package utils

import (
	"bufio"
	"fmt"
	"os"
	"os/exec"
	"os/signal"
	"sync"
	"syscall"
	"time"

	log "github.com/sirupsen/logrus"
)

// CommandWithStdout create a command forwarding stdout and stderr to the OS streams
func CommandWithStdout(name string, args ...string) *exec.Cmd {
	cmd := exec.Command(name, args...)
	if log.GetLevel() > log.InfoLevel {
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
	}
	return cmd
}

// Shell create a shell command
func Shell(command string) *exec.Cmd {
	return CommandWithStdout("bash", "-c", command)
}

// RunCommandUntilCtrlC run a command until ctrl-c is hit
func RunCommandUntilCtrlC(cmd *exec.Cmd) {
	mutex := sync.Mutex{}
	cond := sync.NewCond(&mutex)
	signalChannel := make(chan os.Signal)
	signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM)

	mutex.Lock()

	go func() {
		mutex.Lock()
		f := bufio.NewWriter(os.Stdout)
		defer f.Flush()

		fmt.Println("Hit Ctrl+C to shutdown...")

		err := cmd.Run()

		if err != nil {
			fmt.Println(err)
			cond.Broadcast()
			mutex.Unlock()
			return
		}

		<-signalChannel
		cond.Broadcast()
		mutex.Unlock()
	}()

	cond.Wait()
}

// RunFuncUntilCtrlC run a function until ctrl-c is hit
func RunFuncUntilCtrlC(fn func() error) error {
	mutex := sync.Mutex{}
	cond := sync.NewCond(&mutex)
	errorChannel := make(chan error)
	signalChannel := make(chan os.Signal)
	signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM)

	mutex.Lock()

	go func() {
		mutex.Lock()
		f := bufio.NewWriter(os.Stdout)
		defer f.Flush()

		fmt.Println("Hit Ctrl+C to shutdown...")

		err := fn()

		if err != nil {
			errorChannel <- err
			fmt.Println(err)
			cond.Broadcast()
			mutex.Unlock()
			return
		}

		errorChannel <- nil
		<-signalChannel
		cond.Broadcast()
		mutex.Unlock()
	}()

	cond.Wait()
	return <-errorChannel
}

// RunCommandWithTimeout run a command with timeout.
func RunCommandWithTimeout(cmd *exec.Cmd, timeout time.Duration) error {
	// Start a process:
	if err := cmd.Start(); err != nil {
		log.Fatal(err)
	}

	// Wait for the process to finish or kill it after a timeout (whichever happens first):
	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()

	select {
	case <-time.After(timeout):
		fmt.Printf("Timeout of %ds reached... Killing process...\n", int64(timeout/time.Second))

		if err := cmd.Process.Kill(); err != nil {
			return err
		}
		return fmt.Errorf("timeout of %ds reached", int64(timeout/time.Second))
	case err := <-done:
		return err
	}
}