package plugin

import (
	"github.com/containerd/containerd/diff"
	"github.com/containerd/containerd/diff/apply"
	"github.com/containerd/containerd/diff/walking"
	"github.com/containerd/containerd/metadata"
	"github.com/containerd/containerd/platforms"
	"github.com/containerd/containerd/plugin"
)

func init() {
	plugin.Register(&plugin.Registration{
		Type: plugin.DiffPlugin,
		ID:   "walking",
		Requires: []plugin.Type{
			plugin.MetadataPlugin,
		},
		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
			md, err := ic.Get(plugin.MetadataPlugin)
			if err != nil {
				return nil, err
			}

			ic.Meta.Platforms = append(ic.Meta.Platforms, platforms.DefaultSpec())
			cs := md.(*metadata.DB).ContentStore()

			return diffPlugin{
				Comparer: walking.NewWalkingDiff(cs),
				Applier:  apply.NewFileSystemApplier(cs),
			}, nil
		},
	})
}

type diffPlugin struct {
	diff.Comparer
	diff.Applier
}