Add file selection screen

lib/EpdRenderer/EpdRenderer.cpp

@@ -57,10 +57,10 @@ void EpdRenderer::drawText(const int x, const int y, const char* text, const boo
   getFontRenderer(bold, italic)->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
 }
 
-void EpdRenderer::drawSmallText(const int x, const int y, const char* text) const {
+void EpdRenderer::drawSmallText(const int x, const int y, const char* text, const uint16_t color) const {
   int ypos = y + smallFont->font->data->advanceY + marginTop;
   int xpos = x + marginLeft;
-  smallFont->renderString(text, &xpos, &ypos, GxEPD_BLACK);
+  smallFont->renderString(text, &xpos, &ypos, color > 0 ? GxEPD_BLACK : GxEPD_WHITE);
 }
 
 void EpdRenderer::drawTextBox(const int x, const int y, const std::string& text, const int width, const int height,

lib/EpdRenderer/EpdRenderer.h

@@ -26,7 +26,7 @@ class EpdRenderer {
   int getTextWidth(const char* text, bool bold = false, bool italic = false) const;
   int getSmallTextWidth(const char* text) const;
   void drawText(int x, int y, const char* text, bool bold = false, bool italic = false, uint16_t color = 1) const;
-  void drawSmallText(int x, int y, const char* text) const;
+  void drawSmallText(int x, int y, const char* text, uint16_t color = 1) const;
   void drawTextBox(int x, int y, const std::string& text, int width, int height, bool bold = false,
                    bool italic = false) const;
   void drawLine(int x1, int y1, int x2, int y2, uint16_t color) const;

src/CrossPointState.cpp

@@ -0,0 +1,46 @@
+#include "CrossPointState.h"
+
+#include <HardwareSerial.h>
+#include <SD.h>
+#include <Serialization.h>
+
+#include <fstream>
+
+constexpr uint8_t STATE_VERSION = 1;
+constexpr char STATE_FILE[] = "/sd/.crosspoint/state.bin";
+
+void CrossPointState::serialize(std::ostream& os) const {
+  serialization::writePod(os, STATE_VERSION);
+  serialization::writeString(os, openEpubPath);
+}
+
+CrossPointState* CrossPointState::deserialize(std::istream& is) {
+  const auto state = new CrossPointState();
+
+  uint8_t version;
+  serialization::readPod(is, version);
+  if (version != STATE_VERSION) {
+    Serial.printf("CrossPointState: Unknown version %u\n", version);
+    return state;
+  }
+
+  serialization::readString(is, state->openEpubPath);
+  return state;
+}
+
+void CrossPointState::saveToFile() const {
+  std::ofstream outputFile(STATE_FILE);
+  serialize(outputFile);
+  outputFile.close();
+}
+
+CrossPointState* CrossPointState::loadFromFile() {
+  if (!SD.exists(&STATE_FILE[3])) {
+    return new CrossPointState();
+  }
+
+  std::ifstream inputFile(STATE_FILE);
+  CrossPointState* state = deserialize(inputFile);
+  inputFile.close();
+  return state;
+}

src/CrossPointState.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <iosfwd>
+#include <string>
+
+class CrossPointState {
+  void serialize(std::ostream& os) const;
+  static CrossPointState* deserialize(std::istream& is);
+
+ public:
+  std::string openEpubPath;
+  ~CrossPointState() = default;
+  void saveToFile() const;
+  static CrossPointState* loadFromFile();
+};

src/main.cpp

@@ -6,8 +6,10 @@
 #include <SPI.h>
 
 #include "Battery.h"
+#include "CrossPointState.h"
 #include "Input.h"
 #include "screens/EpubReaderScreen.h"
+#include "screens/FileSelectionScreen.h"
 #include "screens/FullScreenMessageScreen.h"
 
 #define SPI_FQ 40000000
@@ -28,6 +30,7 @@ GxEPD2_BW<GxEPD2_426_GDEQ0426T82, GxEPD2_426_GDEQ0426T82::HEIGHT> display(GxEPD2
                                                                                                  EPD_RST, EPD_BUSY));
 auto renderer = new EpdRenderer(&display);
 Screen* currentScreen;
+CrossPointState* appState;
 
 // Power button timing
 // Time required to confirm boot from sleep
@@ -102,6 +105,21 @@ void setupSerial() {
   }
 }
 
+void onGoHome();
+void onSelectEpubFile(const std::string& path) {
+  enterNewScreen(new FullScreenMessageScreen(renderer, "Loading..."));
+
+  Epub* epub = loadEpub(path);
+  if (epub) {
+    appState->openEpubPath = path;
+    appState->saveToFile();
+    enterNewScreen(new EpubReaderScreen(renderer, epub, onGoHome));
+  } else {
+    enterNewScreen(new FullScreenMessageScreen(renderer, "Failed to load epub"));
+  }
+}
+void onGoHome() { enterNewScreen(new FileSelectionScreen(renderer, onSelectEpubFile)); }
+
 void setup() {
   setupInputPinModes();
 
@@ -127,37 +145,21 @@ void setup() {
   display.setTextColor(GxEPD_BLACK);
   Serial.println("Display initialized");
 
-  enterNewScreen(new FullScreenMessageScreen(renderer, "Loading...", true));
+  enterNewScreen(new FullScreenMessageScreen(renderer, "Booting...", true));
 
   // SD Card Initialization
   SD.begin(SD_SPI_CS, SPI, SPI_FQ);
 
-  // TODO: Add a file selection screen, for now just load the first file
-  File root = SD.open("/");
-  String filename;
-  while (true) {
-    filename = root.getNextFileName();
-    if (!filename) {
-      break;
-    }
-
-    if (filename.substring(filename.length() - 5) == ".epub") {
-      Serial.printf("Found epub: %s\n", filename.c_str());
-      break;
+  appState = CrossPointState::loadFromFile();
+  if (!appState->openEpubPath.empty()) {
+    Epub* epub = loadEpub(appState->openEpubPath);
+    if (epub) {
+      enterNewScreen(new EpubReaderScreen(renderer, epub, onGoHome));
+      return;
     }
   }
 
-  if (!filename) {
-    enterNewScreen(new FullScreenMessageScreen(renderer, "Could not find epub"));
-    return;
-  }
-
-  Epub* epub = loadEpub(std::string(filename.c_str()));
-  if (epub) {
-    enterNewScreen(new EpubReaderScreen(renderer, epub));
-  } else {
-    enterNewScreen(new FullScreenMessageScreen(renderer, "Failed to load epub"));
-  }
+  enterNewScreen(new FileSelectionScreen(renderer, onSelectEpubFile));
 }
 
 void loop() {

src/screens/EpubReaderScreen.cpp

@@ -41,6 +41,7 @@ void EpubReaderScreen::onEnter() {
 
 void EpubReaderScreen::onExit() {
   vTaskDelete(displayTaskHandle);
+  displayTaskHandle = nullptr;
   xSemaphoreTake(sectionMutex, portMAX_DELAY);
   vSemaphoreDelete(sectionMutex);
   sectionMutex = nullptr;
@@ -91,6 +92,8 @@ void EpubReaderScreen::handleInput(const Input input) {
     }
 
     updateRequired = true;
+  } else if (input.button == BACK) {
+    onGoHome();
   }
 }
 

src/screens/EpubReaderScreen.h

@@ -15,6 +15,7 @@ class EpubReaderScreen final : public Screen {
   int currentSpineIndex = 0;
   int nextPageNumber = 0;
   bool updateRequired = false;
+  const std::function<void()> onGoHome;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -22,7 +23,8 @@ class EpubReaderScreen final : public Screen {
   void renderStatusBar() const;
 
  public:
-  explicit EpubReaderScreen(EpdRenderer* renderer, Epub* epub) : Screen(renderer), epub(epub) {}
+  explicit EpubReaderScreen(EpdRenderer* renderer, Epub* epub, const std::function<void()>& onGoHome)
+      : Screen(renderer), epub(epub), onGoHome(onGoHome) {}
   ~EpubReaderScreen() override { free(section); }
   void onEnter() override;
   void onExit() override;

src/screens/FileSelectionScreen.cpp

@@ -0,0 +1,87 @@
+#include "FileSelectionScreen.h"
+
+#include <EpdRenderer.h>
+#include <SD.h>
+
+void FileSelectionScreen::taskTrampoline(void* param) {
+  auto* self = static_cast<FileSelectionScreen*>(param);
+  self->displayTaskLoop();
+}
+
+void FileSelectionScreen::onEnter() {
+  files.clear();
+  auto root = SD.open("/");
+  File file;
+  while ((file = root.openNextFile())) {
+    if (file.isDirectory()) {
+      file.close();
+      continue;
+    }
+
+    auto filename = std::string(file.name());
+    if (filename.substr(filename.length() - 5) != ".epub" || filename[0] == '.') {
+      file.close();
+      continue;
+    }
+
+    files.emplace_back(filename);
+    file.close();
+  }
+  root.close();
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&FileSelectionScreen::taskTrampoline, "FileSelectionScreenTask",
+              1024,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void FileSelectionScreen::onExit() {
+  vTaskDelete(displayTaskHandle);
+  displayTaskHandle = nullptr;
+}
+
+void FileSelectionScreen::handleInput(const Input input) {
+  if (input.button == VOLUME_DOWN) {
+    selectorIndex = (selectorIndex + 1) % files.size();
+    updateRequired = true;
+  } else if (input.button == VOLUME_UP) {
+    selectorIndex = (selectorIndex + files.size() - 1) % files.size();
+    updateRequired = true;
+  } else if (input.button == CONFIRM) {
+    Serial.printf("Selected file: %s\n", files[selectorIndex].c_str());
+    onSelect("/" + files[selectorIndex]);
+  }
+}
+
+void FileSelectionScreen::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      render();
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void FileSelectionScreen::render() const {
+  renderer->clearScreen();
+
+  const auto pageWidth = renderer->getPageWidth();
+  const auto titleWidth = renderer->getTextWidth("CrossPoint Reader", true);
+  renderer->drawText((pageWidth - titleWidth) / 2, 0, "CrossPoint Reader", true);
+
+  // Draw selection
+  renderer->fillRect(0, 50 + selectorIndex * 20 + 2, pageWidth - 1, 20, 1);
+
+  for (size_t i = 0; i < files.size(); i++) {
+    const auto file = files[i];
+    renderer->drawSmallText(50, 50 + i * 20, file.c_str(), i == selectorIndex ? 0 : 1);
+  }
+
+  renderer->flushDisplay();
+}

src/screens/FileSelectionScreen.h

@@ -0,0 +1,28 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+
+#include <functional>
+#include <string>
+#include <vector>
+
+#include "Screen.h"
+
+class FileSelectionScreen final : public Screen {
+  TaskHandle_t displayTaskHandle = nullptr;
+  std::vector<std::string> files;
+  int selectorIndex = 0;
+  bool updateRequired = false;
+  const std::function<void(const std::string&)> onSelect;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+
+ public:
+  explicit FileSelectionScreen(EpdRenderer* renderer, const std::function<void(const std::string&)>& onSelect)
+      : Screen(renderer), onSelect(onSelect) {}
+  void onEnter() override;
+  void onExit() override;
+  void handleInput(Input input) override;
+};