Implement simple menu system

src/state.rs

@@ -157,3 +157,82 @@ where
         }
     }
 }
+
+const MENU_HEIGHT: usize = 240 / 30;
+
+pub trait MenuItem {
+    fn as_text(&self) -> String;
+}
+
+#[derive(Default, Debug, Clone)]
+pub struct Menu<T: MenuItem> {
+    items: Vec<T>,
+    idx: usize,
+    scroll: usize,
+}
+
+impl<T: MenuItem> Menu<T> {
+    pub fn with_item(mut self, item: T) -> Menu<T> {
+        self.items.push(item);
+        self
+    }
+
+    pub fn poll<'s>(&'s mut self, io: &mut AsyncIO) -> Option<&'s T> {
+        use crate::async_io::KeypadButton;
+
+        for _ in 0..io.keypad.get_presses(KeypadButton::KeypadC) {
+            self.previous();
+        }
+        for _ in 0..io.keypad.get_presses(KeypadButton::KeypadD) {
+            self.next();
+        }
+
+        if io.keypad.get_presses(KeypadButton::KeypadA) > 0 {
+            Some(&self.items[self.idx])
+        } else {
+            None
+        }
+    }
+
+    pub fn previous(&mut self) {
+        if self.idx == 0 {
+            // Wrap index around
+            self.idx = self.items.len() - 1;
+            if self.idx >= (self.scroll + MENU_HEIGHT) {
+                self.scroll = (self.idx - MENU_HEIGHT) + 1;
+            }
+        } else {
+            self.idx -= 1;
+            if self.idx < self.scroll {
+                self.scroll = self.idx;
+            }
+        }
+    }
+
+    pub fn next(&mut self) {
+        self.idx = (self.idx + 1) % self.items.len();
+        if self.idx == 0 {
+            self.scroll = 0;
+        } else if self.idx >= (self.scroll + MENU_HEIGHT) {
+            self.scroll = (self.idx - MENU_HEIGHT) + 1;
+        }
+    }
+
+    pub fn draw(&self, data: &mut StateData) {
+        for (i, (idx, item)) in self
+            .items
+            .iter()
+            .enumerate()
+            .skip(self.scroll)
+            .take(MENU_HEIGHT)
+            .enumerate()
+        {
+            let mut settings = TextSettings::default();
+            if idx == self.idx {
+                settings.bg = Rgb565::white();
+                settings.fg = Rgb565::black();
+            }
+            data.draw_text(item.as_text(), Position::new(0, (i * 30) as i16), settings);
+        }
+    }
+}

src/states.rs

@@ -17,7 +17,7 @@ use crate::{
     },
     display::{Position, Rgb565},
     font::{HorizontalAlignment, VerticalAlignment},
-    state::{ATCommandHelper, State, StateData, TextSettings},
+    state::{ATCommandHelper, Menu, MenuItem, State, StateData, TextSettings},
 };
 
 #[derive(Debug, Clone)]
@@ -232,10 +232,7 @@ impl State for EnterPinState {
             match helper.poll(&mut data.io) {
                 Some(response) => match response.unwrap() {
                     EnterPinResult::Ok => {
-                        return Some(Box::new(TextState {
+                        return Some(Box::new(MainMenuState::default()));
-                            text: "SIM entered\nsuccessfully".to_owned(),
-                            after: PhoneNumberState::default(),
-                        }));
                     }
                     EnterPinResult::Error => {
                         return Some(Box::new(TextState {
@@ -275,6 +272,61 @@ impl State for EnterPinState {
     }
 }
 
+#[derive(Debug, Default)]
+enum MainMenuItem {
+    #[default]
+    Item1,
+    Item2,
+    Item3,
+    Item4,
+    Item5,
+    Item6,
+}
+impl MenuItem for MainMenuItem {
+    fn as_text(&self) -> String {
+        match self {
+            MainMenuItem::Item1 => "item1",
+            MainMenuItem::Item2 => "item2",
+            MainMenuItem::Item3 => "item3",
+            MainMenuItem::Item4 => "item4",
+            MainMenuItem::Item5 => "item5",
+            MainMenuItem::Item6 => "item6",
+        }
+        .to_string()
+    }
+}
+
+#[derive(Debug)]
+pub struct MainMenuState {
+    menu: Menu<MainMenuItem>,
+}
+
+impl Default for MainMenuState {
+    fn default() -> Self {
+        Self {
+            menu: Menu::default()
+                .with_item(MainMenuItem::Item1)
+                .with_item(MainMenuItem::Item2)
+                .with_item(MainMenuItem::Item3)
+                .with_item(MainMenuItem::Item4)
+                .with_item(MainMenuItem::Item5)
+                .with_item(MainMenuItem::Item6),
+        }
+    }
+}
+
+impl State for MainMenuState {
+    fn update(&mut self, data: &mut StateData) -> Option<Box<dyn State>> {
+        self.menu.poll(&mut data.io);
+        None
+    }
+
+    fn draw(&self, data: &mut StateData) {
+        data.clear_screen(Rgb565::black().as_color());
+        self.menu.draw(data);
+    }
+}
+
 #[derive(Clone, Default)]
 pub struct PhoneNumberState {
     input: NumberInput,