Merge 03896d5215 into d429966dd4

## Summary

* This PR drastically reshapes the structure of the codebase, moving
from the concept of "Screens" to "Activities", restructing the files and
setting up the concept of subactivities.
* This should help with keep the main file clean and containing all
functional logic in the relevant activity.
* CrossPointState is now also a global singleton which should help with
accessing it from within activities.

## Additional Context

* This is probably going to be a bit disruptive for people with open
PRs, sorry 😞

lib/Epub/Epub.cpp

@@ -148,6 +148,18 @@ bool Epub::load() {
     return false;
   }
 
+  // determine size of spine items
+  size_t spineItemsCount = getSpineItemsCount();
+  size_t spineItemsSize = 0;
+  for (size_t i = 0; i < spineItemsCount; i++) {
+    std::string spineItem = getSpineItem(i);
+    size_t s = 0;
+    getItemSize(spineItem, &s);
+    spineItemsSize += s;
+    cumulativeSpineItemSize.emplace_back(spineItemsSize);
+  }
+  Serial.printf("[%lu] [EBP] Book size: %u\n", millis(), spineItemsSize);
+
   Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
 
   return true;
@@ -255,6 +267,8 @@ bool Epub::getItemSize(const std::string& itemHref, size_t* size) const {
 
 int Epub::getSpineItemsCount() const { return spine.size(); }
 
+size_t Epub::getCumulativeSpineItemSize(const int spineIndex) const { return cumulativeSpineItemSize.at(spineIndex); }
+
 std::string& Epub::getSpineItem(const int spineIndex) {
   if (spineIndex < 0 || spineIndex >= spine.size()) {
     Serial.printf("[%lu] [EBP] getSpineItem index:%d is out of range\n", millis(), spineIndex);
@@ -302,3 +316,14 @@ int Epub::getTocIndexForSpineIndex(const int spineIndex) const {
   Serial.printf("[%lu] [EBP] TOC item not found\n", millis());
   return -1;
 }
+
+size_t Epub::getBookSize() const { return getCumulativeSpineItemSize(getSpineItemsCount() - 1); }
+
+// Calculate progress in book
+uint8_t Epub::calculateProgress(const int currentSpineIndex, const float currentSpineRead) {
+  size_t prevChapterSize = getCumulativeSpineItemSize(currentSpineIndex - 1);
+  size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
+  size_t bookSize = getBookSize();
+  size_t sectionProgSize = currentSpineRead * curChapterSize;
+  return round(static_cast<float>(prevChapterSize + sectionProgSize) / bookSize * 100.0);
+}

lib/Epub/Epub.h

@@ -20,6 +20,8 @@ class Epub {
   std::string filepath;
   // the spine of the EPUB file
   std::vector<std::pair<std::string, std::string>> spine;
+  // the file size of the spine items (proxy to book progress)
+  std::vector<size_t> cumulativeSpineItemSize;
   // the toc of the EPUB file
   std::vector<EpubTocEntry> toc;
   // the base path for items in the EPUB file
@@ -51,8 +53,12 @@ class Epub {
   bool getItemSize(const std::string& itemHref, size_t* size) const;
   std::string& getSpineItem(int spineIndex);
   int getSpineItemsCount() const;
-  EpubTocEntry& getTocItem(int tocTndex);
+  size_t getCumulativeSpineItemSize(const int spineIndex) const;
+  EpubTocEntry& getTocItem(int tocIndex);
   int getTocItemsCount() const;
   int getSpineIndexForTocIndex(int tocIndex) const;
   int getTocIndexForSpineIndex(int spineIndex) const;
+
+  size_t getBookSize() const;
+  uint8_t calculateProgress(const int currentSpineIndex, const float currentSpineRead);
 };

lib/Epub/Epub/Page.cpp

@@ -3,7 +3,9 @@
 #include <HardwareSerial.h>
 #include <Serialization.h>
 
+namespace {
 constexpr uint8_t PAGE_FILE_VERSION = 3;
+}
 
 void PageLine::render(GfxRenderer& renderer, const int fontId) { block->render(renderer, fontId, xPos, yPos); }
 

lib/Epub/Epub/Section.cpp

@@ -9,7 +9,9 @@
 #include "Page.h"
 #include "parsers/ChapterHtmlSlimParser.h"
 
+namespace {
 constexpr uint8_t SECTION_FILE_VERSION = 5;
+}
 
 void Section::onPageComplete(std::unique_ptr<Page> page) {
   const auto filePath = cachePath + "/page_" + std::to_string(pageCount) + ".bin";

lib/JpegToBmpConverter/JpegToBmpConverter.cpp

@@ -0,0 +1,244 @@
+#include "JpegToBmpConverter.h"
+
+#include <picojpeg.h>
+
+#include <cstdio>
+#include <cstring>
+
+// Context structure for picojpeg callback
+struct JpegReadContext {
+  File& file;
+  uint8_t buffer[512];
+  size_t bufferPos;
+  size_t bufferFilled;
+};
+
+// Helper function: Convert 8-bit grayscale to 2-bit (0-3)
+uint8_t JpegToBmpConverter::grayscaleTo2Bit(const uint8_t grayscale) {
+  // Simple threshold mapping:
+  // 0-63 -> 0 (black)
+  // 64-127 -> 1 (dark gray)
+  // 128-191 -> 2 (light gray)
+  // 192-255 -> 3 (white)
+  return grayscale >> 6;
+}
+
+inline void write16(Print& out, const uint16_t value) {
+  // out.write(reinterpret_cast<const uint8_t *>(&value), 2);
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+}
+
+inline void write32(Print& out, const uint32_t value) {
+  // out.write(reinterpret_cast<const uint8_t *>(&value), 4);
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+  out.write((value >> 16) & 0xFF);
+  out.write((value >> 24) & 0xFF);
+}
+
+inline void write32Signed(Print& out, const int32_t value) {
+  // out.write(reinterpret_cast<const uint8_t *>(&value), 4);
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+  out.write((value >> 16) & 0xFF);
+  out.write((value >> 24) & 0xFF);
+}
+
+// Helper function: Write BMP header with 2-bit color depth
+void JpegToBmpConverter::writeBmpHeader(Print& bmpOut, const int width, const int height) {
+  // Calculate row padding (each row must be multiple of 4 bytes)
+  const int bytesPerRow = (width * 2 + 31) / 32 * 4;  // 2 bits per pixel, round up
+  const int imageSize = bytesPerRow * height;
+  const uint32_t fileSize = 70 + imageSize;  // 14 (file header) + 40 (DIB header) + 16 (palette) + image
+
+  // BMP File Header (14 bytes)
+  bmpOut.write('B');
+  bmpOut.write('M');
+  write32(bmpOut, fileSize);  // File size
+  write32(bmpOut, 0);         // Reserved
+  write32(bmpOut, 70);        // Offset to pixel data
+
+  // DIB Header (BITMAPINFOHEADER - 40 bytes)
+  write32(bmpOut, 40);
+  write32Signed(bmpOut, width);
+  write32Signed(bmpOut, -height);  // Negative height = top-down bitmap
+  write16(bmpOut, 1);              // Color planes
+  write16(bmpOut, 2);              // Bits per pixel (2 bits)
+  write32(bmpOut, 0);              // BI_RGB (no compression)
+  write32(bmpOut, imageSize);
+  write32(bmpOut, 2835);  // xPixelsPerMeter (72 DPI)
+  write32(bmpOut, 2835);  // yPixelsPerMeter (72 DPI)
+  write32(bmpOut, 4);     // colorsUsed
+  write32(bmpOut, 4);     // colorsImportant
+
+  // Color Palette (4 colors x 4 bytes = 16 bytes)
+  // Format: Blue, Green, Red, Reserved (BGRA)
+  uint8_t palette[16] = {
+      0x00, 0x00, 0x00, 0x00,  // Color 0: Black
+      0x55, 0x55, 0x55, 0x00,  // Color 1: Dark gray (85)
+      0xAA, 0xAA, 0xAA, 0x00,  // Color 2: Light gray (170)
+      0xFF, 0xFF, 0xFF, 0x00   // Color 3: White
+  };
+  for (const uint8_t i : palette) {
+    bmpOut.write(i);
+  }
+}
+
+// Callback function for picojpeg to read JPEG data
+unsigned char JpegToBmpConverter::jpegReadCallback(unsigned char* pBuf, const unsigned char buf_size,
+                                                   unsigned char* pBytes_actually_read, void* pCallback_data) {
+  auto* context = static_cast<JpegReadContext*>(pCallback_data);
+
+  if (!context || !context->file) {
+    return PJPG_STREAM_READ_ERROR;
+  }
+
+  // Check if we need to refill our context buffer
+  if (context->bufferPos >= context->bufferFilled) {
+    context->bufferFilled = context->file.read(context->buffer, sizeof(context->buffer));
+    context->bufferPos = 0;
+
+    if (context->bufferFilled == 0) {
+      // EOF or error
+      *pBytes_actually_read = 0;
+      return 0;  // Success (EOF is normal)
+    }
+  }
+
+  // Copy available bytes to picojpeg's buffer
+  const size_t available = context->bufferFilled - context->bufferPos;
+  const size_t toRead = available < buf_size ? available : buf_size;
+
+  memcpy(pBuf, context->buffer + context->bufferPos, toRead);
+  context->bufferPos += toRead;
+  *pBytes_actually_read = static_cast<unsigned char>(toRead);
+
+  return 0;  // Success
+}
+
+// Core function: Convert JPEG file to 2-bit BMP
+bool JpegToBmpConverter::jpegFileToBmpStream(File& jpegFile, Print& bmpOut) {
+  Serial.printf("[%lu] [JPG] Converting JPEG to BMP\n", millis());
+
+  // Setup context for picojpeg callback
+  JpegReadContext context = {.file = jpegFile, .bufferPos = 0, .bufferFilled = 0};
+
+  // Initialize picojpeg decoder
+  pjpeg_image_info_t imageInfo;
+  const unsigned char status = pjpeg_decode_init(&imageInfo, jpegReadCallback, &context, 0);
+  if (status != 0) {
+    Serial.printf("[%lu] [JPG] JPEG decode init failed with error code: %d\n", millis(), status);
+    return false;
+  }
+
+  Serial.printf("[%lu] [JPG] JPEG dimensions: %dx%d, components: %d, MCUs: %dx%d\n", millis(), imageInfo.m_width,
+                imageInfo.m_height, imageInfo.m_comps, imageInfo.m_MCUSPerRow, imageInfo.m_MCUSPerCol);
+
+  // Write BMP header
+  writeBmpHeader(bmpOut, imageInfo.m_width, imageInfo.m_height);
+
+  // Calculate row parameters
+  const int bytesPerRow = (imageInfo.m_width * 2 + 31) / 32 * 4;
+
+  // Allocate row buffer for packed 2-bit pixels
+  auto* rowBuffer = static_cast<uint8_t*>(malloc(bytesPerRow));
+  if (!rowBuffer) {
+    Serial.printf("[%lu] [JPG] Failed to allocate row buffer\n", millis());
+    return false;
+  }
+
+  // Allocate a buffer for one MCU row worth of grayscale pixels
+  // This is the minimal memory needed for streaming conversion
+  const int mcuPixelHeight = imageInfo.m_MCUHeight;
+  const int mcuRowPixels = imageInfo.m_width * mcuPixelHeight;
+  auto* mcuRowBuffer = static_cast<uint8_t*>(malloc(mcuRowPixels));
+  if (!mcuRowBuffer) {
+    Serial.printf("[%lu] [JPG] Failed to allocate MCU row buffer\n", millis());
+    free(rowBuffer);
+    return false;
+  }
+
+  // Process MCUs row-by-row and write to BMP as we go (top-down)
+  const int mcuPixelWidth = imageInfo.m_MCUWidth;
+
+  for (int mcuY = 0; mcuY < imageInfo.m_MCUSPerCol; mcuY++) {
+    // Clear the MCU row buffer
+    memset(mcuRowBuffer, 0, mcuRowPixels);
+
+    // Decode one row of MCUs
+    for (int mcuX = 0; mcuX < imageInfo.m_MCUSPerRow; mcuX++) {
+      const unsigned char mcuStatus = pjpeg_decode_mcu();
+      if (mcuStatus != 0) {
+        if (mcuStatus == PJPG_NO_MORE_BLOCKS) {
+          Serial.printf("[%lu] [JPG] Unexpected end of blocks at MCU (%d, %d)\n", millis(), mcuX, mcuY);
+        } else {
+          Serial.printf("[%lu] [JPG] JPEG decode MCU failed at (%d, %d) with error code: %d\n", millis(), mcuX, mcuY,
+                        mcuStatus);
+        }
+        free(mcuRowBuffer);
+        free(rowBuffer);
+        return false;
+      }
+
+      // Process MCU block into MCU row buffer
+      for (int blockY = 0; blockY < mcuPixelHeight; blockY++) {
+        for (int blockX = 0; blockX < mcuPixelWidth; blockX++) {
+          const int pixelX = mcuX * mcuPixelWidth + blockX;
+
+          // Skip pixels outside image width (can happen with MCU alignment)
+          if (pixelX >= imageInfo.m_width) {
+            continue;
+          }
+
+          // Get grayscale value
+          uint8_t gray;
+          if (imageInfo.m_comps == 1) {
+            // Grayscale image
+            gray = imageInfo.m_pMCUBufR[blockY * mcuPixelWidth + blockX];
+          } else {
+            // RGB image - convert to grayscale
+            const uint8_t r = imageInfo.m_pMCUBufR[blockY * mcuPixelWidth + blockX];
+            const uint8_t g = imageInfo.m_pMCUBufG[blockY * mcuPixelWidth + blockX];
+            const uint8_t b = imageInfo.m_pMCUBufB[blockY * mcuPixelWidth + blockX];
+            // Luminance formula: Y = 0.299*R + 0.587*G + 0.114*B
+            // Using integer approximation: (30*R + 59*G + 11*B) / 100
+            gray = (r * 30 + g * 59 + b * 11) / 100;
+          }
+
+          // Store grayscale value in MCU row buffer
+          mcuRowBuffer[blockY * imageInfo.m_width + pixelX] = gray;
+        }
+      }
+    }
+
+    // Write all pixel rows from this MCU row to BMP file
+    const int startRow = mcuY * mcuPixelHeight;
+    const int endRow = (mcuY + 1) * mcuPixelHeight;
+
+    for (int y = startRow; y < endRow && y < imageInfo.m_height; y++) {
+      memset(rowBuffer, 0, bytesPerRow);
+
+      // Pack 4 pixels per byte (2 bits each)
+      for (int x = 0; x < imageInfo.m_width; x++) {
+        const int bufferY = y - startRow;
+        const uint8_t gray = mcuRowBuffer[bufferY * imageInfo.m_width + x];
+        const uint8_t twoBit = grayscaleTo2Bit(gray);
+
+        const int byteIndex = (x * 2) / 8;
+        const int bitOffset = 6 - ((x * 2) % 8);  // 6, 4, 2, 0
+        rowBuffer[byteIndex] |= (twoBit << bitOffset);
+      }
+
+      // Write row with padding
+      bmpOut.write(rowBuffer, bytesPerRow);
+    }
+  }
+
+  // Clean up
+  free(mcuRowBuffer);
+  free(rowBuffer);
+
+  Serial.printf("[%lu] [JPG] Successfully converted JPEG to BMP\n", millis());
+  return true;
+}

lib/JpegToBmpConverter/JpegToBmpConverter.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <FS.h>
+
+class ZipFile;
+
+class JpegToBmpConverter {
+  static void writeBmpHeader(Print& bmpOut, int width, int height);
+  static uint8_t grayscaleTo2Bit(uint8_t grayscale);
+  static unsigned char jpegReadCallback(unsigned char* pBuf, unsigned char buf_size,
+                                        unsigned char* pBytes_actually_read, void* pCallback_data);
+
+ public:
+  static bool jpegFileToBmpStream(File& jpegFile, Print& bmpOut);
+};

lib/picojpeg/picojpeg.h

@@ -0,0 +1,124 @@
+//------------------------------------------------------------------------------
+// picojpeg - Public domain, Rich Geldreich <richgel99@gmail.com>
+//------------------------------------------------------------------------------
+#ifndef PICOJPEG_H
+#define PICOJPEG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Error codes
+enum {
+  PJPG_NO_MORE_BLOCKS = 1,
+  PJPG_BAD_DHT_COUNTS,
+  PJPG_BAD_DHT_INDEX,
+  PJPG_BAD_DHT_MARKER,
+  PJPG_BAD_DQT_MARKER,
+  PJPG_BAD_DQT_TABLE,
+  PJPG_BAD_PRECISION,
+  PJPG_BAD_HEIGHT,
+  PJPG_BAD_WIDTH,
+  PJPG_TOO_MANY_COMPONENTS,
+  PJPG_BAD_SOF_LENGTH,
+  PJPG_BAD_VARIABLE_MARKER,
+  PJPG_BAD_DRI_LENGTH,
+  PJPG_BAD_SOS_LENGTH,
+  PJPG_BAD_SOS_COMP_ID,
+  PJPG_W_EXTRA_BYTES_BEFORE_MARKER,
+  PJPG_NO_ARITHMITIC_SUPPORT,
+  PJPG_UNEXPECTED_MARKER,
+  PJPG_NOT_JPEG,
+  PJPG_UNSUPPORTED_MARKER,
+  PJPG_BAD_DQT_LENGTH,
+  PJPG_TOO_MANY_BLOCKS,
+  PJPG_UNDEFINED_QUANT_TABLE,
+  PJPG_UNDEFINED_HUFF_TABLE,
+  PJPG_NOT_SINGLE_SCAN,
+  PJPG_UNSUPPORTED_COLORSPACE,
+  PJPG_UNSUPPORTED_SAMP_FACTORS,
+  PJPG_DECODE_ERROR,
+  PJPG_BAD_RESTART_MARKER,
+  PJPG_ASSERTION_ERROR,
+  PJPG_BAD_SOS_SPECTRAL,
+  PJPG_BAD_SOS_SUCCESSIVE,
+  PJPG_STREAM_READ_ERROR,
+  PJPG_NOTENOUGHMEM,
+  PJPG_UNSUPPORTED_COMP_IDENT,
+  PJPG_UNSUPPORTED_QUANT_TABLE,
+  PJPG_UNSUPPORTED_MODE,  // picojpeg doesn't support progressive JPEG's
+};
+
+// Scan types
+typedef enum { PJPG_GRAYSCALE, PJPG_YH1V1, PJPG_YH2V1, PJPG_YH1V2, PJPG_YH2V2 } pjpeg_scan_type_t;
+
+typedef struct {
+  // Image resolution
+  int m_width;
+  int m_height;
+
+  // Number of components (1 or 3)
+  int m_comps;
+
+  // Total number of minimum coded units (MCU's) per row/col.
+  int m_MCUSPerRow;
+  int m_MCUSPerCol;
+
+  // Scan type
+  pjpeg_scan_type_t m_scanType;
+
+  // MCU width/height in pixels (each is either 8 or 16 depending on the scan type)
+  int m_MCUWidth;
+  int m_MCUHeight;
+
+  // m_pMCUBufR, m_pMCUBufG, and m_pMCUBufB are pointers to internal MCU Y or RGB pixel component buffers.
+  // Each time pjpegDecodeMCU() is called successfully these buffers will be filled with 8x8 pixel blocks of Y or RGB
+  // pixels. Each MCU consists of (m_MCUWidth/8)*(m_MCUHeight/8) Y/RGB blocks: 1 for greyscale/no subsampling, 2 for
+  // H1V2/H2V1, or 4 blocks for H2V2 sampling factors. Each block is a contiguous array of 64 (8x8) bytes of a single
+  // component: either Y for grayscale images, or R, G or B components for color images.
+  //
+  // The 8x8 pixel blocks are organized in these byte arrays like this:
+  //
+  // PJPG_GRAYSCALE: Each MCU is decoded to a single block of 8x8 grayscale pixels.
+  // Only the values in m_pMCUBufR are valid. Each 8 bytes is a row of pixels (raster order: left to right, top to
+  // bottom) from the 8x8 block.
+  //
+  // PJPG_H1V1: Each MCU contains is decoded to a single block of 8x8 RGB pixels.
+  //
+  // PJPG_YH2V1: Each MCU is decoded to 2 blocks, or 16x8 pixels.
+  // The 2 RGB blocks are at byte offsets: 0, 64
+  //
+  // PJPG_YH1V2: Each MCU is decoded to 2 blocks, or 8x16 pixels.
+  // The 2 RGB blocks are at byte offsets: 0,
+  //                                       128
+  //
+  // PJPG_YH2V2: Each MCU is decoded to 4 blocks, or 16x16 pixels.
+  // The 2x2 block array is organized at byte offsets:   0,  64,
+  //                                                   128, 192
+  //
+  // It is up to the caller to copy or blit these pixels from these buffers into the destination bitmap.
+  unsigned char* m_pMCUBufR;
+  unsigned char* m_pMCUBufG;
+  unsigned char* m_pMCUBufB;
+} pjpeg_image_info_t;
+
+typedef unsigned char (*pjpeg_need_bytes_callback_t)(unsigned char* pBuf, unsigned char buf_size,
+                                                     unsigned char* pBytes_actually_read, void* pCallback_data);
+
+// Initializes the decompressor. Returns 0 on success, or one of the above error codes on failure.
+// pNeed_bytes_callback will be called to fill the decompressor's internal input buffer.
+// If reduce is 1, only the first pixel of each block will be decoded. This mode is much faster because it skips the AC
+// dequantization, IDCT and chroma upsampling of every image pixel. Not thread safe.
+unsigned char pjpeg_decode_init(pjpeg_image_info_t* pInfo, pjpeg_need_bytes_callback_t pNeed_bytes_callback,
+                                void* pCallback_data, unsigned char reduce);
+
+// Decompresses the file's next MCU. Returns 0 on success, PJPG_NO_MORE_BLOCKS if no more blocks are available, or an
+// error code. Must be called a total of m_MCUSPerRow*m_MCUSPerCol times to completely decompress the image. Not thread
+// safe.
+unsigned char pjpeg_decode_mcu(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // PICOJPEG_H

src/CrossPointSettings.cpp

@@ -10,9 +10,11 @@
 // Initialize the static instance
 CrossPointSettings CrossPointSettings::instance;
 
+namespace {
 constexpr uint8_t SETTINGS_FILE_VERSION = 1;
 constexpr uint8_t SETTINGS_COUNT = 2;
 constexpr char SETTINGS_FILE[] = "/sd/.crosspoint/settings.bin";
+}  // namespace
 
 bool CrossPointSettings::saveToFile() const {
   // Make sure the directory exists

src/CrossPointState.cpp

@@ -6,8 +6,12 @@
 
 #include <fstream>
 
+namespace {
 constexpr uint8_t STATE_FILE_VERSION = 1;
 constexpr char STATE_FILE[] = "/sd/.crosspoint/state.bin";
+}  // namespace
+
+CrossPointState CrossPointState::instance;
 
 bool CrossPointState::saveToFile() const {
   std::ofstream outputFile(STATE_FILE);

src/CrossPointState.h

@@ -3,11 +3,20 @@
 #include <string>
 
 class CrossPointState {
+  // Static instance
+  static CrossPointState instance;
+
  public:
   std::string openEpubPath;
   ~CrossPointState() = default;
 
+  // Get singleton instance
+  static CrossPointState& getInstance() { return instance; }
+
   bool saveToFile() const;
 
   bool loadFromFile();
 };
+
+// Helper macro to access settings
+#define APP_STATE CrossPointState::getInstance()

src/activities/Activity.h

@@ -0,0 +1,18 @@
+#pragma once
+#include <InputManager.h>
+
+class GfxRenderer;
+
+class Activity {
+ protected:
+  GfxRenderer& renderer;
+  InputManager& inputManager;
+
+ public:
+  explicit Activity(GfxRenderer& renderer, InputManager& inputManager)
+      : renderer(renderer), inputManager(inputManager) {}
+  virtual ~Activity() = default;
+  virtual void onEnter() {}
+  virtual void onExit() {}
+  virtual void loop() {}
+};

src/activities/ActivityWithSubactivity.cpp

@@ -0,0 +1,21 @@
+#include "ActivityWithSubactivity.h"
+
+void ActivityWithSubactivity::exitActivity() {
+  if (subActivity) {
+    subActivity->onExit();
+    subActivity.reset();
+  }
+}
+
+void ActivityWithSubactivity::enterNewActivity(Activity* activity) {
+  subActivity.reset(activity);
+  subActivity->onEnter();
+}
+
+void ActivityWithSubactivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+  }
+}
+
+void ActivityWithSubactivity::onExit() { exitActivity(); }

src/activities/ActivityWithSubactivity.h

@@ -0,0 +1,17 @@
+#pragma once
+#include <memory>
+
+#include "Activity.h"
+
+class ActivityWithSubactivity : public Activity {
+ protected:
+  std::unique_ptr<Activity> subActivity = nullptr;
+  void exitActivity();
+  void enterNewActivity(Activity* activity);
+
+ public:
+  explicit ActivityWithSubactivity(GfxRenderer& renderer, InputManager& inputManager)
+      : Activity(renderer, inputManager) {}
+  void loop() override;
+  void onExit() override;
+};

src/activities/boot_sleep/BootActivity.cpp

@@ -1,11 +1,11 @@
-#include "BootLogoScreen.h"
+#include "BootActivity.h"
 
 #include <GfxRenderer.h>
 
 #include "config.h"
 #include "images/CrossLarge.h"
 
-void BootLogoScreen::onEnter() {
+void BootActivity::onEnter() {
   const auto pageWidth = GfxRenderer::getScreenWidth();
   const auto pageHeight = GfxRenderer::getScreenHeight();
 

src/activities/boot_sleep/BootActivity.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "../Activity.h"
+
+class BootActivity final : public Activity {
+ public:
+  explicit BootActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  void onEnter() override;
+};

src/activities/boot_sleep/SleepActivity.cpp

@@ -1,4 +1,4 @@
-#include "SleepScreen.h"
+#include "SleepActivity.h"
 
 #include <GfxRenderer.h>
 
@@ -6,7 +6,7 @@
 #include "config.h"
 #include "images/CrossLarge.h"
 
-void SleepScreen::onEnter() {
+void SleepActivity::onEnter() {
   const auto pageWidth = GfxRenderer::getScreenWidth();
   const auto pageHeight = GfxRenderer::getScreenHeight();
 

src/activities/boot_sleep/SleepActivity.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "../Activity.h"
+
+class SleepActivity final : public Activity {
+ public:
+  explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  void onEnter() override;
+};

src/activities/home/HomeActivity.cpp

@@ -0,0 +1,103 @@
+#include "HomeActivity.h"
+
+#include <GfxRenderer.h>
+#include <SD.h>
+
+#include "config.h"
+
+namespace {
+constexpr int menuItemCount = 2;
+}
+
+void HomeActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<HomeActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void HomeActivity::onEnter() {
+  renderingMutex = xSemaphoreCreateMutex();
+
+  selectorIndex = 0;
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&HomeActivity::taskTrampoline, "HomeActivityTask",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void HomeActivity::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 HomeActivity::loop() {
+  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) {
+      onReaderOpen();
+    } 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 HomeActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void HomeActivity::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/activities/home/HomeActivity.h

@@ -0,0 +1,29 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+
+#include "../Activity.h"
+
+class HomeActivity final : public Activity {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  int selectorIndex = 0;
+  bool updateRequired = false;
+  const std::function<void()> onReaderOpen;
+  const std::function<void()> onSettingsOpen;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+
+ public:
+  explicit HomeActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onReaderOpen,
+                        const std::function<void()>& onSettingsOpen)
+      : Activity(renderer, inputManager), onReaderOpen(onReaderOpen), onSettingsOpen(onSettingsOpen) {}
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+};

src/activities/reader/EpubReaderActivity.cpp

@@ -1,4 +1,4 @@
-#include "EpubReaderScreen.h"
+#include "EpubReaderActivity.h"
 
 #include <Epub/Page.h>
 #include <GfxRenderer.h>
@@ -6,23 +6,25 @@
 
 #include "Battery.h"
 #include "CrossPointSettings.h"
-#include "EpubReaderChapterSelectionScreen.h"
+#include "EpubReaderChapterSelectionActivity.h"
 #include "config.h"
 
-constexpr int PAGES_PER_REFRESH = 15;
-constexpr unsigned long SKIP_CHAPTER_MS = 700;
+namespace {
+constexpr int pagesPerRefresh = 15;
+constexpr unsigned long skipChapterMs = 700;
 constexpr float lineCompression = 0.95f;
 constexpr int marginTop = 8;
 constexpr int marginRight = 10;
 constexpr int marginBottom = 22;
 constexpr int marginLeft = 10;
+}  // namespace
 
-void EpubReaderScreen::taskTrampoline(void* param) {
-  auto* self = static_cast<EpubReaderScreen*>(param);
+void EpubReaderActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<EpubReaderActivity*>(param);
   self->displayTaskLoop();
 }
 
-void EpubReaderScreen::onEnter() {
+void EpubReaderActivity::onEnter() {
   if (!epub) {
     return;
   }
@@ -44,7 +46,7 @@ void EpubReaderScreen::onEnter() {
   // Trigger first update
   updateRequired = true;
 
-  xTaskCreate(&EpubReaderScreen::taskTrampoline, "EpubReaderScreenTask",
+  xTaskCreate(&EpubReaderActivity::taskTrampoline, "EpubReaderActivityTask",
               8192,               // Stack size
               this,               // Parameters
               1,                  // Priority
@@ -52,7 +54,7 @@ void EpubReaderScreen::onEnter() {
   );
 }
 
-void EpubReaderScreen::onExit() {
+void EpubReaderActivity::onExit() {
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -65,22 +67,22 @@ void EpubReaderScreen::onExit() {
   epub.reset();
 }
 
-void EpubReaderScreen::handleInput() {
-  // Pass input responsibility to sub screen if exists
-  if (subScreen) {
-    subScreen->handleInput();
+void EpubReaderActivity::loop() {
+  // Pass input responsibility to sub activity if exists
+  if (subAcitivity) {
+    subAcitivity->loop();
     return;
   }
 
-  // Enter chapter selection screen
+  // Enter chapter selection activity
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
-    // Don't start screen transition while rendering
+    // Don't start activity transition while rendering
     xSemaphoreTake(renderingMutex, portMAX_DELAY);
-    subScreen.reset(new EpubReaderChapterSelectionScreen(
+    subAcitivity.reset(new EpubReaderChapterSelectionActivity(
         this->renderer, this->inputManager, epub, currentSpineIndex,
         [this] {
-          subScreen->onExit();
-          subScreen.reset();
+          subAcitivity->onExit();
+          subAcitivity.reset();
           updateRequired = true;
         },
         [this](const int newSpineIndex) {
@@ -89,16 +91,16 @@ void EpubReaderScreen::handleInput() {
             nextPageNumber = 0;
             section.reset();
           }
-          subScreen->onExit();
-          subScreen.reset();
+          subAcitivity->onExit();
+          subAcitivity.reset();
           updateRequired = true;
         }));
-    subScreen->onEnter();
+    subAcitivity->onEnter();
     xSemaphoreGive(renderingMutex);
   }
 
   if (inputManager.wasPressed(InputManager::BTN_BACK)) {
-    onGoHome();
+    onGoBack();
     return;
   }
 
@@ -119,7 +121,7 @@ void EpubReaderScreen::handleInput() {
     return;
   }
 
-  const bool skipChapter = inputManager.getHeldTime() > SKIP_CHAPTER_MS;
+  const bool skipChapter = inputManager.getHeldTime() > skipChapterMs;
 
   if (skipChapter) {
     // We don't want to delete the section mid-render, so grab the semaphore
@@ -165,7 +167,7 @@ void EpubReaderScreen::handleInput() {
   }
 }
 
-void EpubReaderScreen::displayTaskLoop() {
+void EpubReaderActivity::displayTaskLoop() {
   while (true) {
     if (updateRequired) {
       updateRequired = false;
@@ -178,7 +180,7 @@ void EpubReaderScreen::displayTaskLoop() {
 }
 
 // TODO: Failure handling
-void EpubReaderScreen::renderScreen() {
+void EpubReaderActivity::renderScreen() {
   if (!epub) {
     return;
   }
@@ -285,12 +287,12 @@ void EpubReaderScreen::renderScreen() {
   f.close();
 }
 
-void EpubReaderScreen::renderContents(std::unique_ptr<Page> page) {
+void EpubReaderActivity::renderContents(std::unique_ptr<Page> page) {
   page->render(renderer, READER_FONT_ID);
   renderStatusBar();
   if (pagesUntilFullRefresh <= 1) {
     renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
-    pagesUntilFullRefresh = PAGES_PER_REFRESH;
+    pagesUntilFullRefresh = pagesPerRefresh;
   } else {
     renderer.displayBuffer();
     pagesUntilFullRefresh--;
@@ -322,10 +324,16 @@ void EpubReaderScreen::renderContents(std::unique_ptr<Page> page) {
   renderer.restoreBwBuffer();
 }
 
-void EpubReaderScreen::renderStatusBar() const {
+void EpubReaderActivity::renderStatusBar() const {
   constexpr auto textY = 776;
+
+  // Calculate progress in book
+  float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
+  uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
+
   // Right aligned text for progress counter
-  const std::string progress = std::to_string(section->currentPage + 1) + " / " + std::to_string(section->pageCount);
+  const std::string progress = std::to_string(section->currentPage + 1) + "/" + std::to_string(section->pageCount) +
+                               "  " + std::to_string(bookProgress) + "%";
   const auto progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progress.c_str());
   renderer.drawText(SMALL_FONT_ID, GfxRenderer::getScreenWidth() - marginRight - progressTextWidth, textY,
                     progress.c_str());

src/activities/reader/EpubReaderActivity.h

@@ -5,19 +5,19 @@
 #include <freertos/semphr.h>
 #include <freertos/task.h>
 
-#include "Screen.h"
+#include "../Activity.h"
 
-class EpubReaderScreen final : public Screen {
+class EpubReaderActivity final : public Activity {
   std::shared_ptr<Epub> epub;
   std::unique_ptr<Section> section = nullptr;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
-  std::unique_ptr<Screen> subScreen = nullptr;
+  std::unique_ptr<Activity> subAcitivity = nullptr;
   int currentSpineIndex = 0;
   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();
@@ -26,10 +26,10 @@ class EpubReaderScreen final : public Screen {
   void renderStatusBar() const;
 
  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) {}
+  explicit EpubReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::unique_ptr<Epub> epub,
+                              const std::function<void()>& onGoBack)
+      : Activity(renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
   void onEnter() override;
   void onExit() override;
-  void handleInput() override;
+  void loop() override;
 };

src/activities/reader/EpubReaderChapterSelectionActivity.cpp

@@ -1,4 +1,4 @@
-#include "EpubReaderChapterSelectionScreen.h"
+#include "EpubReaderChapterSelectionActivity.h"
 
 #include <GfxRenderer.h>
 #include <SD.h>
@@ -8,12 +8,12 @@
 constexpr int PAGE_ITEMS = 24;
 constexpr int SKIP_PAGE_MS = 700;
 
-void EpubReaderChapterSelectionScreen::taskTrampoline(void* param) {
-  auto* self = static_cast<EpubReaderChapterSelectionScreen*>(param);
+void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<EpubReaderChapterSelectionActivity*>(param);
   self->displayTaskLoop();
 }
 
-void EpubReaderChapterSelectionScreen::onEnter() {
+void EpubReaderChapterSelectionActivity::onEnter() {
   if (!epub) {
     return;
   }
@@ -23,7 +23,7 @@ void EpubReaderChapterSelectionScreen::onEnter() {
 
   // Trigger first update
   updateRequired = true;
-  xTaskCreate(&EpubReaderChapterSelectionScreen::taskTrampoline, "EpubReaderChapterSelectionScreenTask",
+  xTaskCreate(&EpubReaderChapterSelectionActivity::taskTrampoline, "EpubReaderChapterSelectionActivityTask",
               2048,               // Stack size
               this,               // Parameters
               1,                  // Priority
@@ -31,7 +31,7 @@ void EpubReaderChapterSelectionScreen::onEnter() {
   );
 }
 
-void EpubReaderChapterSelectionScreen::onExit() {
+void EpubReaderChapterSelectionActivity::onExit() {
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -42,7 +42,7 @@ void EpubReaderChapterSelectionScreen::onExit() {
   renderingMutex = nullptr;
 }
 
-void EpubReaderChapterSelectionScreen::handleInput() {
+void EpubReaderChapterSelectionActivity::loop() {
   const bool prevReleased =
       inputManager.wasReleased(InputManager::BTN_UP) || inputManager.wasReleased(InputManager::BTN_LEFT);
   const bool nextReleased =
@@ -72,7 +72,7 @@ void EpubReaderChapterSelectionScreen::handleInput() {
   }
 }
 
-void EpubReaderChapterSelectionScreen::displayTaskLoop() {
+void EpubReaderChapterSelectionActivity::displayTaskLoop() {
   while (true) {
     if (updateRequired) {
       updateRequired = false;
@@ -84,7 +84,7 @@ void EpubReaderChapterSelectionScreen::displayTaskLoop() {
   }
 }
 
-void EpubReaderChapterSelectionScreen::renderScreen() {
+void EpubReaderChapterSelectionActivity::renderScreen() {
   renderer.clearScreen();
 
   const auto pageWidth = renderer.getScreenWidth();

src/activities/reader/EpubReaderChapterSelectionActivity.h

@@ -6,9 +6,9 @@
 
 #include <memory>
 
-#include "Screen.h"
+#include "../Activity.h"
 
-class EpubReaderChapterSelectionScreen final : public Screen {
+class EpubReaderChapterSelectionActivity final : public Activity {
   std::shared_ptr<Epub> epub;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
@@ -23,16 +23,16 @@ class EpubReaderChapterSelectionScreen final : public Screen {
   void renderScreen();
 
  public:
-  explicit EpubReaderChapterSelectionScreen(GfxRenderer& renderer, InputManager& inputManager,
-                                            const std::shared_ptr<Epub>& epub, const int currentSpineIndex,
-                                            const std::function<void()>& onGoBack,
-                                            const std::function<void(int newSpineIndex)>& onSelectSpineIndex)
-      : Screen(renderer, inputManager),
+  explicit EpubReaderChapterSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
+                                              const std::shared_ptr<Epub>& epub, const int currentSpineIndex,
+                                              const std::function<void()>& onGoBack,
+                                              const std::function<void(int newSpineIndex)>& onSelectSpineIndex)
+      : Activity(renderer, inputManager),
         epub(epub),
         currentSpineIndex(currentSpineIndex),
         onGoBack(onGoBack),
         onSelectSpineIndex(onSelectSpineIndex) {}
   void onEnter() override;
   void onExit() override;
-  void handleInput() override;
+  void loop() override;
 };

src/activities/reader/FileSelectionActivity.cpp

@@ -1,4 +1,4 @@
-#include "FileSelectionScreen.h"
+#include "FileSelectionActivity.h"
 
 #include <GfxRenderer.h>
 #include <SD.h>
@@ -15,12 +15,12 @@ void sortFileList(std::vector<std::string>& strs) {
   });
 }
 
-void FileSelectionScreen::taskTrampoline(void* param) {
-  auto* self = static_cast<FileSelectionScreen*>(param);
+void FileSelectionActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<FileSelectionActivity*>(param);
   self->displayTaskLoop();
 }
 
-void FileSelectionScreen::loadFiles() {
+void FileSelectionActivity::loadFiles() {
   files.clear();
   selectorIndex = 0;
   auto root = SD.open(basepath.c_str());
@@ -42,7 +42,7 @@ void FileSelectionScreen::loadFiles() {
   sortFileList(files);
 }
 
-void FileSelectionScreen::onEnter() {
+void FileSelectionActivity::onEnter() {
   renderingMutex = xSemaphoreCreateMutex();
 
   basepath = "/";
@@ -52,7 +52,7 @@ void FileSelectionScreen::onEnter() {
   // Trigger first update
   updateRequired = true;
 
-  xTaskCreate(&FileSelectionScreen::taskTrampoline, "FileSelectionScreenTask",
+  xTaskCreate(&FileSelectionActivity::taskTrampoline, "FileSelectionActivityTask",
               2048,               // Stack size
               this,               // Parameters
               1,                  // Priority
@@ -60,7 +60,7 @@ void FileSelectionScreen::onEnter() {
   );
 }
 
-void FileSelectionScreen::onExit() {
+void FileSelectionActivity::onExit() {
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -72,7 +72,7 @@ void FileSelectionScreen::onExit() {
   files.clear();
 }
 
-void FileSelectionScreen::handleInput() {
+void FileSelectionActivity::loop() {
   const bool prevPressed =
       inputManager.wasPressed(InputManager::BTN_UP) || inputManager.wasPressed(InputManager::BTN_LEFT);
   const bool nextPressed =
@@ -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();
@@ -110,7 +110,7 @@ void FileSelectionScreen::handleInput() {
   }
 }
 
-void FileSelectionScreen::displayTaskLoop() {
+void FileSelectionActivity::displayTaskLoop() {
   while (true) {
     if (updateRequired) {
       updateRequired = false;
@@ -122,14 +122,14 @@ void FileSelectionScreen::displayTaskLoop() {
   }
 }
 
-void FileSelectionScreen::render() const {
+void FileSelectionActivity::render() const {
   renderer.clearScreen();
 
   const auto pageWidth = GfxRenderer::getScreenWidth();
   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/activities/reader/FileSelectionActivity.h

@@ -7,9 +7,9 @@
 #include <string>
 #include <vector>
 
-#include "Screen.h"
+#include "../Activity.h"
 
-class FileSelectionScreen final : public Screen {
+class FileSelectionActivity final : public Activity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   std::string basepath = "/";
@@ -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();
@@ -25,11 +25,11 @@ class FileSelectionScreen final : public Screen {
   void loadFiles();
 
  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) {}
+  explicit FileSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
+                                 const std::function<void(const std::string&)>& onSelect,
+                                 const std::function<void()>& onGoHome)
+      : Activity(renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
-  void handleInput() override;
+  void loop() override;
 };

src/activities/reader/ReaderActivity.cpp

@@ -0,0 +1,68 @@
+#include "ReaderActivity.h"
+
+#include <SD.h>
+
+#include "CrossPointState.h"
+#include "Epub.h"
+#include "EpubReaderActivity.h"
+#include "FileSelectionActivity.h"
+#include "activities/util/FullScreenMessageActivity.h"
+
+std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
+  if (!SD.exists(path.c_str())) {
+    Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
+    return nullptr;
+  }
+
+  auto epub = std::unique_ptr<Epub>(new Epub(path, "/.crosspoint"));
+  if (epub->load()) {
+    return epub;
+  }
+
+  Serial.printf("[%lu] [   ] Failed to load epub\n", millis());
+  return nullptr;
+}
+
+void ReaderActivity::onSelectEpubFile(const std::string& path) {
+  exitActivity();
+  enterNewActivity(new FullScreenMessageActivity(renderer, inputManager, "Loading..."));
+
+  auto epub = loadEpub(path);
+  if (epub) {
+    APP_STATE.openEpubPath = path;
+    APP_STATE.saveToFile();
+    onGoToEpubReader(std::move(epub));
+  } else {
+    exitActivity();
+    enterNewActivity(new FullScreenMessageActivity(renderer, inputManager, "Failed to load epub", REGULAR,
+                                                   EInkDisplay::HALF_REFRESH));
+    delay(2000);
+    onGoToFileSelection();
+  }
+}
+
+void ReaderActivity::onGoToFileSelection() {
+  exitActivity();
+  enterNewActivity(new FileSelectionActivity(
+      renderer, inputManager, [this](const std::string& path) { onSelectEpubFile(path); }, onGoBack));
+}
+
+void ReaderActivity::onGoToEpubReader(std::unique_ptr<Epub> epub) {
+  exitActivity();
+  enterNewActivity(new EpubReaderActivity(renderer, inputManager, std::move(epub), [this] { onGoToFileSelection(); }));
+}
+
+void ReaderActivity::onEnter() {
+  if (initialEpubPath.empty()) {
+    onGoToFileSelection();
+    return;
+  }
+
+  auto epub = loadEpub(initialEpubPath);
+  if (!epub) {
+    onGoBack();
+    return;
+  }
+
+  onGoToEpubReader(std::move(epub));
+}

src/activities/reader/ReaderActivity.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <memory>
+
+#include "../ActivityWithSubactivity.h"
+
+class Epub;
+
+class ReaderActivity final : public ActivityWithSubactivity {
+  std::string initialEpubPath;
+  const std::function<void()> onGoBack;
+  static std::unique_ptr<Epub> loadEpub(const std::string& path);
+
+  void onSelectEpubFile(const std::string& path);
+  void onGoToFileSelection();
+  void onGoToEpubReader(std::unique_ptr<Epub> epub);
+
+ public:
+  explicit ReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::string initialEpubPath,
+                          const std::function<void()>& onGoBack)
+      : ActivityWithSubactivity(renderer, inputManager),
+        initialEpubPath(std::move(initialEpubPath)),
+        onGoBack(onGoBack) {}
+  void onEnter() override;
+};

src/activities/settings/SettingsActivity.cpp

@@ -1,4 +1,4 @@
-#include "SettingsScreen.h"
+#include "SettingsActivity.h"
 
 #include <GfxRenderer.h>
 
@@ -7,16 +7,16 @@
 
 // Define the static settings list
 
-const SettingInfo SettingsScreen::settingsList[SettingsScreen::settingsCount] = {
+const SettingInfo SettingsActivity::settingsList[settingsCount] = {
     {"White Sleep Screen", &CrossPointSettings::whiteSleepScreen},
     {"Extra Paragraph Spacing", &CrossPointSettings::extraParagraphSpacing}};
 
-void SettingsScreen::taskTrampoline(void* param) {
-  auto* self = static_cast<SettingsScreen*>(param);
+void SettingsActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<SettingsActivity*>(param);
   self->displayTaskLoop();
 }
 
-void SettingsScreen::onEnter() {
+void SettingsActivity::onEnter() {
   renderingMutex = xSemaphoreCreateMutex();
 
   // Reset selection to first item
@@ -25,7 +25,7 @@ void SettingsScreen::onEnter() {
   // Trigger first update
   updateRequired = true;
 
-  xTaskCreate(&SettingsScreen::taskTrampoline, "SettingsScreenTask",
+  xTaskCreate(&SettingsActivity::taskTrampoline, "SettingsActivityTask",
               2048,               // Stack size
               this,               // Parameters
               1,                  // Priority
@@ -33,7 +33,7 @@ void SettingsScreen::onEnter() {
   );
 }
 
-void SettingsScreen::onExit() {
+void SettingsActivity::onExit() {
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -44,7 +44,7 @@ void SettingsScreen::onExit() {
   renderingMutex = nullptr;
 }
 
-void SettingsScreen::handleInput() {
+void SettingsActivity::loop() {
   // Handle actions with early return
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     toggleCurrentSetting();
@@ -70,7 +70,7 @@ void SettingsScreen::handleInput() {
   }
 }
 
-void SettingsScreen::toggleCurrentSetting() {
+void SettingsActivity::toggleCurrentSetting() {
   // Validate index
   if (selectedSettingIndex < 0 || selectedSettingIndex >= settingsCount) {
     return;
@@ -84,7 +84,7 @@ void SettingsScreen::toggleCurrentSetting() {
   SETTINGS.saveToFile();
 }
 
-void SettingsScreen::displayTaskLoop() {
+void SettingsActivity::displayTaskLoop() {
   while (true) {
     if (updateRequired) {
       updateRequired = false;
@@ -96,7 +96,7 @@ void SettingsScreen::displayTaskLoop() {
   }
 }
 
-void SettingsScreen::render() const {
+void SettingsActivity::render() const {
   renderer.clearScreen();
 
   const auto pageWidth = GfxRenderer::getScreenWidth();

src/activities/settings/SettingsActivity.h

@@ -7,7 +7,7 @@
 #include <string>
 #include <vector>
 
-#include "Screen.h"
+#include "../Activity.h"
 
 class CrossPointSettings;
 
@@ -17,7 +17,7 @@ struct SettingInfo {
   uint8_t CrossPointSettings::* valuePtr;  // Pointer to member in CrossPointSettings
 };
 
-class SettingsScreen final : public Screen {
+class SettingsActivity final : public Activity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
@@ -34,9 +34,9 @@ class SettingsScreen final : public Screen {
   void toggleCurrentSetting();
 
  public:
-  explicit SettingsScreen(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onGoHome)
-      : Screen(renderer, inputManager), onGoHome(onGoHome) {}
+  explicit SettingsActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onGoHome)
+      : Activity(renderer, inputManager), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
-  void handleInput() override;
+  void loop() override;
 };

src/activities/util/FullScreenMessageActivity.cpp

@@ -1,10 +1,10 @@
-#include "FullScreenMessageScreen.h"
+#include "FullScreenMessageActivity.h"
 
 #include <GfxRenderer.h>
 
 #include "config.h"
 
-void FullScreenMessageScreen::onEnter() {
+void FullScreenMessageActivity::onEnter() {
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (GfxRenderer::getScreenHeight() - height) / 2;
 

src/activities/util/FullScreenMessageActivity.h

@@ -0,0 +1,21 @@
+#pragma once
+#include <EInkDisplay.h>
+#include <EpdFontFamily.h>
+
+#include <string>
+#include <utility>
+
+#include "../Activity.h"
+
+class FullScreenMessageActivity final : public Activity {
+  std::string text;
+  EpdFontStyle style;
+  EInkDisplay::RefreshMode refreshMode;
+
+ public:
+  explicit FullScreenMessageActivity(GfxRenderer& renderer, InputManager& inputManager, std::string text,
+                                     const EpdFontStyle style = REGULAR,
+                                     const EInkDisplay::RefreshMode refreshMode = EInkDisplay::FAST_REFRESH)
+      : Activity(renderer, inputManager), text(std::move(text)), style(style), refreshMode(refreshMode) {}
+  void onEnter() override;
+};

src/main.cpp

@@ -16,13 +16,13 @@
 #include "Battery.h"
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
+#include "activities/boot_sleep/BootActivity.h"
+#include "activities/boot_sleep/SleepActivity.h"
+#include "activities/home/HomeActivity.h"
+#include "activities/reader/ReaderActivity.h"
+#include "activities/settings/SettingsActivity.h"
+#include "activities/util/FullScreenMessageActivity.h"
 #include "config.h"
-#include "screens/BootLogoScreen.h"
-#include "screens/EpubReaderScreen.h"
-#include "screens/FileSelectionScreen.h"
-#include "screens/FullScreenMessageScreen.h"
-#include "screens/SettingsScreen.h"
-#include "screens/SleepScreen.h"
 
 #define SPI_FQ 40000000
 // Display SPI pins (custom pins for XteinkX4, not hardware SPI defaults)
@@ -41,8 +41,7 @@
 EInkDisplay einkDisplay(EPD_SCLK, EPD_MOSI, EPD_CS, EPD_DC, EPD_RST, EPD_BUSY);
 InputManager inputManager;
 GfxRenderer renderer(einkDisplay);
-Screen* currentScreen;
-CrossPointState appState;
+Activity* currentActivity;
 
 // Fonts
 EpdFont bookerlyFont(&bookerly_2b);
@@ -66,31 +65,16 @@ constexpr unsigned long POWER_BUTTON_SLEEP_MS = 500;
 // Auto-sleep timeout (10 minutes of inactivity)
 constexpr unsigned long AUTO_SLEEP_TIMEOUT_MS = 10 * 60 * 1000;
 
-std::unique_ptr<Epub> loadEpub(const std::string& path) {
-  if (!SD.exists(path.c_str())) {
-    Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
-    return nullptr;
-  }
-
-  auto epub = std::unique_ptr<Epub>(new Epub(path, "/.crosspoint"));
-  if (epub->load()) {
-    return epub;
-  }
-
-  Serial.printf("[%lu] [   ] Failed to load epub\n", millis());
-  return nullptr;
-}
-
-void exitScreen() {
-  if (currentScreen) {
-    currentScreen->onExit();
-    delete currentScreen;
+void exitActivity() {
+  if (currentActivity) {
+    currentActivity->onExit();
+    delete currentActivity;
   }
 }
 
-void enterNewScreen(Screen* screen) {
-  currentScreen = screen;
-  currentScreen->onEnter();
+void enterNewActivity(Activity* activity) {
+  currentActivity = activity;
+  currentActivity->onEnter();
 }
 
 // Verify long press on wake-up from deep sleep
@@ -134,8 +118,8 @@ void waitForPowerRelease() {
 
 // Enter deep sleep mode
 void enterDeepSleep() {
-  exitScreen();
-  enterNewScreen(new SleepScreen(renderer, inputManager));
+  exitActivity();
+  enterNewActivity(new SleepActivity(renderer, inputManager));
 
   Serial.printf("[%lu] [   ] Power button released after a long press. Entering deep sleep.\n", millis());
   delay(1000);  // Allow Serial buffer to empty and display to update
@@ -150,33 +134,20 @@ void enterDeepSleep() {
 }
 
 void onGoHome();
-void onSelectEpubFile(const std::string& path) {
-  exitScreen();
-  enterNewScreen(new FullScreenMessageScreen(renderer, inputManager, "Loading..."));
-
-  auto epub = loadEpub(path);
-  if (epub) {
-    appState.openEpubPath = path;
-    appState.saveToFile();
-    exitScreen();
-    enterNewScreen(new EpubReaderScreen(renderer, inputManager, std::move(epub), onGoHome));
-  } else {
-    exitScreen();
-    enterNewScreen(
-        new FullScreenMessageScreen(renderer, inputManager, "Failed to load epub", REGULAR, EInkDisplay::HALF_REFRESH));
-    delay(2000);
-    onGoHome();
-  }
+void onGoToReader(const std::string& initialEpubPath) {
+  exitActivity();
+  enterNewActivity(new ReaderActivity(renderer, inputManager, initialEpubPath, onGoHome));
 }
+void onGoToReaderHome() { onGoToReader(std::string()); }
 
 void onGoToSettings() {
-  exitScreen();
-  enterNewScreen(new SettingsScreen(renderer, inputManager, onGoHome));
+  exitActivity();
+  enterNewActivity(new SettingsActivity(renderer, inputManager, onGoHome));
 }
 
 void onGoHome() {
-  exitScreen();
-  enterNewScreen(new FileSelectionScreen(renderer, inputManager, onSelectEpubFile, onGoToSettings));
+  exitActivity();
+  enterNewActivity(new HomeActivity(renderer, inputManager, onGoToReaderHome, onGoToSettings));
 }
 
 void setup() {
@@ -202,28 +173,20 @@ void setup() {
   renderer.insertFont(SMALL_FONT_ID, smallFontFamily);
   Serial.printf("[%lu] [   ] Fonts setup\n", millis());
 
-  exitScreen();
-  enterNewScreen(new BootLogoScreen(renderer, inputManager));
+  exitActivity();
+  enterNewActivity(new BootActivity(renderer, inputManager));
 
   // SD Card Initialization
   SD.begin(SD_SPI_CS, SPI, SPI_FQ);
 
   SETTINGS.loadFromFile();
-  appState.loadFromFile();
-  if (!appState.openEpubPath.empty()) {
-    auto epub = loadEpub(appState.openEpubPath);
-    if (epub) {
-      exitScreen();
-      enterNewScreen(new EpubReaderScreen(renderer, inputManager, std::move(epub), onGoHome));
-      // Ensure we're not still holding the power button before leaving setup
-      waitForPowerRelease();
-      return;
-    }
+  APP_STATE.loadFromFile();
+  if (APP_STATE.openEpubPath.empty()) {
+    onGoHome();
+  } else {
+    onGoToReader(APP_STATE.openEpubPath);
   }
 
-  exitScreen();
-  enterNewScreen(new FileSelectionScreen(renderer, inputManager, onSelectEpubFile, onGoToSettings));
-
   // Ensure we're not still holding the power button before leaving setup
   waitForPowerRelease();
 }
@@ -259,7 +222,7 @@ void loop() {
     return;
   }
 
-  if (currentScreen) {
-    currentScreen->handleInput();
+  if (currentActivity) {
+    currentActivity->loop();
   }
 }

src/screens/BootLogoScreen.h

@@ -1,8 +0,0 @@
-#pragma once
-#include "Screen.h"
-
-class BootLogoScreen final : public Screen {
- public:
-  explicit BootLogoScreen(GfxRenderer& renderer, InputManager& inputManager) : Screen(renderer, inputManager) {}
-  void onEnter() override;
-};

src/screens/FullScreenMessageScreen.h

@@ -1,21 +0,0 @@
-#pragma once
-#include <EInkDisplay.h>
-#include <EpdFontFamily.h>
-
-#include <string>
-#include <utility>
-
-#include "Screen.h"
-
-class FullScreenMessageScreen final : public Screen {
-  std::string text;
-  EpdFontStyle style;
-  EInkDisplay::RefreshMode refreshMode;
-
- public:
-  explicit FullScreenMessageScreen(GfxRenderer& renderer, InputManager& inputManager, std::string text,
-                                   const EpdFontStyle style = REGULAR,
-                                   const EInkDisplay::RefreshMode refreshMode = EInkDisplay::FAST_REFRESH)
-      : Screen(renderer, inputManager), text(std::move(text)), style(style), refreshMode(refreshMode) {}
-  void onEnter() override;
-};

src/screens/Screen.h

@@ -1,17 +0,0 @@
-#pragma once
-#include <InputManager.h>
-
-class GfxRenderer;
-
-class Screen {
- protected:
-  GfxRenderer& renderer;
-  InputManager& inputManager;
-
- public:
-  explicit Screen(GfxRenderer& renderer, InputManager& inputManager) : renderer(renderer), inputManager(inputManager) {}
-  virtual ~Screen() = default;
-  virtual void onEnter() {}
-  virtual void onExit() {}
-  virtual void handleInput() {}
-};

src/screens/SleepScreen.h

@@ -1,8 +0,0 @@
-#pragma once
-#include "Screen.h"
-
-class SleepScreen final : public Screen {
- public:
-  explicit SleepScreen(GfxRenderer& renderer, InputManager& inputManager) : Screen(renderer, inputManager) {}
-  void onEnter() override;
-};