added yaml,json + configurable keys

src/app.rs

@@ -1,4 +1,5 @@
-use crate::env::EnvVar;
+use crate::format::EnvVar;
+use tui_input::Input;
 
 pub enum Mode {
     Normal,
@@ -11,22 +12,26 @@ pub struct App {
     pub mode: Mode,
     pub running: bool,
     pub status_message: Option<String>,
+    pub input: Input,
 }
 
 impl App {
     pub fn new(vars: Vec<EnvVar>) -> Self {
+        let initial_input = vars.get(0).map(|v| v.value.clone()).unwrap_or_default();
         Self {
             vars,
             selected: 0,
             mode: Mode::Normal,
             running: true,
             status_message: None,
+            input: Input::new(initial_input),
         }
     }
 
     pub fn next(&mut self) {
         if !self.vars.is_empty() {
             self.selected = (self.selected + 1) % self.vars.len();
+            self.sync_input_with_selected();
         }
     }
 
@@ -37,14 +42,29 @@ impl App {
             } else {
                 self.selected -= 1;
             }
+            self.sync_input_with_selected();
+        }
+    }
+
+    pub fn sync_input_with_selected(&mut self) {
+        if let Some(var) = self.vars.get(self.selected) {
+            self.input = Input::new(var.value.clone());
+        }
+    }
+
+    pub fn commit_input(&mut self) {
+        if let Some(var) = self.vars.get_mut(self.selected) {
+            var.value = self.input.value().to_string();
         }
     }
 
     pub fn enter_insert(&mut self) {
         self.mode = Mode::Insert;
+        self.status_message = None;
     }
 
     pub fn enter_normal(&mut self) {
+        self.commit_input();
         self.mode = Mode::Normal;
     }