/**
 * @file ssd1306.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "ssd1306.h"
#include "driver/i2c.h"
#include "disp_spi.h"
#include "driver/gpio.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

/*********************
 *      DEFINES
 *********************/
#define TAG "SSD1306"

// Code from https://github.com/yanbe/ssd1306-esp-idf-i2c.git is used as a starting point,
// in addition to code from https://github.com/espressif/esp-iot-solution.
// Following definitions are borrowed from
// http://robotcantalk.blogspot.com/2015/03/interfacing-arduino-with-ssd1306-driven.html
// For LittlevGL the forum has been used, in particular: https://blog.littlevgl.com/2019-05-06/oled

// SLA (0x3C) + WRITE_MODE (0x00) =  0x78 (0b01111000)
#define OLED_I2C_ADDRESS                    0x3C
#define OLED_WIDTH                          128
#define OLED_HEIGHT                         64
#define OLED_COLUMNS                        128
#define OLED_PAGES                          8
#define OLED_PIXEL_PER_PAGE                 8

// Control byte
#define OLED_CONTROL_BYTE_CMD_SINGLE        0x80
#define OLED_CONTROL_BYTE_CMD_STREAM        0x00
#define OLED_CONTROL_BYTE_DATA_STREAM       0x40

// Fundamental commands (pg.28)
#define OLED_CMD_SET_CONTRAST               0x81    // follow with 0x7F
#define OLED_CMD_DISPLAY_RAM                0xA4
#define OLED_CMD_DISPLAY_ALLON              0xA5
#define OLED_CMD_DISPLAY_NORMAL             0xA6
#define OLED_CMD_DISPLAY_INVERTED           0xA7
#define OLED_CMD_DISPLAY_OFF                0xAE
#define OLED_CMD_DISPLAY_ON                 0xAF

// Addressing Command Table (pg.30)
#define OLED_CMD_SET_MEMORY_ADDR_MODE       0x20    // follow with 0x00 = HORZ mode
#define OLED_CMD_SET_COLUMN_RANGE           0x21    // can be used only in HORZ/VERT mode - follow with 0x00 and 0x7F = COL127
#define OLED_CMD_SET_PAGE_RANGE             0x22    // can be used only in HORZ/VERT mode - follow with 0x00 and 0x07 = PAGE7

// Hardware Config (pg.31)
#define OLED_CMD_SET_DISPLAY_START_LINE     0x40
#define OLED_CMD_SET_SEGMENT_REMAP          0xA1
#define OLED_CMD_SET_MUX_RATIO              0xA8    // follow with 0x3F = 64 MUX
#define OLED_CMD_SET_COM_SCAN_MODE_NORMAL   0xC0
#define OLED_CMD_SET_COM_SCAN_MODE_REMAP    0xC8
#define OLED_CMD_SET_DISPLAY_OFFSET         0xD3    // follow with 0x00
#define OLED_CMD_SET_COM_PIN_MAP            0xDA    // follow with 0x12
#define OLED_CMD_NOP                        0xE3    // NOP

// Timing and Driving Scheme (pg.32)
#define OLED_CMD_SET_DISPLAY_CLK_DIV        0xD5    // follow with 0x80
#define OLED_CMD_SET_PRECHARGE              0xD9    // follow with 0xF1
#define OLED_CMD_SET_VCOMH_DESELCT          0xDB    // follow with 0x30

// Charge Pump (pg.62)
#define OLED_CMD_SET_CHARGE_PUMP            0x8D    // follow with 0x14

#define OLED_IIC_FREQ_HZ                    400000  // I2C colock frequency

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

#define BIT_SET(a,b) ((a) |= (1U<<(b)))
#define BIT_CLEAR(a,b) ((a) &= ~(1U<<(b)))

/**********************
 *   GLOBAL FUNCTIONS
 **********************/
void ssd1306_init()
{
	esp_err_t ret;
	i2c_cmd_handle_t cmd = i2c_cmd_link_create();

	i2c_master_start(cmd);
	i2c_master_write_byte(cmd, (OLED_I2C_ADDRESS << 1) | I2C_MASTER_WRITE, true);
	i2c_master_write_byte(cmd, OLED_CONTROL_BYTE_CMD_STREAM, true);

	i2c_master_write_byte(cmd, OLED_CMD_SET_CHARGE_PUMP, true);
	i2c_master_write_byte(cmd, 0x14, true);

#if defined (CONFIG_DISPLAY_ORIENTATION_PORTRAIT)
        i2c_master_write_byte(cmd, OLED_CMD_SET_SEGMENT_REMAP, true);
	i2c_master_write_byte(cmd, OLED_CMD_SET_COM_SCAN_MODE_REMAP, true);
#elif defined (CONFIG_DISPLAY_ORIENTATION_PORTRAIT_INVERTED)
        i2c_master_write_byte(cmd, 0xA0, true);
        i2c_master_write_byte(cmd, OLED_CMD_SET_COM_SCAN_MODE_NORMAL, true);
#else
    #error "Unsopported orientation"
#endif

	i2c_master_write_byte(cmd, OLED_CMD_SET_CONTRAST, true);

#if defined CONFIG_LV_INVERT_DISPLAY
	i2c_master_write_byte(cmd, OLED_CMD_DISPLAY_INVERTED, true); // Inverted display
#else
	i2c_master_write_byte(cmd, OLED_CMD_DISPLAY_NORMAL, true); // Non-inverted display
#endif 


	i2c_master_write_byte(cmd, 0xFF, true);

	i2c_master_write_byte(cmd, OLED_CMD_DISPLAY_ON, true);
	i2c_master_stop(cmd);

	ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 10/portTICK_PERIOD_MS);
	if (ret == ESP_OK) {
		ESP_LOGI(TAG, "OLED configured successfully");
	} else {
		ESP_LOGE(TAG, "OLED configuration failed. code: 0x%.2X", ret);
	}
	i2c_cmd_link_delete(cmd);
}

void ssd1306_set_px_cb(lv_disp_drv_t * disp_drv, uint8_t * buf, lv_coord_t buf_w, lv_coord_t x, lv_coord_t y,
        lv_color_t color, lv_opa_t opa) {
    uint16_t byte_index = x + (( y>>3 ) * buf_w);
    uint8_t  bit_index  = y & 0x7;

    if ((color.full == 0) && (LV_OPA_TRANSP != opa)) {
        BIT_SET(buf[byte_index], bit_index);
    } else {
        BIT_CLEAR(buf[byte_index], bit_index);
    }
}

void ssd1306_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p)
{
    uint8_t row1 = 0, row2 = 0;
   	i2c_cmd_handle_t cmd;

    // Divide by 8
    row1 = area->y1 >> 3;
    row2 = area->y2 >> 3;

	cmd = i2c_cmd_link_create();
	i2c_master_start(cmd);
	i2c_master_write_byte(cmd, (OLED_I2C_ADDRESS << 1) | I2C_MASTER_WRITE, true);

	i2c_master_write_byte(cmd, OLED_CONTROL_BYTE_CMD_STREAM, true);
	i2c_master_write_byte(cmd, OLED_CMD_SET_MEMORY_ADDR_MODE, true);
	i2c_master_write_byte(cmd, 0x00, true);
	i2c_master_write_byte(cmd, OLED_CMD_SET_COLUMN_RANGE, true);
	i2c_master_write_byte(cmd, area->x1, true);
	i2c_master_write_byte(cmd, area->x2, true);
	i2c_master_write_byte(cmd, OLED_CMD_SET_PAGE_RANGE, true);
	i2c_master_write_byte(cmd, row1, true);
	i2c_master_write_byte(cmd, row2, true);
	i2c_master_stop(cmd);
	i2c_master_cmd_begin(I2C_NUM_0, cmd, 10/portTICK_PERIOD_MS);
	i2c_cmd_link_delete(cmd);

	cmd = i2c_cmd_link_create();
	i2c_master_start(cmd);
	i2c_master_write_byte(cmd, (OLED_I2C_ADDRESS << 1) | I2C_MASTER_WRITE, true);

	i2c_master_write_byte(cmd, OLED_CONTROL_BYTE_DATA_STREAM, true);
	i2c_master_write(cmd, (uint8_t *)color_p, OLED_COLUMNS * (1+row2-row1), true);
	i2c_master_stop(cmd);
	i2c_master_cmd_begin(I2C_NUM_0, cmd, 10/portTICK_PERIOD_MS);
	i2c_cmd_link_delete(cmd);

    lv_disp_flush_ready(disp_drv);
}

// workaround: always send complete size display buffer, no partial update
void ssd1306_rounder(lv_disp_drv_t * disp_drv, lv_area_t *area)
{
  	// area->y1 = (area->y1 & (~0x7));
  	// area->y2 = (area->y2 & (~0x7)) + 7;

    uint8_t hor_max = disp_drv->hor_res;
    uint8_t ver_max = disp_drv->ver_res;

	area->x1 = 0;
	area->y1 = 0;
	area->x2 = hor_max - 1;
	area->y2 = ver_max - 1;
}

void ssd1306_sleep_in()
{
    esp_err_t ret;
	i2c_cmd_handle_t cmd = i2c_cmd_link_create();

	i2c_master_start(cmd);
	i2c_master_write_byte(cmd, (OLED_I2C_ADDRESS << 1) | I2C_MASTER_WRITE, true);
	i2c_master_write_byte(cmd, OLED_CONTROL_BYTE_CMD_STREAM, true);

	i2c_master_write_byte(cmd, OLED_CMD_DISPLAY_OFF, true);
	i2c_master_stop(cmd);

	ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 10/portTICK_PERIOD_MS);
	if (ret != ESP_OK) {
		ESP_LOGE(TAG, "ssd1306_display_off configuration failed. code: 0x%.2X", ret);
	}
	i2c_cmd_link_delete(cmd);
}

void ssd1306_sleep_out()
{
    esp_err_t ret;
	i2c_cmd_handle_t cmd = i2c_cmd_link_create();

	i2c_master_start(cmd);
	i2c_master_write_byte(cmd, (OLED_I2C_ADDRESS << 1) | I2C_MASTER_WRITE, true);
	i2c_master_write_byte(cmd, OLED_CONTROL_BYTE_CMD_STREAM, true);
	i2c_master_write_byte(cmd, OLED_CMD_DISPLAY_ON, true);
	i2c_master_stop(cmd);

	ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 10/portTICK_PERIOD_MS);
	if (ret != ESP_OK) {
		ESP_LOGE(TAG, "ssd1306_display_on configuration failed. code: 0x%.2X", ret);
	}
	i2c_cmd_link_delete(cmd);
}

/**********************
 *   STATIC FUNCTIONS
 **********************/