initial commit, enjoy the ride

src/fleen_app.rs

@@ -0,0 +1,81 @@
+use std::ops::Index;
+use std::path::PathBuf;
+use std::process::Command;
+use rfd::MessageDialogResult::No;
+use thiserror::Error;
+use crate::fleen_app::FleenError::{RootDirNonexistenceError, RootDirPopulatedError};
+use crate::fleen_app::TreeEntry::{CloseDir, Dir};
+
+#[derive(Error, Debug, Clone)]
+pub enum FleenError {
+    #[error("Can't reach root dir {0}")]
+    RootDirNonexistenceError(PathBuf),
+    #[error("Root dir is nonempty, you probably don't want to create an app here: {0}")]
+    RootDirPopulatedError(PathBuf)
+}
+
+#[derive(Clone, Debug)]
+pub enum TreeEntry {
+    File(PathBuf),
+    Dir(PathBuf),
+    CloseDir
+}
+
+#[derive(Clone)]
+pub struct FleenApp {
+    root: PathBuf,
+    files_cache: Option<Vec<TreeEntry>>
+}
+
+impl FleenApp {
+    pub fn open(root: PathBuf) -> Result<Self, FleenError> {
+        match root.try_exists() {
+            Ok(true) => Ok(Self { root, files_cache: None }),
+            _ => Err(RootDirNonexistenceError(root))
+        }
+    }
+
+    pub fn create(root: PathBuf) -> Result<Self, FleenError> {
+        match root.read_dir() {
+            Ok(mut iter) => {
+                if iter.next().is_some() {
+                    Err(RootDirPopulatedError(root))
+                } else {
+                    Ok(Self { root, files_cache: None })
+                }
+            }
+            Err(_) => {
+                Err(RootDirNonexistenceError(root))
+            }
+        }
+    }
+
+    pub fn file_tree_entries(&mut self) -> impl IntoIterator<Item=TreeEntry> {
+        if self.files_cache.is_none() {
+            let mut entries = vec![];
+
+            fn visit_dir(dir: &PathBuf, entries: &mut Vec<TreeEntry>) {
+                for entry in dir.read_dir().unwrap() {
+                    let path = entry.unwrap().path();
+                    if path.is_file() {
+                        entries.push(TreeEntry::File(path))
+                    } else if path.is_dir() {
+                        entries.push(Dir(path.clone()));
+                        visit_dir(&path, entries);
+                        entries.push(CloseDir)
+                    }
+                }
+            }
+
+            visit_dir(&self.root, &mut entries);
+            self.files_cache = Some(entries)
+        }
+        self.files_cache.as_ref().unwrap().clone()
+    }
+
+    pub fn open_file_at_index(&self, index: usize) {
+        if let TreeEntry::File(path) = &self.files_cache.as_ref().unwrap()[index] {
+            Command::new("open").arg(path).spawn();
+        }
+    }
+}