From ec0300cfcddf589cdeb00e0a0629efac75edc9ca96d8e8ccd1c9f35ded1ef1a8 Mon Sep 17 00:00:00 2001
From: Nicholas Johnson <nick@nicholasjohnson.ch>
Date: Sat, 20 Apr 2024 00:00:00 +0000
Subject: Replace hardcoded error msgs with custom parsing

---
 src/main.rs | 71 +++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 38 insertions(+), 33 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 0da3b0e..0aba5f0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,9 +16,8 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-use clap::{value_parser, Parser};
-use colored::Colorize;
-use std::process::exit;
+use clap::Parser;
+use std::ops::RangeInclusive;
 
 mod hitomezashi;
 
@@ -26,17 +25,17 @@ mod hitomezashi;
 #[command(version, about, long_about = None)] // Read from `Cargo.toml`
 struct Cli {
     /// Pattern width
-    #[arg(value_parser = value_parser!(usize))]
+    #[arg(value_parser = dimension_in_range)]
     width: usize,
 
     /// Pattern height
-    #[arg(value_parser = value_parser!(usize))]
+    #[arg(value_parser = dimension_in_range)]
     height: usize,
 
     /// Set skew
     #[arg(short, long)]
     #[arg(default_value_t = 0.5)]
-    #[arg(value_parser = value_parser!(f64))]
+    #[arg(value_parser = skew_in_range)]
     skew: f64,
 }
 
@@ -44,35 +43,41 @@ struct Cli {
 fn main() {
     let cli = Cli::parse();
 
-    // validate bounds of width [1..]
-    if cli.width < 1 {
-        println!("{} invalid value '{}' for '{}': valid values are [1..]\n\nFor more information, try '{}'.",
-			"error:".red().bold(),
-			cli.width.to_string().yellow(),
-			"<WIDTH>".bold(),
-			"--help".bold());
-        exit(2);
-    }
+    hitomezashi::hitomezashi(cli.width, cli.height, Some(cli.skew));
+}
 
-    // validate bounds of height [1..]
-    if cli.height < 1 {
-        println!("{} invalid value '{}' for '{}': valid values are [1..]\n\nFor more information, try '{}'.",
-			"error:".red().bold(),
-			cli.height.to_string().yellow(),
-			"<HEIGHT>".bold(),
-			"--help".bold());
-        exit(2);
-    }
+const DIMENSION_RANGE: RangeInclusive<usize> = 1..=std::usize::MAX;
+
+fn dimension_in_range(s: &str) -> Result<usize, String> {
+    let dimension: usize = s
+        .parse()
+        .map_err(|_| format!("`{s}` isn't a dimension value!"))?;
 
-    // validate bounds of skew [0-1]
-    if cli.skew < 0.0 || cli.skew > 1.0 {
-        println!("{} invalid value '{}' for '{}': valid values are [0-1]\n\nFor more information, try '{}'.",
-			"error:".red().bold(),
-			cli.skew.to_string().yellow(),
-			"--skew <SKEW>".bold(),
-			"--help".bold());
-        exit(2);
+    if DIMENSION_RANGE.contains(&dimension) {
+        Ok(dimension)
+    } else {
+        Err(format!(
+            "Dimension not in range {}-{}",
+            DIMENSION_RANGE.start(),
+            DIMENSION_RANGE.end()
+        ))
     }
+}
 
-    hitomezashi::hitomezashi(cli.width, cli.height, Some(cli.skew));
+const SKEW_RANGE: RangeInclusive<f64> = 0.0..=1.0;
+
+fn skew_in_range(s: &str) -> Result<f64, String> {
+    let skew: f64 = s
+        .parse()
+        .map_err(|_| format!("`{s}` isn't a skew value!"))?;
+
+    if SKEW_RANGE.contains(&skew) {
+        Ok(skew)
+    } else {
+        Err(format!(
+            "Skew not in range {}-{}",
+            SKEW_RANGE.start(),
+            SKEW_RANGE.end()
+        ))
+    }
 }
-- 
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