1 files changed, 77 insertions, 15 deletions

diff --git a/src/app.rs b/src/app.rs
index 92f89c0..bc12812 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -1,11 +1,76 @@
 use crate::input::{InputMode, InputParam, Row};
 
-pub const INPUT_TAB_INDEX: usize = 0;
-pub const CONFIG_TAB_INDEX: usize = 1;
+#[derive(Copy, Clone)]
+pub enum Tab {
+    Const = 0,
+    Input = 1,
+    Config = 2,
+}
+
+impl Tab {
+    fn next(&self) -> Self {
+        match self {
+            Self::Const => Self::Input,
+            Self::Input => Self::Config,
+            Self::Config => Self::Const,
+        }
+    }
+
+    fn previous(&self) -> Self {
+        match self {
+            Self::Const => Self::Config,
+            Self::Input => Self::Const,
+            Self::Config => Self::Input,
+        }
+    }
+
+    fn string(&self) -> String {
+        match self {
+            Self::Const => "Const".to_string(),
+            Self::Input => "Input".to_string(),
+            Self::Config => "Config".to_string(),
+        }
+    }
+}
+
+impl IntoIterator for Tab {
+    type Item = Tab;
+    type IntoIter = TabIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        TabIter { tab: Some(self) }
+    }
+}
+
+pub struct TabIter {
+    tab: Option<Tab>,
+}
+
+impl Iterator for TabIter {
+    type Item = Tab;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.tab {
+            Some(Tab::Const) => {
+                self.tab = Some(Tab::Input);
+                Some(Tab::Const)
+            }
+            Some(Tab::Input) => {
+                self.tab = Some(Tab::Config);
+                Some(Tab::Input)
+            }
+            Some(Tab::Config) => {
+                self.tab = None;
+                Some(Tab::Config)
+            }
+            None => None,
+        }
+    }
+}
 
 pub struct App {
-    pub tab_index: usize,
-    tab_titles: [&'static str; 2],
+    pub tab: Tab,
+    tab_titles: Vec<String>,
 
     rows: Vec<Row>,
     selected_row: usize,
@@ -19,20 +84,16 @@ impl App {
         &self.rows
     }
 
-    pub fn tab_titles(&self) -> &[&str] {
+    pub fn tab_titles(&self) -> &Vec<String> {
         &self.tab_titles
     }
 
     pub fn next_tab(&mut self) {
-        self.tab_index = (self.tab_index + 1) % self.tab_titles.len();
+        self.tab = self.tab.next();
     }
 
     pub fn previous_tab(&mut self) {
-        if self.tab_index > 0 {
-            self.tab_index -= 1;
-        } else {
-            self.tab_index = self.tab_titles.len() - 1;
-        }
+        self.tab = self.tab.previous();
     }
 
     pub fn next_row(&mut self) {
@@ -67,8 +128,9 @@ impl App {
     pub fn remove_row(&mut self) {
         if self.rows.len() > 1 {
             self.rows.remove(self.selected_row);
-            if self.selected_row > 0 {
-                self.selected_row -= 1;
+            // If we remove the last row, the selected row will be out of range.
+            if self.selected_row >= self.rows.len() {
+                self.selected_row = self.rows.len() - 1;
             }
         }
     }
@@ -93,8 +155,8 @@ impl App {
 impl Default for App {
     fn default() -> App {
         App {
-            tab_index: INPUT_TAB_INDEX,
-            tab_titles: ["Input", "Config"],
+            tab: Tab::Const,
+            tab_titles: Tab::Const.into_iter().map(|t| t.string()).collect(),
             rows: vec![Row::default()],
             selected_row: 0,
             selected_column: InputParam::Rpm(String::new()),