#include "GfxRenderer.h"

#include <Utf8.h>

void GfxRenderer::insertFont(const int fontId, EpdFontFamily font) { fontMap.insert({fontId, font}); }

void GfxRenderer::rotateCoordinates(const int x, const int y, int* rotatedX, int* rotatedY) const {
  switch (orientation) {
    case Portrait: {
      // Logical portrait (480x800) → panel (800x480)
      // Rotation: 90 degrees clockwise
      *rotatedX = y;
      *rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - x;
      break;
    }
    case LandscapeClockwise: {
      // Logical landscape (800x480) rotated 180 degrees (swap top/bottom and left/right)
      *rotatedX = EInkDisplay::DISPLAY_WIDTH - 1 - x;
      *rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - y;
      break;
    }
    case PortraitInverted: {
      // Logical portrait (480x800) → panel (800x480)
      // Rotation: 90 degrees counter-clockwise
      *rotatedX = EInkDisplay::DISPLAY_WIDTH - 1 - y;
      *rotatedY = x;
      break;
    }
    case LandscapeCounterClockwise: {
      // Logical landscape (800x480) aligned with panel orientation
      *rotatedX = x;
      *rotatedY = y;
      break;
    }
  }
}

void GfxRenderer::drawPixel(const int x, const int y, const bool state) const {
  uint8_t* frameBuffer = einkDisplay.getFrameBuffer();

  // Early return if no framebuffer is set
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer\n", millis());
    return;
  }

  int rotatedX = 0;
  int rotatedY = 0;
  rotateCoordinates(x, y, &rotatedX, &rotatedY);

  // Bounds checking against physical panel dimensions
  if (rotatedX < 0 || rotatedX >= EInkDisplay::DISPLAY_WIDTH || rotatedY < 0 ||
      rotatedY >= EInkDisplay::DISPLAY_HEIGHT) {
    Serial.printf("[%lu] [GFX] !! Outside range (%d, %d) -> (%d, %d)\n", millis(), x, y, rotatedX, rotatedY);
    return;
  }

  // Calculate byte position and bit position
  const uint16_t byteIndex = rotatedY * EInkDisplay::DISPLAY_WIDTH_BYTES + (rotatedX / 8);
  const uint8_t bitPosition = 7 - (rotatedX % 8);  // MSB first

  if (state) {
    frameBuffer[byteIndex] &= ~(1 << bitPosition);  // Clear bit
  } else {
    frameBuffer[byteIndex] |= 1 << bitPosition;  // Set bit
  }
}

int GfxRenderer::getTextWidth(const int fontId, const char* text, const EpdFontFamily::Style style) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  int w = 0, h = 0;
  fontMap.at(fontId).getTextDimensions(text, &w, &h, style);
  return w;
}

void GfxRenderer::drawCenteredText(const int fontId, const int y, const char* text, const bool black,
                                   const EpdFontFamily::Style style) const {
  const int x = (getScreenWidth() - getTextWidth(fontId, text, style)) / 2;
  drawText(fontId, x, y, text, black, style);
}

void GfxRenderer::drawText(const int fontId, const int x, const int y, const char* text, const bool black,
                           const EpdFontFamily::Style style) const {
  const int yPos = y + getFontAscenderSize(fontId);
  int xpos = x;

  // cannot draw a NULL / empty string
  if (text == nullptr || *text == '\0') {
    return;
  }

  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return;
  }
  const auto font = fontMap.at(fontId);

  // no printable characters
  if (!font.hasPrintableChars(text, style)) {
    return;
  }

  uint32_t cp;
  while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
    renderChar(font, cp, &xpos, &yPos, black, style);
  }
}

void GfxRenderer::drawLine(int x1, int y1, int x2, int y2, const bool state) const {
  if (x1 == x2) {
    if (y2 < y1) {
      std::swap(y1, y2);
    }
    for (int y = y1; y <= y2; y++) {
      drawPixel(x1, y, state);
    }
  } else if (y1 == y2) {
    if (x2 < x1) {
      std::swap(x1, x2);
    }
    for (int x = x1; x <= x2; x++) {
      drawPixel(x, y1, state);
    }
  } else {
    // TODO: Implement
    Serial.printf("[%lu] [GFX] Line drawing not supported\n", millis());
  }
}

void GfxRenderer::drawRect(const int x, const int y, const int width, const int height, const bool state) const {
  drawLine(x, y, x + width - 1, y, state);
  drawLine(x + width - 1, y, x + width - 1, y + height - 1, state);
  drawLine(x + width - 1, y + height - 1, x, y + height - 1, state);
  drawLine(x, y, x, y + height - 1, state);
}

void GfxRenderer::fillRect(const int x, const int y, const int width, const int height, const bool state) const {
  for (int fillY = y; fillY < y + height; fillY++) {
    drawLine(x, fillY, x + width - 1, fillY, state);
  }
}

void GfxRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, const int width, const int height) const {
  // TODO: Rotate bits
  int rotatedX = 0;
  int rotatedY = 0;
  rotateCoordinates(x, y, &rotatedX, &rotatedY);
  einkDisplay.drawImage(bitmap, rotatedX, rotatedY, width, height);
}

void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, const int maxWidth, const int maxHeight,
                             const float cropX, const float cropY) const {
  // For 1-bit bitmaps, use optimized 1-bit rendering path (no crop support for 1-bit)
  if (bitmap.is1Bit() && cropX == 0.0f && cropY == 0.0f) {
    drawBitmap1Bit(bitmap, x, y, maxWidth, maxHeight);
    return;
  }

  float scale = 1.0f;
  bool isScaled = false;
  int cropPixX = std::floor(bitmap.getWidth() * cropX / 2.0f);
  int cropPixY = std::floor(bitmap.getHeight() * cropY / 2.0f);
  Serial.printf("[%lu] [GFX] Cropping %dx%d by %dx%d pix, is %s\n", millis(), bitmap.getWidth(), bitmap.getHeight(),
                cropPixX, cropPixY, bitmap.isTopDown() ? "top-down" : "bottom-up");

  if (maxWidth > 0 && (1.0f - cropX) * bitmap.getWidth() > maxWidth) {
    scale = static_cast<float>(maxWidth) / static_cast<float>((1.0f - cropX) * bitmap.getWidth());
    isScaled = true;
  }
  if (maxHeight > 0 && (1.0f - cropY) * bitmap.getHeight() > maxHeight) {
    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>((1.0f - cropY) * bitmap.getHeight()));
    isScaled = true;
  }
  Serial.printf("[%lu] [GFX] Scaling by %f - %s\n", millis(), scale, isScaled ? "scaled" : "not scaled");

  // Calculate output row size (2 bits per pixel, packed into bytes)
  // IMPORTANT: Use int, not uint8_t, to avoid overflow for images > 1020 pixels wide
  const int outputRowSize = (bitmap.getWidth() + 3) / 4;
  auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
  auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));

  if (!outputRow || !rowBytes) {
    Serial.printf("[%lu] [GFX] !! Failed to allocate BMP row buffers\n", millis());
    free(outputRow);
    free(rowBytes);
    return;
  }

  for (int bmpY = 0; bmpY < (bitmap.getHeight() - cropPixY); bmpY++) {
    // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
    // Screen's (0, 0) is the top-left corner.
    int screenY = -cropPixY + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
    if (isScaled) {
      screenY = std::floor(screenY * scale);
    }
    screenY += y;  // the offset should not be scaled
    if (screenY >= getScreenHeight()) {
      break;
    }

    if (bitmap.readNextRow(outputRow, rowBytes) != BmpReaderError::Ok) {
      Serial.printf("[%lu] [GFX] Failed to read row %d from bitmap\n", millis(), bmpY);
      free(outputRow);
      free(rowBytes);
      return;
    }

    if (screenY < 0) {
      continue;
    }

    if (bmpY < cropPixY) {
      // Skip the row if it's outside the crop area
      continue;
    }

    for (int bmpX = cropPixX; bmpX < bitmap.getWidth() - cropPixX; bmpX++) {
      int screenX = bmpX - cropPixX;
      if (isScaled) {
        screenX = std::floor(screenX * scale);
      }
      screenX += x;  // the offset should not be scaled
      if (screenX >= getScreenWidth()) {
        break;
      }
      if (screenX < 0) {
        continue;
      }

      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;

      if (renderMode == BW && val < 3) {
        drawPixel(screenX, screenY);
      } else if (renderMode == GRAYSCALE_MSB && (val == 1 || val == 2)) {
        drawPixel(screenX, screenY, false);
      } else if (renderMode == GRAYSCALE_LSB && val == 1) {
        drawPixel(screenX, screenY, false);
      }
    }
  }

  free(outputRow);
  free(rowBytes);
}

void GfxRenderer::drawBitmap1Bit(const Bitmap& bitmap, const int x, const int y, const int maxWidth,
                                 const int maxHeight) const {
  float scale = 1.0f;
  bool isScaled = false;
  if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
    scale = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
    isScaled = true;
  }
  if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight()));
    isScaled = true;
  }

  // For 1-bit BMP, output is still 2-bit packed (for consistency with readNextRow)
  const int outputRowSize = (bitmap.getWidth() + 3) / 4;
  auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
  auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));

  if (!outputRow || !rowBytes) {
    Serial.printf("[%lu] [GFX] !! Failed to allocate 1-bit BMP row buffers\n", millis());
    free(outputRow);
    free(rowBytes);
    return;
  }

  for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
    // Read rows sequentially using readNextRow
    if (bitmap.readNextRow(outputRow, rowBytes) != BmpReaderError::Ok) {
      Serial.printf("[%lu] [GFX] Failed to read row %d from 1-bit bitmap\n", millis(), bmpY);
      free(outputRow);
      free(rowBytes);
      return;
    }

    // Calculate screen Y based on whether BMP is top-down or bottom-up
    const int bmpYOffset = bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY;
    int screenY = y + (isScaled ? static_cast<int>(std::floor(bmpYOffset * scale)) : bmpYOffset);
    if (screenY >= getScreenHeight()) {
      continue;  // Continue reading to keep row counter in sync
    }
    if (screenY < 0) {
      continue;
    }

    for (int bmpX = 0; bmpX < bitmap.getWidth(); bmpX++) {
      int screenX = x + (isScaled ? static_cast<int>(std::floor(bmpX * scale)) : bmpX);
      if (screenX >= getScreenWidth()) {
        break;
      }
      if (screenX < 0) {
        continue;
      }

      // Get 2-bit value (result of readNextRow quantization)
      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;

      // For 1-bit source: 0 or 1 -> map to black (0,1,2) or white (3)
      // val < 3 means black pixel (draw it)
      if (val < 3) {
        drawPixel(screenX, screenY, true);
      }
      // White pixels (val == 3) are not drawn (leave background)
    }
  }

  free(outputRow);
  free(rowBytes);
}

void GfxRenderer::fillPolygon(const int* xPoints, const int* yPoints, int numPoints, bool state) const {
  if (numPoints < 3) return;

  // Find bounding box
  int minY = yPoints[0], maxY = yPoints[0];
  for (int i = 1; i < numPoints; i++) {
    if (yPoints[i] < minY) minY = yPoints[i];
    if (yPoints[i] > maxY) maxY = yPoints[i];
  }

  // Clip to screen
  if (minY < 0) minY = 0;
  if (maxY >= getScreenHeight()) maxY = getScreenHeight() - 1;

  // Allocate node buffer for scanline algorithm
  auto* nodeX = static_cast<int*>(malloc(numPoints * sizeof(int)));
  if (!nodeX) {
    Serial.printf("[%lu] [GFX] !! Failed to allocate polygon node buffer\n", millis());
    return;
  }

  // Scanline fill algorithm
  for (int scanY = minY; scanY <= maxY; scanY++) {
    int nodes = 0;

    // Find all intersection points with edges
    int j = numPoints - 1;
    for (int i = 0; i < numPoints; i++) {
      if ((yPoints[i] < scanY && yPoints[j] >= scanY) || (yPoints[j] < scanY && yPoints[i] >= scanY)) {
        // Calculate X intersection using fixed-point to avoid float
        int dy = yPoints[j] - yPoints[i];
        if (dy != 0) {
          nodeX[nodes++] = xPoints[i] + (scanY - yPoints[i]) * (xPoints[j] - xPoints[i]) / dy;
        }
      }
      j = i;
    }

    // Sort nodes by X (simple bubble sort, numPoints is small)
    for (int i = 0; i < nodes - 1; i++) {
      for (int k = i + 1; k < nodes; k++) {
        if (nodeX[i] > nodeX[k]) {
          int temp = nodeX[i];
          nodeX[i] = nodeX[k];
          nodeX[k] = temp;
        }
      }
    }

    // Fill between pairs of nodes
    for (int i = 0; i < nodes - 1; i += 2) {
      int startX = nodeX[i];
      int endX = nodeX[i + 1];

      // Clip to screen
      if (startX < 0) startX = 0;
      if (endX >= getScreenWidth()) endX = getScreenWidth() - 1;

      // Draw horizontal line
      for (int x = startX; x <= endX; x++) {
        drawPixel(x, scanY, state);
      }
    }
  }

  free(nodeX);
}

void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScreen(color); }

void GfxRenderer::invertScreen() const {
  uint8_t* buffer = einkDisplay.getFrameBuffer();
  if (!buffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in invertScreen\n", millis());
    return;
  }
  for (int i = 0; i < EInkDisplay::BUFFER_SIZE; i++) {
    buffer[i] = ~buffer[i];
  }
}

void GfxRenderer::displayBuffer(const EInkDisplay::RefreshMode refreshMode) const {
  einkDisplay.displayBuffer(refreshMode);
}

std::string GfxRenderer::truncatedText(const int fontId, const char* text, const int maxWidth,
                                       const EpdFontFamily::Style style) const {
  std::string item = text;
  int itemWidth = getTextWidth(fontId, item.c_str(), style);
  while (itemWidth > maxWidth && item.length() > 8) {
    item.replace(item.length() - 5, 5, "...");
    itemWidth = getTextWidth(fontId, item.c_str(), style);
  }
  return item;
}

// Note: Internal driver treats screen in command orientation; this library exposes a logical orientation
int GfxRenderer::getScreenWidth() const {
  switch (orientation) {
    case Portrait:
    case PortraitInverted:
      // 480px wide in portrait logical coordinates
      return EInkDisplay::DISPLAY_HEIGHT;
    case LandscapeClockwise:
    case LandscapeCounterClockwise:
      // 800px wide in landscape logical coordinates
      return EInkDisplay::DISPLAY_WIDTH;
  }
  return EInkDisplay::DISPLAY_HEIGHT;
}

int GfxRenderer::getScreenHeight() const {
  switch (orientation) {
    case Portrait:
    case PortraitInverted:
      // 800px tall in portrait logical coordinates
      return EInkDisplay::DISPLAY_WIDTH;
    case LandscapeClockwise:
    case LandscapeCounterClockwise:
      // 480px tall in landscape logical coordinates
      return EInkDisplay::DISPLAY_HEIGHT;
  }
  return EInkDisplay::DISPLAY_WIDTH;
}

int GfxRenderer::getSpaceWidth(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  return fontMap.at(fontId).getGlyph(' ', EpdFontFamily::REGULAR)->advanceX;
}

int GfxRenderer::getFontAscenderSize(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  return fontMap.at(fontId).getData(EpdFontFamily::REGULAR)->ascender;
}

int GfxRenderer::getLineHeight(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }

  return fontMap.at(fontId).getData(EpdFontFamily::REGULAR)->advanceY;
}

void GfxRenderer::drawButtonHints(const int fontId, const char* btn1, const char* btn2, const char* btn3,
                                  const char* btn4) {
  const Orientation orig_orientation = getOrientation();
  setOrientation(Orientation::Portrait);

  const int pageHeight = getScreenHeight();
  constexpr int buttonWidth = 106;
  constexpr int buttonHeight = 40;
  constexpr int buttonY = 40;     // Distance from bottom
  constexpr int textYOffset = 7;  // Distance from top of button to text baseline
  constexpr int buttonPositions[] = {25, 130, 245, 350};
  const char* labels[] = {btn1, btn2, btn3, btn4};

  for (int i = 0; i < 4; i++) {
    // Only draw if the label is non-empty
    if (labels[i] != nullptr && labels[i][0] != '\0') {
      const int x = buttonPositions[i];
      fillRect(x, pageHeight - buttonY, buttonWidth, buttonHeight, false);
      drawRect(x, pageHeight - buttonY, buttonWidth, buttonHeight);
      const int textWidth = getTextWidth(fontId, labels[i]);
      const int textX = x + (buttonWidth - 1 - textWidth) / 2;
      drawText(fontId, textX, pageHeight - buttonY + textYOffset, labels[i]);
    }
  }

  setOrientation(orig_orientation);
}

void GfxRenderer::drawSideButtonHints(const int fontId, const char* topBtn, const char* bottomBtn) const {
  const int screenWidth = getScreenWidth();
  constexpr int buttonWidth = 40;   // Width on screen (height when rotated)
  constexpr int buttonHeight = 80;  // Height on screen (width when rotated)
  constexpr int buttonX = 5;        // Distance from right edge
  // Position for the button group - buttons share a border so they're adjacent
  constexpr int topButtonY = 345;  // Top button position

  const char* labels[] = {topBtn, bottomBtn};

  // Draw the shared border for both buttons as one unit
  const int x = screenWidth - buttonX - buttonWidth;

  // Draw top button outline (3 sides, bottom open)
  if (topBtn != nullptr && topBtn[0] != '\0') {
    drawLine(x, topButtonY, x + buttonWidth - 1, topButtonY);                                       // Top
    drawLine(x, topButtonY, x, topButtonY + buttonHeight - 1);                                      // Left
    drawLine(x + buttonWidth - 1, topButtonY, x + buttonWidth - 1, topButtonY + buttonHeight - 1);  // Right
  }

  // Draw shared middle border
  if ((topBtn != nullptr && topBtn[0] != '\0') || (bottomBtn != nullptr && bottomBtn[0] != '\0')) {
    drawLine(x, topButtonY + buttonHeight, x + buttonWidth - 1, topButtonY + buttonHeight);  // Shared border
  }

  // Draw bottom button outline (3 sides, top is shared)
  if (bottomBtn != nullptr && bottomBtn[0] != '\0') {
    drawLine(x, topButtonY + buttonHeight, x, topButtonY + 2 * buttonHeight - 1);  // Left
    drawLine(x + buttonWidth - 1, topButtonY + buttonHeight, x + buttonWidth - 1,
             topButtonY + 2 * buttonHeight - 1);                                                             // Right
    drawLine(x, topButtonY + 2 * buttonHeight - 1, x + buttonWidth - 1, topButtonY + 2 * buttonHeight - 1);  // Bottom
  }

  // Draw text for each button
  for (int i = 0; i < 2; i++) {
    if (labels[i] != nullptr && labels[i][0] != '\0') {
      const int y = topButtonY + i * buttonHeight;

      // Draw rotated text centered in the button
      const int textWidth = getTextWidth(fontId, labels[i]);
      const int textHeight = getTextHeight(fontId);

      // Center the rotated text in the button
      const int textX = x + (buttonWidth - textHeight) / 2;
      const int textY = y + (buttonHeight + textWidth) / 2;

      drawTextRotated90CW(fontId, textX, textY, labels[i]);
    }
  }
}

int GfxRenderer::getTextHeight(const int fontId) const {
  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return 0;
  }
  return fontMap.at(fontId).getData(EpdFontFamily::REGULAR)->ascender;
}

void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y, const char* text, const bool black,
                                      const EpdFontFamily::Style style) const {
  // Cannot draw a NULL / empty string
  if (text == nullptr || *text == '\0') {
    return;
  }

  if (fontMap.count(fontId) == 0) {
    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
    return;
  }
  const auto font = fontMap.at(fontId);

  // No printable characters
  if (!font.hasPrintableChars(text, style)) {
    return;
  }

  // For 90° clockwise rotation:
  // Original (glyphX, glyphY) -> Rotated (glyphY, -glyphX)
  // Text reads from bottom to top

  int yPos = y;  // Current Y position (decreases as we draw characters)

  uint32_t cp;
  while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
    const EpdGlyph* glyph = font.getGlyph(cp, style);
    if (!glyph) {
      glyph = font.getGlyph(REPLACEMENT_GLYPH, style);
    }
    if (!glyph) {
      continue;
    }

    const int is2Bit = font.getData(style)->is2Bit;
    const uint32_t offset = glyph->dataOffset;
    const uint8_t width = glyph->width;
    const uint8_t height = glyph->height;
    const int left = glyph->left;
    const int top = glyph->top;

    const uint8_t* bitmap = &font.getData(style)->bitmap[offset];

    if (bitmap != nullptr) {
      for (int glyphY = 0; glyphY < height; glyphY++) {
        for (int glyphX = 0; glyphX < width; glyphX++) {
          const int pixelPosition = glyphY * width + glyphX;

          // 90° clockwise rotation transformation:
          // screenX = x + (ascender - top + glyphY)
          // screenY = yPos - (left + glyphX)
          const int screenX = x + (font.getData(style)->ascender - top + glyphY);
          const int screenY = yPos - left - glyphX;

          if (is2Bit) {
            const uint8_t byte = bitmap[pixelPosition / 4];
            const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
            const uint8_t bmpVal = 3 - (byte >> bit_index) & 0x3;

            if (renderMode == BW && bmpVal < 3) {
              drawPixel(screenX, screenY, black);
            } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
              drawPixel(screenX, screenY, false);
            } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
              drawPixel(screenX, screenY, false);
            }
          } else {
            const uint8_t byte = bitmap[pixelPosition / 8];
            const uint8_t bit_index = 7 - (pixelPosition % 8);

            if ((byte >> bit_index) & 1) {
              drawPixel(screenX, screenY, black);
            }
          }
        }
      }
    }

    // Move to next character position (going up, so decrease Y)
    yPos -= glyph->advanceX;
  }
}

uint8_t* GfxRenderer::getFrameBuffer() const { return einkDisplay.getFrameBuffer(); }

size_t GfxRenderer::getBufferSize() { return EInkDisplay::BUFFER_SIZE; }

void GfxRenderer::grayscaleRevert() const { einkDisplay.grayscaleRevert(); }

void GfxRenderer::copyGrayscaleLsbBuffers() const { einkDisplay.copyGrayscaleLsbBuffers(einkDisplay.getFrameBuffer()); }

void GfxRenderer::copyGrayscaleMsbBuffers() const { einkDisplay.copyGrayscaleMsbBuffers(einkDisplay.getFrameBuffer()); }

void GfxRenderer::displayGrayBuffer() const { einkDisplay.displayGrayBuffer(); }

void GfxRenderer::freeBwBufferChunks() {
  for (auto& bwBufferChunk : bwBufferChunks) {
    if (bwBufferChunk) {
      free(bwBufferChunk);
      bwBufferChunk = nullptr;
    }
  }
}

/**
 * This should be called before grayscale buffers are populated.
 * A `restoreBwBuffer` call should always follow the grayscale render if this method was called.
 * Uses chunked allocation to avoid needing 48KB of contiguous memory.
 * Returns true if buffer was stored successfully, false if allocation failed.
 */
bool GfxRenderer::storeBwBuffer() {
  const uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in storeBwBuffer\n", millis());
    return false;
  }

  // Allocate and copy each chunk
  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
    // Check if any chunks are already allocated
    if (bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! BW buffer chunk %zu already stored - this is likely a bug, freeing chunk\n",
                    millis(), i);
      free(bwBufferChunks[i]);
      bwBufferChunks[i] = nullptr;
    }

    const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
    bwBufferChunks[i] = static_cast<uint8_t*>(malloc(BW_BUFFER_CHUNK_SIZE));

    if (!bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! Failed to allocate BW buffer chunk %zu (%zu bytes)\n", millis(), i,
                    BW_BUFFER_CHUNK_SIZE);
      // Free previously allocated chunks
      freeBwBufferChunks();
      return false;
    }

    memcpy(bwBufferChunks[i], frameBuffer + offset, BW_BUFFER_CHUNK_SIZE);
  }

  Serial.printf("[%lu] [GFX] Stored BW buffer in %zu chunks (%zu bytes each)\n", millis(), BW_BUFFER_NUM_CHUNKS,
                BW_BUFFER_CHUNK_SIZE);
  return true;
}

/**
 * This can only be called if `storeBwBuffer` was called prior to the grayscale render.
 * It should be called to restore the BW buffer state after grayscale rendering is complete.
 * Uses chunked restoration to match chunked storage.
 */
void GfxRenderer::restoreBwBuffer() {
  // Check if any all chunks are allocated
  bool missingChunks = false;
  for (const auto& bwBufferChunk : bwBufferChunks) {
    if (!bwBufferChunk) {
      missingChunks = true;
      break;
    }
  }

  if (missingChunks) {
    freeBwBufferChunks();
    return;
  }

  uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
  if (!frameBuffer) {
    Serial.printf("[%lu] [GFX] !! No framebuffer in restoreBwBuffer\n", millis());
    freeBwBufferChunks();
    return;
  }

  for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
    // Check if chunk is missing
    if (!bwBufferChunks[i]) {
      Serial.printf("[%lu] [GFX] !! BW buffer chunks not stored - this is likely a bug\n", millis());
      freeBwBufferChunks();
      return;
    }

    const size_t offset = i * BW_BUFFER_CHUNK_SIZE;
    memcpy(frameBuffer + offset, bwBufferChunks[i], BW_BUFFER_CHUNK_SIZE);
  }

  einkDisplay.cleanupGrayscaleBuffers(frameBuffer);

  freeBwBufferChunks();
  Serial.printf("[%lu] [GFX] Restored and freed BW buffer chunks\n", millis());
}

/**
 * Cleanup grayscale buffers using the current frame buffer.
 * Use this when BW buffer was re-rendered instead of stored/restored.
 */
void GfxRenderer::cleanupGrayscaleWithFrameBuffer() const {
  uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
  if (frameBuffer) {
    einkDisplay.cleanupGrayscaleBuffers(frameBuffer);
  }
}

void GfxRenderer::renderChar(const EpdFontFamily& fontFamily, const uint32_t cp, int* x, const int* y,
                             const bool pixelState, const EpdFontFamily::Style style) const {
  const EpdGlyph* glyph = fontFamily.getGlyph(cp, style);
  if (!glyph) {
    glyph = fontFamily.getGlyph(REPLACEMENT_GLYPH, style);
  }

  // no glyph?
  if (!glyph) {
    Serial.printf("[%lu] [GFX] No glyph for codepoint %d\n", millis(), cp);
    return;
  }

  const int is2Bit = fontFamily.getData(style)->is2Bit;
  const uint32_t offset = glyph->dataOffset;
  const uint8_t width = glyph->width;
  const uint8_t height = glyph->height;
  const int left = glyph->left;

  const uint8_t* bitmap = nullptr;
  bitmap = &fontFamily.getData(style)->bitmap[offset];

  if (bitmap != nullptr) {
    for (int glyphY = 0; glyphY < height; glyphY++) {
      const int screenY = *y - glyph->top + glyphY;
      for (int glyphX = 0; glyphX < width; glyphX++) {
        const int pixelPosition = glyphY * width + glyphX;
        const int screenX = *x + left + glyphX;

        if (is2Bit) {
          const uint8_t byte = bitmap[pixelPosition / 4];
          const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
          // the direct bit from the font is 0 -> white, 1 -> light gray, 2 -> dark gray, 3 -> black
          // we swap this to better match the way images and screen think about colors:
          // 0 -> black, 1 -> dark grey, 2 -> light grey, 3 -> white
          const uint8_t bmpVal = 3 - (byte >> bit_index) & 0x3;

          if (renderMode == BW && bmpVal < 3) {
            // Black (also paints over the grays in BW mode)
            drawPixel(screenX, screenY, pixelState);
          } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
            // Light gray (also mark the MSB if it's going to be a dark gray too)
            // We have to flag pixels in reverse for the gray buffers, as 0 leave alone, 1 update
            drawPixel(screenX, screenY, false);
          } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
            // Dark gray
            drawPixel(screenX, screenY, false);
          }
        } else {
          const uint8_t byte = bitmap[pixelPosition / 8];
          const uint8_t bit_index = 7 - (pixelPosition % 8);

          if ((byte >> bit_index) & 1) {
            drawPixel(screenX, screenY, pixelState);
          }
        }
      }
    }
  }

  *x += glyph->advanceX;
}

void GfxRenderer::getOrientedViewableTRBL(int* outTop, int* outRight, int* outBottom, int* outLeft) const {
  switch (orientation) {
    case Portrait:
      *outTop = VIEWABLE_MARGIN_TOP;
      *outRight = VIEWABLE_MARGIN_RIGHT;
      *outBottom = VIEWABLE_MARGIN_BOTTOM;
      *outLeft = VIEWABLE_MARGIN_LEFT;
      break;
    case LandscapeClockwise:
      *outTop = VIEWABLE_MARGIN_LEFT;
      *outRight = VIEWABLE_MARGIN_TOP;
      *outBottom = VIEWABLE_MARGIN_RIGHT;
      *outLeft = VIEWABLE_MARGIN_BOTTOM;
      break;
    case PortraitInverted:
      *outTop = VIEWABLE_MARGIN_BOTTOM;
      *outRight = VIEWABLE_MARGIN_LEFT;
      *outBottom = VIEWABLE_MARGIN_TOP;
      *outLeft = VIEWABLE_MARGIN_RIGHT;
      break;
    case LandscapeCounterClockwise:
      *outTop = VIEWABLE_MARGIN_RIGHT;
      *outRight = VIEWABLE_MARGIN_BOTTOM;
      *outBottom = VIEWABLE_MARGIN_LEFT;
      *outLeft = VIEWABLE_MARGIN_TOP;
      break;
  }
}
