#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"
#include "esp_adc/adc_oneshot.h"
#include "esp_adc/adc_continuous.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 ADC_CHANNEL_4
// TODO99: Consider Adding AVG_WINDOW and SENSOR_THRESHOLD as global defines
#define AVG_WINDOW 10
#define SENSOR_THRESHOLD 500


adc_oneshot_unit_handle_t adc1_handle;



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

    while (1) {
        currentTime = pdTICKS_TO_MS( xTaskGetTickCount() );
        led_status = !led_status;      
        gpio_set_level(LED_PIN, led_status);  //TODO: Set LED pin high or low based on led_status flag;
          //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
       
    
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

//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() );
        
        // Prints a periodic message based on a thematic area. Output a timestamp (ms) and period (ms)
        printf("Satellite Communication TRANSMITTING @ time %lu [period = %lu]!\n",currentTime, currentTime-previousTime);
        vTaskDelay(pdMS_TO_TICKS(1000)); // Delay for 1000 ms
    }
    vTaskDelete(NULL); // We'll never get here; tasks run forever
}

//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_12); //could be ADC_ATTEN_DB_11
    // Configure ADC channel
adc_oneshot_chan_cfg_t config = {
    .atten = ADC_ATTEN_DB_12,
    .bitwidth = ADC_BITWIDTH_12,
};
adc_oneshot_config_channel(adc1_handle, LDR_ADC_CHANNEL, &config);

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

    //TODO11a consider where AVG_WINDOW is defined, it could be here, or global value 
    //int AVG_WINDOW = 10;
    //int SENSOR_THRESHOLD = 500;

    //See TODO 99
    // Pre-fill the readings array with an initial sample to avoid startup anomaly
    for(int i = 0; i < AVG_WINDOW; ++i) {
        adc_oneshot_read(adc1_handle, LDR_ADC_CHANNEL, &raw);
        Vmeasure = ((float)raw / 4095.0f) * 3.3f;

        if (Vmeasure < 0.01f) Vmeasure = 0.01f;
        if (Vmeasure > 3.29f) Vmeasure = 3.29f;

        float Rfixed = 10000.0f;
        Rmeasure = Rfixed * (Vmeasure / (3.3f - Vmeasure));

        float gamma = 0.7f;
        float RL = 50000.0f;

        lux = pow((RL * pow(10.0f, gamma)) / Rmeasure, (1.0f / gamma));
        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
        adc_oneshot_read(adc1_handle, LDR_ADC_CHANNEL, &raw);
        //printf("**raw **: Sensor %d\n", raw);

        // Compute LUX
        Vmeasure = ((float)raw / 4095.0f) * 3.3f;

        if (Vmeasure < 0.01f) Vmeasure = 0.01f;
        if (Vmeasure > 3.29f) Vmeasure = 3.29f;

        float Rfixed = 10000.0f;
        Rmeasure = Rfixed * (Vmeasure / (3.3f - Vmeasure));

        float gamma = 0.7f;
        float RL = 50000.0f;

        lux = pow((RL * pow(10.0f, gamma)) / Rmeasure, (1.0f / gamma));
       
        // 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("**CAUTION** Solar energy %d exceeds threshold %d! Communication may be interrupted \n", avg, SENSOR_THRESHOLD);
        } else {
          //TODO11i
          printf("Solar energy normal\n");
        }
        //TODO11j: Print out time period [to help with answering Eng/Analysis quetionst (hint check Application Solution #1 )
        //https://wokwi.com/projects/430683087703949313
        printf("%ld\n", pdMS_TO_TICKS(500));
        //TODO11k Replace vTaskDelay with vTaskDelayUntil with parameters &lastWakeTime and periodTicks
        vTaskDelayUntil(&lastWakeTime, pdMS_TO_TICKS(500));

    }
}



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 [2 lines mirroring those above]
    gpio_reset_pin(LDR_PIN);
    gpio_set_direction(LDR_PIN, GPIO_MODE_INPUT);

    // Create ADC unit
adc_oneshot_unit_init_cfg_t init_config = {
    .unit_id = ADC_UNIT_1,
};
adc_oneshot_new_unit(&init_config, &adc1_handle);

// Configure ADC channel
adc_oneshot_chan_cfg_t config = {
    .atten = ADC_ATTEN_DB_12,
    .bitwidth = ADC_BITWIDTH_12,
};
adc_oneshot_config_channel(adc1_handle, LDR_ADC_CHANNEL, &config);

    

    // 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
    
    // TODO7: Pin tasks to core 1    
    // Convert these xTaskCreate function calls to  xTaskCreatePinnedToCore() function calls
    // The new function takes one more parameter at the end (0 or 1);
    // pin all your tasks to core 1 

    // This is a special (custom) espressif FreeRTOS function
    // . 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
    // . core [0,1] to pin task too 
    // https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/system/freertos_additions.html#_CPPv423xTaskCreatePinnedToCore14TaskFunction_tPCKcK8uint32_tPCv11UBaseType_tPC12TaskHandle_tK10BaseType_t
    xTaskCreatePinnedToCore(led_task, "LED", 2048, NULL, 1, NULL,1);
    xTaskCreatePinnedToCore(print_status_task, "STATUS", 2048, NULL, 2, NULL,1);

    // TODO8: Make sure everything still works as expected before moving on to TODO9 (above).
    

    //TODO12 Add in new Sensor task; make sure it has the correct priority to preempt 
    //the other two tasks.
    xTaskCreatePinnedToCore(sensor_task, "SensorTask", 4096, NULL,0,NULL,1);

    //TODO13: Make sure the output is working as expected and move on to the engineering
    //and analysis part of the application. You may need to make modifications for experiments. 
    //Make sure you can return back to the working version!
}