#include "pms5003.h"
#include "hardware/uart.h"
#include "pico/stdlib.h"
#include <hardware/gpio.h>
#include <hardware/regs/intctrl.h>
#include <stdint.h>
#include <stdio.h>

/**
Lib for Plantower PMS5003 Particulate Matter (PM) Sensor

Detects PM1, PM2.5, PM10 particulates

Sourcces:
    -
https://shop.pimoroni.com/products/pms5003-particulate-matter-sensor-with-cable
    - https://github.com/pimoroni/pms5003-python/blob/main/pms5003/__init__.py
    - https://github.com/vogelrh/pms5003c/tree/master
    -
https://github.com/raspberrypi/pico-examples/blob/master/uart/hello_uart/hello_uart.c
*/

static uint8_t rx_buf[32] = {0};
static uint8_t rx_i = 0;

static float last_pm1_reading = 0;
static float last_pm2_5_reading = 0;
static float last_pm10_reading = 0;

static void extract_pm_values_from_rx_buf() {
  uint8_t pm1_low = rx_buf[9];
  uint8_t pm1_high = rx_buf[10];
  uint16_t pm1 = ((uint16_t)pm1_high << 8) | pm1_low;

  uint8_t pm2_5_low = rx_buf[11];
  uint8_t pm2_5_high = rx_buf[12];
  uint16_t pm2_5 = ((uint16_t)pm2_5_high << 8) | pm2_5_low;

  uint8_t pm10_low = rx_buf[13];
  uint8_t pm10_high = rx_buf[14];
  uint16_t pm10 = ((uint16_t)pm10_high << 8) | pm10_low;

  last_pm1_reading = (float)pm1;
  last_pm2_5_reading = (float)pm2_5;
  last_pm10_reading = (float)pm10;
}

static void on_uart_rx() {
  while (uart_is_readable(uart1)) {
    uint8_t ch = uart_getc(uart1);
    // start of a message
    if (ch == 0x42) {
      printf("pms5003 reading received\n");
      rx_i = 0;
    }
    rx_buf[rx_i] = ch;
    rx_i++;
    // end of message
    if (rx_i == 31) {
      extract_pm_values_from_rx_buf();
    }

    // guard
    if (rx_i > 32) {
      rx_i = 0;
    }
  }
}

static unsigned char pms5003_command_prefix[] = {0x42, 0x4D};
void pms5003_init(pms5003_config *new_config, uart_inst_t *uart, uint8_t tx_pin,
                  uint8_t rx_pin, uint8_t enable_pin, uint8_t reset_pin) {
  gpio_set_function(tx_pin, UART_FUNCSEL_NUM(uart, tx_pin));
  gpio_set_function(rx_pin, UART_FUNCSEL_NUM(uart, rx_pin));
  uart_init(uart, 9600);
  uart_set_format(uart, 8, 1, UART_PARITY_NONE);
  irq_set_exclusive_handler(UART1_IRQ, on_uart_rx);
  irq_set_enabled(UART1_IRQ, true);
  uart_set_irq_enables(uart, true, false);

  // high level or suspending is normal working status, while low level is sleeping mode.
  gpio_init(enable_pin);
  gpio_set_dir(enable_pin, GPIO_OUT);
  gpio_put(enable_pin, 0);

  // low resets
  // gpio_init(reset_pin);
  // gpio_set_dir(reset_pin, GPIO_OUT);
  // gpio_set_pulls(enable_pin, true, false); // pull up
  // gpio_put(enable_pin, 1);

  new_config->uart = uart;
  new_config->enable_pin = enable_pin;
  new_config->reset_pin = reset_pin;
}

/**
    Reads should happen min of 30sec after waking the sensor
*/
pms5003_reading pms5003_read(pms5003_config *config) {
  pms5003_reading reading;
  reading.pm1 = last_pm1_reading;
  reading.pm2_5 = last_pm2_5_reading;
  reading.pm10 = last_pm10_reading;
  return reading;
}