#include <stdio.h>
#include <stdbool.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"

#include "driver/gpio.h"
#include "driver/adc.h"

// ================= PIN CONFIG =================
#define LDR_PIN         ADC1_CHANNEL_6   // GPIO34
#define TEMP_PIN        ADC1_CHANNEL_7   // GPIO35

#define LED_LAMP        GPIO_NUM_2
#define LED_FAN         GPIO_NUM_4
#define BUTTON_PIN      GPIO_NUM_14

// ================= THRESHOLD =================
#define LIGHT_THRESHOLD 2000
#define TEMP_THRESHOLD  30.0

// ================= STRUCT =================
typedef struct {

    int lightValue;

    float temperature;

} SensorData;


// ================= RTOS OBJECT =================
QueueHandle_t sensorQueue;

SemaphoreHandle_t buttonSemaphore;


// ================= GLOBAL VARIABLE =================
bool manualOverride = false;


// ================= ISR BUTTON =================
void IRAM_ATTR buttonISR(void *arg) {

    BaseType_t xHigherPriorityTaskWoken = pdFALSE;

    xSemaphoreGiveFromISR(
        buttonSemaphore,
        &xHigherPriorityTaskWoken
    );

    if (xHigherPriorityTaskWoken) {

        portYIELD_FROM_ISR();
    }
}


// ================= SENSOR TASK =================
void sensorTask(void *pvParameters) {

    SensorData data;

    while (1) {

        // ===== READ LDR =====
        int rawLight = adc1_get_raw(LDR_PIN);

        // ===== READ POTENTIOMETER =====
        int rawTemp = adc1_get_raw(TEMP_PIN);

        // ===== CONVERT TO CELSIUS =====
        // 0 - 4095  =>  0 - 100 C
        float temperatureC =
            ((float)rawTemp / 4095.0) * 100.0;

        // ===== SAVE DATA =====
        data.lightValue = rawLight;

        data.temperature = temperatureC;

        // ===== SEND TO QUEUE =====
        xQueueSend(
            sensorQueue,
            &data,
            portMAX_DELAY
        );

        vTaskDelay(pdMS_TO_TICKS(500));
    }
}


// ================= DECISION TASK =================
void decisionTask(void *pvParameters) {

    SensorData receivedData;

    while (1) {

        if (xQueueReceive(
                sensorQueue,
                &receivedData,
                portMAX_DELAY
            )) {

            printf("\n===== SENSOR DATA =====\n");

            printf(
                "Light ADC : %d\n",
                receivedData.lightValue
            );

            printf(
                "Temperature : %.2f C\n",
                receivedData.temperature
            );

            // ================= LIGHT CONTROL =================
            if (receivedData.lightValue
                < LIGHT_THRESHOLD) {

                gpio_set_level(LED_LAMP, 1);

                printf(
                    "Condition : DARK -> Lamp ON\n"
                );

            } else {

                gpio_set_level(LED_LAMP, 0);

                printf(
                    "Condition : BRIGHT -> Lamp OFF\n"
                );
            }

            // ================= FAN CONTROL =================
            if (manualOverride) {

                gpio_set_level(LED_FAN, 1);

                printf(
                    "Manual Override -> Fan ON\n"
                );

            } else {

                if (receivedData.temperature
                    > TEMP_THRESHOLD) {

                    gpio_set_level(LED_FAN, 1);

                    printf(
                        "Condition : HOT -> Fan ON\n"
                    );

                } else {

                    gpio_set_level(LED_FAN, 0);

                    printf(
                        "Condition : NORMAL -> Fan OFF\n"
                    );
                }
            }
        }
    }
}


// ================= BUTTON TASK =================
void buttonTask(void *pvParameters) {

    while (1) {

        if (xSemaphoreTake(
                buttonSemaphore,
                portMAX_DELAY
            )) {

            manualOverride = !manualOverride;

            printf(
                "\n=== BUTTON PRESSED ===\n"
            );

            if (manualOverride) {

                printf(
                    "Manual Override ENABLED\n"
                );

            } else {

                printf(
                    "Manual Override DISABLED\n"
                );
            }
        }
    }
}


// ================= MAIN =================
void app_main() {

    // ================= GPIO OUTPUT =================
    gpio_set_direction(
        LED_LAMP,
        GPIO_MODE_OUTPUT
    );

    gpio_set_direction(
        LED_FAN,
        GPIO_MODE_OUTPUT
    );

    // ================= BUTTON INPUT =================
    gpio_set_direction(
        BUTTON_PIN,
        GPIO_MODE_INPUT
    );

    gpio_pullup_en(BUTTON_PIN);

    // ================= INTERRUPT =================
    gpio_set_intr_type(
        BUTTON_PIN,
        GPIO_INTR_NEGEDGE
    );

    gpio_install_isr_service(0);

    gpio_isr_handler_add(
        BUTTON_PIN,
        buttonISR,
        NULL
    );

    // ================= ADC CONFIG =================
    adc1_config_width(
        ADC_WIDTH_BIT_12
    );

    adc1_config_channel_atten(
        LDR_PIN,
        ADC_ATTEN_DB_11
    );

    adc1_config_channel_atten(
        TEMP_PIN,
        ADC_ATTEN_DB_11
    );

    // ================= QUEUE =================
    sensorQueue = xQueueCreate(
        5,
        sizeof(SensorData)
    );

    // ================= SEMAPHORE =================
    buttonSemaphore =
        xSemaphoreCreateBinary();

    // ================= CREATE TASK =================
    xTaskCreate(
        sensorTask,
        "Sensor Task",
        2048,
        NULL,
        1,
        NULL
    );

    xTaskCreate(
        decisionTask,
        "Decision Task",
        4096,
        NULL,
        2,
        NULL
    );

    xTaskCreate(
        buttonTask,
        "Button Task",
        2048,
        NULL,
        3,
        NULL
    );
}