Move TUI code to module

src/main.rs

@@ -1,82 +1,7 @@
-use crossterm::{
-    event::{self, Event, KeyCode},
-    execute,
-    terminal::{EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode, enable_raw_mode},
-};
-use ratatui::{
-    Terminal,
-    backend::CrosstermBackend,
-    layout::{Constraint, Direction, Layout},
-    style::{Color, Style},
-    widgets::{Block, Borders, Paragraph},
-};
-use std::io;
+mod tui;
 
-fn main() -> io::Result<()> {
-    enable_raw_mode()?;
-    let mut stdout = io::stdout();
-    execute!(stdout, EnterAlternateScreen)?;
-
-    let backend = CrosstermBackend::new(stdout);
-    let mut terminal = Terminal::new(backend)?;
-
-    let mut username = String::new();
-    let mut password = String::new();
-    let mut focus = 0; // 0 user, 1 password
-
-    loop {
-        terminal.draw(|f| {
-            let chunks = Layout::default()
-                .direction(Direction::Vertical)
-                .constraints([Constraint::Length(3), Constraint::Length(3)])
-                .split(f.area());
-
-            let user = Paragraph::new(username.as_str())
-                .block(Block::default().borders(Borders::ALL).title("User"))
-                .style(if focus == 0 {
-                    Style::new().fg(Color::from_u32(0x00235759))
-                } else {
-                    Style::default()
-                });
-
-            let pass = Paragraph::new(password.as_str())
-                .block(Block::default().borders(Borders::ALL).title("Password"))
-                .style(if focus == 1 {
-                    Style::new().fg(Color::from_u32(0x00235759))
-                } else {
-                    Style::default()
-                });
-
-            f.render_widget(user, chunks[0]);
-            f.render_widget(pass, chunks[1]);
-        })?;
-
-        if let Event::Key(key) = event::read()? {
-            match key.code {
-                KeyCode::Esc => break,
-                KeyCode::Tab => focus = (focus + 1) % 2,
-                KeyCode::Enter => break,
-                KeyCode::Backspace => {
-                    if focus == 0 {
-                        username.pop();
-                    } else {
-                        password.pop();
-                    }
-                }
-                KeyCode::Char(c) => {
-                    if focus == 0 {
-                        username.push(c);
-                    } else {
-                        password.push(c);
-                    }
-                }
-                _ => {}
-            }
-        }
-    }
-
-    disable_raw_mode()?;
-    execute!(terminal.backend_mut(), LeaveAlternateScreen)?;
+fn main() -> std::io::Result<()> {
+    let (username, password) = tui::run()?;
 
     println!("user = {username}");
     println!("pass = {password}");

src/tui.rs

@@ -0,0 +1,84 @@
+use crossterm::{
+    event::{self, Event, KeyCode},
+    execute,
+    terminal::{EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode, enable_raw_mode},
+};
+use ratatui::{
+    Terminal,
+    backend::CrosstermBackend,
+    layout::{Constraint, Direction, Layout},
+    style::{Color, Style},
+    widgets::{Block, Borders, Paragraph},
+};
+use std::io;
+
+/// Runs the TUI and returns the entered username and password.
+/// This module owns all terminal state.
+pub fn run() -> io::Result<(String, String)> {
+    enable_raw_mode()?;
+    let mut stdout = io::stdout();
+    execute!(stdout, EnterAlternateScreen)?;
+
+    let backend = CrosstermBackend::new(stdout);
+    let mut terminal = Terminal::new(backend)?;
+
+    let mut username = String::new();
+    let mut password = String::new();
+    let mut focus = 0;
+
+    loop {
+        terminal.draw(|f| {
+            let chunks = Layout::default()
+                .direction(Direction::Vertical)
+                .constraints([Constraint::Length(3), Constraint::Length(3)])
+                .split(f.area());
+
+            let user = Paragraph::new(username.as_str())
+                .block(Block::default().borders(Borders::ALL).title("User"))
+                .style(if focus == 0 {
+                    Style::new().fg(Color::from_u32(0x00235759))
+                } else {
+                    Style::default()
+                });
+
+            let pass = Paragraph::new(password.as_str())
+                .block(Block::default().borders(Borders::ALL).title("Password"))
+                .style(if focus == 1 {
+                    Style::new().fg(Color::from_u32(0x00235759))
+                } else {
+                    Style::default()
+                });
+
+            f.render_widget(user, chunks[0]);
+            f.render_widget(pass, chunks[1]);
+        })?;
+
+        if let Event::Key(key) = event::read()? {
+            match key.code {
+                KeyCode::Esc => break,
+                KeyCode::Tab => focus = (focus + 1) % 2,
+                KeyCode::Enter => break,
+                KeyCode::Backspace => {
+                    if focus == 0 {
+                        username.pop();
+                    } else {
+                        password.pop();
+                    }
+                }
+                KeyCode::Char(c) => {
+                    if focus == 0 {
+                        username.push(c);
+                    } else {
+                        password.push(c);
+                    }
+                }
+                _ => {}
+            }
+        }
+    }
+
+    disable_raw_mode()?;
+    execute!(terminal.backend_mut(), LeaveAlternateScreen)?;
+
+    Ok((username, password))
+}