Add home screen (#42)

## Summary

* Add home screen
* Sits as new root screen, allows for navigation to settings or file
list

src/main.cpp

@@ -21,6 +21,7 @@
 #include "screens/EpubReaderScreen.h"
 #include "screens/FileSelectionScreen.h"
 #include "screens/FullScreenMessageScreen.h"
+#include "screens/HomeScreen.h"
 #include "screens/SettingsScreen.h"
 #include "screens/SleepScreen.h"
 
@@ -150,6 +151,7 @@ void enterDeepSleep() {
 }
 
 void onGoHome();
+void onGoToFileSelection();
 void onSelectEpubFile(const std::string& path) {
   exitScreen();
   enterNewScreen(new FullScreenMessageScreen(renderer, inputManager, "Loading..."));
@@ -159,16 +161,21 @@ void onSelectEpubFile(const std::string& path) {
     appState.openEpubPath = path;
     appState.saveToFile();
     exitScreen();
-    enterNewScreen(new EpubReaderScreen(renderer, inputManager, std::move(epub), onGoHome));
+    enterNewScreen(new EpubReaderScreen(renderer, inputManager, std::move(epub), onGoToFileSelection));
   } else {
     exitScreen();
     enterNewScreen(
         new FullScreenMessageScreen(renderer, inputManager, "Failed to load epub", REGULAR, EInkDisplay::HALF_REFRESH));
     delay(2000);
-    onGoHome();
+    onGoToFileSelection();
   }
 }
 
+void onGoToFileSelection() {
+  exitScreen();
+  enterNewScreen(new FileSelectionScreen(renderer, inputManager, onSelectEpubFile, onGoHome));
+}
+
 void onGoToSettings() {
   exitScreen();
   enterNewScreen(new SettingsScreen(renderer, inputManager, onGoHome));
@@ -176,7 +183,7 @@ void onGoToSettings() {
 
 void onGoHome() {
   exitScreen();
-  enterNewScreen(new FileSelectionScreen(renderer, inputManager, onSelectEpubFile, onGoToSettings));
+  enterNewScreen(new HomeScreen(renderer, inputManager, onGoToFileSelection, onGoToSettings));
 }
 
 void setup() {
@@ -221,8 +228,7 @@ void setup() {
     }
   }
 
-  exitScreen();
-  enterNewScreen(new FileSelectionScreen(renderer, inputManager, onSelectEpubFile, onGoToSettings));
+  onGoHome();
 
   // Ensure we're not still holding the power button before leaving setup
   waitForPowerRelease();

src/screens/EpubReaderScreen.cpp

@@ -98,7 +98,7 @@ void EpubReaderScreen::handleInput() {
   }
 
   if (inputManager.wasPressed(InputManager::BTN_BACK)) {
-    onGoHome();
+    onGoBack();
     return;
   }
 

src/screens/EpubReaderScreen.h

@@ -17,7 +17,7 @@ class EpubReaderScreen final : public Screen {
   int nextPageNumber = 0;
   int pagesUntilFullRefresh = 0;
   bool updateRequired = false;
-  const std::function<void()> onGoHome;
+  const std::function<void()> onGoBack;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -27,8 +27,8 @@ class EpubReaderScreen final : public Screen {
 
  public:
   explicit EpubReaderScreen(GfxRenderer& renderer, InputManager& inputManager, std::unique_ptr<Epub> epub,
-                            const std::function<void()>& onGoHome)
-      : Screen(renderer, inputManager), epub(std::move(epub)), onGoHome(onGoHome) {}
+                            const std::function<void()>& onGoBack)
+      : Screen(renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
   void onEnter() override;
   void onExit() override;
   void handleInput() override;

src/screens/FileSelectionScreen.cpp

@@ -98,8 +98,8 @@ void FileSelectionScreen::handleInput() {
       loadFiles();
       updateRequired = true;
     } else {
-      // At root level, go to settings
-      onSettingsOpen();
+      // At root level, go back home
+      onGoHome();
     }
   } else if (prevPressed) {
     selectorIndex = (selectorIndex + files.size() - 1) % files.size();
@@ -129,7 +129,7 @@ void FileSelectionScreen::render() const {
   renderer.drawCenteredText(READER_FONT_ID, 10, "CrossPoint Reader", true, BOLD);
 
   // Help text
-  renderer.drawText(SMALL_FONT_ID, 20, GfxRenderer::getScreenHeight() - 30, "Press BACK for Settings");
+  renderer.drawText(SMALL_FONT_ID, 20, GfxRenderer::getScreenHeight() - 30, "Press BACK for Home");
 
   if (files.empty()) {
     renderer.drawText(UI_FONT_ID, 20, 60, "No EPUBs found");

src/screens/FileSelectionScreen.h

@@ -17,7 +17,7 @@ class FileSelectionScreen final : public Screen {
   int selectorIndex = 0;
   bool updateRequired = false;
   const std::function<void(const std::string&)> onSelect;
-  const std::function<void()> onSettingsOpen;
+  const std::function<void()> onGoHome;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -27,8 +27,8 @@ class FileSelectionScreen final : public Screen {
  public:
   explicit FileSelectionScreen(GfxRenderer& renderer, InputManager& inputManager,
                                const std::function<void(const std::string&)>& onSelect,
-                               const std::function<void()>& onSettingsOpen)
-      : Screen(renderer, inputManager), onSelect(onSelect), onSettingsOpen(onSettingsOpen) {}
+                               const std::function<void()>& onGoHome)
+      : Screen(renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void handleInput() override;

src/screens/HomeScreen.cpp

@@ -0,0 +1,99 @@
+#include "HomeScreen.h"
+
+#include <GfxRenderer.h>
+#include <SD.h>
+
+#include "config.h"
+
+void HomeScreen::taskTrampoline(void* param) {
+  auto* self = static_cast<HomeScreen*>(param);
+  self->displayTaskLoop();
+}
+
+void HomeScreen::onEnter() {
+  renderingMutex = xSemaphoreCreateMutex();
+
+  selectorIndex = 0;
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&HomeScreen::taskTrampoline, "HomeScreenTask",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void HomeScreen::onExit() {
+  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void HomeScreen::handleInput() {
+  const bool prevPressed =
+      inputManager.wasPressed(InputManager::BTN_UP) || inputManager.wasPressed(InputManager::BTN_LEFT);
+  const bool nextPressed =
+      inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT);
+
+  if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+    if (selectorIndex == 0) {
+      onFileSelectionOpen();
+    } else if (selectorIndex == 1) {
+      onSettingsOpen();
+    }
+  } else if (prevPressed) {
+    selectorIndex = (selectorIndex + menuItemCount - 1) % menuItemCount;
+    updateRequired = true;
+  } else if (nextPressed) {
+    selectorIndex = (selectorIndex + 1) % menuItemCount;
+    updateRequired = true;
+  }
+}
+
+void HomeScreen::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void HomeScreen::render() const {
+  renderer.clearScreen();
+
+  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageHeight = GfxRenderer::getScreenHeight();
+  renderer.drawCenteredText(READER_FONT_ID, 10, "CrossPoint Reader", true, BOLD);
+
+  // Draw selection
+  renderer.fillRect(0, 60 + selectorIndex * 30 + 2, pageWidth - 1, 30);
+  renderer.drawText(UI_FONT_ID, 20, 60, "Read", selectorIndex != 0);
+  renderer.drawText(UI_FONT_ID, 20, 90, "Settings", selectorIndex != 1);
+
+  renderer.drawRect(25, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 25 + (105 - renderer.getTextWidth(UI_FONT_ID, "Back")) / 2, pageHeight - 35, "Back");
+
+  renderer.drawRect(130, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 130 + (105 - renderer.getTextWidth(UI_FONT_ID, "Confirm")) / 2, pageHeight - 35,
+                    "Confirm");
+
+  renderer.drawRect(245, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 245 + (105 - renderer.getTextWidth(UI_FONT_ID, "Left")) / 2, pageHeight - 35, "Left");
+
+  renderer.drawRect(350, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 350 + (105 - renderer.getTextWidth(UI_FONT_ID, "Right")) / 2, pageHeight - 35, "Right");
+
+  renderer.displayBuffer();
+}

src/screens/HomeScreen.h

@@ -0,0 +1,31 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+
+#include "Screen.h"
+
+class HomeScreen final : public Screen {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  int selectorIndex = 0;
+  bool updateRequired = false;
+  const std::function<void()> onFileSelectionOpen;
+  const std::function<void()> onSettingsOpen;
+
+  static constexpr int menuItemCount = 2;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+
+ public:
+  explicit HomeScreen(GfxRenderer& renderer, InputManager& inputManager,
+                      const std::function<void()>& onFileSelectionOpen, const std::function<void()>& onSettingsOpen)
+      : Screen(renderer, inputManager), onFileSelectionOpen(onFileSelectionOpen), onSettingsOpen(onSettingsOpen) {}
+  void onEnter() override;
+  void onExit() override;
+  void handleInput() override;
+};