/* --------------------------------------------------------------
   Application: 02 - Rev1
   Release Type: Baseline Preemption
   Class: Real Time Systems - Fa 2025
   Ryan Ramdihal
---------------------------------------------------------------*/
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

// TODO1: ADD IN additional INCLUDES BELOW
#include "driver/adc.h"
#include <math.h>
// TODO1: ADD IN additional INCLUDES ABOVE

#define LED_PIN GPIO_NUM_2  // Using GPIO2 for the LED

// TODO2: ADD IN LDR_PIN to gpio pin 32
#define LDR_PIN GPIO_NUM_32

// TODO3: ADD IN LDR_ADC_CHANNEL -- if you used gpio pin 32 it should map to ADC1_CHANNEL4
#define LDR_ADC_CHANNEL ADC1_CHANNEL_4

// TODO99: Consider Adding AVG_WINDOW and SENSOR_THRESHOLD as global defines
#define AVG_WINDOW 10
#define SENSOR_THRESHOLD 500
#define VSOURCE 3.3
#define R_FIXED 10000
#define GAMMA 0.7
#define R_LUX_REF 250000

//TODO9: Adjust Task to blink an LED at 1 Hz (1000 ms period: 500 ms ON, 500 ms OFF);
void led_task(void *pvParameters) {
    bool led_on = false;
    TickType_t currentTime;

    while (1) {
        currentTime = pdTICKS_TO_MS(xTaskGetTickCount());
        // TODO9: blink LED using led_on variable
        gpio_set_level(LED_PIN, led_on); // Changed to led_on variable
        led_on = !led_on;                // toggle state for next time

        printf("Heartbeat Monitor LED toggled\n");//prints the message which makes an audible sounds about the heart rate
        vTaskDelay(pdMS_TO_TICKS(500)); // 500 ms delay
    }
    vTaskDelete(NULL);
}

//TODO10: Task to print a message every 1000 ms (1 seconds)
void print_status_task(void *pvParameters) {
    TickType_t currentTime = pdTICKS_TO_MS(xTaskGetTickCount());
    TickType_t previousTime = 0;

    while (1) {
        previousTime = currentTime;
        currentTime = pdTICKS_TO_MS(xTaskGetTickCount());

        printf("Monitor active for %lu seconds [period = %lu ms]\n", 
               currentTime/1000, (currentTime - previousTime));

        vTaskDelay(pdMS_TO_TICKS(1000)); // 1000 ms delay
    }
    vTaskDelete(NULL);
}

//TODO11: Create new task for sensor reading every 500ms
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);

    // 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;

    

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

    while (1) {
        raw = adc1_get_raw(LDR_ADC_CHANNEL);
        Vmeasure = (raw / 4095.0f) * VSOURCE;                   // TODO11e
        Rmeasure = R_FIXED * Vmeasure / (VSOURCE - Vmeasure);  // TODO11f
        lux = pow((R_LUX_REF / Rmeasure), (1 / GAMMA));            // TODO11g

        // Update moving average
        sum -= luxreadings[idx];
        luxreadings[idx] = lux;
        sum += lux;
        idx = (idx + 1) % AVG_WINDOW;
        float avg = sum / AVG_WINDOW;

        // TODO11h: Check threshold
        if (avg >= SENSOR_THRESHOLD) {
            printf("**Alert**: avg = %.4f exceeds Sensor Threshold %d\n", avg, SENSOR_THRESHOLD);
        } else {
            // TODO11i: optional debug output
            printf("[Sensor Readings] raw=%d V=%.3f R=%.1f lux=%.4f avg=%.4f\n",
                   raw, Vmeasure, Rmeasure, lux, avg);
        }

        // TODO11k: use vTaskDelayUntil
        vTaskDelayUntil(&lastWakeTime, periodTicks);
    }
    vTaskDelete(NULL);
}

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

    // TODO4: Initialize LDR pin as INPUT
    gpio_reset_pin(LDR_PIN);
    gpio_set_direction(LDR_PIN, GPIO_MODE_INPUT);

    // TODO5: Set ADC1's resolution
    adc1_config_width(ADC_WIDTH_BIT_12);

    // TODO6: Set ADC channel attenuation
    adc1_config_channel_atten(LDR_ADC_CHANNEL, ADC_ATTEN_DB_11);

    // TODO7: Pin tasks to core 1
    xTaskCreatePinnedToCore(led_task, "LED", 2048, NULL, 1, NULL, 1);
    xTaskCreatePinnedToCore(print_status_task, "STATUS", 2048, NULL, 2, NULL, 1);
    xTaskCreatePinnedToCore(sensor_task, "SENSOR", 4096, NULL, 3, NULL, 1); // TODO12: sensor task highest priority

    // TODO8: Verify everything works
    // TODO13: Perform engineering analysis
}