/*
 * Project: Arrow
 * Author: 	curiousmuch
 * Description: This project is an APRS transceiver based on the ESP32 and CC1200.
 * TODO: Refactor Code to isolate into seperate components
 * TODO: Isolate BT_SPP.C functionality
 * TODO: Transfer DSP functions to APRS folder
 * TODO: Abstract includes to be nicer (#include aprs.h) for example
 */

/* Standard Includes */
#include <stdio.h>
#include <stddef.h>

/* ESP-IDF */
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/ringbuf.h"
#include "nvs.h"
#include "nvs_flash.h"
#include "esp_log.h"


/* Application Specific */
#include "bt_spp.h"
#include "board.h"
#include "radio.h"
#include "kiss.h"
#include "fcs_calc.h"


/* Data Structures */
typedef enum {
	TNC_TX=0,
	TNC_RX,
	TNC_IDLE
} tnc_status_t;

typedef struct {
	uint8_t tnc_number;
	uint8_t tx_delay;
	uint8_t P;
	uint8_t slot_time;
	uint8_t full_duplex;
	uint8_t tx_tail;
	uint8_t frequency_index;
	uint8_t mode_index;
	uint32_t freq;
	radio_config_t mode;
	tnc_status_t status;
	TaskHandle_t tnc_task;
} tnc_settings_t;


/* Public Variables */
static tnc_settings_t tnc_settings;
static SemaphoreHandle_t xRadioTXSemaphore;
uint8_t ax25_rx_buf[1024];
RingbufHandle_t ax25_tx_buf;

uint32_t ax_freq_table[16] = { 	144390000, 		// APRS - North America
								145512500,		// Arrow - AX25 test frequencies...
								145537500,
								145562500,
								145587500,
								145612500,
								145637500,
								145662500,
								145687500,
								145712500,
								145737500,
								145762500,
								145787500,
								145812500,
								145837500,		// ...145.5 to 145.8 is experimental band
								145862500 };	// 25kHz spacing


/* Radio Callback Functions */

void radio_rx_ax25_cb(uint8_t *frame, uint32_t len)
{
	// TODO: move kiss processing to other core??
	kiss_transmit(KISS_DATAFRAME, frame, len);
}

void radio_tx_ax25_cb(void)
{
	// unlock scheduling task to allow next packet to be sent
	xSemaphoreGive(xRadioTXSemaphore);
}

/* KISS callback Functions */

void tnc_print_settings(void)
{
	ESP_LOGI("tnc", "TX Delay: %d", tnc_settings.tx_delay*10);
	ESP_LOGI("tnc", "TX Tail: %d", tnc_settings.tx_tail*10);
	ESP_LOGI("tnc", "Slot Time: %d", tnc_settings.slot_time*10);
	ESP_LOGI("tnc", "P: %d", tnc_settings.P);
	ESP_LOGI("tnc", "Frequency: %d", tnc_settings.freq);
}

void kiss_tx_cb(uint8_t *frame, uint32_t len)
{
	// TODO: move function to other core
	// TODO: Add functionality which indicates if BLE connection is present or not
	// send data to UART via bluetooth
	bt_spp_tx(frame, len);
	ESP_LOGI("tnc", "kiss packet sent");
}

void kiss_rx_cb(uint8_t *frame, uint32_t len)
{
	uint8_t data_byte;
	data_byte = frame[0] & 0x0F;	// remove tnc_number information

	// process dataframe
	if (data_byte == KISS_DATAFRAME)
	{

		ESP_LOGI("tnc", "kiss packet received");

		// feed packet to ring buffer
		uint32_t fcs = fcs_calc(&frame[1], len-1);
		frame[len] = fcs & 0xFF;
		frame[len+1] = fcs>>8 & 0xFF;
		if (xRingbufferSend(ax25_tx_buf, &frame[1], ((len+1)*sizeof(uint8_t)),10/portTICK_PERIOD_MS) == pdFALSE)
		{
			ESP_LOGE("tnc", "packet buffer overflow");
		}
	}
	else // assume command
	{
		ESP_LOGI("tnc", "received tnc command");
		switch(data_byte)
		{
			case KISS_CMD_TXDELAY:
				tnc_settings.tx_delay = frame[1];
				break;
			case KISS_CMD_P:
				tnc_settings.P = frame[1];
				break;
			case KISS_CMD_SLOTTIME:
				tnc_settings.slot_time = frame[1];
				break;
			case KISS_CMD_TXTAIL:
				tnc_settings.tx_tail = frame[1];
				break;
			case KISS_CMD_FULLDUPLEX:
				tnc_settings.full_duplex = frame[1];
				break;
			case KISS_CMD_SETHARDWARE:
			{
				uint8_t freq_index = frame[1] & 0x0F;
				tnc_settings.freq = ax_freq_table[freq_index];
				break;
			}
			default:
				ESP_LOGE("tnc", "unknown data byte for KISS protocol");
		}

		// wait for radio to finish transmitting
		ESP_LOGW("tnc", "waiting to disable tnc...");
		while(tnc_settings.status != TNC_RX)
		{
			vTaskDelay(100 / portTICK_PERIOD_MS); // wait 100ms and try again
		}

		// show user new settings
		tnc_print_settings();

		// disable TNC task
		vTaskSuspend(tnc_settings.tnc_task);
		ESP_LOGW("tnc", "disabled tnc");

		// re-initialize radio
		ax25_param_t ax25_param;
		ax25_param.tx_tail = tnc_settings.tx_tail;
		ax25_param.tx_delay = tnc_settings.tx_delay;
		ax25_param.sample_rate = 13200;
		ax25_param.symbol0_freq = 1200;
		ax25_param.symbol1_freq = 2200;
		ax25_param.rx_cb = radio_rx_ax25_cb;
		ax25_param.tx_cb = radio_tx_ax25_cb;
		ax25_param.rx_buf = ax25_rx_buf;
		ax25_param.rx_buf_len = sizeof(ax25_rx_buf) / sizeof(ax25_rx_buf[0]);
		ax25_param.cpu_core = 1;

		radio_reinit(AX25, &ax25_param);
		radio_set_frequency(tnc_settings.freq);

		// set radio back to RX
		radio_packet_rx(NULL);

		// resume TNC task
		vTaskResume(tnc_settings.tnc_task);
		ESP_LOGI("tnc", "re-enabled tnc");
	}
}

/* TNC Tasks */
void tnc_task(void *para)
{
	uint8_t *packet;
	size_t packet_size;
	uint8_t P;

	radio_packet_rx(NULL);
	tnc_settings.status = TNC_RX;

	while(1)
	{
		// indicate RX
		enable_green_led();
		disable_red_led();

		// check ring buffer for packet
		packet = xRingbufferReceive(ax25_tx_buf, &packet_size, portMAX_DELAY);
		ESP_LOGI("tnc", "scheduling transmission");

		if (packet != NULL)
		{
			// wait based on persistance algorithm
			while (1)
			{
				// TODO: carrier detect is causing a crash somehow when it gets locked on
				// to high. I'm confused as the unit should continue to run despite this...
				if (radio_get_cs() == 0)
				{
					ESP_LOGV("radio", "carrier not detected");

					P = (uint8_t) esp_random();
					if (P <= tnc_settings.P)
					{
						ESP_LOGI("radio", "transmission scheduled");
						break;
					}
					else
					{
						ESP_LOGV("radio", "transmission postponed");
						vTaskDelay((tnc_settings.slot_time * 10) / portTICK_PERIOD_MS);
					}
				}
				else
				{
					ESP_LOGV("radio", "carrier detected");
					vTaskDelay(10 / portTICK_PERIOD_MS);		// re-check in 10ms
				}
			}

			// indicate TX
			enable_red_led();
			disable_green_led();

			// TODO: modify code so the full TX DELAY isn't used when multiple packets are sent.
			// dump all the packets in the buffer
			while(packet != NULL)
			{
				// setup packet to be transmitted
				tnc_settings.status = TNC_TX;
				radio_packet_tx(packet, packet_size, NULL);

				// sleep until packet is finished being sent
				xSemaphoreTake(xRadioTXSemaphore, portMAX_DELAY);
				tnc_settings.status = TNC_IDLE;

				// remove packet from ring buffer and load next one if it exists
				vRingbufferReturnItem(ax25_tx_buf, (void *)packet);
				packet = xRingbufferReceive(ax25_tx_buf, &packet_size, 0);
			}
		}
		else
		{
			ESP_LOGE("tnc", "buffer error");
		}
		// setup again for reception
		radio_packet_rx(NULL);
		tnc_settings.status = TNC_RX;
	}
}

void app_main()
{
	// Inter-Task Communication
	ax25_tx_buf = xRingbufferCreate(1028, RINGBUF_TYPE_NOSPLIT);
	xRadioTXSemaphore = xSemaphoreCreateBinary();

	// Initialize Flash
	esp_err_t ret = nvs_flash_init();
	if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
		ESP_ERROR_CHECK(nvs_flash_erase());
		ret = nvs_flash_init();
	}
	ESP_ERROR_CHECK( ret );

	// Board IO Initialize
	board_init();

	// Load default TNC settings
	tnc_settings.P = 63;
	tnc_settings.tx_tail = 0; 		// 10ms units
	tnc_settings.tx_delay = 10; 		// 10ms units
	tnc_settings.P = 63;
	tnc_settings.slot_time = 10; 	// 10ms units
	tnc_settings.tnc_number = 0;
	tnc_settings.status = TNC_IDLE;
	tnc_settings.freq = 144390000;
	tnc_settings.mode  = AX25;

	// Radio Initialize
	ax25_param_t ax25_param;
	ax25_param.tx_tail = tnc_settings.tx_tail;
	ax25_param.tx_delay = tnc_settings.tx_delay;
	ax25_param.sample_rate = 13200;
	ax25_param.symbol0_freq = 1200;
	ax25_param.symbol1_freq = 2200;
	ax25_param.rx_cb = radio_rx_ax25_cb;
	ax25_param.tx_cb = radio_tx_ax25_cb;
	ax25_param.rx_buf = ax25_rx_buf;
	ax25_param.rx_buf_len = sizeof(ax25_rx_buf) / sizeof(ax25_rx_buf[0]);
	ax25_param.cpu_core = 1;

	// TODO: setup switch statement for settings parameters or for mode....
	tnc_print_settings();
	radio_init(AX25, &ax25_param);
	radio_set_frequency(tnc_settings.freq);

	// Kiss Decoder and Encoder
	kiss_init(tnc_settings.tnc_number, kiss_tx_cb, kiss_rx_cb);

	// BLE and SPP
	bt_spp_init();

	// Tasks
	xTaskCreatePinnedToCore(tnc_task, "tnc task", 1024*4, 0, 2, &tnc_settings.tnc_task, 1);

}