/* LCD LVGL porting example

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_timer.h"
#include "esp_lcd_panel_io.h"
#include "esp_lcd_panel_vendor.h"
#include "esp_lcd_panel_ops.h"
#include "driver/gpio.h"
#include "esp_err.h"
#include "esp_log.h"
#include "lvgl.h"

static const char *TAG = "example";

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////// Please update the following configuration according to your LCD spec //////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#define EXAMPLE_LCD_PIXEL_CLOCK_HZ     (10 * 1000 * 1000)
#define EXAMPLE_LCD_BK_LIGHT_ON_LEVEL  1
#define EXAMPLE_LCD_BK_LIGHT_OFF_LEVEL !EXAMPLE_LCD_BK_LIGHT_ON_LEVEL
#define EXAMPLE_PIN_NUM_DATA0          19
#define EXAMPLE_PIN_NUM_DATA1          21
#define EXAMPLE_PIN_NUM_DATA2          0
#define EXAMPLE_PIN_NUM_DATA3          22
#define EXAMPLE_PIN_NUM_DATA4          23
#define EXAMPLE_PIN_NUM_DATA5          33
#define EXAMPLE_PIN_NUM_DATA6          32
#define EXAMPLE_PIN_NUM_DATA7          27
#define EXAMPLE_PIN_NUM_PCLK           18
#define EXAMPLE_PIN_NUM_CS             4
#define EXAMPLE_PIN_NUM_DC             5
#define EXAMPLE_PIN_NUM_RST            -1
#define EXAMPLE_PIN_NUM_BK_LIGHT       2

// The pixel number in horizontal and vertical
#define EXAMPLE_LCD_H_RES              240
#define EXAMPLE_LCD_V_RES              280
// Bit number used to represent command and parameter
#define EXAMPLE_LCD_CMD_BITS           8
#define EXAMPLE_LCD_PARAM_BITS         8

#define EXAMPLE_LVGL_TICK_PERIOD_MS    2

extern void example_lvgl_demo_ui(lv_obj_t *scr);

static bool example_notify_lvgl_flush_ready(esp_lcd_panel_io_handle_t panel_io, void *user_data, void *event_data)
{
    lv_disp_drv_t *disp_driver = (lv_disp_drv_t *)user_data;
    lv_disp_flush_ready(disp_driver);
    return false;
}

static void example_lvgl_flush_cb(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *color_map)
{
    esp_lcd_panel_handle_t panel_handle = (esp_lcd_panel_handle_t) drv->user_data;
    int offsetx1 = area->x1;
    int offsetx2 = area->x2;
    int offsety1 = area->y1;
    int offsety2 = area->y2;
    // copy a buffer's content to a specific area of the display
    esp_lcd_panel_draw_bitmap(panel_handle, offsetx1, offsety1, offsetx2 + 1, offsety2 + 1, color_map);
}

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

void app_main(void)
{
    static lv_disp_draw_buf_t disp_buf; // contains internal graphic buffer(s) called draw buffer(s)
    static lv_disp_drv_t disp_drv;      // contains callback functions

    ESP_LOGI(TAG, "Turn off LCD backlight");
    gpio_config_t bk_gpio_config = {
        .mode = GPIO_MODE_OUTPUT,
        .pin_bit_mask = 1ULL << EXAMPLE_PIN_NUM_BK_LIGHT
    };
    ESP_ERROR_CHECK(gpio_config(&bk_gpio_config));
    gpio_set_level(EXAMPLE_PIN_NUM_BK_LIGHT, EXAMPLE_LCD_BK_LIGHT_OFF_LEVEL);

    ESP_LOGI(TAG, "Initialize Intel 8080 bus");
    esp_lcd_i80_bus_handle_t i80_bus = NULL;
    esp_lcd_i80_bus_config_t bus_config = {
        .dc_gpio_num = EXAMPLE_PIN_NUM_DC,
        .wr_gpio_num = EXAMPLE_PIN_NUM_PCLK,
        .data_gpio_nums = {
            EXAMPLE_PIN_NUM_DATA0,
            EXAMPLE_PIN_NUM_DATA1,
            EXAMPLE_PIN_NUM_DATA2,
            EXAMPLE_PIN_NUM_DATA3,
            EXAMPLE_PIN_NUM_DATA4,
            EXAMPLE_PIN_NUM_DATA5,
            EXAMPLE_PIN_NUM_DATA6,
            EXAMPLE_PIN_NUM_DATA7,
        },
        .bus_width = 8,
        .max_transfer_bytes = EXAMPLE_LCD_H_RES * 40 * sizeof(uint16_t)
    };
    ESP_ERROR_CHECK(esp_lcd_new_i80_bus(&bus_config, &i80_bus));
    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_i80_config_t io_config = {
        .cs_gpio_num = EXAMPLE_PIN_NUM_CS,
        .pclk_hz = EXAMPLE_LCD_PIXEL_CLOCK_HZ,
        .trans_queue_depth = 10,
        .dc_levels = {
            .dc_idle_level = 0,
            .dc_cmd_level = 0,
            .dc_dummy_level = 0,
            .dc_data_level = 1,
        },
        .on_color_trans_done = example_notify_lvgl_flush_ready,
        .user_data = &disp_drv,
        .lcd_cmd_bits = EXAMPLE_LCD_CMD_BITS,
        .lcd_param_bits = EXAMPLE_LCD_PARAM_BITS,
    };
    ESP_ERROR_CHECK(esp_lcd_new_panel_io_i80(i80_bus, &io_config, &io_handle));

    ESP_LOGI(TAG, "Install LCD driver of st7789");
    esp_lcd_panel_handle_t panel_handle = NULL;
    esp_lcd_panel_dev_config_t panel_config = {
        .reset_gpio_num = EXAMPLE_PIN_NUM_RST,
        .color_space = ESP_LCD_COLOR_SPACE_RGB,
        .bits_per_pixel = 16,
    };
    ESP_ERROR_CHECK(esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle));

    esp_lcd_panel_reset(panel_handle);
    esp_lcd_panel_init(panel_handle);
    esp_lcd_panel_invert_color(panel_handle, true);
    // the gap is LCD panel specific, even panels with the same driver IC, can have different gap value
    esp_lcd_panel_set_gap(panel_handle, 0, 20);

    ESP_LOGI(TAG, "Turn on LCD backlight");
    gpio_set_level(EXAMPLE_PIN_NUM_BK_LIGHT, EXAMPLE_LCD_BK_LIGHT_ON_LEVEL);

    ESP_LOGI(TAG, "Initialize LVGL library");
    lv_init();
    // alloc draw buffers used by LVGL
    // it's recommended to choose the size of the draw buffer(s) to be at least 1/10 screen sized
    lv_color_t *buf1 = heap_caps_malloc(EXAMPLE_LCD_H_RES * 20 * sizeof(lv_color_t), MALLOC_CAP_DMA);
    assert(buf1);
    lv_color_t *buf2 = heap_caps_malloc(EXAMPLE_LCD_H_RES * 20 * sizeof(lv_color_t), MALLOC_CAP_DMA);
    assert(buf2);
    // initialize LVGL draw buffers
    lv_disp_draw_buf_init(&disp_buf, buf1, buf2, EXAMPLE_LCD_H_RES * 20);

    ESP_LOGI(TAG, "Register display driver to LVGL");
    lv_disp_drv_init(&disp_drv);
    disp_drv.hor_res = EXAMPLE_LCD_H_RES;
    disp_drv.ver_res = EXAMPLE_LCD_V_RES;
    disp_drv.flush_cb = example_lvgl_flush_cb;
    disp_drv.draw_buf = &disp_buf;
    disp_drv.user_data = panel_handle;
    lv_disp_t *disp = lv_disp_drv_register(&disp_drv);

    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, EXAMPLE_LVGL_TICK_PERIOD_MS * 1000));

    ESP_LOGI(TAG, "Display LVGL animation");
    lv_obj_t *scr = lv_disp_get_scr_act(disp);
    example_lvgl_demo_ui(scr);

    while (1) {
        // raise the task priority of LVGL and/or reduce the handler period can improve the performance
        vTaskDelay(pdMS_TO_TICKS(10));
        // The task running lv_timer_handler should have lower priority than that running `lv_tick_inc`
        lv_timer_handler();
    }
}