package main

import (
	"context"
	"path/filepath"
	"strings"
	"syscall"
	"time"

	"github.com/containerd/containerd"
	"github.com/containerd/containerd/cio"
	"github.com/containerd/containerd/oci"
	specs "github.com/opencontainers/runtime-spec/specs-go"
	"github.com/sirupsen/logrus"
)

type execWorker struct {
	worker
}

func (w *execWorker) exec(ctx, tctx context.Context) {
	defer func() {
		w.wg.Done()
		logrus.Infof("worker %d finished", w.id)
	}()
	// create and start the exec container
	w.spec.Linux.CgroupsPath = filepath.Join("/", "stress", "exec-container")
	w.spec.Process.Args = []string{
		"sleep", "30d",
	}
	c, err := w.client.NewContainer(ctx, "exec-container",
		containerd.WithNewSnapshot("exec-container", w.image),
		containerd.WithSpec(w.spec, oci.WithUsername("games")),
	)
	if err != nil {
		logrus.WithError(err).Error("create exec container")
		return
	}
	defer c.Delete(ctx, containerd.WithSnapshotCleanup)

	task, err := c.NewTask(ctx, cio.NullIO)
	if err != nil {
		logrus.WithError(err).Error("create exec container's task")
		return
	}
	defer task.Delete(ctx, containerd.WithProcessKill)

	statusC, err := task.Wait(ctx)
	if err != nil {
		logrus.WithError(err).Error("wait exec container's task")
		return
	}

	pspec := w.spec.Process
	pspec.Args = []string{"true"}

	for {
		select {
		case <-tctx.Done():
			if err := task.Kill(ctx, syscall.SIGKILL); err != nil {
				logrus.WithError(err).Error("kill exec container's task")
			}
			<-statusC
			return
		default:
		}

		w.count++
		id := w.getID()
		logrus.Debugf("starting exec %s", id)
		start := time.Now()

		if err := w.runExec(ctx, task, id, pspec); err != nil {
			if err != context.DeadlineExceeded ||
				!strings.Contains(err.Error(), context.DeadlineExceeded.Error()) {
				w.failures++
				logrus.WithError(err).Errorf("running exec %s", id)
				errCounter.WithValues(err.Error()).Inc()
			}
			continue
		}
		// only log times are success so we don't scew the results from failures that go really fast
		execTimer.WithValues(w.commit).UpdateSince(start)
	}
}

func (w *execWorker) runExec(ctx context.Context, task containerd.Task, id string, spec *specs.Process) (err error) {
	process, err := task.Exec(ctx, id, spec, cio.NullIO)
	if err != nil {
		return err
	}
	defer func() {
		if _, derr := process.Delete(ctx, containerd.WithProcessKill); err == nil {
			err = derr
		}
	}()
	statusC, err := process.Wait(ctx)
	if err != nil {
		return err
	}
	if err := process.Start(ctx); err != nil {
		return err
	}
	status := <-statusC
	_, _, err = status.Result()
	if err != nil {
		if err == context.DeadlineExceeded || err == context.Canceled {
			return nil
		}
		w.failures++
		errCounter.WithValues(err.Error()).Inc()
	}
	return nil
}