package exec

import (
	"context"
	"io"
	"os/exec"
	"syscall"
	"time"
)

const (
	DefaultRunCmdTimeout = time.Second * 3
)

// RunCmd executes the given command and arguments and stdin and ensures the
// command takes no longer than the timeout before the command is terminated.
func RunCmd(timeout time.Duration, env []string, command string, stdin io.Reader, args ...string) (string, error) {
	var (
		ctx    context.Context
		cancel context.CancelFunc
	)

	if timeout > 0 {
		ctx, cancel = context.WithTimeout(context.Background(), timeout)
	} else {
		ctx, cancel = context.WithCancel(context.Background())
	}
	defer cancel()

	cmd := exec.CommandContext(ctx, command, args...)
	cmd.Env = append(cmd.Env, env...)
	cmd.Stdin = stdin

	out, err := cmd.CombinedOutput()
	if err != nil {
		if exitError, ok := err.(*exec.ExitError); ok {
			if ws, ok := exitError.Sys().(syscall.WaitStatus); ok && ws.Signal() == syscall.SIGKILL {
				err = &ErrCommandKilled{Err: err, Signal: ws.Signal()}
			} else {
				err = &ErrCommandFailed{Err: err, Status: exitError.ExitCode()}
			}
		}

		return string(out), err
	}

	return string(out), nil
}