package main
import (
	"bufio"
	"fmt"
	"log"
	"os"
	"sync"
)
// Consumer task to operate on queue
func consumer_task(task_num int) {
	
	fmt.Printf("I'm consumer task #%v ", task_num)
	fmt.Println("Line being popped off queue: " + queue[0])
	queue = queue[1:]
}
// Initialize queue
var queue = make([]string, 0)
func main() {
	// Initialize wait group 
	var wg sync.WaitGroup
	// Get number of tasks to run from user
	var numof_tasks int
	fmt.Print("Enter number of tasks to run: ")
	fmt.Scan(&numof_tasks)
	
	// Open file
	file, err := os.Open("test.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()
	// Scanner to scan the file
	scanner := bufio.NewScanner(file)
	if err := scanner.Err(); err != nil {
        log.Fatal(err)
    }
	// Loop through each line in the file and append it to the queue
	for scanner.Scan() {
        line := scanner.Text()  
		queue = append(queue, line)
    }
	// Start specified # of consumer tasks
	for i := 1; i <= numof_tasks; i++ {
		wg.Add(1)
		go func(i int) { 
			consumer_task(i) 
			wg.Done()
		}(i)
	}
	wg.Wait()
	fmt.Println("All done")
	fmt.Println(queue)
}

func consumer_task(task_num int, ch <-chan string) {
	fmt.Printf("I'm consumer task #%v\n", task_num)
	for item := range ch {
		fmt.Printf("task %d consuming: Line item: %v\n", task_num, item)
	}
    // each worker will drop out of their loop when channel is closed
}

queue := make(chan string)
go func() {
	// Loop through each line in the file and append it to the queue
	for scanner.Scan() {
		queue <- scanner.Text()
	}
	close(queue) // signal to workers that there is no more items
}()

go func(i int) {
    consumer_task(i, queue) // add the queue parameter
	wg.Done()
}(i)