architecture

src/app.rs

@@ -158,8 +158,32 @@ impl Default for App {
 }
 
 impl App {
-    pub fn new(title: &str, enhanced_graphics: bool) -> App {
-        Self::default()
+    pub fn next(&mut self) {
+        let i = match self.selected_database.selected() {
+            Some(i) => {
+                if i >= self.databases.len() - 1 {
+                    0
+                } else {
+                    i + 1
+                }
+            }
+            None => 0,
+        };
+        self.selected_database.select(Some(i));
+    }
+
+    pub fn previous(&mut self) {
+        let i = match self.selected_database.selected() {
+            Some(i) => {
+                if i == 0 {
+                    self.databases.len() - 1
+                } else {
+                    i - 1
+                }
+            }
+            None => 0,
+        };
+        self.selected_database.select(Some(i));
     }
 
     pub fn next_database(&mut self) {

src/handlers/table_list.rs

@@ -0,0 +1,43 @@
+use tui::widgets::TableState;
+
+pub struct TableList {
+    state: TableState,
+    tables: Vec<Vec<String>>,
+}
+
+impl TableList {
+    fn new() -> Self {
+        Self {
+            state: TableState::default(),
+            tables: vec![],
+        }
+    }
+
+    pub fn next(&mut self) {
+        let i = match self.state.selected() {
+            Some(i) => {
+                if i >= self.tables.len() - 1 {
+                    0
+                } else {
+                    i + 1
+                }
+            }
+            None => 0,
+        };
+        self.state.select(Some(i));
+    }
+
+    pub fn previous(&mut self) {
+        let i = match self.state.selected() {
+            Some(i) => {
+                if i == 0 {
+                    self.tables.len() - 1
+                } else {
+                    i - 1
+                }
+            }
+            None => 0,
+        };
+        self.state.select(Some(i));
+    }
+}

src/ui/mod.rs

@@ -87,14 +87,17 @@ pub fn draw<B: Backend>(f: &mut Frame<'_, B>, app: &mut App) -> anyhow::Result<(
     f.render_stateful_widget(tasks, left_chunks[0], &mut app.selected_database);
 
     let databases = app.databases.clone();
-    let tables: Vec<ListItem> = databases[app.selected_database.selected().unwrap_or(0)]
-        .tables
-        .iter()
-        .map(|i| {
-            ListItem::new(vec![Spans::from(Span::raw(&i.name))])
-                .style(Style::default().fg(Color::White))
-        })
-        .collect();
+    let tables: Vec<ListItem> = databases[match app.selected_database.selected() {
+        Some(index) => index,
+        None => 0,
+    }]
+    .tables
+    .iter()
+    .map(|i| {
+        ListItem::new(vec![Spans::from(Span::raw(&i.name))])
+            .style(Style::default().fg(Color::White))
+    })
+    .collect();
     let tasks = List::new(tables)
         .block(Block::default().borders(Borders::ALL).title("Tables"))
         .highlight_style(Style::default().fg(Color::Green))