Fix screen stack popping and add a menu

MenuScreen.h

@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2019  Max Regan
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "macros.h"
+
+#include <initializer_list>
+
+#include "SystemFonts.h"
+#include "ScreenManager.h"
+#include "Screen.h"
+
+struct MenuScreenItem {
+
+    enum class Type{
+                     NONE,
+                     SCREEN,
+                     BACK,
+    };
+
+    MenuScreenItem()
+        : m_text(nullptr)
+        , m_screen(nullptr)
+        , m_type(Type::NONE)
+    {}
+
+    MenuScreenItem(const char *item, Screen &m_screen)
+        : m_text(item)
+        , m_screen(&m_screen)
+        , m_type(Type::SCREEN)
+    {}
+
+    MenuScreenItem(const char *item)
+        : m_text(item)
+        , m_screen(nullptr)
+        , m_type(Type::BACK)
+    {}
+
+    const char *m_text;
+    Screen *m_screen;
+    Type m_type;
+};
+
+class MenuScreen : public Screen {
+public:
+
+    static constexpr std::size_t MAX_ITEMS = 10;
+
+    MenuScreen(BSP::DisplayDriver &display,
+               ScreenManager &manager,
+               std::initializer_list<MenuScreenItem> items)
+        : m_driver(display)
+        , m_manager(manager)
+        , m_items()
+        , m_num_items{0}
+        , m_selected{0}
+    {
+        for (auto &item : items) {
+            m_items[m_num_items++] = item;
+
+            // Leave room for "back"
+            if (m_num_items == MAX_ITEMS - 1) {
+                break;
+            }
+        }
+
+        new (&m_items[m_num_items++]) MenuScreenItem("Back");
+    }
+
+    void render() {
+        const struct font &font = default_font;
+        // const uint32_t font_width = default_font_width;
+
+        m_driver.clear();
+
+        for (std::size_t i = 0; i < m_num_items; i++) {
+            uint32_t x = 0;
+            uint32_t y = 8 + (font.size + 8) * i;
+            const char *spacer = " ";
+            if (i == m_selected) {
+                spacer = ">";
+            }
+            m_driver.string_at(&x, y, spacer, &font);
+            m_driver.string_at(&x, y, m_items[i].m_text, &font);
+        }
+        m_driver.refresh();
+    }
+
+    Common::ReturnCode init() {
+        return Common::ReturnCode::OK;
+    }
+
+    Common::Schedule::NextTime execute() override {
+        return Common::Schedule::NextTime::never();
+    }
+
+    void enable() override {
+        m_selected = 0;
+        render();
+    }
+
+    void disable() override {
+        m_driver.clear();
+    }
+
+    void notify_up_button() override {
+        if (m_selected == 0) {
+            m_selected = m_num_items - 1;
+        } else {
+            m_selected--;
+        }
+
+        render();
+    }
+
+    void notify_middle_button() override {
+        MenuScreenItem &item = m_items[m_selected];
+        if (item.m_type == MenuScreenItem::Type::SCREEN) {
+            m_manager.push_screen(*item.m_screen);
+        } else if (item.m_type == MenuScreenItem::Type::BACK) {
+            m_manager.pop_screen();
+        }
+    }
+
+    void notify_down_button() override {
+        if (m_selected == m_num_items - 1) {
+            m_selected = 0;
+        } else {
+            m_selected++;
+        }
+
+        render();
+    }
+
+private:
+
+    BSP::DisplayDriver &m_driver;
+    ScreenManager &m_manager;
+    MenuScreenItem m_items[MAX_ITEMS];
+    std::size_t m_num_items;
+    std::size_t m_selected;
+
+
+};