reworked code and added ability to build slides

src/app/fs_util/mod.rs

@@ -0,0 +1,74 @@
+use std::fs;
+
+struct RecursivePathFetch {
+    paths: Vec<String>,
+    ends_with: String,
+    path: String
+}
+
+impl RecursivePathFetch {
+    pub fn new_with_extension_filter(path: String, ends_with: String) -> Self {
+        return Self {
+            paths: vec![],
+            ends_with,
+            path
+        }
+    }
+
+    pub fn new(path: String) -> Self {
+        return Self {
+            paths: vec![],
+            ends_with: "".to_string(),
+            path
+        }
+    }
+
+    pub fn fetch(&mut self) -> Result<Vec<String>, String> {
+        if let Err(error) = self.read_dir(self.path.clone()) {
+            return Err(error);
+        } else {
+            return Ok(self.paths.clone());
+        }
+    }
+
+    fn read_dir(&mut self, path: String) -> Result<(), String> {
+        let Ok(entries) = fs::read_dir(path) else {
+            return self.dir_not_found();
+        };
+
+        for result in entries  {
+            let entry = result.unwrap();
+            let path = entry.path();
+            let str_path = path.to_str().unwrap();
+
+            if path.is_file() {
+                if str_path.ends_with(&self.ends_with) {
+                    self.paths.push(str_path.to_string())
+                }
+            } else if path.is_dir() {
+                let read_result = self.read_dir(str_path.to_string());
+                if  read_result.is_err() {
+                    return read_result;
+                }
+            }
+        }
+
+        return Ok(())
+    }
+
+    fn dir_not_found(&self) -> Result<(), String> {
+        return Err(format!(
+                "directory {} was not found or was changed while building",
+                self.path
+        ))
+    }
+}
+
+pub fn fetch_paths_recursive(path: &str, ends_with: &str) -> Result<Vec<String>, String> {
+    let mut path_fetch = RecursivePathFetch::new_with_extension_filter(
+        path.to_string(),
+        ends_with.to_string()
+    );
+
+    return path_fetch.fetch();
+}