refactor: extract template to its own file (#49)

src/template.txt

@@ -0,0 +1,26 @@
+advent_of_code::solution!(%DAY_NUMBER%);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    None
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, None);
+    }
+}

src/template/commands/scaffold.rs

@@ -6,33 +6,8 @@ use std::{
 
 use crate::template::Day;
 
-const MODULE_TEMPLATE: &str = r#"advent_of_code::solution!(DAY_NUMBER);
-
-pub fn part_one(input: &str) -> Option<u32> {
-    None
-}
-
-pub fn part_two(input: &str) -> Option<u32> {
-    None
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_part_one() {
-        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
-        assert_eq!(result, None);
-    }
-
-    #[test]
-    fn test_part_two() {
-        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
-        assert_eq!(result, None);
-    }
-}
-"#;
+const MODULE_TEMPLATE: &str =
+    include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/src/template.txt"));
 
 fn safe_create_file(path: &str) -> Result<File, std::io::Error> {
     OpenOptions::new().write(true).create_new(true).open(path)
@@ -57,7 +32,7 @@ pub fn handle(day: Day) {
 
     match file.write_all(
         MODULE_TEMPLATE
-            .replace("DAY_NUMBER", &day.into_inner().to_string())
+            .replace("%DAY_NUMBER%", &day.into_inner().to_string())
             .as_bytes(),
     ) {
         Ok(()) => {