package events

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/containerd/containerd"
	eventtypes "github.com/containerd/containerd/api/events"
	"github.com/containerd/containerd/containers"
	ctrevents "github.com/containerd/containerd/events"
	typeurl "github.com/containerd/typeurl/v2"

	criruntime "k8s.io/cri-api/pkg/apis/runtime/v1"

	devicecontainers "edge-infra.dev/pkg/sds/devices/agent/containers"

	"edge-infra.dev/pkg/sds/devices/class"
	"edge-infra.dev/pkg/sds/devices/logger"
)

// ContainerEventConstructor returns a constructor function that instantiates a new device container event for given container event
func ContainerEventConstructor(containers map[string]*containers.Container, ctrClient *containerd.Client, runtimeClient criruntime.RuntimeServiceClient) func(ctx context.Context, ctrEvent *ctrevents.Envelope) (DeviceEvent, error) {
	return func(ctx context.Context, ctrEvent *ctrevents.Envelope) (DeviceEvent, error) {
		event, err := typeurl.UnmarshalAny(ctrEvent.Event)
		if err != nil {
			return nil, fmt.Errorf("error reading container event: %w", err)
		}

		log := logger.FromContext(ctx)
		if createEvent, ok := event.(*eventtypes.ContainerCreate); ok {
			log.Debug("container was created", "containerID", createEvent.ID)
			ctr, err := devicecontainers.FetchContainer(ctx, ctrClient, runtimeClient, createEvent.ID)
			if err != nil {
				log.Error("could not fetch container", "containerID", createEvent.ID, "error", err)
				return nil, nil
			}
			if ctr == nil {
				return nil, nil
			}

			containers[ctr.ID] = ctr
			event, err := NewContainerEvent(ctr)
			if err != nil {
				return nil, fmt.Errorf("error generating container event: %w", err)
			}
			return event, nil
		}

		if deleteEvent, ok := event.(*eventtypes.ContainerDelete); ok {
			log.Debug("container was deleted", "containerID", deleteEvent.ID)
			delete(containers, deleteEvent.ID)
		}
		return nil, nil
	}
}

// NewContainerEvent returns a new device event from created container
func NewContainerEvent(container *containers.Container) (DeviceEvent, error) {
	if container == nil {
		return nil, errors.New("container cannot be nil")
	}
	container.Labels[class.DefaultClass] = requested
	return &containerEvent{
		event: &event{
			containers: map[string]*containers.Container{
				container.ID: container,
			},
			postHookFn: func(context.Context) {},
			timestamp:  time.Now(),
		},
	}, nil
}