#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"

static int sharedCounter = 0;
SemaphoreHandle_t mutex;  // mutex for protecting sharedCounter (not used in flawed code)

void incrementTask1(void *pvParameters) {
    for (int i = 0; i < 100; ++i) {
        // Reading and updating sharedCounter without lock (not atomic)
        int temp = sharedCounter;
        // Simulate some work where context switch could happen
        vTaskDelay(pdMS_TO_TICKS(1));  
        temp = temp + 1;
        sharedCounter = temp;  // write back updated value
        // If a context switch happened, Task2 might have updated sharedCounter in the meantime,
        // causing Task1 to overwrite Task2's increment (lost update).
        // xSemaphoreTake(mutex, portMAX_DELAY);
        // sharedCounter++;               // **Fix:** perform update while holding mutex
        // xSemaphoreGive(mutex);
    }
    printf("Task1 final counter value: %d\n", sharedCounter);
    vTaskDelete(NULL);
}

void incrementTask2(void *pvParameters) {
    for (int i = 0; i < 100; ++i) {
        int temp = sharedCounter;
        vTaskDelay(pdMS_TO_TICKS(1));
        temp = temp - 1;
        sharedCounter = temp;
        // xSemaphoreTake(mutex, portMAX_DELAY);
        // sharedCounter++;
        // xSemaphoreGive(mutex);
    }
    printf("Task2 final counter value: %d\n", sharedCounter);
    vTaskDelete(NULL);
}

void app_main() {
    // Create a mutex (not used in the flawed version of code)
    mutex = xSemaphoreCreateMutex();
    // Create two tasks of equal priority that both increment the shared counter
    xTaskCreate(incrementTask1, "IncTask1", 2048, NULL, 1, NULL);
    xTaskCreate(incrementTask2, "IncTask2", 2048, NULL, 1, NULL);
    // Both tasks will run and then delete themselves after completing 100 increments each.
    vTaskDelay(pdMS_TO_TICKS(500));  // wait for tasks to finish
    printf("Expected final counter value = 200, Actual final counter value = %d\n", sharedCounter);
    // (Due to race condition, actual value will likely be less than 200 because of lost updates)
    vTaskDelete(NULL);
}