/*
   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 proxy

import (
	"context"
	"errors"
	"io"

	"google.golang.org/protobuf/types/known/anypb"

	transferapi "github.com/containerd/containerd/api/services/transfer/v1"
	transfertypes "github.com/containerd/containerd/api/types/transfer"
	"github.com/containerd/containerd/log"
	"github.com/containerd/containerd/pkg/streaming"
	"github.com/containerd/containerd/pkg/transfer"
	tstreaming "github.com/containerd/containerd/pkg/transfer/streaming"
	"github.com/containerd/typeurl/v2"
)

type proxyTransferrer struct {
	client        transferapi.TransferClient
	streamCreator streaming.StreamCreator
}

// NewTransferrer returns a new transferrer which communicates over a GRPC
// connection using the containerd transfer API
func NewTransferrer(client transferapi.TransferClient, sc streaming.StreamCreator) transfer.Transferrer {
	return &proxyTransferrer{
		client:        client,
		streamCreator: sc,
	}
}

func (p *proxyTransferrer) Transfer(ctx context.Context, src interface{}, dst interface{}, opts ...transfer.Opt) error {
	o := &transfer.Config{}
	for _, opt := range opts {
		opt(o)
	}
	apiOpts := &transferapi.TransferOptions{}
	if o.Progress != nil {
		sid := tstreaming.GenerateID("progress")
		stream, err := p.streamCreator.Create(ctx, sid)
		if err != nil {
			return err
		}
		apiOpts.ProgressStream = sid
		go func() {
			for {
				a, err := stream.Recv()
				if err != nil {
					if !errors.Is(err, io.EOF) {
						log.G(ctx).WithError(err).Error("progress stream failed to recv")
					}
					return
				}
				i, err := typeurl.UnmarshalAny(a)
				if err != nil {
					log.G(ctx).WithError(err).Warnf("failed to unmarshal progress object: %v", a.GetTypeUrl())
				}
				switch v := i.(type) {
				case *transfertypes.Progress:
					o.Progress(transfer.Progress{
						Event:    v.Event,
						Name:     v.Name,
						Parents:  v.Parents,
						Progress: v.Progress,
						Total:    v.Total,
					})
				default:
					log.G(ctx).Warnf("unhandled progress object %T: %v", i, a.GetTypeUrl())
				}
			}
		}()
	}
	asrc, err := p.marshalAny(ctx, src)
	if err != nil {
		return err
	}
	adst, err := p.marshalAny(ctx, dst)
	if err != nil {
		return err
	}
	req := &transferapi.TransferRequest{
		Source: &anypb.Any{
			TypeUrl: asrc.GetTypeUrl(),
			Value:   asrc.GetValue(),
		},
		Destination: &anypb.Any{
			TypeUrl: adst.GetTypeUrl(),
			Value:   adst.GetValue(),
		},
		Options: apiOpts,
	}
	_, err = p.client.Transfer(ctx, req)
	return err
}
func (p *proxyTransferrer) marshalAny(ctx context.Context, i interface{}) (typeurl.Any, error) {
	switch m := i.(type) {
	case streamMarshaler:
		return m.MarshalAny(ctx, p.streamCreator)
	}
	return typeurl.MarshalAny(i)
}

type streamMarshaler interface {
	MarshalAny(context.Context, streaming.StreamCreator) (typeurl.Any, error)
}