package main

import "core:fmt"
import "core:thread"
import "core:time"
import "core:sync"

myMutex :sync.Mutex

arr := []int{1,2,3}

main :: proc(){
  // creating a dynamic array of len of array which stores pointer to a thread
  threadPool := make([dynamic]^thread.Thread, 0, len(arr))
  defer delete(threadPool)
  
  for i in 0..<len(arr){
    thr := thread.create(worker) // creating a thread
    if thr != nil{
      // setting up context for our thread
      thr.init_context = context
      // giving our thread id
      thr.user_index = i 
      // Adding our thread to thread pool
      append(&threadPool, thr) 
      
      thread.start(thr) // running our thread
    }
  }
  
  // looping till all of our threads have done their work
  // i.e till our threadPool is empty
  // our threadPool becomes empty because after each 
  for len(threadPool) > 0{
    for i := 0; i < len(threadPool); {
      // Getting a threads address at index i
      t := threadPool[i]
      if thread.is_done(t){
        fmt.printf("Thread %d is done\n\n", arr[t.user_index])
        thread.destroy(t)
        // removing address of destroyed thread from out pool
        ordered_remove(&threadPool, i)
      }else{
        // If current thread process is not done then go to next one
        i += 1 
      }
    }
  }
}

/*
worker :: proc(t: ^thread.Thread){
  // with the help of context we get what thread we are using.
  fmt.printf("work of t%d\n", arr[t.user_index])
}
*/

worker :: proc(t: ^thread.Thread){
  /*
  when we come to this line
  it will check if myMutex is available or not
  if it isn't then it will wait for it
  and once its available then it will pass and run below code
  */
  //sync.lock(myMutex) // locking before we do our opeartion
  sync.mutex_lock(&myMutex) // locking before we do our opeartion
  
  fmt.printf("work of t%d started\n", arr[t.user_index])
  time.sleep(time.Second)
  fmt.printf("work of t%d completed\n", arr[t.user_index])
  //fmt.println()
  
  //sync.unlock(myMutex) // unlocking for other threads to use it
  sync.mutex_unlock(&myMutex) // unlocking for other threads to use it
}


/*

odin run thr3.odin -file
work of t1 started
work of t1 completed
Thread 1 is done

work of t2 started
work of t2 completed
Thread 2 is done

work of t3 started
work of t3 completed
Thread 3 is done


odin run thr3.odin -file
work of t2 started
work of t2 completed
Thread 2 is done

work of t1 started
work of t1 completed
Thread 1 is done

work of t3 started
work of t3 completed
Thread 3 is done

*/