uzor-window-desktop 1.3.1

//! [`WinitWindowProvider`] — implements [`uzor::layout::window::WindowProvider`]
//! over an [`Arc<winit::window::Window>`].
//!
//! # Ownership model
//!
//! `WinitWindowProvider` does NOT own the winit `EventLoop`. The caller creates
//! the event loop, creates a window on `Resumed`, wraps it with
//! `WinitWindowProvider::new`, and feeds `WindowEvent`s via
//! [`push_winit_event`](WinitWindowProvider::push_winit_event) from inside the
//! `ApplicationHandler` callback.
//!
//! ```rust,ignore
//! // Inside ApplicationHandler::window_event:
//! provider.push_winit_event(&event);
//! if matches!(event, WindowEvent::CloseRequested) {
//!     provider.mark_close();
//! }
//! ```

use std::sync::Arc;

use winit::event::WindowEvent;
use winit::raw_window_handle::{RawDisplayHandle, RawWindowHandle};
use winit::window::Window;

use uzor::core::types::Rect;
use uzor::platform::PlatformEvent;

use uzor::layout::window::{
    CornerStyle, RawHandle, ResizeDirection, RgbaIcon, SoftwarePresenter,
    WindowDecorations, WindowProvider,
};

// ─── SendSyncHandlePair ───────────────────────────────────────────────────────

/// Newtype wrapping `(RawWindowHandle, RawDisplayHandle)` with manual `Send +
/// Sync` impls.
///
/// `RawWindowHandle` is not automatically `Send + Sync` because some platform
/// variants (e.g. `UiKitWindowHandle`) contain `NonNull<c_void>`.
/// On all supported desktop platforms (Win32, macOS, X11/Wayland) raw handles
/// are safe to copy between threads when the underlying OS object remains alive.
///
/// # Safety
///
/// The caller must ensure the OS window / display outlive any thread that reads
/// these handles.
pub struct SendSyncHandlePair(pub RawWindowHandle, pub RawDisplayHandle);

// SAFETY: see doc comment above.
unsafe impl Send for SendSyncHandlePair {}
unsafe impl Sync for SendSyncHandlePair {}

/// Desktop window provider backed by a winit [`Window`].
///
/// Implements [`WindowProvider`] so it can be passed to
/// `uzor_framework::AppBuilder::window(Box::new(provider))`.
///
/// Create one per window after the winit event loop has been started
/// (i.e. inside `ApplicationHandler::resumed`).
pub struct WinitWindowProvider {
    window: Arc<Window>,
    pending_events: Vec<PlatformEvent>,
    should_close: bool,
}

impl WinitWindowProvider {
    /// Construct from an existing winit `Window`.
    ///
    /// The caller is responsible for continuing to drive the winit `EventLoop`
    /// and feeding events via [`push_winit_event`](Self::push_winit_event).
    pub fn new(window: Arc<Window>) -> Self {
        Self {
            window,
            pending_events: Vec::new(),
            should_close: false,
        }
    }

    /// Translate a winit `WindowEvent` and push it onto the internal queue.
    ///
    /// Call this from your `ApplicationHandler::window_event` implementation
    /// before delegating to the framework runtime.
    pub fn push_winit_event(&mut self, event: &WindowEvent) {
        use crate::event_mapper::EventMapper;
        if let Some(ev) = EventMapper::map_window_event(event) {
            self.pending_events.push(ev);
        }
    }

    /// Signal that the window should close on the next frame check.
    ///
    /// Call this when you receive `WindowEvent::CloseRequested`.
    pub fn mark_close(&mut self) {
        self.should_close = true;
    }
}

impl WindowProvider for WinitWindowProvider {
    /// Drain all buffered platform events and return them.
    ///
    /// Called once per frame by the runtime. The buffer is cleared after this call.
    fn poll_events(&mut self) -> Vec<PlatformEvent> {
        std::mem::take(&mut self.pending_events)
    }

    /// Current logical rect of the window's content area, in **window-local
    /// coordinates** (origin = `(0, 0)`).
    ///
    /// Layout uses local coords because the GPU draws into the window's own
    /// surface; using screen-relative `outer_position` would make every widget
    /// drift across the window content as the user dragged the title bar.
    fn window_rect(&self) -> Rect {
        let size = self.window.inner_size();
        let scale = self.window.scale_factor();
        Rect::new(
            0.0,
            0.0,
            size.width as f64 / scale,
            size.height as f64 / scale,
        )
    }

    /// Device pixel ratio (HiDPI scale factor).
    fn scale_factor(&self) -> f64 {
        self.window.scale_factor()
    }

    /// Request an OS redraw for the next vsync.
    fn request_redraw(&mut self) {
        self.window.request_redraw();
    }

    /// `true` once [`mark_close`](Self::mark_close) has been called.
    fn should_close(&self) -> bool {
        self.should_close
    }

    /// Begin an OS-level window drag so the user can reposition the window.
    ///
    /// Forwards to [`winit::window::Window::drag_window`]. Errors (e.g. called
    /// outside a mouse-button-down event) are silently ignored.
    fn drag_window(&mut self) {
        let _ = self.window.drag_window();
    }

    /// Begin an OS-level resize-drag operation along the requested edge/corner.
    fn drag_resize_window(&mut self, direction: ResizeDirection) {
        use winit::window::ResizeDirection as W;
        let dir = match direction {
            ResizeDirection::North     => W::North,
            ResizeDirection::South     => W::South,
            ResizeDirection::East      => W::East,
            ResizeDirection::West      => W::West,
            ResizeDirection::NorthEast => W::NorthEast,
            ResizeDirection::NorthWest => W::NorthWest,
            ResizeDirection::SouthEast => W::SouthEast,
            ResizeDirection::SouthWest => W::SouthWest,
        };
        let _ = self.window.drag_resize_window(dir);
    }

    fn set_minimized(&mut self, on: bool) {
        self.window.set_minimized(on);
    }

    fn set_maximized(&mut self, on: bool) {
        self.window.set_maximized(on);
    }

    fn is_maximized(&self) -> bool {
        self.window.is_maximized()
    }

    fn request_close(&mut self) {
        self.mark_close();
    }

    /// Set or clear the OS window icon (taskbar / window caption).
    ///
    /// Converts `RgbaIcon` to a `winit::window::Icon` and delegates to
    /// `Window::set_window_icon`. Conversion failures are silently ignored.
    fn set_window_icon(&mut self, rgba: Option<RgbaIcon>) {
        let icon = rgba.and_then(|i| {
            winit::window::Icon::from_rgba(i.pixels, i.width, i.height).ok()
        });
        self.window.set_window_icon(icon);
    }

    /// Update the OS window title.
    fn set_title(&mut self, title: &str) {
        self.window.set_title(title);
    }

    /// Show or hide the window.
    fn set_visible(&mut self, visible: bool) {
        self.window.set_visible(visible);
    }

    /// Return a [`RawHandle::RawWindowHandle`] wrapping winit's raw window and
    /// display handles for GPU surface creation.
    ///
    /// Uses `winit::raw_window_handle::{HasWindowHandle, HasDisplayHandle}`.
    fn raw_window_handle(&self) -> Option<RawHandle> {
        use winit::raw_window_handle::{HasDisplayHandle, HasWindowHandle};

        let window_handle = self.window.window_handle().ok()?.as_raw();
        let display_handle = self.window.display_handle().ok()?.as_raw();

        // Wrap in a newtype that is Send + Sync.
        // SAFETY: raw window handles are plain integer/pointer data. On Windows
        // the HWND is a thread-local concept but wgpu's surface creation is
        // invoked synchronously from the main thread (inside the event loop
        // callback), so sharing the values across thread boundaries is safe in
        // this usage pattern. On other platforms the handles are similarly safe
        // to copy to the GPU thread.
        let pair: Box<dyn std::any::Any + Send + Sync> =
            Box::new(SendSyncHandlePair(window_handle, display_handle));

        Some(RawHandle::RawWindowHandle(pair))
    }

    /// Create a softbuffer-backed [`SoftwarePresenter`] for this window.
    ///
    /// Returns `None` only when softbuffer context or surface creation fails,
    /// which should not happen on any supported desktop platform.
    fn create_software_presenter(&self) -> Option<Box<dyn SoftwarePresenter>> {
        match WinitSoftbufferPresenter::new(self.window.clone()) {
            Ok(p) => Some(Box::new(p)),
            Err(e) => {
                eprintln!("[uzor-window-desktop] softbuffer presenter init failed: {e}");
                None
            }
        }
    }

    fn push_platform_event(&mut self, ev: PlatformEvent) {
        self.pending_events.push(ev);
    }
}

// ── WindowDecorations for WinitWindowProvider ─────────────────────────────────

impl WindowDecorations for WinitWindowProvider {
    /// Set the native corner-rounding style.
    ///
    /// On Windows 11+ calls `DwmSetWindowAttribute(DWMWA_WINDOW_CORNER_PREFERENCE)`.
    /// On macOS prints a one-time stub notice. On Linux silently no-ops.
    fn set_corner_style(&mut self, style: CornerStyle) {
        #[cfg(target_os = "windows")]
        if let Some(hwnd) = crate::win_dwm::extract_hwnd(&self.window) {
            crate::win_dwm::set_dwm_corner_preference(hwnd, style);
        }
        #[cfg(target_os = "macos")]
        {
            let _ = style;
            eprintln!(
                "[uzor-window-desktop] macOS corner/border decorations not yet implemented"
            );
        }
        #[cfg(not(any(target_os = "windows", target_os = "macos")))]
        {
            let _ = style;
        }
    }

    /// Set the native window border accent colour.
    ///
    /// On Windows 11+ calls `DwmSetWindowAttribute(DWMWA_BORDER_COLOR)`.
    /// `None` resets to the OS default. On other platforms silently no-ops.
    fn set_border_color(&mut self, color: Option<u32>) {
        #[cfg(target_os = "windows")]
        if let Some(hwnd) = crate::win_dwm::extract_hwnd(&self.window) {
            crate::win_dwm::set_dwm_border_color(hwnd, color);
        }
        #[cfg(not(target_os = "windows"))]
        {
            let _ = color;
        }
    }

    /// Toggle the OS drop shadow. Silently no-ops on all platforms for now.
    fn set_shadow(&mut self, _on: bool) {}
}

// ── WinitSoftbufferPresenter ──────────────────────────────────────────────────

/// Softbuffer-backed [`SoftwarePresenter`] for winit windows.
///
/// Wraps a `softbuffer::Surface` bound to the winit window. Each call to
/// [`present`](SoftwarePresenter::present) converts the caller-supplied RGBA8
/// buffer into softbuffer's native `0x00RRGGBB` u32 format and blits it to
/// the OS window.
///
/// Constructed via [`WinitWindowProvider::create_software_presenter`].
pub struct WinitSoftbufferPresenter {
    surface: softbuffer::Surface<Arc<Window>, Arc<Window>>,
}

impl WinitSoftbufferPresenter {
    fn new(window: Arc<Window>) -> Result<Self, Box<dyn std::error::Error>> {
        let ctx = softbuffer::Context::new(window.clone())
            .map_err(|e| format!("softbuffer context: {e:?}"))?;
        let surface = softbuffer::Surface::new(&ctx, window)
            .map_err(|e| format!("softbuffer surface: {e:?}"))?;
        Ok(Self { surface })
    }
}

impl SoftwarePresenter for WinitSoftbufferPresenter {
    /// Resize the softbuffer back-buffer.
    ///
    /// Forwards to `softbuffer::Surface::resize`. A no-op for zero dimensions.
    fn resize(&mut self, width: u32, height: u32) {
        if let (Some(w), Some(h)) = (
            std::num::NonZeroU32::new(width),
            std::num::NonZeroU32::new(height),
        ) {
            let _ = self.surface.resize(w, h);
        }
    }

    /// Convert `pixels` (RGBA8) to `0x00RRGGBB` u32 and present.
    ///
    /// Silently skips the frame for zero dimensions or on surface errors.
    fn present(&mut self, pixels: &[u8], width: u32, height: u32) {
        let (Some(w), Some(h)) = (
            std::num::NonZeroU32::new(width),
            std::num::NonZeroU32::new(height),
        ) else {
            return;
        };

        if let Err(e) = self.surface.resize(w, h) {
            eprintln!("[uzor-window-desktop] softbuffer resize error: {e:?}");
            return;
        }

        let Ok(mut buf) = self.surface.buffer_mut() else {
            return;
        };

        let n = (width as usize).saturating_mul(height as usize);
        let available = pixels.len() / 4;
        let count = n.min(available).min(buf.len());

        for i in 0..count {
            let src = i * 4;
            let r = pixels[src] as u32;
            let g = pixels[src + 1] as u32;
            let b = pixels[src + 2] as u32;
            buf[i] = (r << 16) | (g << 8) | b;
        }

        let _ = buf.present();
    }
}