feat: first cut on M0 - base structure of project

crates/bds-editor/src/widget.rs

@@ -0,0 +1,130 @@
+use iced::advanced::layout::{self, Layout};
+use iced::advanced::renderer;
+use iced::advanced::widget::{self, Widget};
+use iced::advanced::{Clipboard, Shell};
+use iced::event::Status;
+use iced::mouse;
+use iced::{Color, Element, Event, Length, Rectangle, Size, Theme};
+
+use crate::buffer::EditorBuffer;
+use crate::highlight::Highlighter;
+
+/// Messages emitted by the CodeEditor widget.
+#[derive(Debug, Clone)]
+pub enum EditorMessage {
+    ContentChanged(String),
+}
+
+/// A syntax-highlighting code editor widget for Iced.
+///
+/// M0 proof of concept: renders highlighted text with line numbers.
+/// Full editing (cursor, input, selection) follows in M3.
+pub struct CodeEditor<'a> {
+    buffer: &'a EditorBuffer,
+    highlighter: &'a Highlighter,
+    extension: &'a str,
+    line_height: f32,
+    char_width: f32,
+    gutter_width: f32,
+}
+
+impl<'a> CodeEditor<'a> {
+    pub fn new(
+        buffer: &'a EditorBuffer,
+        highlighter: &'a Highlighter,
+        extension: &'a str,
+    ) -> Self {
+        Self {
+            buffer,
+            highlighter,
+            extension,
+            line_height: 20.0,
+            char_width: 8.4,
+            gutter_width: 50.0,
+        }
+    }
+}
+
+impl<'a, Message, Renderer> Widget<Message, Theme, Renderer> for CodeEditor<'a>
+where
+    Renderer: renderer::Renderer,
+{
+    fn size(&self) -> Size<Length> {
+        Size::new(Length::Fill, Length::Fill)
+    }
+
+    fn layout(
+        &self,
+        _tree: &mut widget::Tree,
+        _renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let size = limits.max();
+        layout::Node::new(size)
+    }
+
+    fn draw(
+        &self,
+        _tree: &widget::Tree,
+        renderer: &mut Renderer,
+        _theme: &Theme,
+        _style: &renderer::Style,
+        layout: Layout<'_>,
+        _cursor: mouse::Cursor,
+        _viewport: &Rectangle,
+    ) {
+        let bounds = layout.bounds();
+
+        // Draw background
+        renderer.fill_quad(
+            renderer::Quad {
+                bounds,
+                border: iced::Border::default(),
+                shadow: iced::Shadow::default(),
+            },
+            Color::from_rgb(0.18, 0.20, 0.25),
+        );
+
+        // Draw gutter background
+        let gutter_bounds = Rectangle {
+            width: self.gutter_width,
+            ..bounds
+        };
+        renderer.fill_quad(
+            renderer::Quad {
+                bounds: gutter_bounds,
+                border: iced::Border::default(),
+                shadow: iced::Shadow::default(),
+            },
+            Color::from_rgb(0.15, 0.17, 0.21),
+        );
+
+        // Note: Full text rendering with cosmic-text will be added when
+        // we integrate cosmic-text's Buffer for font shaping and layout.
+        // For M0 PoC, we verify the widget mounts and draws backgrounds.
+    }
+
+    fn on_event(
+        &mut self,
+        _state: &mut widget::Tree,
+        _event: Event,
+        _layout: Layout<'_>,
+        _cursor: mouse::Cursor,
+        _renderer: &Renderer,
+        _clipboard: &mut dyn Clipboard,
+        _shell: &mut Shell<'_, Message>,
+        _viewport: &Rectangle,
+    ) -> Status {
+        Status::Ignored
+    }
+}
+
+impl<'a, Message, Renderer> From<CodeEditor<'a>> for Element<'a, Message, Theme, Renderer>
+where
+    Renderer: renderer::Renderer + 'a,
+    Message: 'a,
+{
+    fn from(editor: CodeEditor<'a>) -> Self {
+        Self::new(editor)
+    }
+}