/*
   Copyright The containerd Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package local

import (
	"context"
	"encoding/json"

	"github.com/containerd/containerd/content"
	"github.com/containerd/containerd/errdefs"
	"github.com/containerd/containerd/images"
	"github.com/containerd/containerd/pkg/transfer"
	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)

func (ts *localTransferService) importStream(ctx context.Context, i transfer.ImageImporter, is transfer.ImageStorer, tops *transfer.Config) error {
	ctx, done, err := ts.withLease(ctx)
	if err != nil {
		return err
	}
	defer done(ctx)

	if tops.Progress != nil {
		tops.Progress(transfer.Progress{
			Event: "Importing",
		})
	}

	index, err := i.Import(ctx, ts.content)
	if err != nil {
		return err
	}

	var descriptors []ocispec.Descriptor

	// If save index, add index
	descriptors = append(descriptors, index)

	var handler images.HandlerFunc = func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
		// Only save images at top level
		if desc.Digest != index.Digest {
			return images.Children(ctx, ts.content, desc)
		}

		p, err := content.ReadBlob(ctx, ts.content, desc)
		if err != nil {
			return nil, err
		}

		var idx ocispec.Index
		if err := json.Unmarshal(p, &idx); err != nil {
			return nil, err
		}

		for _, m := range idx.Manifests {
			m1 := m
			m1.Annotations = mergeMap(m.Annotations, map[string]string{"io.containerd.import.ref-type": "name"})
			descriptors = append(descriptors, m1)

			// If add digest references, add twice
			m2 := m
			m2.Annotations = mergeMap(m.Annotations, map[string]string{"io.containerd.import.ref-type": "digest"})
			descriptors = append(descriptors, m2)
		}

		return idx.Manifests, nil
	}

	if f, ok := is.(transfer.ImageFilterer); ok {
		handler = f.ImageFilter(handler, ts.content)
	}

	if err := images.WalkNotEmpty(ctx, handler, index); err != nil {
		return err
	}

	for _, desc := range descriptors {
		img, err := is.Store(ctx, desc, ts.images)
		if err != nil {
			if errdefs.IsNotFound(err) {
				continue
			}
			return err
		}

		if tops.Progress != nil {
			tops.Progress(transfer.Progress{
				Event: "saved",
				Name:  img.Name,
			})
		}
	}

	if tops.Progress != nil {
		tops.Progress(transfer.Progress{
			Event: "Completed import",
		})
	}

	return nil
}

func mergeMap(m1, m2 map[string]string) map[string]string {
	merged := make(map[string]string, len(m1)+len(m2))
	for k, v := range m1 {
		merged[k] = v
	}
	for k, v := range m2 {
		merged[k] = v
	}
	return merged
}