1 files changed, 146 insertions, 0 deletions

diff --git a/src/keybind.rs b/src/keybind.rs
new file mode 100644
index 0000000..8ab479a
--- /dev/null
+++ b/src/keybind.rs
@@ -0,0 +1,146 @@
+use std::{fmt, str::FromStr};
+
+use sdl2::keyboard::{Keycode, Mod};
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub struct Keybind {
+    keycode: Keycode,
+    keymod: Mod,
+}
+
+impl Keybind {
+    pub fn new(keycode: Keycode, keymod: Mod) -> Self {
+        Self { keycode, keymod }
+    }
+}
+
+// ctrl keys: C-<letter>   len 3
+// shift keys: S-<letter>  len 3
+// normal keys: <letter>   len 1
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum KeybindError {
+    Parse,
+    InvalidMod,
+    InvalidKey,
+}
+
+impl fmt::Display for KeybindError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Parse => write!(f, "error parsing keybind"),
+            Self::InvalidKey => write!(f, "unsupported keybind, try `A-Z0-9`"),
+            Self::InvalidMod => {
+                write!(f, "unsupported keybind modifier, try `C-<key> or S-<key>`")
+            }
+        }
+    }
+}
+
+impl std::error::Error for KeybindError {}
+
+impl FromStr for Keybind {
+    type Err = KeybindError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        parse_from_str(s)
+    }
+}
+
+fn parse_from_str(s: &str) -> Result<Keybind, KeybindError> {
+    let s = s.to_lowercase();
+    match s.len() {
+        // either ctrl or shift key
+        3 => {
+            let keymod = parse_modifier(&s[..2])?;
+            let keybind = parse_keybind(&s[2..])?;
+            Ok(Keybind::new(keybind, keymod))
+        }
+        1 => {
+            let keybind = parse_keybind(&s)?;
+            Ok(Keybind::new(keybind, Mod::NOMOD))
+        }
+        _ => Err(KeybindError::Parse),
+    }
+}
+
+fn parse_modifier(s: &str) -> Result<Mod, KeybindError> {
+    match s {
+        "c-" => Ok(Mod::LCTRLMOD),
+        "s-" => Ok(Mod::LSHIFTMOD),
+        _ => Err(KeybindError::InvalidMod),
+    }
+}
+
+fn parse_keybind(s: &str) -> Result<Keycode, KeybindError> {
+    match s.to_uppercase().as_str() {
+        "0" => Ok(Keycode::Num0),
+        "1" => Ok(Keycode::Num1),
+        "2" => Ok(Keycode::Num2),
+        "3" => Ok(Keycode::Num3),
+        "4" => Ok(Keycode::Num4),
+        "5" => Ok(Keycode::Num5),
+        "6" => Ok(Keycode::Num6),
+        "7" => Ok(Keycode::Num7),
+        "8" => Ok(Keycode::Num8),
+        "9" => Ok(Keycode::Num9),
+        "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | "N" | "O"
+        | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" => {
+            Ok(Keycode::from_name(s).unwrap())
+        }
+        _ => Err(KeybindError::InvalidKey),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn without_mod() {
+        assert_eq!(
+            Keybind::from_str("x").unwrap(),
+            Keybind::new(Keycode::X, Mod::NOMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("X").unwrap(),
+            Keybind::new(Keycode::X, Mod::NOMOD)
+        );
+    }
+    #[test]
+    fn with_ctrl_mod() {
+        assert_eq!(
+            Keybind::from_str("c-x").unwrap(),
+            Keybind::new(Keycode::X, Mod::LCTRLMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("C-x").unwrap(),
+            Keybind::new(Keycode::X, Mod::LCTRLMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("c-X").unwrap(),
+            Keybind::new(Keycode::X, Mod::LCTRLMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("C-X").unwrap(),
+            Keybind::new(Keycode::X, Mod::LCTRLMOD)
+        );
+    }
+    #[test]
+    fn with_shift_mod() {
+        assert_eq!(
+            Keybind::from_str("s-x").unwrap(),
+            Keybind::new(Keycode::X, Mod::LSHIFTMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("S-x").unwrap(),
+            Keybind::new(Keycode::X, Mod::LSHIFTMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("s-X").unwrap(),
+            Keybind::new(Keycode::X, Mod::LSHIFTMOD)
+        );
+        assert_eq!(
+            Keybind::from_str("S-X").unwrap(),
+            Keybind::new(Keycode::X, Mod::LSHIFTMOD)
+        );
+    }
+}