minimal implementation

.github/workflows/ci.yml

@@ -15,5 +15,5 @@ jobs:
       - uses: Swatinem/rust-cache@v1
       - name: rustfmt
         run: cargo fmt -- --check --color always
-      # - name: clippy
-      #   run: cargo clippy --color always -- -D warnings
+      - name: clippy
+        run: cargo clippy --color always -- -D warnings

Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+tui = "0.18"

README.md

@@ -0,0 +1,6 @@
+tui-textarea
+============
+
+tui-textarea is a simple text editor like `<textarea>` in HTML for [tui-rs][]. This library is designed as backend-agnostic.
+
+[tui-rs]: https://github.com/fdehau/tui-rs

src/lib.rs

@@ -1,8 +1,100 @@
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        let result = 2 + 2;
-        assert_eq!(result, 4);
+use tui::style::{Modifier, Style};
+use tui::text::{Span, Spans, Text};
+use tui::widgets::{Block, Paragraph, Widget};
+
+pub enum Key {
+    Char(char),
+    Backspace,
+    Enter,
+    Left,
+    Right,
+    Up,
+    Down,
+    Tab,
+    Delete,
+    Home,
+    End,
+}
+
+pub struct Input {
+    pub key: Key,
+    pub ctrl: bool,
+}
+
+pub struct TextArea<'a> {
+    lines: Vec<String>,
+    block: Option<Block<'a>>,
+    style: Style,
+    cursor: (usize, usize),
+}
+
+impl<'a> Default for TextArea<'a> {
+    fn default() -> Self {
+        Self {
+            lines: vec![" ".to_string()],
+            block: None,
+            style: Style::default(),
+            cursor: (0, 0),
+        }
+    }
+}
+
+impl<'a> TextArea<'a> {
+    pub fn input(&mut self, input: Input) {
+        if input.ctrl {
+            // TODO
+        } else {
+            match input.key {
+                Key::Char(c) => self.insert_char(c),
+                Key::Backspace => self.delete_char(),
+                _ => {}
+            }
+        }
+    }
+
+    pub fn insert_char(&mut self, c: char) {
+        let (row, col) = self.cursor;
+        let line = &mut self.lines[row];
+        if let Some((i, _)) = line.char_indices().nth(col) {
+            line.insert(i, c);
+            self.cursor.1 += 1;
+        }
+    }
+
+    pub fn delete_char(&mut self) {
+        let (row, col) = self.cursor;
+        let line = &mut self.lines[row];
+        if col == 0 {
+            return;
+        }
+        if let Some((i, _)) = line.char_indices().nth(col - 1) {
+            line.remove(i);
+            self.cursor.1 -= 1;
+        }
+    }
+
+    pub fn widget(&'a self) -> impl Widget + 'a {
+        let mut lines = Vec::with_capacity(self.lines.len());
+        for (i, l) in self.lines.iter().enumerate() {
+            if i == self.cursor.0 {
+                let (i, c) = l
+                    .char_indices()
+                    .nth(self.cursor.1)
+                    .unwrap_or((l.len() - 1, ' '));
+                let j = i + c.len_utf8();
+                lines.push(Spans::from(vec![
+                    Span::from(&l[..i]),
+                    Span::styled(&l[i..j], Style::default().add_modifier(Modifier::REVERSED)),
+                    Span::from(&l[j..]),
+                ]));
+            } else {
+                lines.push(Spans::from(l.as_str()));
+            }
+        }
+        let mut p = Paragraph::new(Text::from(lines)).style(self.style);
+        if let Some(b) = self.block.clone() {
+            p = p.block(b);
+        }
+        p
     }
 }