#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "driver/adc.h"
#include <math.h>

#define RED_LED GPIO_NUM_4
#define GREEN_LED GPIO_NUM_2
#define LDR_PIN GPIO_NUM_32
#define AVG_WINDOW 10
#define SENSOR_THRESHOLD 500
const float GAMMA = 0.7;
const float RL10 = 50;
float ALA = 0; // Ambient Light Average -- name used to fit theme
float printLux = 0;

#define LDR_ADC_CHANNEL ADC1_CHANNEL_4 

int Tstate;
int DCIstate;

// Task to blink an LED at 1 Hz (1000 ms period:500 ms ON, 500 ms OFF)
void blink_task(void *pvParameters)
{
  Tstate = 0; // (TRANSMITTER STATE - 0 for not busy, 1 for busy)
  DCIstate = 0; // DATA COLLECTION INDICATOR STATE
  TickType_t currentTime = pdTICKS_TO_MS(xTaskGetTickCount());

  while(1)
  {
    currentTime =pdTICKS_TO_MS(xTaskGetTickCount());
    if(Tstate == 0)
    {
      gpio_set_level(RED_LED, 0);
      DCIstate = !DCIstate;
      gpio_set_level(GREEN_LED, DCIstate);
    }
    else if(Tstate == 1)
    {
      gpio_set_level(GREEN_LED, 0);
      DCIstate = !DCIstate;
      gpio_set_level(RED_LED, DCIstate);
    }
    // printf("LED Cycle %d @ %ld\n", DCIstate, currentTime); // used for testing
    vTaskDelay(pdMS_TO_TICKS(500));
  }
}
// Task to print a message every 1000 ms (1 seconds)
void print_task(void *pvParameters)
{
  int counter = 0;
  while (1) 
  {
    if(counter < 10)
    {
      Tstate = 0;
      printf("Scan in %d seconds...   Current Lux : %.2f\n", (10 - counter), printLux);
      counter++;
    }
    else if(counter >= 10)
    {
      Tstate = 1;
      printf("Scanning...\n");
      if(counter > 12)
      {
        printf("Scan Complete... ALA : %.2f\n\n", ALA);
        counter = -1;
      }
      counter++;
    }
    vTaskDelay(pdMS_TO_TICKS(1000));
  }
}

void sensor_task(void *pvParameters)
{
  adc1_config_width(ADC_WIDTH_BIT_12);
  adc1_config_channel_atten(LDR_ADC_CHANNEL, ADC_ATTEN_DB_11);

  int raw;
  float vMeasured = 0.;
  float rMeasured = 0.;
  float lux = 0.;

  int luxReadings[AVG_WINDOW] = {0};
  int idx = 0;
  float sum = 0;

  for(int i = 0; i < AVG_WINDOW; ++i)
  {
    raw = adc1_get_raw(LDR_ADC_CHANNEL);
    vMeasured = raw / 4096. * 3.3;
    rMeasured = 10000 * vMeasured / (3.3 - vMeasured);
    lux = pow(RL10 * 1e3 * pow(10, GAMMA) / rMeasured, (1 / GAMMA));
    printLux = lux;
    // printf("LUX : %.2f\n", lux); // removed, was being used for testing
    luxReadings[i] = lux;
    sum += luxReadings[i];
  }

  const TickType_t periodTicks = pdMS_TO_TICKS(500);
  TickType_t lastWakeTime = xTaskGetTickCount();

  while(1)
  {
    raw = adc1_get_raw(LDR_ADC_CHANNEL);
    // printf("** raw ** : Sensor %d\n", raw);
    vMeasured = raw / 4096. * 3.3;
    rMeasured = 10000 * vMeasured / (3.3 - vMeasured);
    lux = pow(RL10 * 1e3 * pow(10, GAMMA) / rMeasured, (1 / GAMMA));
    printLux = lux;
    // printf("LUX : %.2f\n", lux); // removed, was being used for testing

    sum -= luxReadings[idx];

    luxReadings[idx] = lux;
    sum += lux;
    idx = (idx + 1) % AVG_WINDOW;
    float avg = sum / AVG_WINDOW;
    ALA = avg;

    if(avg > SENSOR_THRESHOLD)
    {
      printf("**ALERT** : Average ambient lighting exceeding optimal levels : %.2f\n", avg); // changed name of printed variable to fit theme
    }
    else
    {
      // printf("Ambient Light Average : %.2f\n", avg); // changed name of printed variable to fit theme
    }
    TickType_t currentTick = xTaskGetTickCount();
    vTaskDelayUntil(&lastWakeTime, periodTicks); // remove for BONUS CODE
  }


  
}

void app_main() {
    // Initialize LED GPIO     
    gpio_reset_pin(RED_LED);
    gpio_reset_pin(GREEN_LED);
    gpio_reset_pin(LDR_PIN);
    gpio_set_direction(RED_LED, GPIO_MODE_OUTPUT);
    gpio_set_direction(GREEN_LED, GPIO_MODE_OUTPUT);
    gpio_set_direction(LDR_PIN, GPIO_MODE_INPUT);


    
    // Instantiate/ Create tasks: 
    // . pointer to task function, 
    // . descriptive name, [has a max length; located in the FREERTOS_CONFIG.H]
    // . stack depth, 
    // . parameters [optional] = NULL 
    // . priority [0 = low], 
    // . pointer referencing this created task [optional] = NULL
    // Learn more here https://www.freertos.org/Documentation/02-Kernel/04-API-references/01-Task-creation/01-xTaskCreate
    xTaskCreatePinnedToCore(blink_task, "DCIOperation", 2048, NULL, 1, NULL, 1);
    xTaskCreatePinnedToCore(print_task, "Print Task", 2048, NULL, 1, NULL, 1);
    xTaskCreatePinnedToCore(sensor_task, "Sensor Task", 4096, NULL, 2, NULL, 1);

}