From 3857265728b6edf546e22bf2293313b6679b5bbf Mon Sep 17 00:00:00 2001
From: Nathan Fisher <jeang3nie@hitchhiker-linux.org>
Date: Sat, 7 Jan 2023 11:44:35 -0500
Subject: [PATCH] Added `rev` applet

---
 src/cmd/mod.rs     |   9 ++--
 src/cmd/rev/mod.rs | 100 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+), 3 deletions(-)
 create mode 100644 src/cmd/rev/mod.rs

diff --git a/src/cmd/mod.rs b/src/cmd/mod.rs
index dfc45d2..296a96e 100644
--- a/src/cmd/mod.rs
+++ b/src/cmd/mod.rs
@@ -22,6 +22,7 @@ pub mod mountpoint;
 mod mv;
 pub mod nologin;
 mod pwd;
+pub mod rev;
 mod rm;
 mod rmdir;
 pub mod shitbox;
@@ -32,7 +33,7 @@ pub mod r#true;
 pub use {
     self::hostname::Hostname, base32::Base32, base64::Base64, bootstrap::Bootstrap,
     dirname::Dirname, echo::Echo, factor::Factor, head::Head, mountpoint::Mountpoint,
-    nologin::Nologin, r#false::False, r#true::True, shitbox::Shitbox, sleep::Sleep,
+    nologin::Nologin, r#false::False, r#true::True, rev::Rev, shitbox::Shitbox, sleep::Sleep,
 };
 
 pub trait Cmd: fmt::Debug + Sync {
@@ -54,6 +55,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
         "head" => Some(Box::new(Head::default())),
         "mountpoint" => Some(Box::new(Mountpoint::default())),
         "nologin" => Some(Box::new(Nologin::default())),
+        "rev" => Some(Box::new(Rev::default())),
         "shitbox" => Some(Box::new(Shitbox::default())),
         "sleep" => Some(Box::new(Sleep::default())),
         "true" => Some(Box::new(True::default())),
@@ -61,7 +63,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
     }
 }
 
-pub static COMMANDS: [&'static str; 14] = [
+pub static COMMANDS: [&'static str; 15] = [
     "base32",
     "base64",
     "bootstrap",
@@ -73,7 +75,8 @@ pub static COMMANDS: [&'static str; 14] = [
     "hostname",
     "mountpoint",
     "nologin",
-    "true",
+    "rev",
     "sleep",
     "shitbox",
+    "true",
 ];
diff --git a/src/cmd/rev/mod.rs b/src/cmd/rev/mod.rs
new file mode 100644
index 0000000..c0234e4
--- /dev/null
+++ b/src/cmd/rev/mod.rs
@@ -0,0 +1,100 @@
+use crate::Cmd;
+use clap::{Arg, Command, ArgAction};
+use std::{
+    fs::File,
+    io::{self, BufRead, BufReader, ErrorKind, Write},
+};
+use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
+
+#[derive(Debug)]
+pub struct Rev {
+    name: &'static str,
+    path: Option<crate::Path>,
+}
+
+impl Default for Rev {
+    fn default() -> Self {
+        Self {
+            name: "rev",
+            path: Some(crate::Path::UsrBin),
+        }
+    }
+}
+
+impl Cmd for Rev {
+    fn name(&self) -> &str {
+        self.name
+    }
+
+    fn cli(&self) -> clap::Command {
+        Command::new(self.name)
+            .about("reverse lines characterwise")
+            .author("Nathan Fisher")
+            .args([
+                Arg::new("verbose")
+                    .short('v')
+                    .long("verbose")
+                    .help("print a header between each file")
+                    .action(ArgAction::SetTrue),
+                Arg::new("color")
+                    .short('c')
+                    .long("color")
+                    .value_parser(["always", "ansi", "auto", "never"]),
+                Arg::new("file")
+                    .help("if file is '-' read from stdin")
+                    .num_args(0..),
+            ])
+    }
+
+    fn run(&self, matches: Option<&clap::ArgMatches>) -> Result<(), Box<dyn std::error::Error>> {
+        let Some(matches) = matches else {
+            return Err(Box::new(io::Error::new(ErrorKind::Other, "No input")));
+        };
+        let files: Vec<_> = match matches.get_many::<String>("file") {
+            Some(c) => c.cloned().collect(),
+            None => vec![String::from("-")],
+        };
+        let color = match matches.get_one::<String>("color").map(String::as_str) {
+            Some("always") => ColorChoice::Always,
+            Some("ansi") => ColorChoice::AlwaysAnsi,
+            Some("auto") => {
+                if atty::is(atty::Stream::Stdout) {
+                    ColorChoice::Auto
+                } else {
+                    ColorChoice::Never
+                }
+            }
+            _ => ColorChoice::Never,
+        };
+        for (index, file) in files.into_iter().enumerate() {
+            if matches.get_flag("verbose") {
+                let mut stdout = StandardStream::stdout(color);
+                stdout.set_color(ColorSpec::new().set_fg(Some(Color::Green)))?;
+                match index {
+                    0 => writeln!(stdout, "===> {file} <==="),
+                    _ => writeln!(stdout, "\n===> {file} <==="),
+                }?;
+                stdout.reset()?;
+            }
+            rev_file(&file)?;
+        }
+        Ok(())
+    }
+
+    fn path(&self) -> Option<crate::Path> {
+        self.path
+    }
+}
+
+fn rev_file(file: &str) -> Result<(), io::Error> {
+    let reader: Box<dyn BufRead> = if file == "-" {
+        Box::new(BufReader::new(io::stdin()))
+    } else {
+        let buf = File::open(file)?;
+        Box::new(BufReader::new(buf))
+    };
+    for line in reader.lines() {
+        println!("{}", line.unwrap().chars().rev().collect::<String>());
+    }
+    Ok(())
+}