#include "Display_PNG.h"

static PNG png;
static File Image_file;
static int16_t xpos = 0;
static int16_t ypos = 0;

// ── PNG callbacks ─────────────────────────────────────────────────────────────
static void* pngOpen(const char* filePath, int32_t* size) {
  Image_file = SD_MMC.open(filePath);
  if (!Image_file) { printf("PNG: failed to open %s\r\n", filePath); return nullptr; }
  *size = Image_file.size();
  return &Image_file;
}

static void pngClose(void* handle) {
  File* fp = (File*)handle;
  if (fp && *fp) fp->close();
}

static int32_t pngRead(PNGFILE* page, uint8_t* buffer, int32_t length) {
  if (!Image_file) return 0;
  return Image_file.read(buffer, length);
}

static int32_t pngSeek(PNGFILE* page, int32_t position) {
  if (!Image_file) return 0;
  return Image_file.seek(position);
}

static uint16_t lineBuffer[MAX_IMAGE_WIDTH];
static void pngDraw(PNGDRAW* pDraw) {
  png.getLineAsRGB565(pDraw, lineBuffer, PNG_RGB565_BIG_ENDIAN, 0xffffffff);
  uint32_t w = pDraw->iWidth;
  for (size_t i = 0; i < w; i++) lineBuffer[i] = __builtin_bswap16(lineBuffer[i]);
  LCD_addWindow(xpos, pDraw->y, xpos + w - 1, ypos + pDraw->y, lineBuffer);
}

// ── Screen fill ───────────────────────────────────────────────────────────────
static void clearScreen() {
  static uint16_t blackLine[MAX_IMAGE_WIDTH];
  memset(blackLine, 0, sizeof(blackLine));
  for (int y = 0; y < LCD_HEIGHT; y++)
    LCD_addWindow(0, y, LCD_WIDTH - 1, y, blackLine);
}

// ── Public API ────────────────────────────────────────────────────────────────
void Display_Image_From_SD(const char* fullPath) {
  printf("PNG: loading %s\r\n", fullPath);
  int16_t rc = png.open(fullPath, pngOpen, pngClose, pngRead, pngSeek, pngDraw);
  if (rc != PNG_SUCCESS) {
    printf("PNG: open failed, rc=%d\r\n", rc);
    return;
  }
  if (png.getWidth() > MAX_IMAGE_WIDTH) {
    printf("PNG: image too wide (%d px)\r\n", png.getWidth());
    png.close();
    return;
  }
  clearScreen();
  png.decode(NULL, 0);
  png.close();
}

void Display_Memory_Photo(int memoryIndex) {
  if (memoryIndex < 0 || memoryIndex >= g_memoryCount) {
    printf("PNG: invalid memory index %d\r\n", memoryIndex);
    return;
  }
  char path[120];
  snprintf(path, sizeof(path), "/photos/%s", g_memories[memoryIndex].photo);
  Display_Image_From_SD(path);
}