/* --------------------------------------------------------------
   Application: 01 - Rev1: Martian Greenhouse
   Release Type: Baseline Multitask Skeleton Starter Code 
   Class: Real Time Systems - Su 2025
   Theme: Earth Spacehub Communication Link Blink and Mars Greenhouse Telemetry System
   AI Use: Commented inline. 
---------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

// TODO1:
#include "driver/adc.h" 
#include "math.h"

#define LED_PIN GPIO_NUM_4  // Using GPIO4 for the LED
#define LDR_PIN GPIO_NUM_32 // TODO2: AO on 32
#define LDR_ADC_CHANNEL ADC1_CHANNEL_4 // TODO3: ADC Channel connected to PIN32

#define AVG_WINDOW 10


// TODO99: Consider Adding AVG_WINDOW and SENSOR_THRESHOLD as global defines

// simulate environment variable data for theme
// note: AI used to generate a realistic random range for values
float get_oxygen_level() {
    return 20.0 + (rand() % 10) / 10.0; // ~20.0–21.0%
}

// TODO9:
// LED blink showing Earth Spacehub communication link is active ( 500 ms ON, 500 ms OFF)
void commLink_task(void *pvParameters) {
    bool led_on = false;
    TickType_t last_wake = xTaskGetTickCount();

    while (1) {

        // variables to keep track of period and timestaps
        TickType_t now = xTaskGetTickCount();
        unsigned long time_ms = now * portTICK_PERIOD_MS;
        unsigned long period_ms = (now - last_wake) * portTICK_PERIOD_MS;
        last_wake = now;
        
        // TODO: Set LED pin high or low based on led_on flag; right now it's always on... boring; hint in the commented out print statement
        if (led_on){
            unsigned long timestamp = (unsigned long)(xTaskGetTickCount() * portTICK_PERIOD_MS);

            gpio_set_level(LED_PIN, 1); // LED ON
            printf("\n***Earth Spacehub CommLink: [ACTIVE]*** \nBeacon ON at %lu ms", timestamp);
        } else {
            unsigned long timestamp = (unsigned long)(xTaskGetTickCount() * portTICK_PERIOD_MS);

            gpio_set_level(LED_PIN, 0); // LED OFF
            printf("\nBeacon OFF at %lu ms", timestamp);
        }

        printf("  Task Period: %lu ms\n", period_ms);  // Log task cycle time
        
        led_on = !led_on;  // toggle state 
        vTaskDelay(pdMS_TO_TICKS(500)); // Delay for 500 ms using MS to Ticks Function vs alternative which is MS / ticks per ms
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

// TODO10: Log Martian Greenhouse Environment Status to console every 1s 1000ms
void print_task(void *pvParameters) {
    TickType_t last_telemetry = xTaskGetTickCount();

    while (1) {
      TickType_t now = xTaskGetTickCount();
      unsigned long time_ms = now * portTICK_PERIOD_MS;
      unsigned long period_ms = (now - last_telemetry) * portTICK_PERIOD_MS;
      last_telemetry = now;
        
    
      // generate values for greenhouse simulation
      float oxygen = get_oxygen_level();

      // AI used to create a readable console statement
      printf("Martian greenhouse up and running @ Time: %lu ms Period: %lums with O₂: %.1f%% ",
             time_ms, period_ms, oxygen);        vTaskDelay(pdMS_TO_TICKS(1000));  // 1 second delay. needed to prevent starvation
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

// TODO11: sesnor readings every 500ms
void sunlightSensor_task(void *pvParameters) {
  // TODO10: configure ADC channel
  adc1_config_width(ADC_WIDTH_BIT_12);
  adc1_config_channel_atten(LDR_ADC_CHANNEL, ADC_ATTEN_DB_11);

  // TODO11a Variables to compute LUX. AVE_WINDOW globally defined
  int raw, SENSOR_THRESHOLD = 500;
  float Vmeasure = 0., Rmeasure = 0., lux = 0.; 

  // Variables for moving average
  int luxreadings[AVG_WINDOW] = {0}, idx = 0; 
  float sum = 0;
  
  // Pre-fill the readings array with an initial sample to avoid startup anomaly
    for(int i = 0; i < AVG_WINDOW; ++i) {
        raw =  adc1_get_raw(LDR_ADC_CHANNEL);
        
        Vmeasure = (raw / 4095.0) * 3.3; //TODO11b correct this with the equation seen earlier
        Rmeasure = 10000.0 / ((3.3 - Vmeasure) -1); //TODO11c correct this with the equation seen earlier
        lux = pow((50.0 * 1000.0) / Rmeasure, 1.0 / 0.7); //TODO11d correct this with the equation seen earlier
        
        luxreadings[i] = lux;
        sum += luxreadings[i];
    }

    const TickType_t periodTicks = pdMS_TO_TICKS(500); // e.g. 500 ms period
    TickType_t lastWakeTime = xTaskGetTickCount(); // initialize last wake time

    while (1) {
        // Read current sensor value
        raw = adc1_get_raw(LDR_ADC_CHANNEL);
        
        printf("**raw **: Sensor %d\n", raw);

        // Compute LUX
        Vmeasure = (raw / 4095.0) * 3.3;                    //TODO11e correct this with the equation seen earlier
        Rmeasure = (Vmeasure * 10000.0) / (3.3 - Vmeasure); //TODO11f correct this with the equation seen earlier
        lux = pow((50.0 * 1000.0) / Rmeasure, 1.0 / 0.7);   //TODO11g correct this with the equation seen earlier
       
        // Update moving average buffer 
        sum -= luxreadings[idx];          // remove oldest value from sum
        luxreadings[idx] = lux;           // place new reading
        sum += lux;                       // add new value to sum
        idx = (idx + 1) % AVG_WINDOW;
        int avg = sum / AVG_WINDOW;       // compute average

        //TODO11h Check threshold and print alert if exceeded or below based on context
        if (avg > SENSOR_THRESHOLD) {
            printf("**Alert**: Sunlight exposure too high! Plants can burn! Avg %d  > threshold %d\n", avg, SENSOR_THRESHOLD);
        } else {
            //TODO11i
            printf("Sunlight OK: Avg lux is %d\n", avg);  // for debugging
        }
        //TODO11j: Print out time period [to help with answering Eng/Analysis quetionst (hint check Application Solution #1 )
        unsigned long timestamp = xTaskGetTickCount() * portTICK_PERIOD_MS;
        printf("Sunlight Sensor Task Time Period: %lu ms\n", timestamp);

        //TODO11k Replace vTaskDelay with vTaskDelayUntil with parameters &lastWakeTime and periodTicks
        //vTaskDelay(periodTicks); OLD!!
        vTaskDelayUntil(&lastWakeTime, periodTicks);  // NEW
        //**** IF vTASKDELAYUNTIL IS REMOVED, THE SYSTEM WILL BE STARVED!

    }
}

void app_main() {

    // Initialize LED GPIO     
    gpio_reset_pin(LED_PIN);
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
    
    // TODO4: initialize LDR and configure ADC
    gpio_reset_pin(LDR_PIN);
    gpio_set_direction(LDR_PIN, GPIO_MODE_INPUT); 


    // create tasks on core1, saving core0 for wifi etc...
    // note: the higher the number the higher the priority
    // (ptr_name, "desc name", stack depth, opt para, priority 0 low, opt ptr ref, core #)

    xTaskCreatePinnedToCore(commLink_task, "Earth CommLink Beacon Task", 2048, NULL, 0, NULL, 1);   // TODO 12
    xTaskCreatePinnedToCore(print_task, "Greenhouse Environment Telemetry Task", 2048, NULL, 1, NULL, 1); // TODO 8
    xTaskCreatePinnedToCore(sunlightSensor_task, "SENSOR", 2048, NULL, 2, NULL, 1);                       // TODO 8

    // the sunlightSensor task has the highest priority, then the print and then the LED blink. 
}