#include "sx127x_driver.h"
#include "sx127x_internal.h"
#include "sx127x_registers.h"

#include <esp_log.h>
#include <string.h>

const char *SX127X_TAG = "sx127x";

esp_err_t sx127x_init(sx127x_config_t *config, sx127x_t **handle_ptr) {
  esp_err_t ret;
  sx127x_t *handle = malloc(sizeof(sx127x_t));
  SX127X_CHECK(handle != NULL, "malloc error", ESP_ERR_NO_MEM);

  handle->task_handle = NULL;
  memcpy(&handle->config, config, sizeof(sx127x_config_t));

  ret = gpio_set_direction(config->rst_io_num, GPIO_MODE_OUTPUT);
  SX127X_ERROR_CHECK2(ret, gpio_set_direction)

  // perform reset
  gpio_set_level(config->rst_io_num, 0);
  vTaskDelay(RESET_DELAY);
  gpio_set_level(config->rst_io_num, 1);
  vTaskDelay(RESET_DELAY);

  spi_bus_config_t bus_config = {.mosi_io_num     = config->mosi_io_num,
                                 .miso_io_num     = config->miso_io_num,
                                 .sclk_io_num     = config->sck_io_num,
                                 .quadhd_io_num   = -1,
                                 .quadwp_io_num   = -1,
                                 .max_transfer_sz = SX127X_MAX_TRANSFER};
  ret                         = spi_bus_initialize(config->spi_host, &bus_config, 1);
  SX127X_ERROR_CHECK2(ret, spi_bus_initialize)

  spi_device_interface_config_t device_config = {
      .command_bits     = 0,
      .address_bits     = 8,
      .dummy_bits       = 0,
      .mode             = 0,
      .duty_cycle_pos   = 0,
      .cs_ena_pretrans  = 0,
      .cs_ena_posttrans = 0,
      .clock_speed_hz   = SPI_CLOCK_HZ, // 8mhz
      .input_delay_ns   = 0,
      .spics_io_num     = config->cs_io_num,
      .flags            = 0,
      .queue_size       = 8,
      .pre_cb           = NULL,
      .post_cb          = NULL,
  };
  ret = spi_bus_add_device(config->spi_host, &device_config, &handle->device_handle);
  SX127X_ERROR_CHECK2(ret, spi_bus_add_device)

  // read version and check that it is compatible
  uint8_t version;
  ret = sx127x_read_register(handle, REG_VERSION, &version);
  SX127X_ERROR_CHECK2(ret, sx127x_read_register);
  SX127X_CHECK(version == 0x12, "unsupported version %#x", ESP_ERR_INVALID_VERSION, version);

  ret = sx127x_sleep(handle);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_set_frequency(handle, config->frequency);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_write_register(handle, REG_FIFO_TX_BASE_ADDR, 0);
  SX127X_ERROR_CHECK(ret);
  sx127x_write_register(handle, REG_FIFO_RX_BASE_ADDR, 0);
  SX127X_ERROR_CHECK(ret);

  uint8_t reg_lna;
  ret = sx127x_read_register(handle, REG_LNA, &reg_lna);
  SX127X_ERROR_CHECK(ret);
  reg_lna |= 0x03; // set LNA boost
  ret = sx127x_write_register(handle, REG_LNA, reg_lna);
  SX127X_ERROR_CHECK(ret);

  // set auto AGC
  ret = sx127x_write_register(handle, REG_MODEM_CONFIG_3, CONFIG3_AUTO_AGC);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_set_tx_power(handle, config->tx_power, true);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_set_spreading_factor(handle, config->spreading_factor);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_set_sync_word(handle, config->sync_word);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_set_crc(handle, config->crc);
  SX127X_ERROR_CHECK(ret);

  ret = sx127x_standby(handle);
  ESP_ERROR_CHECK(ret);

  *handle_ptr = handle;
  return ESP_OK;
}

esp_err_t sx127x_free(sx127x_t *handle) {
  esp_err_t ret;

  if (handle->task_handle) {
    ret = sx127x_stop(handle);
    SX127X_ERROR_CHECK(ret);
  }

  ret = spi_bus_remove_device(handle->device_handle);
  SX127X_ERROR_CHECK2(ret, spi_bus_remove_device)

  ret = spi_bus_free(handle->config.spi_host);
  SX127X_ERROR_CHECK2(ret, spi_bus_free)

  free(handle);

  return ESP_OK;
}

void sx127x_isr(void *arg) {
  sx127x_t *handle = (sx127x_t *)arg;
  ESP_LOGI(SX127X_TAG, "sx127x_isr");
}

void sx127x_task(void *arg) {
  sx127x_t *handle = (sx127x_t *)arg;
  while (handle->task_running) {
    vTaskDelay(pdMS_TO_TICKS(10));
  }
}

esp_err_t sx127x_start(sx127x_t *handle) {
  esp_err_t ret;

  SX127X_CHECK(handle->task_handle == NULL, "task already running", ESP_ERR_INVALID_STATE);

  ret = sx127x_write_register(handle, REG_DIO_MAPPING_1, 0x00);
  SX127X_ERROR_CHECK(ret);

  gpio_config_t irq_io_config;
  irq_io_config.intr_type    = GPIO_INTR_POSEDGE;
  irq_io_config.mode         = GPIO_MODE_INPUT;
  irq_io_config.pin_bit_mask = (1ULL << handle->config.irq_io_num);
  irq_io_config.pull_down_en = 0;
  irq_io_config.pull_up_en   = 0;
  ret                        = gpio_config(&irq_io_config);
  SX127X_ERROR_CHECK2(ret, gpio_config)

  ret = gpio_install_isr_service(ESP_INTR_FLAG_LEVEL1);
  SX127X_ERROR_CHECK2(ret, gpio_install_isr_service);
  ret = gpio_isr_handler_add(handle->config.irq_io_num, sx127x_isr, (void *)handle);
  SX127X_ERROR_CHECK2(ret, gpio_isr_handler_add);

  handle->task_running = true;

  BaseType_t pdRet =
      xTaskCreate(sx127x_task, "sx127x_task", TASK_STACK_SIZE, (void *)handle, TASK_PRIORITY, &handle->task_handle);
  SX127X_CHECK(pdRet == pdPASS, "failed to create task", ESP_FAIL);
  return ESP_OK;
}

esp_err_t sx127x_stop(sx127x_t *handle) {
  esp_err_t ret;

  SX127X_CHECK(handle->task_handle != NULL, "task has not been started", ESP_ERR_INVALID_STATE);
  handle->task_running = false;
  xTaskNotify(handle->task_handle, 0, eNoAction);

  ret = gpio_isr_handler_remove(handle->config.irq_io_num);
  SX127X_ERROR_CHECK2(ret, gpio_isr_handler_remove);
  gpio_uninstall_isr_service();

  return ESP_OK;
}