1 files changed, 118 insertions, 0 deletions
diff --git a/CLI/rust/src/game_of_life/opts/validators.rs b/CLI/rust/src/game_of_life/opts/validators.rs
new file mode 100644
index 0000000..0de7b3f
--- /dev/null
+++ b/CLI/rust/src/game_of_life/opts/validators.rs
@@ -0,0 +1,118 @@
+//! Clap validators module
+//!
+//! Used for validating different CLI args (like width, height and delay)
+//! Ref: https://docs.rs/clap/3.0.0-beta.2/clap/struct.Arg.html#method.validator
+
+use terminal_size::{terminal_size, Height, Width};
+
+/// Validator to check if width configuration can be used
+///
+/// The maximum width allowed is the current terminal window width
+pub(crate) fn is_fitting_term_width(val: &str) -> Result<(), String> {
+    let (Width(term_width), Height(_)) = terminal_size().unwrap();
+    match val.parse::<u16>() {
+        Ok(n) if n > 0 && n <= term_width => Ok(()),
+        Ok(_) => Err(format!(
+            "must be between 1 and {} (current terminal width)",
+            term_width
+        )),
+        Err(e) => Err(e.to_string()),
+    }
+}
+
+#[cfg(test)]
+mod is_fitting_term_width {
+    use super::*;
+
+    #[test]
+    fn positive_value() {
+        assert!(is_fitting_term_width("13").is_ok());
+    }
+
+    #[test]
+    fn value_too_large() {
+        assert!(is_fitting_term_width("1337").is_err());
+    }
+
+    #[test]
+    fn negative_value() {
+        assert!(is_fitting_term_width("-13").is_err());
+    }
+
+    #[test]
+    fn string_value() {
+        assert!(is_fitting_term_width("not a number").is_err());
+    }
+}
+
+/// Validator to check if height configuration can be used
+///
+/// The maximum height allowed is the current terminal window height - 2
+/// The last 2 lines are used for status reporting (seed/input) and space
+/// for ease of use
+pub(crate) fn is_fitting_term_height(val: &str) -> Result<(), String> {
+    let (Width(_), Height(term_height)) = terminal_size().unwrap();
+    let term_height = term_height - 2;
+    match val.parse::<u16>() {
+        Ok(n) if n > 0 && n <= term_height => Ok(()),
+        Ok(_) => Err(format!(
+            "must be between 1 and {} (current terminal height)",
+            term_height
+        )),
+        Err(e) => Err(e.to_string()),
+    }
+}
+
+#[cfg(test)]
+mod is_fitting_term_height {
+    use super::*;
+
+    #[test]
+    fn positive_value() {
+        assert!(is_fitting_term_height("13").is_ok());
+    }
+
+    #[test]
+    fn value_too_large() {
+        assert!(is_fitting_term_height("1337").is_err());
+    }
+
+    #[test]
+    fn negative_value() {
+        assert!(is_fitting_term_height("-13").is_err());
+    }
+
+    #[test]
+    fn string_value() {
+        assert!(is_fitting_term_height("not a number").is_err());
+    }
+}
+
+/// Validator to check if delay value is positive
+pub(crate) fn is_positive(val: &str) -> Result<(), String> {
+    match val.parse::<i16>() {
+        Ok(n) if n.is_positive() => Ok(()),
+        Ok(_) => Err(String::from("must be postive value (so far)")),
+        Err(e) => Err(e.to_string()),
+    }
+}
+
+#[cfg(test)]
+mod is_positive {
+    use super::*;
+
+    #[test]
+    fn positive_value() {
+        assert!(is_positive("1337").is_ok());
+    }
+
+    #[test]
+    fn negative_value() {
+        assert!(is_positive("-1337").is_err());
+    }
+
+    #[test]
+    fn string_value() {
+        assert!(is_positive("not a number").is_err());
+    }
+}