package agent

import (
	"context"
	"os"
	"time"

	"github.com/containerd/containerd/containers"

	"edge-infra.dev/pkg/lib/uuid"
	cc "edge-infra.dev/pkg/sds/devices/agent/common"
	"edge-infra.dev/pkg/sds/devices/agent/metrics"
	dsv1 "edge-infra.dev/pkg/sds/devices/k8s/apis/v1"
	"edge-infra.dev/pkg/sds/devices/logger"
)

type deviceConfigJob interface {
	Run(ctx context.Context)
}

type job struct {
	allDeviceClasses map[string]*dsv1.DeviceClass
	containers       map[string]*containers.Container
	postHookFns      []func(context.Context)
}

func newJob(containers map[string]*containers.Container, postHookFns []func(context.Context), allDeviceClasses map[string]*dsv1.DeviceClass) deviceConfigJob {
	return &job{
		allDeviceClasses: allDeviceClasses,
		containers:       containers,
		postHookFns:      postHookFns,
	}
}

func (j job) Run(ctx context.Context) {
	j.applyDeviceConfigurationUpdate(ctx)
}

// applyDeviceConfigurationUpdate will apply cgroups to the containers and runs posthook events
func (j job) applyDeviceConfigurationUpdate(ctx context.Context) {
	requestID := uuid.New().UUID
	log := logger.FromContext(ctx).With("requestId", requestID)
	ctx = logger.IntoContext(ctx, log)
	changedContainerNames := []string{}

	configUpdate := func(ctx context.Context) {
		log.Debug("device request started")

		for _, ctr := range j.containers {
			ctrName := ctr.Labels[cc.AnnContainerName]
			changedContainerNames = append(changedContainerNames, ctrName)
			ApplyCgroupsToContainer(ctx, requestID, ctr, j.allDeviceClasses)
		}

		for _, postHookFn := range j.postHookFns {
			postHookFn(ctx)
		}
		log.Debug("device request finished", "containers", changedContainerNames)
	}

	duration := timeConfigUpdate(ctx, configUpdate)
	if len(changedContainerNames) != 0 {
		log.Info("applied device update to containers", "updated containers", changedContainerNames, "time", duration)
	}
}

// timeConfigUpdate will time how long it takes to process the container configuration update
func timeConfigUpdate(ctx context.Context, fn func(ctx context.Context)) string {
	startTime := time.Now()
	fn(ctx)
	endTime := time.Now()
	diff := endTime.Sub(startTime)
	metrics.RecordDuration(nodeName(), diff.Seconds())
	return diff.String()
}

func nodeName() string {
	return os.Getenv("HOSTNAME")
}