#include "mbed.h"       //Include file for all mbed libraries
#include "rtos.h"       //Include the mbed rtos functions
 
osThreadId mainThreadID;        //Declare thread ID for use with signals - main thread
osThreadId thead1_ThreadID;    //Declare thread ID for use with signals - green led thread
osThreadId thread2_ThreadID;   //Declare thread ID for use with signals - orange led thread
osThreadId thread3_ThreadID;      //Declare thread ID for use with signals - red led thread
osThreadId thread4_ThreadID;     //Declare thread ID for use with signals - blue led thread
 
//Define symbols for signal numbers as signals are numbered in 2 to the power off (binary)
#define s1  1        //Use s1 symbol for signal number 1
#define s2  2        //Use s2 symbol for signal number 2
#define s3  4        //Use s3 symbol for signal number 4
#define s4  8        //Use s4 symbol for signal number 8

Mutex print_mutex;      //Mutex to protect printf
 
// thread1
void thread1(void const *args) {    //Define a thread
    thead1_ThreadID = osThreadGetId();     //Read green led thread ID needed for thread termination and creation
    while (true) {                          //Thread always in infinite loop
        print_mutex.lock();                 //Wait for printf mutex to become available
        printf("Thread 1 is running\n\n");  //Write message to indicate the thread is running
        print_mutex.unlock();               //Release printf mutex
        osSignalSet(mainThreadID, s1);      //Send a signal to main thread using thread ID and signal 1             
        Thread::wait(3000);                 //Thread put into wait state for time period in mS
    }
}
 
// thread2
void thread2(void const *args) {   //Define a thread
    thread2_ThreadID = osThreadGetId();     //thread ID needed for thread termination and creation
    while (true) {                          //Thread always in infinite loop
        print_mutex.lock();                 //Wait for printf mutex to become available
        printf("Thread 2 is running\n\n");  //Write message to indicate the thread is running
        print_mutex.unlock();               //Release printf mutex
        osSignalSet(mainThreadID, s2);      //Send a signal to main thread using thread ID and signal 2
        Thread::wait(3000);                 //Thread put into wait state for time period in mS
    }
}
 
// thread3
void thread3(void const *args) {  //Define a thread
    thread3_ThreadID = osThreadGetId();     //thread ID needed for thread termination and creation
    while (true) {                          //Thread always in infinite loop
        print_mutex.lock();                 //Wait for printf mutex to become available
        printf("Thread 3 is running\n\n");  //Write message to indicate the thread is running
        print_mutex.unlock();               //Release printf mutex
        osSignalSet(mainThreadID, s3);      //Send a signal to main thread using thread ID and signal 3
        Thread::wait(3000);                 //Thread put into wait state for time period in mS
    }
}
 
// thread4
void thread4(void const *args) {     //Define a thread
    thread4_ThreadID = osThreadGetId();     //thread ID needed for thread termination and creation
    while (true) {                          //Thread always in infinite loop
        print_mutex.lock();                 //Wait for printf mutex to become available
        printf("Thread 4 is running\n\n");  //Write message to indicate the thread is running
        print_mutex.unlock();               //Release printf mutex
        osSignalSet(mainThreadID, s4);      //Send a signal to main thread using thread ID and signal 4
        osDelay(3000);                      //Thread put into wait state for time period in mS
    }
}
 
int main() {                             //Main function is also a thread - NB
 
    mainThreadID = osThreadGetId();      //Thread must have its thread ID to identify the signal sent to it
   
    Thread thread_1(thread1, NULL, osPriorityNormal, 2048);  //Create and start thread with normal priority and stated stack size.
    Thread thread_2(thread2);     //Create and start thread with default normal priority and default stack size - 2k
    Thread thread_3(thread3);           //Create and start the red led thread
    Thread thread_4(thread4);         //Create and start the blue led thread
   
    while (true) {                      //Infinite loop
 
    osEvent evt;                //Create variable to store the event status
    evt =  osSignalWait(0, 0);  //Check if any signal have been received without any wait period - see RTOS handbook!
 
    //Use a switch/case to evaluate the thread signals stored in variable evt.value.signals
    //Example - if its contents is 7 (binary 111) means that signals 1, 2 and 3 is set
    switch(evt.value.signals) {      //The current status of all the signals sent to this thread is stored in this variable
        case 1 :    //Only signal 1 is set
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signal 1 received other 3 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 2 :    //Only signal 2 is set
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signal 2 received other 3 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 3 :    //Signals 1 and 2 is set
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 2 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 4 :    //Only signal 3 is set
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signal 3 received other 3 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 5 :    //Signal 1 and 3 is set
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 3 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 6 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 2 + 3 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 7 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
            printf("Signals 1 + 2 + 3 received other 1 is off\n\n" );
            print_mutex.unlock(); }               //Release printf mutex
        break;
        case 8 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signal 4 received other 3 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 9 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 4 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 10:
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 2 + 4 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 11 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 2 + 4 received other 1 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 12 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 3 + 4 received other 2 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 13 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 3 +4 received other 1 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 14 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 2 + 3 + 4 received other 1 is off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
        case 15 :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("Signals 1 + 2 + 3 + 4 received\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
    default :
            {print_mutex.lock();                 //Wait for printf mutex to become available
             printf("All signals are off\n\n" );
             print_mutex.unlock(); }               //Release printf mutex
        break;
    }
       Thread::wait(1000);
  }
}