#include <lvgl.h>
#include "tft_hal_esp32.h"
#include "sleep_hal_esp32.h"

// -----------------------
// https://docs.lvgl.io/master/porting/display.html#two-buffers
// With two buffers, the rendering and refreshing of the display become parallel operations
// Second buffer needs 15.360 bytes more memory in heap.
#define useTwoBuffersForlvgl

// Display flushing
static void my_disp_flush( lv_display_t *disp, const lv_area_t *area, uint8_t *px_map ) {
  uint32_t w = (area->x2 - area->x1 + 1);
  uint32_t h = (area->y2 - area->y1 + 1);

  tft.startWrite();
  tft.setAddrWindow(area->x1, area->y1, w, h);
  #ifdef useTwoBuffersForlvgl
  tft.pushPixelsDMA((uint16_t*)px_map, w * h);
  #else
  tft.pushColors((uint16_t *)px_map, w * h, true);
  #endif
  tft.endWrite();

  lv_display_flush_ready(disp);
}

// Read the touchpad
static void my_touchpad_read(lv_indev_t *indev_driver, lv_indev_data_t *data) {
  int16_t touchX;
  int16_t touchY;
  get_touchpoint(&touchX, &touchY);
  
  bool touched = false;
  if ((touchX > 0) || (touchY > 0)) {
    touched = true;
    setLastActivityTimestamp_HAL();
  }

  if( !touched ){
    data->state = LV_INDEV_STATE_RELEASED;
  }
  else{
    data->state = LV_INDEV_STATE_PRESSED;

    // Set the coordinates
    data->point.x = SCR_WIDTH - touchX;
    data->point.y = SCR_HEIGHT - touchY;

    //Serial.print( "touchpoint: x" );
    //Serial.print( touchX );
    //Serial.print( " y" );
    //Serial.println( touchY );
    //tft.drawFastHLine(0, SCR_HEIGHT - touchY, SCR_WIDTH, TFT_RED);
    //tft.drawFastVLine(SCR_WIDTH - touchX, 0, SCR_HEIGHT, TFT_RED);
  }
}

/*LVGL draw into this buffer, 1/10 screen size usually works well. The size is in bytes*/
#define DRAW_BUF_SIZE (SCR_WIDTH * SCR_HEIGHT / 10 * (LV_COLOR_DEPTH / 8))

static uint32_t my_tick_get_cb(void) {
  return millis();
}

void init_lvgl_HAL() {
  // first init TFT
  init_tft();

  // new in lvgl 9
  lv_tick_set_cb(my_tick_get_cb);
  
  // https://github.com/lvgl/lvgl/blob/release/v9.0/docs/CHANGELOG.rst#display-api
  // https://docs.lvgl.io/master/get-started/quick-overview.html#add-lvgl-into-your-project
  lv_display_t *disp = lv_display_create(SCR_WIDTH, SCR_HEIGHT);
  lv_display_set_flush_cb(disp, my_disp_flush);

  // https://github.com/lvgl/lvgl/blob/release/v9.0/docs/CHANGELOG.rst#migration-guide
  // lv_display_set_buffers(display, buf1, buf2, buf_size_byte, mode) is more or less the equivalent of lv_disp_draw_buf_init(&draw_buf_dsc, buf1, buf2, buf_size_px) from v8, however in v9 the buffer size is set in bytes.
  #ifdef useTwoBuffersForlvgl
  uint8_t *bufA = (uint8_t *) malloc(DRAW_BUF_SIZE);
  uint8_t *bufB = (uint8_t *) malloc(DRAW_BUF_SIZE);
  lv_display_set_buffers(disp, bufA, bufB, DRAW_BUF_SIZE, LV_DISPLAY_RENDER_MODE_PARTIAL);
  #else
  uint8_t *bufA = (uint8_t *) malloc(DRAW_BUF_SIZE);
  lv_display_set_buffers(disp, bufA, NULL, DRAW_BUF_SIZE, LV_DISPLAY_RENDER_MODE_PARTIAL);
  #endif

  // Initialize the touchscreen driver
  // https://github.com/lvgl/lvgl/blob/release/v9.0/docs/CHANGELOG.rst#indev-api
  static lv_indev_t * indev = lv_indev_create();
  lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER);
  lv_indev_set_read_cb(indev, my_touchpad_read);

}