#include "GxEPDDisplay.h"

#ifdef EXP_PIN_BACKLIGHT
  #include <PCA9557.h>
  extern PCA9557 expander;
#endif

#ifndef DISPLAY_ROTATION
  #define DISPLAY_ROTATION 0
#endif

#ifdef ESP32
  SPIClass SPI1 = SPIClass(FSPI);
#endif

// GFX fonts use the baseline as the cursor origin. UI code assumes top-of-cell
// coordinates (same convention as the OLED driver). Add the font ascender so
// the two conventions match.
static int fontAscender(int sz, bool use_lemon, int scale) {
  if (sz == 3) return 26;              // FreeSans18pt7b: proportional, baseline origin
  if (use_lemon) return 8 * scale;    // Lemon GFX font: baseline origin, ascender 8px×scale
  return 0;                           // GFX built-in font: cursor is top-left of cell
}

bool GxEPDDisplay::begin() {
  display.epd2.selectSPI(SPI1, SPISettings(4000000, MSBFIRST, SPI_MODE0));
#ifdef ESP32
  SPI1.begin(PIN_DISPLAY_SCLK, PIN_DISPLAY_MISO, PIN_DISPLAY_MOSI, PIN_DISPLAY_CS);
#else
  SPI1.begin();
#endif
  display.init(115200, true, 2, false);
  display.setRotation(DISPLAY_ROTATION);
  setTextSize(1);
  display.setPartialWindow(0, 0, display.width(), display.height());
  display.fillScreen(GxEPD_WHITE);
  display.display(true);
#if DISP_BACKLIGHT
  digitalWrite(DISP_BACKLIGHT, LOW);
  pinMode(DISP_BACKLIGHT, OUTPUT);
#endif
  _init = true;
  return true;
}

void GxEPDDisplay::turnOn() {
  if (!_init) begin();
#if defined(DISP_BACKLIGHT) && !defined(BACKLIGHT_BTN)
  digitalWrite(DISP_BACKLIGHT, HIGH);
#elif defined(EXP_PIN_BACKLIGHT) && !defined(BACKLIGHT_BTN)
  expander.digitalWrite(EXP_PIN_BACKLIGHT, HIGH);
#endif
  _isOn = true;
}

void GxEPDDisplay::turnOff() {
#if defined(DISP_BACKLIGHT) && !defined(BACKLIGHT_BTN)
  digitalWrite(DISP_BACKLIGHT, LOW);
#elif defined(EXP_PIN_BACKLIGHT) && !defined(BACKLIGHT_BTN)
  expander.digitalWrite(EXP_PIN_BACKLIGHT, LOW);
#endif
  _isOn = false;
}

void GxEPDDisplay::clear() {
  display.fillScreen(GxEPD_WHITE);
  display.setTextColor(GxEPD_BLACK);
  display_crc.reset();
}

void GxEPDDisplay::startFrame(Color bkg) {
  display.fillScreen(GxEPD_WHITE);
  display.setTextColor(_curr_color = GxEPD_BLACK);
  _text_sz = 1;
  int sc = (width() >= height()) ? 2 : 1;
  display.setFont(_use_lemon ? &Lemon : NULL);
  display.setTextSize(sc);
  display_crc.reset();
}

void GxEPDDisplay::setTextSize(int sz) {
  _text_sz = sz;
  display_crc.update<int>(sz);
  // Size 1 scales with orientation: 1× in portrait (≈OLED width), 2× in landscape.
  // Size 2 always uses 2× built-in (12×16) — fixed because layout Y-positions are hardcoded.
  // Size 3 always uses FreeSans18pt for large headings.
  int sc = (width() >= height()) ? 2 : 1;
  switch (sz) {
    case 3:
      display.setFont(&FreeSans18pt7b);
      display.setTextSize(1);
      break;
    case 2:
      display.setFont(NULL);
      display.setTextSize(2);
      break;
    default:
      display.setFont(_use_lemon ? &Lemon : NULL);
      display.setTextSize(sc);
      break;
  }
}

void GxEPDDisplay::setColor(Color c) {
  display_crc.update<Color>(c);
  // e-ink: DARK background = white paper, LIGHT foreground = black ink
  if (c == DARK) {
    display.setTextColor(_curr_color = GxEPD_WHITE);
  } else {
    display.setTextColor(_curr_color = GxEPD_BLACK);
  }
}

void GxEPDDisplay::setCursor(int x, int y) {
  display_crc.update<int>(x);
  display_crc.update<int>(y);
  // Offset y by the font ascender: callers pass top-of-cell y, GFX fonts
  // expect baseline y. Without this, text would be clipped at the top.
  int sc = (width() >= height()) ? 2 : 1;
  display.setCursor(x, y + fontAscender(_text_sz, _use_lemon, sc));
}

void GxEPDDisplay::print(const char* str) {
  display_crc.update<char>(str, strlen(str));
  display.print(str);
}

void GxEPDDisplay::fillRect(int x, int y, int w, int h) {
  display_crc.update<int>(x);
  display_crc.update<int>(y);
  display_crc.update<int>(w);
  display_crc.update<int>(h);
  display.fillRect(x, y, w, h, _curr_color);
}

void GxEPDDisplay::drawRect(int x, int y, int w, int h) {
  display_crc.update<int>(x);
  display_crc.update<int>(y);
  display_crc.update<int>(w);
  display_crc.update<int>(h);
  display.drawRect(x, y, w, h, _curr_color);
}

void GxEPDDisplay::drawXbm(int x, int y, const uint8_t* bits, int w, int h) {
  display_crc.update<int>(x);
  display_crc.update<int>(y);
  display_crc.update<int>(w);
  display_crc.update<int>(h);
  display_crc.update<uint8_t>(bits, w * h / 8);
  uint16_t widthInBytes = (w + 7) / 8;
  for (uint16_t by = 0; by < h; by++) {
    for (uint16_t bx = 0; bx < w; bx++) {
      uint16_t byteOffset = (by * widthInBytes) + (bx / 8);
      uint8_t bitMask = 0x80 >> (bx & 7);
      if (pgm_read_byte(bits + byteOffset) & bitMask) {
        display.drawPixel(x + bx, y + by, _curr_color);
      }
    }
  }
}

uint16_t GxEPDDisplay::getTextWidth(const char* str) {
  int16_t x1, y1;
  uint16_t w, h;
  display.getTextBounds(str, 0, 0, &x1, &y1, &w, &h);
  return w;
}

void GxEPDDisplay::setDisplayRotation(uint8_t rot) {
  display.setRotation(rot & 3);
  setDimensions(display.width(), display.height());
  last_display_crc_value = -1;  // force redraw on next endFrame
}

void GxEPDDisplay::endFrame() {
  uint32_t crc = display_crc.finalize();
  if (crc != last_display_crc_value) {
    display.display(true);
    last_display_crc_value = crc;
  }
}