feat: implement the ruby module (#131)

src/modules/mod.rs

@@ -10,6 +10,7 @@ mod line_break;
 mod nodejs;
 mod package;
 mod python;
+mod ruby;
 mod rust;
 mod username;
 
@@ -23,6 +24,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
         "nodejs" => nodejs::module(context),
         "rust" => rust::module(context),
         "python" => python::module(context),
+        "ruby" => ruby::module(context),
         "golang" => golang::module(context),
         "line_break" => line_break::module(context),
         "package" => package::module(context),

src/modules/ruby.rs

@@ -0,0 +1,59 @@
+use ansi_term::Color;
+use std::process::Command;
+
+use super::{Context, Module};
+
+/// Creates a module with the current Ruby version
+///
+/// Will display the Ruby version if any of the following criteria are met:
+///     - Current directory contains a `.rb` file
+///     - Current directory contains a `Gemfile` file
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let is_rb_project = context
+        .new_scan_dir()
+        .set_files(&["Gemfile"])
+        .set_extensions(&["rb"])
+        .scan();
+
+    if !is_rb_project {
+        return None;
+    }
+
+    match get_ruby_version() {
+        Some(ruby_version) => {
+            const RUBY_CHAR: &str = "💎 ";
+            let module_color = Color::Red.bold();
+
+            let mut module = context.new_module("ruby")?;
+            module.set_style(module_color);
+
+            let formatted_version = format_ruby_version(&ruby_version)?;
+            module.new_segment("symbol", RUBY_CHAR);
+            module.new_segment("version", &formatted_version);
+
+            Some(module)
+        }
+        None => None,
+    }
+}
+
+fn get_ruby_version() -> Option<String> {
+    match Command::new("ruby").arg("-v").output() {
+        Ok(output) => Some(String::from_utf8(output.stdout).unwrap()),
+        Err(_) => None,
+    }
+}
+
+fn format_ruby_version(ruby_version: &str) -> Option<String> {
+    let version = ruby_version
+        // split into ["ruby", "2.6.0p0", "linux/amd64"]
+        .split_whitespace()
+        // return "2.6.0p0"
+        .nth(1)?
+        .get(0..5)?;
+
+    let mut formatted_version = String::with_capacity(version.len() + 1);
+    formatted_version.push('v');
+    formatted_version.push_str(version);
+    Some(formatted_version)
+}