abacus/abacus-ui/src/editor.rs

use druid::{
    piet::{Text, TextLayout, TextLayoutBuilder},
    Color, Data, Event, FontFamily, Lens, LifeCycle, RenderContext, Widget,
};

#[derive(Clone, Data, PartialEq, Eq)]
pub enum EditMode {
    Normal,
    Insert,
}

pub struct AbacusEditor;

#[derive(Data, Lens, Clone)]
pub struct EditorData {
    pub raw_content: String,
    pub cursor_pos: usize,
    pub mode: EditMode,
}

impl Default for EditorData {
    fn default() -> Self {
        Self {
            raw_content: "let x = 1;\nx+1".to_string(),
            cursor_pos: 5,
            mode: EditMode::Normal,
        }
    }
}

impl EditorData {
    pub fn push_str(&mut self, s: &str) {
        self.raw_content.push_str(s);
        self.cursor_to_end();
    }

    pub fn push(&mut self, c: char) {
        self.raw_content.push(c);
        self.cursor_to_end();
    }

    pub fn cursor_to_end(&mut self) {
        self.cursor_pos = self.raw_content.len();
    }

    pub fn delete_char_back(&mut self) {
        self.raw_content.pop();
        self.cursor_to_end();
    }
}

impl Widget<EditorData> for AbacusEditor {
    fn paint(&mut self, ctx: &mut druid::PaintCtx, data: &EditorData, env: &druid::Env) {
        let size = ctx.size();
        let rect = size.to_rect();

        if ctx.is_focused() {
            ctx.fill(rect, &Color::rgb8(10, 10, 10));
        } else {
            ctx.fill(rect, &Color::rgb8(20, 20, 20));
        }

        let layout = ctx
            .text()
            .new_text_layout(data.raw_content.clone())
            .font(FontFamily::MONOSPACE, 24.0)
            .text_color(Color::rgb8(255, 255, 255))
            .build()
            .unwrap();

        dbg!(layout.rects_for_range((data.cursor_pos - 1)..data.cursor_pos));
        ctx.fill(
            layout
                .rects_for_range((data.cursor_pos - 1)..data.cursor_pos)
                .last()
                .unwrap(),
            &Color::rgb8(50, 50, 50),
        );
        ctx.draw_text(&layout, (1.0, 1.0));

        dbg!(ctx.is_focused());
    }

    fn event(
        &mut self,
        ctx: &mut druid::EventCtx,
        event: &druid::Event,
        data: &mut EditorData,
        env: &druid::Env,
    ) {
        match event {
            Event::KeyUp(e) => match &e.key {
                druid::keyboard_types::Key::Character(c) => {
                    data.push_str(c);
                    ctx.request_paint();
                }
                druid::keyboard_types::Key::Enter => {
                    data.push('\n');
                    ctx.request_paint();
                }
                druid::keyboard_types::Key::Backspace => {
                    data.delete_char_back();
                    ctx.request_paint();
                }
                druid::keyboard_types::Key::Escape => {
                    data.mode == EditMode::Normal;
                }
                e => {
                    dbg!(e);
                }
            },
            Event::MouseDown(_) => {
                if !ctx.is_focused() {
                    ctx.request_focus();
                }
            }
            _ => {}
        }
    }

    fn lifecycle(
        &mut self,
        ctx: &mut druid::LifeCycleCtx,
        event: &druid::LifeCycle,
        data: &EditorData,
        env: &druid::Env,
    ) {
        match event {
            LifeCycle::FocusChanged(_) => {
                ctx.request_paint();
            }
            LifeCycle::WidgetAdded => {
                // ctx.register_text_input(document)
            }
            LifeCycle::BuildFocusChain => {
                ctx.register_for_focus();
            }
            _ => {}
        }
    }

    fn update(
        &mut self,
        ctx: &mut druid::UpdateCtx,
        old_data: &EditorData,
        data: &EditorData,
        env: &druid::Env,
    ) {
    }

    fn layout(
        &mut self,
        ctx: &mut druid::LayoutCtx,
        bc: &druid::BoxConstraints,
        data: &EditorData,
        env: &druid::Env,
    ) -> druid::Size {
        bc.max()
    }
}