#include "stdint.h"
#include "driver/uart.h"
#include "dfplayermini.h"

#define BUF_SIZE    (1024)
#define PACKET_LEN  (8)
#define BYTE_START  (0x7E)
#define BYTE_END    (0xEF)


struct DFPlayerMini {
  uart_config_t *uart_config;
} dfplayermini;

/*
 * 0x7E START
 * 0xFF VER
 * 0x06 LEN
 * 0x00 ACK
 * 0x01 CMD
 * 0x00 PARAM-hi
 * 0x00 PARAM-lo
 * 0x00 CHECK-hi
 * 0x00 CHECK-lo
 * 0xEF FIN
 */
uint8_t packet[] = { 0x7E, 0xFF, 0x06, 0x00, 0x01, 0x00, 0x00, 0xEF };

uint8_t send_packet(uint8_t cmd, uint8_t arg_low, uint8_t arg_high) {
  uint8_t i = 0;
  uint16_t sum = 0;

  packet[3] = cmd;
  packet[4] = 1;
  packet[5] = arg_high;
  packet[6] = arg_low;

  for(i = 1; i < 7; i++) {
    sum += packet[i];
  }

  //packet[7] = -sum << 8;
  //packet[8] = -sum;

  return uart_write_bytes(UART_NUM_1, (const char*)&packet, PACKET_LEN);
}

uint8_t set_volume(uint8_t vol) {
  return send_packet(0x06, vol, 0);
}
 
void dfplayermini_uart_read_task(void *arg) {
  setvbuf(stdout, NULL, _IONBF, 0);

  uint8_t buf[PACKET_LEN];
  uint8_t err;
  uint8_t idx = 0;
  uint8_t inited = 0;
  uint8_t timeout = 1;

  while(true) {
    int len = uart_read_bytes(UART_NUM_1, &buf[idx], 1, 20 / portTICK_RATE_MS);

    if(len == 0) {
      if(inited == 0 && timeout++ == 0) {
        printf("timeout, sending reset\n");
        send_packet(0x0C, 0, 0);
      }

      continue;
    }

    if(buf[0] == BYTE_START) {
      printf("0x%02X ", buf[idx]);

      idx++;
      //printf("got start byte\n");
    }

    if(buf[idx - 1] == BYTE_END) {
      printf("\n");

      switch(buf[3]) {
        case 0x3F:
          printf("player ready\n");
          inited = 1;

          //send_packet(0x0C, 0, 0);
          //vTaskDelay(10 / portTICK_RATE_MS);

          //if(!(err = send_packet(0x09, 1, 0))) {
            //printf("Failed to set play source: %d\n", err);
          //}

          if(!(err = set_volume(10))) {
            printf("Failed to set volume: %d\n", err);
          }

          vTaskDelay(100 / portTICK_RATE_MS);

          send_packet(0x03, 0, 0);

          break;
      }

      idx = 0;
    }
  }
}

uint8_t dfplayermini_init() {
  uart_config_t uart_config = {
    .baud_rate = 9600,
    .data_bits = UART_DATA_8_BITS,
    .parity    = UART_PARITY_DISABLE,
    .stop_bits = UART_STOP_BITS_1,
    .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
    .source_clk = UART_SCLK_APB,
  };

  dfplayermini.uart_config = &uart_config;

  uart_driver_install(UART_NUM_1, BUF_SIZE * 2, 0, 0, NULL, 0);
  uart_param_config(UART_NUM_1, dfplayermini.uart_config);
  uart_set_pin(UART_NUM_1, 13, 34, -1, -1);

  xTaskCreate(dfplayermini_uart_read_task, "dfplayermini_uart_read_task", 2048, NULL, 10, NULL);

  return 0;
}