Initial import.

2 files changed, 338 insertions, 0 deletions

diff --git a/helix-term/src/line.rs b/helix-term/src/line.rs
new file mode 100644
index 00000000..90fb5e6f
--- /dev/null
+++ b/helix-term/src/line.rs
@@ -0,0 +1,111 @@
+use termwiz::cell::AttributeChange;
+use termwiz::color::{AnsiColor, ColorAttribute, RgbColor};
+use termwiz::lineedit::*;
+
+#[derive(Default)]
+struct Host {
+    history: BasicHistory,
+}
+
+impl LineEditorHost for Host {
+    // Render the prompt with a darkslateblue background color if
+    // the terminal supports true color, otherwise render it with
+    // a navy blue ansi color.
+    fn render_prompt(&self, prompt: &str) -> Vec<OutputElement> {
+        vec![
+            OutputElement::Attribute(AttributeChange::Background(
+                ColorAttribute::TrueColorWithPaletteFallback(
+                    RgbColor::from_named("darkslateblue").unwrap(),
+                    AnsiColor::Navy.into(),
+                ),
+            )),
+            OutputElement::Text(prompt.to_owned()),
+        ]
+    }
+
+    fn history(&mut self) -> &mut dyn History {
+        &mut self.history
+    }
+
+    /// Demo of the completion API for words starting with "h" or "he"
+    fn complete(&self, line: &str, cursor_position: usize) -> Vec<CompletionCandidate> {
+        let mut candidates = vec![];
+        if let Some((range, word)) = word_at_cursor(line, cursor_position) {
+            let words = &["hello", "help", "he-man"];
+
+            for w in words {
+                if w.starts_with(word) {
+                    candidates.push(CompletionCandidate {
+                        range: range.clone(),
+                        text: w.to_string(),
+                    });
+                }
+            }
+        }
+        candidates
+    }
+}
+
+/// This is a conceptually simple function that computes the bounds
+/// of the whitespace delimited word at the specified cursor position
+/// in the supplied line string.
+/// It returns the range and the corresponding slice out of the line.
+/// This function is sufficient for example purposes; in a real application
+/// the equivalent function would need to be aware of quoting and other
+/// application specific context.
+fn word_at_cursor(line: &str, cursor_position: usize) -> Option<(std::ops::Range<usize>, &str)> {
+    let char_indices: Vec<(usize, char)> = line.char_indices().collect();
+    if char_indices.is_empty() {
+        return None;
+    }
+    let char_position = char_indices
+        .iter()
+        .position(|(idx, _)| *idx == cursor_position)
+        .unwrap_or(char_indices.len());
+
+    // Look back until we find whitespace
+    let mut start_position = char_position;
+    while start_position > 0
+        && start_position <= char_indices.len()
+        && !char_indices[start_position - 1].1.is_whitespace()
+    {
+        start_position -= 1;
+    }
+
+    // Look forwards until we find whitespace
+    let mut end_position = char_position;
+    while end_position < char_indices.len() && !char_indices[end_position].1.is_whitespace() {
+        end_position += 1;
+    }
+
+    if end_position > start_position {
+        let range = char_indices[start_position].0
+            ..char_indices
+                .get(end_position)
+                .map(|c| c.0 + 1)
+                .unwrap_or(line.len());
+        Some((range.clone(), &line[range]))
+    } else {
+        None
+    }
+}
+
+fn main() -> anyhow::Result<()> {
+    println!("Type `exit` to quit this example, or start a word with `h` and press Tab.");
+    let mut terminal = line_editor_terminal()?;
+    let mut editor = LineEditor::new(&mut terminal);
+
+    let mut host = Host::default();
+    loop {
+        if let Some(line) = editor.read_line(&mut host)? {
+            println!("read line: {:?}", line);
+            if line == "exit" {
+                break;
+            }
+
+            host.history().add(&line);
+        }
+    }
+
+    Ok(())
+}
diff --git a/helix-term/src/main.rs b/helix-term/src/main.rs
new file mode 100644
index 00000000..e13309eb
--- /dev/null
+++ b/helix-term/src/main.rs
@@ -0,0 +1,227 @@
+//! This example shows how to make a basic widget that accumulates
+//! text input and renders it to the screen
+#![allow(unused)]
+use anyhow::Error;
+use termwiz::caps::Capabilities;
+use termwiz::cell::AttributeChange;
+use termwiz::color::{AnsiColor, ColorAttribute, RgbColor};
+use termwiz::input::*;
+use termwiz::surface::Change;
+use termwiz::terminal::buffered::BufferedTerminal;
+use termwiz::terminal::{new_terminal, Terminal};
+use termwiz::widgets::*;
+
+/// This is a widget for our application
+struct MainScreen {}
+
+impl MainScreen {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+impl Widget for MainScreen {
+    fn process_event(&mut self, event: &WidgetEvent, _args: &mut UpdateArgs) -> bool {
+        true // handled it all
+    }
+
+    /// Draw ourselves into the surface provided by RenderArgs
+    fn render(&mut self, args: &mut RenderArgs) {
+        // args.surface.add_change(Change::ClearScreen(
+        //     ColorAttribute::TrueColorWithPaletteFallback(
+        //         RgbColor::new(0x31, 0x1B, 0x92),
+        //         AnsiColor::Black.into(),
+        //     ),
+        // ));
+        // args.surface
+        //     .add_change(Change::Attribute(AttributeChange::Foreground(
+        //         ColorAttribute::TrueColorWithPaletteFallback(
+        //             RgbColor::new(0xB3, 0x88, 0xFF),
+        //             AnsiColor::Purple.into(),
+        //         ),
+        //     )));
+    }
+
+    fn get_size_constraints(&self) -> layout::Constraints {
+        let mut constraints = layout::Constraints::default();
+        constraints.child_orientation = layout::ChildOrientation::Vertical;
+        constraints
+    }
+}
+
+struct Buffer<'a> {
+    /// Holds the input text that we wish the widget to display
+    text: &'a mut String,
+}
+
+impl<'a> Buffer<'a> {
+    /// Initialize the widget with the input text
+    pub fn new(text: &'a mut String) -> Self {
+        Self { text }
+    }
+}
+
+impl<'a> Widget for Buffer<'a> {
+    fn process_event(&mut self, event: &WidgetEvent, _args: &mut UpdateArgs) -> bool {
+        match event {
+            WidgetEvent::Input(InputEvent::Key(KeyEvent {
+                key: KeyCode::Char(c),
+                ..
+            })) => self.text.push(*c),
+            WidgetEvent::Input(InputEvent::Key(KeyEvent {
+                key: KeyCode::Enter,
+                ..
+            })) => {
+                self.text.push_str("\r\n");
+            }
+            WidgetEvent::Input(InputEvent::Paste(s)) => {
+                self.text.push_str(&s);
+            }
+            _ => {}
+        }
+
+        true // handled it all
+    }
+
+    /// Draw ourselves into the surface provided by RenderArgs
+    fn render(&mut self, args: &mut RenderArgs) {
+        args.surface
+            .add_change(Change::ClearScreen(ColorAttribute::Default));
+
+        // args.surface
+        //     .add_change(Change::Attribute(AttributeChange::Foreground(
+        //         ColorAttribute::TrueColorWithPaletteFallback(
+        //             RgbColor::new(0x11, 0x00, 0xFF),
+        //             AnsiColor::Purple.into(),
+        //         ),
+        //     )));
+        let dims = args.surface.dimensions();
+        args.surface
+            .add_change(format!("🤷 surface size is {:?}\r\n", dims));
+        args.surface.add_change(self.text.clone());
+
+        // Place the cursor at the end of the text.
+        // A more advanced text editing widget would manage the
+        // cursor position differently.
+        *args.cursor = CursorShapeAndPosition {
+            coords: args.surface.cursor_position().into(),
+            shape: termwiz::surface::CursorShape::SteadyBar,
+            ..Default::default()
+        };
+    }
+
+    fn get_size_constraints(&self) -> layout::Constraints {
+        let mut c = layout::Constraints::default();
+        c.set_valign(layout::VerticalAlignment::Top);
+        c
+    }
+}
+
+struct StatusLine {}
+
+impl StatusLine {
+    pub fn new() -> Self {
+        StatusLine {}
+    }
+}
+impl Widget for StatusLine {
+    fn process_event(&mut self, event: &WidgetEvent, _args: &mut UpdateArgs) -> bool {
+        true
+    }
+
+    fn render(&mut self, args: &mut RenderArgs) {
+        args.surface.add_change(Change::ClearScreen(
+            ColorAttribute::TrueColorWithPaletteFallback(
+                RgbColor::new(0xFF, 0xFF, 0xFF),
+                AnsiColor::Black.into(),
+            ),
+        ));
+        args.surface
+            .add_change(Change::Attribute(AttributeChange::Foreground(
+                ColorAttribute::TrueColorWithPaletteFallback(
+                    RgbColor::new(0x00, 0x00, 0x00),
+                    AnsiColor::Black.into(),
+                ),
+            )));
+
+        args.surface.add_change(" helix");
+    }
+
+    fn get_size_constraints(&self) -> layout::Constraints {
+        *layout::Constraints::default()
+            .set_fixed_height(1)
+            .set_valign(layout::VerticalAlignment::Bottom)
+    }
+}
+
+fn main() -> Result<(), Error> {
+    // Start with an empty string; typing into the app will
+    // update this string.
+    let mut typed_text = String::new();
+
+    {
+        // Create a terminal and put it into full screen raw mode
+        let caps = Capabilities::new_from_env()?;
+        let mut buf = BufferedTerminal::new(new_terminal(caps)?)?;
+        buf.terminal().enter_alternate_screen()?;
+        buf.terminal().set_raw_mode()?;
+
+        // Set up the UI
+        let mut ui = Ui::new();
+
+        let root_id = ui.set_root(MainScreen::new());
+        let buffer_id = ui.add_child(root_id, Buffer::new(&mut typed_text));
+        // let root_id = ui.set_root(Buffer::new(&mut typed_text));
+        ui.add_child(root_id, StatusLine::new());
+        ui.set_focus(buffer_id);
+
+        loop {
+            ui.process_event_queue()?;
+
+            // After updating and processing all of the widgets, compose them
+            // and render them to the screen.
+            if ui.render_to_screen(&mut buf)? {
+                // We have more events to process immediately; don't block waiting
+                // for input below, but jump to the top of the loop to re-run the
+                // updates.
+                continue;
+            }
+            // Compute an optimized delta to apply to the terminal and display it
+            buf.flush()?;
+
+            // Wait for user input
+            match buf.terminal().poll_input(None) {
+                Ok(Some(InputEvent::Resized { rows, cols })) => {
+                    // FIXME: this is working around a bug where we don't realize
+                    // that we should redraw everything on resize in BufferedTerminal.
+                    buf.add_change(Change::ClearScreen(Default::default()));
+                    buf.resize(cols, rows);
+                }
+                Ok(Some(input)) => match input {
+                    InputEvent::Key(KeyEvent {
+                        key: KeyCode::Escape,
+                        ..
+                    }) => {
+                        // Quit the app when escape is pressed
+                        break;
+                    }
+                    input @ _ => {
+                        // Feed input into the Ui
+                        ui.queue_event(WidgetEvent::Input(input));
+                    }
+                },
+                Ok(None) => {}
+                Err(e) => {
+                    print!("{:?}\r\n", e);
+                    break;
+                }
+            }
+        }
+    }
+
+    // After we've stopped the full screen raw terminal,
+    // print out the final edited value of the input text.
+    println!("The text you entered: {}", typed_text);
+
+    Ok(())
+}