Init Terminal User Interface

1 files changed, 98 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index 1a93aef..9b45fca 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,14 @@
 mod trace;
+use crossterm::{
+    event::{self, Event, KeyCode},
+    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
+    ExecutableCommand,
+};
+use ratatui::{prelude::*, widgets::*};
+use std::{
+    io::{self, stdout},
+    str,
+};
 
 use crate::trace::{exec, trace};
 use clap::Parser;
@@ -15,9 +25,31 @@ struct Args {
     file_to_print: Option<String>,
 }
 
+struct UI {
+    height: usize,
+    max_lines: usize,
+    scroll: usize,
+}
+
+impl UI {
+    fn new() -> UI {
+        UI {
+            height: 0,
+            max_lines: 0,
+            scroll: 0,
+        }
+    }
+}
+
 /// Create a fork of the program and execute the process in the child. Parent gets the pid
 /// value and trace it.
 fn main() -> anyhow::Result<()> {
+    enable_raw_mode()?;
+    stdout().execute(EnterAlternateScreen)?;
+    let mut terminal = Terminal::new(CrosstermBackend::new(stdout()))?;
+
+    let mut ui = UI::new();
+
     let args = Args::parse();
 
     let pid = match fork() {
@@ -25,8 +57,73 @@ fn main() -> anyhow::Result<()> {
         Ok(Fork::Parent(child)) => Pid::from_raw(child as i32),
         Err(err) => panic!("fork() failed: {err}"),
     };
+    let output = trace(pid, args.file_to_print)?;
+    let lines = str::from_utf8(&output)?;
+    ui.max_lines = lines.split('\n').count();
+
+    let mut should_quit = false;
+    while !should_quit {
+        ui.height = terminal.get_frame().size().height as usize;
+        terminal.draw(move |frame| {
+            let size = frame.size();
+            frame.render_widget(
+                Paragraph::new(lines)
+                    .block(
+                        Block::default()
+                            .border_style(Style::default().fg(Color::Yellow))
+                            .title(format!("[{pid}]"))
+                            .title(
+                                block::Title::from(format!(
+                                    "[lines {}-{}]",
+                                    ui.scroll,
+                                    ui.scroll + ui.height
+                                ))
+                                .position(block::Position::Bottom)
+                                .alignment(Alignment::Right),
+                            )
+                            .borders(Borders::ALL),
+                    )
+                    .scroll((ui.scroll as u16, 0)),
+                size,
+            );
+        })?;
+        should_quit = handle_events(&mut ui)?;
+    }
 
-    trace(pid, args.file_to_print)?;
+    disable_raw_mode()?;
+    stdout().execute(LeaveAlternateScreen)?;
 
     Ok(())
 }
+
+fn handle_events(ui: &mut UI) -> io::Result<bool> {
+    if event::poll(std::time::Duration::from_millis(50))? {
+        if let Event::Key(key) = event::read()? {
+            if key.kind == event::KeyEventKind::Press {
+                match key.code {
+                    KeyCode::Char('q') => {
+                        return Ok(true);
+                    }
+                    KeyCode::Char('j') => {
+                        if ui.scroll < (ui.max_lines - ui.height + 1) {
+                            ui.scroll += 1;
+                        }
+                    }
+                    KeyCode::Char('J') => {
+                        ui.scroll = ui.max_lines - ui.height + 1;
+                    }
+                    KeyCode::Char('k') => {
+                        if ui.scroll > 1 {
+                            ui.scroll -= 1;
+                        }
+                    }
+                    KeyCode::Char('K') => {
+                        ui.scroll = ui.height;
+                    }
+                    _ => {}
+                }
+            }
+        }
+    }
+    Ok(false)
+}