import kotlinx.coroutines.*

// this will execute on background thread
suspend fun getDataFromDatabase() : Array<Int> = withContext(Dispatchers.IO) {
    delay(1000)
    println("Thread name inside context: ${Thread.currentThread().name}")
    Array(10) { i -> i }
}

fun main(args : Array<String>) = runBlocking {

    // CoroutineScope is like a handle that you can use to control your coroutines
    // As far as I understand, related coroutines should be launched from the same scope.
    // If one of them fails, all other will be canceled (unless you're using supervisorscope)

    val coroutineScope = this

    // On android you would use Dispatchers.Main for android UI thread
    // val coroutineScope = CoroutineScope(Dispatchers.Main)

    var jobNames = arrayOf<Int>()

    // will launch on main thread
    val job = coroutineScope.launch {

        jobNames = getDataFromDatabase()

        // this will be scheduled to execute on the main thread (meaning it can make changes on the UI)
        println(jobNames.joinToString(prefix = "[", postfix = "]"))

        println("Thread name inside coroutine: ${Thread.currentThread().name}")
    }

    // count will be zero
    var count = jobNames.size

    // Will not execute
    for (i in 1..count) {
        println("count inside loop: $count")
    }

    // count will still be zero
    println("count outside loop: $count")

    job.join()

    count = jobNames.size;
    println("Count again: $count")
    println("Thread name on main function: ${Thread.currentThread().name}")
}