term_kit/
listselector.rs

1use crossterm::{
2    cursor,
3    event::{read, Event, KeyCode, KeyEvent, KeyEventKind},
4    execute,
5    style::{Print, Stylize},
6    terminal::{size, Clear, ClearType, EnterAlternateScreen, LeaveAlternateScreen},
7};
8use std::io::{stdout, Write};
9
10pub struct ListSelector {
11    options: Vec<String>,
12    selected_index: usize,
13    top_visible_index: usize,
14}
15
16impl ListSelector {
17    pub fn new(options: Vec<String>) -> Self {
18        Self {
19            options,
20            selected_index: 0,
21            top_visible_index: 0,
22        }
23    }
24
25    pub fn get_selected_option(&self) -> Option<&str> {
26        self.options.get(self.selected_index).map(String::as_str)
27    }
28
29    pub fn render(&self) {
30        let mut stdout = stdout();
31        let (_cols, rows) = size().unwrap();
32
33        let num_visible_options = (rows - 1) as usize; // Leave a line for the cursor
34        let start_index = self.top_visible_index;
35        let end_index = (start_index + num_visible_options).min(self.options.len());
36
37        for i in start_index..end_index {
38            let y = (i - start_index) as u16;
39            execute!(stdout, cursor::MoveTo(0, y), Clear(ClearType::CurrentLine),).unwrap();
40            if i == self.selected_index {
41                execute!(stdout, Print(format!("> {}", self.options[i]).reverse()),).unwrap();
42            } else {
43                execute!(stdout, Print(self.options[i].clone()),).unwrap();
44            }
45        }
46        stdout.flush().unwrap();
47    }
48
49    pub fn run(&mut self) -> Result<Option<&str>, Box<dyn std::error::Error>> {
50        let mut stdout = stdout();
51        execute!(
52            stdout,
53            EnterAlternateScreen,
54            cursor::Hide,
55            Clear(ClearType::All)
56        )?;
57        self.render();
58
59        loop {
60            match read()? {
61                Event::Key(KeyEvent {
62                    code,
63                    kind: KeyEventKind::Press,
64                    ..
65                }) => match code {
66                    KeyCode::Up | KeyCode::Char('j') | KeyCode::Char('J') => {
67                        if self.selected_index > 0 {
68                            self.selected_index -= 1;
69                            if self.selected_index < self.top_visible_index {
70                                self.top_visible_index -= 1;
71                            }
72                        }
73                        self.render();
74                    }
75                    KeyCode::Down | KeyCode::Char('k') | KeyCode::Char('K') => {
76                        if self.selected_index < self.options.len() - 1 {
77                            self.selected_index += 1;
78                            let (_, rows) = size().unwrap();
79                            let max_visible_index = (self.top_visible_index + (rows - 2) as usize)
80                                .min(self.options.len() - 1);
81                            if self.selected_index > max_visible_index {
82                                self.top_visible_index += 1;
83                            }
84                        }
85                        self.render();
86                    }
87                    KeyCode::Enter => break,
88                    _ => {}
89                },
90                _ => {}
91            }
92        }
93
94        execute!(stdout, LeaveAlternateScreen, cursor::Show)?;
95        Ok(self.get_selected_option())
96    }
97}
term_kit/listselector.rs

term_kit/
listselector.rs
