#include <stdio.h>
#include <string.h>

#include "esp_log.h"
#include "sdkconfig.h"

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

#include "u8g2_esp32_hal.h"

static const char* TAG = "u8g2_hal";
static const unsigned int I2C_TIMEOUT_MS = 1000;

static spi_device_handle_t handle_spi;   // SPI handle.
static i2c_cmd_handle_t handle_i2c;      // I2C handle.
static u8g2_esp32_hal_t u8g2_esp32_hal;  // HAL state data.

#define HOST    SPI2_HOST

#undef ESP_ERROR_CHECK
#define ESP_ERROR_CHECK(x)                   \
  do {                                       \
    esp_err_t rc = (x);                      \
    if (rc != ESP_OK) {                      \
      ESP_LOGE("err", "esp_err_t = %d", rc); \
      assert(0 && #x);                       \
    }                                        \
  } while (0);

/*
 * Initialze the ESP32 HAL.
 */
void u8g2_esp32_hal_init(u8g2_esp32_hal_t u8g2_esp32_hal_param) {
  u8g2_esp32_hal = u8g2_esp32_hal_param;
}  // u8g2_esp32_hal_init

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is
 * invoked to handle SPI communications.
 */
uint8_t u8g2_esp32_spi_byte_cb(u8x8_t* u8x8,
                               uint8_t msg,
                               uint8_t arg_int,
                               void* arg_ptr) {
  ESP_LOGD(TAG, "spi_byte_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p",
           msg, arg_int, arg_ptr);
  switch (msg) {
    case U8X8_MSG_BYTE_SET_DC:
      if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.dc, arg_int);
      }
      break;

    case U8X8_MSG_BYTE_INIT: {
      if (u8g2_esp32_hal.bus.spi.clk == U8G2_ESP32_HAL_UNDEFINED ||
          u8g2_esp32_hal.bus.spi.mosi == U8G2_ESP32_HAL_UNDEFINED ||
          u8g2_esp32_hal.bus.spi.cs == U8G2_ESP32_HAL_UNDEFINED) {
        break;
      }

      spi_bus_config_t bus_config;
      memset(&bus_config, 0, sizeof(spi_bus_config_t));
      bus_config.sclk_io_num = u8g2_esp32_hal.bus.spi.clk;   // CLK
      bus_config.mosi_io_num = u8g2_esp32_hal.bus.spi.mosi;  // MOSI
      bus_config.miso_io_num = GPIO_NUM_NC;                  // MISO
      bus_config.quadwp_io_num = GPIO_NUM_NC;                // Not used
      bus_config.quadhd_io_num = GPIO_NUM_NC;                // Not used
      // ESP_LOGI(TAG, "... Initializing bus.");
      ESP_ERROR_CHECK(spi_bus_initialize(HOST, &bus_config, 1));

      spi_device_interface_config_t dev_config;
      dev_config.address_bits = 0;
      dev_config.command_bits = 0;
      dev_config.dummy_bits = 0;
      dev_config.mode = 0;
      dev_config.duty_cycle_pos = 0;
      dev_config.cs_ena_posttrans = 0;
      dev_config.cs_ena_pretrans = 0;
      dev_config.clock_speed_hz = 10000;
      dev_config.spics_io_num = u8g2_esp32_hal.bus.spi.cs;
      dev_config.flags = 0;
      dev_config.queue_size = 200;
      dev_config.pre_cb = NULL;
      dev_config.post_cb = NULL;
      // ESP_LOGI(TAG, "... Adding device bus.");
      ESP_ERROR_CHECK(spi_bus_add_device(HOST, &dev_config, &handle_spi));

      break;
    }

    case U8X8_MSG_BYTE_SEND: {
      spi_transaction_t trans_desc;
      trans_desc.addr = 0;
      trans_desc.cmd = 0;
      trans_desc.flags = 0;
      trans_desc.length = 8 * arg_int;  // Number of bits NOT number of bytes.
      trans_desc.rxlength = 0;
      trans_desc.tx_buffer = arg_ptr;
      trans_desc.rx_buffer = NULL;

      // ESP_LOGI(TAG, "... Transmitting %d bytes.", arg_int);
      ESP_ERROR_CHECK(spi_device_transmit(handle_spi, &trans_desc));
      break;
    }
  }
  return 0;
}  // u8g2_esp32_spi_byte_cb

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is
 * invoked to handle I2C communications.
 */
uint8_t u8g2_esp32_i2c_byte_cb(u8x8_t* u8x8,
                               uint8_t msg,
                               uint8_t arg_int,
                               void* arg_ptr) {
  ESP_LOGD(TAG, "i2c_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p", msg,
           arg_int, arg_ptr);

  switch (msg) {
    case U8X8_MSG_BYTE_SET_DC: {
      if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.dc, arg_int);
      }
      break;
    }

    case U8X8_MSG_BYTE_INIT: {
      if (u8g2_esp32_hal.bus.i2c.sda == U8G2_ESP32_HAL_UNDEFINED ||
          u8g2_esp32_hal.bus.i2c.scl == U8G2_ESP32_HAL_UNDEFINED) {
        break;
      }

      i2c_config_t conf = {0};
      conf.mode = I2C_MODE_MASTER;
      ESP_LOGI(TAG, "sda_io_num %d", u8g2_esp32_hal.bus.i2c.sda);
      conf.sda_io_num = u8g2_esp32_hal.bus.i2c.sda;
      conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
      ESP_LOGI(TAG, "scl_io_num %d", u8g2_esp32_hal.bus.i2c.scl);
      conf.scl_io_num = u8g2_esp32_hal.bus.i2c.scl;
      conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
      ESP_LOGI(TAG, "clk_speed %d", I2C_MASTER_FREQ_HZ);
      conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
      ESP_LOGI(TAG, "i2c_param_config %d", conf.mode);
      ESP_ERROR_CHECK(i2c_param_config(I2C_MASTER_NUM, &conf));
      ESP_LOGI(TAG, "i2c_driver_install %d", I2C_MASTER_NUM);
      ESP_ERROR_CHECK(i2c_driver_install(I2C_MASTER_NUM, conf.mode,
                                         I2C_MASTER_RX_BUF_DISABLE,
                                         I2C_MASTER_TX_BUF_DISABLE, 0));
      break;
    }

    case U8X8_MSG_BYTE_SEND: {
      uint8_t* data_ptr = (uint8_t*)arg_ptr;
      ESP_LOG_BUFFER_HEXDUMP(TAG, data_ptr, arg_int, ESP_LOG_VERBOSE);

      while (arg_int > 0) {
        ESP_ERROR_CHECK(
            i2c_master_write_byte(handle_i2c, *data_ptr, ACK_CHECK_EN));
        data_ptr++;
        arg_int--;
      }
      break;
    }

    case U8X8_MSG_BYTE_START_TRANSFER: {
      uint8_t i2c_address = u8x8_GetI2CAddress(u8x8);
      handle_i2c = i2c_cmd_link_create();
      ESP_LOGD(TAG, "Start I2C transfer to %02X.", i2c_address >> 1);
      ESP_ERROR_CHECK(i2c_master_start(handle_i2c));
      ESP_ERROR_CHECK(i2c_master_write_byte(
          handle_i2c, i2c_address | I2C_MASTER_WRITE, ACK_CHECK_EN));
      break;
    }

    case U8X8_MSG_BYTE_END_TRANSFER: {
      ESP_LOGD(TAG, "End I2C transfer.");
      ESP_ERROR_CHECK(i2c_master_stop(handle_i2c));
      ESP_ERROR_CHECK(i2c_master_cmd_begin(I2C_MASTER_NUM, handle_i2c,
                                           pdMS_TO_TICKS(I2C_TIMEOUT_MS)));
      i2c_cmd_link_delete(handle_i2c);
      break;
    }
  }
  return 0;
}  // u8g2_esp32_i2c_byte_cb

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is
 * invoked to handle callbacks for GPIO and delay functions.
 */
uint8_t u8g2_esp32_gpio_and_delay_cb(u8x8_t* u8x8,
                                     uint8_t msg,
                                     uint8_t arg_int,
                                     void* arg_ptr) {
  ESP_LOGD(TAG,
           "gpio_and_delay_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p",
           msg, arg_int, arg_ptr);

  switch (msg) {
      // Initialize the GPIO and DELAY HAL functions.  If the pins for DC and
      // RESET have been specified then we define those pins as GPIO outputs.
    case U8X8_MSG_GPIO_AND_DELAY_INIT: {
      uint64_t bitmask = 0;
      if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED) {
        bitmask = bitmask | (1ull << u8g2_esp32_hal.dc);
      }
      if (u8g2_esp32_hal.reset != U8G2_ESP32_HAL_UNDEFINED) {
        bitmask = bitmask | (1ull << u8g2_esp32_hal.reset);
      }
      if (u8g2_esp32_hal.bus.spi.cs != U8G2_ESP32_HAL_UNDEFINED) {
        bitmask = bitmask | (1ull << u8g2_esp32_hal.bus.spi.cs);
      }

      if (bitmask == 0) {
        break;
      }
      gpio_config_t gpioConfig;
      gpioConfig.pin_bit_mask = bitmask;
      gpioConfig.mode = GPIO_MODE_OUTPUT;
      gpioConfig.pull_up_en = GPIO_PULLUP_DISABLE;
      gpioConfig.pull_down_en = GPIO_PULLDOWN_ENABLE;
      gpioConfig.intr_type = GPIO_INTR_DISABLE;
      gpio_config(&gpioConfig);
      break;
    }

      // Set the GPIO reset pin to the value passed in through arg_int.
    case U8X8_MSG_GPIO_RESET:
      if (u8g2_esp32_hal.reset != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.reset, arg_int);
      }
      break;
      // Set the GPIO client select pin to the value passed in through arg_int.
    case U8X8_MSG_GPIO_CS:
      if (u8g2_esp32_hal.bus.spi.cs != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.bus.spi.cs, arg_int);
      }
      break;
      // Set the Software I²C pin to the value passed in through arg_int.
    case U8X8_MSG_GPIO_I2C_CLOCK:
      if (u8g2_esp32_hal.bus.i2c.scl != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.bus.i2c.scl, arg_int);
        //				printf("%c",(arg_int==1?'C':'c'));
      }
      break;
      // Set the Software I²C pin to the value passed in through arg_int.
    case U8X8_MSG_GPIO_I2C_DATA:
      if (u8g2_esp32_hal.bus.i2c.sda != U8G2_ESP32_HAL_UNDEFINED) {
        gpio_set_level(u8g2_esp32_hal.bus.i2c.sda, arg_int);
        //				printf("%c",(arg_int==1?'D':'d'));
      }
      break;

      // Delay for the number of milliseconds passed in through arg_int.
    case U8X8_MSG_DELAY_MILLI:
      vTaskDelay(arg_int / portTICK_PERIOD_MS);
      break;
  }
  return 0;
}  // u8g2_esp32_gpio_and_delay_cb
