package main

import (
    "fmt"
    "os"
    "os/signal"
    "strconv"
    "syscall"
    "time"
)

func main() {
    sigs := make(chan os.Signal)
    done := make(chan bool, 1)
    prios := []int{}

    signal.Notify(sigs, os.Interrupt, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGTSTP)

    go handle(sigs, &prios)
    go exec(&prios)

    brojac := 0
    go func() {
        for true {
            if len(prios) == 0 {
                fmt.Println("Glavni program: " + strconv.Itoa(brojac) + "/30")
                brojac += 1
                if brojac == 30 {
                    done <- true
                }
                time.Sleep(time.Second)
            }
        }
    }()

    <-done
}

func handle(sigs chan os.Signal, prios *[]int) {
    sig := <-sigs
    if sig == syscall.SIGINT {
        fmt.Println("signal SIGINT")
        if arrFind(prios, 1) == -1 {
            *prios = append(*prios, 1)
        }
    } else if sig == syscall.SIGQUIT {
        fmt.Println("signal SIGQUIT")
        if arrFind(prios, 2) == -1 {
            *prios = append(*prios, 2)
        }
    } else if sig == syscall.SIGTSTP {
        fmt.Println("signal SIGTSTP")
        if arrFind(prios, 3) == -1 {
            *prios = append(*prios, 3)
        }
    }

    handle(sigs, prios)
}

func exec(prios *[]int) {
    brojac := [4]int{0, 0, 0, 0}
    for true {
        for brojac[3] != 30 && arrHighest(prios, 3) {
            fmt.Println("izvrsavam prioritet 3 " + strconv.Itoa(brojac[3]) + "/30")
            brojac[3] += 1
            time.Sleep(time.Second)
        }
        if brojac[3] == 30 {
            arrDeleteVal(prios, 3)
            brojac[3] = 0
        }
        for brojac[2] != 30 && arrHighest(prios, 2) {
            fmt.Println("izvrsavam prioritet 2 " + strconv.Itoa(brojac[2]) + "/30")
            brojac[2] += 1
            time.Sleep(time.Second)
        }
        if brojac[2] == 30 {
            arrDeleteVal(prios, 2)
            brojac[2] = 0
        }
        for brojac[1] != 30 && arrHighest(prios, 1) {
            fmt.Println("izvrsavam prioritet 1 " + strconv.Itoa(brojac[1]) + "/30")
            brojac[1] += 1
            time.Sleep(time.Second)
        }
        if brojac[1] == 30 {
            arrDeleteVal(prios, 1)
            brojac[1] = 0
        }
    }
}

func arrFind(arr *[]int, find int) int {
    ret := -1
    for i, val := range *arr {
        if val == find {
            ret = i
            break
        }
    }
    return ret
}

func arrHighest(arr *[]int, find int) bool {
    max := 0
    for _, val := range *arr {
        if val > max {
            max = val
        }
    }
    return find == max
}

func arrDeleteVal(arr *[]int, val int) {
    idx := arrFind(arr, val)
    (*arr)[idx] = (*arr)[len(*arr)-1]
    (*arr)[len(*arr)-1] = 0
    (*arr) = (*arr)[:len(*arr)-1]
}