feat: colored console output

Closes #6.

src/ansi.rs

@@ -0,0 +1,51 @@
+use crate::cli::ColorChoice;
+
+/// Resets all colors and styles.
+const RESET: &str = "\x1b[0m";
+
+/// Bold.
+const BOLD: &str = "\x1b[1m";
+
+/// Dim.
+const DIM: &str = "\x1b[2m";
+
+/// Info (cyan).
+const INFO: &str = "\x1b[36m";
+
+/// Success (green).
+const SUCCESS: &str = "\x1b[32m";
+
+/// Error (magenta).
+const ERROR: &str = "\x1b[35m";
+
+pub struct Color {
+    pub reset: &'static str,
+    pub bold: &'static str,
+    pub dim: &'static str,
+    pub info: &'static str,
+    pub success: &'static str,
+    pub error: &'static str,
+}
+
+impl Color {
+    pub fn from_color_choice(choice: ColorChoice) -> Self {
+        match choice {
+            ColorChoice::Always => Color {
+                reset: RESET,
+                bold: BOLD,
+                dim: DIM,
+                info: INFO,
+                success: SUCCESS,
+                error: ERROR,
+            },
+            ColorChoice::Never => Color {
+                reset: "",
+                bold: "",
+                dim: "",
+                info: "",
+                success: "",
+                error: "",
+            },
+        }
+    }
+}

src/cli.rs

@@ -1,5 +1,5 @@
 use anyhow::{ensure, Context};
-use argh::FromArgs;
+use argh::{FromArgValue, FromArgs};
 use serde::Deserialize;
 use std::{
     path::PathBuf,
@@ -29,6 +29,10 @@ pub struct CLI {
     /// the total amount of chunks
     #[argh(option)]
     pub total_chunks: Option<usize>,
+
+    /// when to use color in the terminal output, either "always" or "never"
+    #[argh(option, default = "ColorChoice::Always")]
+    pub color: ColorChoice,
 }
 
 impl CLI {
@@ -55,6 +59,22 @@ impl CLI {
     }
 }
 
+#[derive(Clone, Copy, Debug)]
+pub enum ColorChoice {
+    Always,
+    Never,
+}
+
+impl FromArgValue for ColorChoice {
+    fn from_arg_value(value: &str) -> Result<Self, String> {
+        match value {
+            "always" => Ok(Self::Always),
+            "never" => Ok(Self::Never),
+            _ => Err("must be `always` or `never`.".to_string()),
+        }
+    }
+}
+
 /// Represents the output of `cargo-locate-project`.
 #[derive(Deserialize, Debug)]
 struct ProjectLocation {

src/main.rs

@@ -1,3 +1,4 @@
+mod ansi;
 mod chunk;
 mod cli;
 mod combos;
@@ -6,6 +7,7 @@ mod intern;
 mod metadata;
 mod runner;
 
+use ansi::*;
 use anyhow::{bail, Context};
 use chunk::select_chunk;
 use cli::CLI;
@@ -27,6 +29,15 @@ fn main() -> anyhow::Result<()> {
         None => Config::default(),
     };
 
+    let Color {
+        reset,
+        bold,
+        dim,
+        info,
+        success,
+        error,
+    } = Color::from_color_choice(cli.color);
+
     let metadata = load_metadata(&cli.manifest_path).context("Failed to load Cargo metadata.")?;
 
     let packages =
@@ -47,8 +58,11 @@ fn main() -> anyhow::Result<()> {
             .with_context(|| format!("Total features: {}, Max combo size: {max_k:?}", storage.len()))
             .with_context(|| format!("Unable to estimate checks required for all feature combinations of package {name}."))?;
 
-        println!("Package {name} with {} features.", storage.len());
-        println!("Estimated checks: {}", estimated_checks);
+        println!(
+            "{bold}Package {info}{name}{reset}{bold} with {info}{}{reset}{bold} features.{reset}",
+            storage.len()
+        );
+        println!("{bold}Estimated checks: {info}{}{reset}", estimated_checks);
 
         for combo in feature_combos(
             &storage,
@@ -64,7 +78,7 @@ fn main() -> anyhow::Result<()> {
 
             features.sort_unstable();
 
-            println!("\tChecking: {:?}", features);
+            println!("\t{dim}Checking:{reset} {info}{:?}{reset}", features);
 
             let status = check_with_features(&name, &cli.manifest_path, &combo, &storage)
                 .with_context(|| format!("Tried checking package {name}."))?;
@@ -79,16 +93,16 @@ fn main() -> anyhow::Result<()> {
     }
 
     if !failures.is_empty() {
-        eprintln!("Failure report:");
+        eprintln!("{error}{bold}Failure report:{reset}");
 
         for CheckFailure { package, features } in failures {
-            eprintln!("\tFailed checking package {package} with features {features:?}.");
+            eprintln!("\t{error}Failed checking package {bold}{package}{reset} {error}with features{reset} {features:?}.");
         }
 
         bail!("Some packages failed to be checked.");
     }
 
-    println!("Feature combination checks successful! Congrats :)");
+    println!("{success}{bold}Feature combination checks successful! Congrats :){reset}");
 
     Ok(())
 }