#include <inttypes.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/lock.h>

#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#include "esp_err.h"
#include "esp_log.h"
#include "esp_timer.h"
#include "esp_lcd_panel_ops.h"
#include "esp_lcd_panel_rgb.h"
#include "driver/i2c_master.h"

#include "lvgl.h"

#define LCD_HRES        800
#define LCD_VRES        480
#define LCD_PIXEL_SIZE    2

// in ms
#define LVGL_TICK_PERIOD     2
#define LVGL_TASK_PRIORITY   2
#define LVGL_TASK_STACK_SIZE (4 * 1024)

static const char *TAG = "valconomy";

i2c_master_bus_handle_t i2c_bus_handle;

// LVGL library is not thread-safe, this example will call LVGL APIs from different tasks, so use a mutex to protect it
static _lock_t lvgl_api_lock;

extern void example_lvgl_demo_ui(lv_display_t *disp);

static bool example_on_vsync(esp_lcd_panel_handle_t panel, const esp_lcd_rgb_panel_event_data_t *event_data, void *user_ctx) {
  return false;
}

static void example_lvgl_flush_cb(lv_display_t *disp, const lv_area_t *area, uint8_t *px_map) {
  esp_lcd_panel_handle_t panel_handle = lv_display_get_user_data(disp);
  // pass the draw buffer to the driver
  esp_lcd_panel_draw_bitmap(panel_handle, area->x1, area->y1, area->x2 + 1, area->y2 + 1, px_map);
  lv_disp_flush_ready(disp);
}

static void example_increase_lvgl_tick(void *arg) {
  /* Tell LVGL how many milliseconds has elapsed */
  lv_tick_inc(LVGL_TICK_PERIOD);
}

static void example_lvgl_port_task(void *arg) {
  ESP_LOGI(TAG, "Starting LVGL task");
  uint32_t time_till_next_ms = 0;
  while (1) {
    _lock_acquire(&lvgl_api_lock);
    time_till_next_ms = lv_timer_handler();
    _lock_release(&lvgl_api_lock);

    // in case of task watch dog timeout, set the minimal delay to 10ms
    if (time_till_next_ms < 10) {
       time_till_next_ms = 10;
     }

     usleep(1000 * time_till_next_ms);
    }
}

static esp_err_t i2c_master_init(void) {
  i2c_master_bus_config_t i2c_mst_config = {
    .clk_source = I2C_CLK_SRC_DEFAULT,
    .i2c_port = I2C_NUM_0,
    .scl_io_num = 9,
    .sda_io_num = 8,
    .glitch_ignore_cnt = 7,
    .flags.enable_internal_pullup = true,
  };

  return i2c_new_master_bus(&i2c_mst_config, &i2c_bus_handle);
}

static void setup_lcd() {
  ESP_LOGI(TAG, "Init I2C");
  ESP_ERROR_CHECK(i2c_master_init());

  i2c_device_config_t exio_dev_cfg = {
    .dev_addr_length = I2C_ADDR_BIT_LEN_7,
    .device_address = 0x24, // CH422G config register
    .scl_speed_hz = 100000,
  };

  i2c_master_dev_handle_t exio_cfg_handle, exio_o_handle;
  ESP_ERROR_CHECK(i2c_master_bus_add_device(i2c_bus_handle, &exio_dev_cfg, &exio_cfg_handle));
  exio_dev_cfg.device_address = 0x38;
  ESP_ERROR_CHECK(i2c_master_bus_add_device(i2c_bus_handle, &exio_dev_cfg, &exio_o_handle));

  uint8_t i2c_b;
  i2c_b = 0x01; // Output enable
  ESP_ERROR_CHECK(i2c_master_transmit(exio_cfg_handle, &i2c_b, 1, -1));

  i2c_b = 0x00; // Reset everything
  ESP_ERROR_CHECK(i2c_master_transmit(exio_o_handle, &i2c_b, 1, -1));
  usleep(10 * 1000);
  i2c_b = 0x08; // Pull LCD out of reset
  ESP_ERROR_CHECK(i2c_master_transmit(exio_o_handle, &i2c_b, 1, -1));
  usleep(100 * 1000);

  ESP_LOGI(TAG, "Install RGB LCD panel driver");
  esp_lcd_panel_handle_t panel_handle = NULL;
  esp_lcd_rgb_panel_config_t panel_config = {
    .data_width = 16, // RGB565
    .psram_trans_align = 64,
    .num_fbs = 2,

    .clk_src = LCD_CLK_SRC_DEFAULT,
    .disp_gpio_num = -1, // Only accessible via GPIO expander
    .pclk_gpio_num = 7,
    .vsync_gpio_num = 3,
    .hsync_gpio_num = 46,
    .de_gpio_num = 5,
    .data_gpio_nums = {
      14, // B3
      38, // B4
      18, // B5
      17, // B6
      10, // B7
      39, // G2
       0, // G3
      45, // G4
      48, // G5
      47, // G6
      21, // G7
       1, // R3
       2, // R4
      42, // R5
      41, // R6
      40, // R7
    },
    .timings = {
      .pclk_hz = 18 * 1000 * 1000, // 18000000 / (hs+hbp+hfp+hres) / (vs+vbp+hfp+vres) = ~42Hz
      .h_res = LCD_HRES,
      .v_res = LCD_VRES,
      .hsync_back_porch = 8,
      .hsync_front_porch = 8,
      .hsync_pulse_width = 4,
      .vsync_back_porch = 16,
      .vsync_front_porch = 16,
      .vsync_pulse_width = 4,
      .flags = {
        .pclk_active_neg = true,
      },
    },
    .flags.fb_in_psram = true, // allocate frame buffer in PSRAM
  };
  ESP_ERROR_CHECK(esp_lcd_new_rgb_panel(&panel_config, &panel_handle));

  ESP_LOGI(TAG, "Initialize RGB LCD panel");
  ESP_ERROR_CHECK(esp_lcd_panel_reset(panel_handle));
  ESP_ERROR_CHECK(esp_lcd_panel_init(panel_handle));

  ESP_LOGI(TAG, "Turn on LCD backlight");
  i2c_b = 0x0e; // LCD out of reset, backlight on
  ESP_ERROR_CHECK(i2c_master_transmit(exio_o_handle, &i2c_b, 1, -1));

  ESP_LOGI(TAG, "Initialize LVGL library");
  lv_init();
  // create a lvgl display
  lv_display_t *display = lv_display_create(LCD_HRES, LCD_VRES);
  // associate the rgb panel handle to the display
  lv_display_set_user_data(display, panel_handle);
  // set color depth
  lv_display_set_color_format(display, LV_COLOR_FORMAT_RGB565);

  // create draw buffers
  void *buf1 = NULL;
  void *buf2 = NULL;
  ESP_LOGI(TAG, "Use frame buffers as LVGL draw buffers");
  ESP_ERROR_CHECK(esp_lcd_rgb_panel_get_frame_buffer(panel_handle, 2, &buf1, &buf2));
  // set LVGL draw buffers and direct mode
  lv_display_set_buffers(display, buf1, buf2, LCD_HRES * LCD_VRES * LCD_PIXEL_SIZE, LV_DISPLAY_RENDER_MODE_DIRECT);

  // set the callback which can copy the rendered image to an area of the display
  lv_display_set_flush_cb(display, example_lvgl_flush_cb);

  ESP_LOGI(TAG, "Register event callbacks");
  esp_lcd_rgb_panel_event_callbacks_t cbs = {
    .on_vsync = example_on_vsync,
  };
  ESP_ERROR_CHECK(esp_lcd_rgb_panel_register_event_callbacks(panel_handle, &cbs, display));

  ESP_LOGI(TAG, "Install LVGL tick timer");
  // Tick interface for LVGL (using esp_timer to generate 2ms periodic event)
  const esp_timer_create_args_t lvgl_tick_timer_args = {
    .callback = &example_increase_lvgl_tick,
    .name = "lvgl_tick"
  };
  esp_timer_handle_t lvgl_tick_timer = NULL;
  ESP_ERROR_CHECK(esp_timer_create(&lvgl_tick_timer_args, &lvgl_tick_timer));
  ESP_ERROR_CHECK(esp_timer_start_periodic(lvgl_tick_timer, LVGL_TICK_PERIOD * 1000));

  ESP_LOGI(TAG, "Create LVGL task");
  xTaskCreate(example_lvgl_port_task, "LVGL", LVGL_TASK_STACK_SIZE, NULL, LVGL_TASK_PRIORITY, NULL);

  ESP_LOGI(TAG, "Display LVGL UI");
  // Lock the mutex due to the LVGL APIs are not thread-safe
  _lock_acquire(&lvgl_api_lock);
  example_lvgl_demo_ui(display);
  _lock_release(&lvgl_api_lock);
}

void app_main(void) {
  setup_lcd();
}