! fn app_logic(state: &mut AppState) -> impl WidgetView<AppState> {
//!     MapView::new(state.renderer.clone())
//! }
//! ```
//!
//! # Usage (raw Masonry widget)
//!
//! ```ignore
//! use masonry::core::NewWidget;
//! let widget = cartography::xilem::MapWidget::new(renderer.clone());
//! ```

use std::sync::Arc;

use ccutils::{log::log_error, sync::ArcRwLock};
use crossbeam::channel::Receiver;
use masonry::{
  accesskit::{Node, Role},
  core::{
    AccessCtx, AccessEvent, BoxConstraints, ChildrenIds, EventCtx, LayoutCtx, PaintCtx,
    PointerButton, PointerButtonEvent, PointerEvent, PointerScrollEvent, PointerUpdate,
    PropertiesMut, PropertiesRef, RegisterCtx, ScrollDelta, TextEvent, Update, UpdateCtx, Widget,
  },
  kurbo::Size,
  peniko::ImageSampler,
  vello::Scene,
};
use xilem::{
  Blob, Pod, ViewCtx,
  core::{MessageContext, MessageResult, Mut, View, ViewMarker},
};

use crate::{Result, map, renderer, styling};

/// Map renderer for use with the Xilem / Masonry widget.
///
/// Owns a background render thread (via [`crate::vello::ThreadedRenderer`])
/// and a channel that delivers rendered CPU images to the widget.
///
/// Wrap in a [`SharedRenderer`] (`ArcRwLock<Renderer>`) so that the
/// Xilem app state and the widget can share the same renderer instance.
pub struct Renderer
{
  vello_renderer: crate::vello::ThreadedRenderer,
  cpu_image_sub: Receiver<crate::vello::CpuImage>,
  /// Latest rendered frame, ready to be painted.
  pub(crate) latest_image: Option<(Arc<Vec<u8>>, u32, u32)>,
}

impl Renderer
{
  /// Create a new `Renderer` for the given map and style.
  pub fn new<TFeature: map::Feature + 'static>(
    map: Arc<map::Map<TFeature>>,
    style: styling::Style<TFeature>,
  ) -> Result<Self>
  {
    let (device, queue) = crate::vello::ThreadedRenderer::new_device()?;
    let mut vello_renderer = crate::vello::ThreadedRenderer::new_thread(device, queue, map, style)?;
    let cpu_image_sub = vello_renderer.subscribe_to_cpu_image()?;
    Ok(Self {
      vello_renderer,
      cpu_image_sub,
      latest_image: None,
    })
  }

  /// Trigger a re-render (e.g. after changing layer visibility or styles).
  pub fn update(&mut self) -> Result<()>
  {
    self.vello_renderer.update()
  }

  /// Add a secondary map/style rendered according to `z_order`.
  ///
  /// `z_order = 0` is the primary layer. Higher values render on top.
  pub fn add_overlay<TFeature: map::Feature + 'static>(
    &mut self,
    map: Arc<map::Map<TFeature>>,
    style: styling::Style<TFeature>,
    z_order: i32,
  ) -> Result<()>
  {
    self.vello_renderer.add_overlay(map, style, z_order)
  }

  /// Trigger a re-render after mutating an overlay map's contents.
  pub fn update_overlay(&mut self, z_order: i32) -> Result<()>
  {
    self.vello_renderer.update_overlay(z_order)
  }

  /// Apply a function to the [`renderer::ViewController`] (pan / zoom).
  pub fn update_view_controller(&mut self, u: impl Fn(&mut renderer::ViewController))
  {
    self.vello_renderer.update_view_controller(u)
  }

  /// Read from the [`renderer::ViewController`] without mutating it.
  pub fn use_view_controller<T>(&self, u: impl FnOnce(&renderer::ViewController) -> T) -> T
  {
    self.vello_renderer.use_view_controller(u)
  }

  /// Poll the render channel for a new CPU image.
  /// Returns `true` if a new image was received and stored.
  pub(crate) fn poll_image(&mut self) -> bool
  {
    if let Ok(cpu_image) = self.cpu_image_sub.try_recv()
    {
      self.latest_image = Some((Arc::new(cpu_image.data), cpu_image.width, cpu_image.height));
      true
    }
    else
    {
      false
    }
  }

  /// Resize the render surface and trigger a re-render.
  pub(crate) fn resize(&mut self, width: u32, height: u32) -> Result<()>
  {
    self
      .vello_renderer
      .resize(width, height, Option::<fn(&crate::vello::Texture)>::None)?;
    self.vello_renderer.update_view_controller(|vc| {
      vc.set_view(geo::Rect::new(
        geo::Coord { x: 0.0, y: 0.0 },
        geo::Coord {
          x: width as f64,
          y: height as f64,
        },
      ));
    });
    self.update()
  }
}

/// Type alias for a thread-safe, shared [`Renderer`].
pub type SharedRenderer = ArcRwLock<Renderer>;

/// Convenience constructor for a [`SharedRenderer`].
///
/// # Errors
/// Returns an error if the wgpu device/queue cannot be created.
pub fn shared_renderer<TFeature: map::Feature + 'static>(
  map: Arc<map::Map<TFeature>>,
  style: styling::Style<TFeature>,
) -> Result<SharedRenderer>
{
  Ok(ArcRwLock::new(Renderer::new(map, style)?))
}

/// Convenience constructor for a renderer with one overlay layer.
pub fn shared_renderer_with_overlays<TBase, TOverlay>(
  base_map: Arc<map::Map<TBase>>,
  base_style: styling::Style<TBase>,
  overlay_map: Arc<map::Map<TOverlay>>,
  overlay_style: styling::Style<TOverlay>,
) -> Result<SharedRenderer>
where
  TBase: map::Feature + 'static,
  TOverlay: map::Feature + 'static,
{
  let mut renderer = Renderer::new(base_map, base_style)?;
  renderer.add_overlay(overlay_map, overlay_style, 10)?;
  Ok(ArcRwLock::new(renderer))
}

/// A Masonry [`Widget`] that displays a cartography map.
///
/// - **Drag** (primary button) to pan.
/// - **Scroll** (wheel or trackpad) to zoom.
///
/// The widget requests animation frames continuously so new rendered frames
/// are displayed without any explicit invalidation from user code.
pub struct MapWidget
{
  renderer: SharedRenderer,
  /// Ceiling size from the last layout pass, used to detect resize.
  rendering_size: (u32, u32),
  /// Size from the last layout pass, used to detect resize.
  layout_size: Size,
  /// Widget-local position of the last pointer event during a drag.
  last_drag_pos: Option<masonry::kurbo::Point>,
}

/// Actions emitted by [`MapWidget`].
///
/// Currently uninhabited — the widget handles pan/zoom internally and does
/// not emit actions to the application.
#[derive(Debug)]
pub enum MapAction {}

impl MapWidget
{
  /// Create a new `MapWidget` backed by `renderer`.
  pub fn new(renderer: SharedRenderer) -> Self
  {
    Self {
      renderer,
      rendering_size: (0, 0),
      layout_size: Size::ZERO,
      last_drag_pos: None,
    }
  }
}

impl Widget for MapWidget
{
  type Action = MapAction;

  fn on_pointer_event(
    &mut self,
    ctx: &mut EventCtx<'_>,
    _props: &mut PropertiesMut<'_>,
    event: &PointerEvent,
  )
  {
    match event
    {
      PointerEvent::Down(PointerButtonEvent {
        button: Some(PointerButton::Primary),
        state,
        ..
      }) =>
      {
        self.last_drag_pos = Some(ctx.local_position(state.position));
        ctx.capture_pointer();
      }

      PointerEvent::Up(PointerButtonEvent {
        button: Some(PointerButton::Primary),
        ..
      }) =>
      {
        self.last_drag_pos = None;
      }

      PointerEvent::Move(PointerUpdate { current: state, .. }) =>
      {
        if let Some(last) = self.last_drag_pos
        {
          let pos = ctx.local_position(state.position);
          let dx = pos.x - last.x;
          let dy = pos.y - last.y;
          self.last_drag_pos = Some(pos);

          let mut r = self.renderer.write().unwrap();
          r.update_view_controller(|vc| {
            let m = vc.motion_view_to_coord(&(dx, dy).into());
            vc.pan(-m.x, -m.y);
          });
          log_error!(r.update(), "While panning map");
          ctx.request_render();
        }
      }

      PointerEvent::Scroll(PointerScrollEvent { delta, .. }) =>
      {
        let dy = match delta
        {
          ScrollDelta::LineDelta(_, y) => *y as f64,
          ScrollDelta::PixelDelta(p) => p.y,
          ScrollDelta::PageDelta(_, y) => *y as f64,
        };
        let factor = if dy < 0.0 { 0.75 } else { 1.0 / 0.75 };
        let mut r = self.renderer.write().unwrap();
        r.update_view_controller(|vc| vc.zoom(factor));
        log_error!(r.update(), "While zooming map");
        ctx.request_render();
      }

      _ =>
      {}
    }
  }

  fn on_text_event(
    &mut self,
    _ctx: &mut EventCtx<'_>,
    _props: &mut PropertiesMut<'_>,
    _event: &TextEvent,
  )
  {
  }

  fn on_access_event(
    &mut self,
    _ctx: &mut EventCtx<'_>,
    _props: &mut PropertiesMut<'_>,
    _event: &AccessEvent,
  )
  {
  }

  fn on_anim_frame(
    &mut self,
    ctx: &mut UpdateCtx<'_>,
    _props: &mut PropertiesMut<'_>,
    _interval: u64,
  )
  {
    let new = self.renderer.write().unwrap().poll_image();
    if new
    {
      ctx.request_render();
    }
    ctx.request_anim_frame();
  }

  fn update(&mut self, _ctx: &mut UpdateCtx<'_>, _props: &mut PropertiesMut<'_>, _event: &Update) {}

  fn layout(
    &mut self,
    _ctx: &mut LayoutCtx<'_>,
    _props: &mut PropertiesMut<'_>,
    bc: &BoxConstraints,
  ) -> Size
  {
    let size = bc.max();
    let size = if size.width.is_infinite() || size.height.is_infinite()
    {
      bc.constrain(Size::new(512.0, 512.0))
    }
    else
    {
      size
    };
    let rsize = (size.width.ceil() as u32, size.height.ceil() as u32);

    if rsize != self.rendering_size && rsize.0 > 0 && rsize.1 > 0
    {
      self.rendering_size = rsize;
      log_error!(
        self.renderer.write().unwrap().resize(rsize.0, rsize.1),
        "While resizing map"
      );
    }
    self.layout_size = size;

    size
  }

  fn paint(&mut self, _ctx: &mut PaintCtx<'_>, _props: &PropertiesRef<'_>, scene: &mut Scene)
  {
    use masonry::kurbo::{Affine, Rect};
    use masonry::vello::peniko::{ImageBrush, ImageData, ImageFormat};

    let Some((image_data, image_width, image_height)) =
      self.renderer.read().unwrap().latest_image.clone()
    else
    {
      return;
    };

    if self.rendering_size.0 == 0 || self.rendering_size.1 == 0
    {
      return;
    }

    let image = ImageData {
      data: Blob::new(image_data),
      format: ImageFormat::Rgba8,
      width: image_width,
      height: image_height,
      alpha_type: masonry::peniko::ImageAlphaType::Alpha,
    };

    let brush = ImageBrush {
      image,
      sampler: ImageSampler::new(),
    };

    scene.fill(
      masonry::vello::peniko::Fill::NonZero,
      Affine::IDENTITY,
      &brush,
      None,
      &Rect::new(0.0, 0.0, self.layout_size.width, self.layout_size.height),
    );
  }

  fn accessibility_role(&self) -> Role
  {
    Role::Image
  }

  fn accessibility(
    &mut self,
    _ctx: &mut AccessCtx<'_>,
    _props: &PropertiesRef<'_>,
    _node: &mut Node,
  )
  {
  }

  fn register_children(&mut self, _ctx: &mut RegisterCtx<'_>) {}

  fn children_ids(&self) -> ChildrenIds
  {
    ChildrenIds::new()
  }
}

/// A Xilem Widget that displays a cartography map.
///
/// Return this from your `app_logic` closure each frame.  Because the renderer
/// is shared via `Arc`, the widget sees new frames automatically without any
/// rebuild work.
///
/// # Example
///
/// ```ignore
/// fn app_logic(state: &mut AppState) -> impl WidgetView<AppState> {
///     MapView::new(state.renderer.clone())
/// }
/// ```
pub struct MapView
{
  renderer: SharedRenderer,
}

impl MapView
{
  /// Create a `MapView` backed by `renderer`.
  pub fn new(renderer: SharedRenderer) -> Self
  {
    Self { renderer }
  }
}

impl ViewMarker for MapView {}

impl<State: 'static, Action: 'static> View<State, Action, ViewCtx> for MapView
{
  type Element = Pod<MapWidget>;
  type ViewState = ();

  fn build(&self, ctx: &mut ViewCtx, _app_state: &mut State) -> (Self::Element, Self::ViewState)
  {
    let pod = ctx.create_pod(MapWidget::new(self.renderer.clone()));
    (pod, ())
  }

  fn rebuild(
    &self,
    _prev: &Self,
    _view_state: &mut Self::ViewState,
    _ctx: &mut ViewCtx,
    _element: Mut<'_, Self::Element>,
    _app_state: &mut State,
  )
  {
  }

  fn teardown(
    &self,
    _view_state: &mut Self::ViewState,
    ctx: &mut ViewCtx,
    element: Mut<'_, Self::Element>,
  )
  {
    ctx.teardown_leaf(element);
  }

  fn message(
    &self,
    _view_state: &mut Self::ViewState,
    _message: &mut MessageContext,
    _element: Mut<'_, Self::Element>,
    _app_state: &mut State,
  ) -> MessageResult<Action>
  {
    MessageResult::Stale
  }
}