/* --------------------------------------------------------------
   Application: 02
   Release Type: Baseline Multitask Skeleton Starter Code 
   Class: Real Time Systems - Su 2025
   AI Use: Commented inline
---------------------------------------------------------------*/
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "driver/adc.h"
#include <math.h>

#define LDR_PIN GPIO_NUM_32
#define LDR_ADC_CHANNEL ADC1_CHANNEL_4
#define LED_PIN GPIO_NUM_2  // Using GPIO2 for the LED
#define AVG_WINDOW 10
#define SENSOR_THRESHOLD 500

// Task to blink an LED at 2 Hz (500 ms period: 250 ms ON, 250 ms OFF)
void blink_task(void *pvParameters) {
   bool led_status = false;
    TickType_t currentTime = pdTICKS_TO_MS( xTaskGetTickCount() );
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);

    while (1) {
        currentTime = pdTICKS_TO_MS( xTaskGetTickCount() );
        gpio_set_level(LED_PIN, 1);  //TODO: Set LED pin high or low based on led_status flag;
        led_status = led_status;  //TODO: toggle state for next loop 
        
       // printf("LED Cycle %s @ %lu\n", led_status ? "ON" : "OFF", currentTime);
        vTaskDelay(pdMS_TO_TICKS(500)); // Delay for 500 ms using MS to Ticks Function vs alternative which is MS / ticks per ms
       gpio_set_level(LED_PIN, 0); 
       vTaskDelay(pdMS_TO_TICKS(500));
    
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

// Task to print a message every 10000 ms (10 seconds)
void print_task(void *pvParameters) {
    TickType_t currentTime = pdTICKS_TO_MS( xTaskGetTickCount() );
    TickType_t previousTime = 0;
    while (1) {
        previousTime = currentTime;
        currentTime = pdTICKS_TO_MS( xTaskGetTickCount() );
        
        // Prints a periodic message based on a thematic area. Output a timestamp (ms) and period (ms)
        //printf("I'm up and running @ time %lu [period = %lu]!\n",currentTime, currentTime-previousTime);
        printf("SECURITY SYSTEM ONLINE @ time %lu [period = %lu]!\n",currentTime, currentTime-previousTime); //Theme customization
        vTaskDelay(pdMS_TO_TICKS(1000)); // Delay for 1000 ms
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

void sensor_task(void *pvParameters) {
//TODO110 Configure ADC (12-bit width, 0-3.3V range with 11dB attenuation)
    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(LDR_ADC_CHANNEL, ADC_ATTEN_DB_11); //could be ADC_ATTEN_DB_11

    // Variables to compute LUX
    int raw;
    float Vmeasure = 0.;
    float Rmeasure = 0.;
    float lux = 0.;
    // Variables for moving average
    int luxreadings[AVG_WINDOW] = {0};
    int idx = 0;
    float sum = 0;

    //TODO11a consider where AVG_WINDOW is defined, it could be here, or global value 
   

    //See TODO 99
    // 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/(4096*3.3); //TODO11b correct this with the equation seen earlier
        Rmeasure = (2000*Vmeasure)/(1-(Vmeasure/3.3)); //TODO11c correct this with the equation seen earlier
        lux = pow((pow(50*10000*10, 0.7)/Rmeasure), 1/0.7); //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/(4096*3.3); //TODO11e correct this with the equation seen earlier
        Rmeasure = (2000*Vmeasure)/(1-(Vmeasure/3.3)); //TODO11f correct this with the equation seen earlier
        lux = pow((pow(50*10000*10, 0.7)/Rmeasure), 1/0.7); //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) { //if avg goes above 500, alert
            //printf("**Alert**: Sensor average %d exceeds threshold %d!\n ", avg, SENSOR_THRESHOLD);
            printf("**ALERT**: SECURITY BREACH: Sensor average %d exceeds threshold %d!\n ", avg, SENSOR_THRESHOLD); // Theme customization
        } else {
          //TODO11i
          // (you could print the avg value for debugging)
          //printf("avg = %d\n", avg);
        }
        //TODO11j: Print out time period [to help with answering Eng/Analysis quetionst (hint check Application Solution #1 )
        vTaskDelayUntil(&lastWakeTime, periodTicks); 
        //https://wokwi.com/projects/430683087703949313
        //TODO11k Replace vTaskDelay with vTaskDelayUntil with parameters &lastWakeTime and periodTicks
      //  vTaskDelay(periodTicks);

    }
}


void app_main() {
    // Initialize LED GPIO     
    gpio_reset_pin(LED_PIN);
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);

    gpio_reset_pin(LDR_PIN);
    gpio_set_direction(LDR_PIN, GPIO_MODE_INPUT);

    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(LDR_ADC_CHANNEL, ADC_ATTEN_DB_11);
    
    // 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(sensor_task, "Sensor Task", 4096, NULL, 1, NULL,1);
    xTaskCreatePinnedToCore(blink_task, "Blink Task", 2048, NULL, 3, NULL, 1);
    xTaskCreatePinnedToCore(print_task, "Print Task", 2048, NULL, 2, NULL, 1);

    
    //Setting different priorities: xTaskCreate(print_task, "Print Task", 2048, NULL, 2, NULL);

}