/*
   Copyright Docker attest 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 attestation_test

import (
	"context"
	"time"

	"github.com/docker/attest/attestation"
	"github.com/docker/attest/oci"
	"github.com/docker/attest/signerverifier"
	v1 "github.com/google/go-containerregistry/pkg/v1"
	intoto "github.com/in-toto/in-toto-golang/in_toto"
	"github.com/in-toto/in-toto-golang/in_toto/slsa_provenance/common"
)

func ExampleManifest() {
	// configure signerverifier
	// local signer (unsafe for production)
	signer, err := signerverifier.GenKeyPair()
	if err != nil {
		panic(err)
	}
	// example using AWS KMS signer
	// aws_arn := "arn:aws:kms:us-west-2:123456789012:key/12345678-1234-1234-1234-123456789012"
	// aws_region := "us-west-2"
	// signer, err := signerverifier.GetAWSSigner(cmd.Context(), aws_arn, aws_region)

	// configure signing options
	opts := &attestation.SigningOptions{
		TransparencyLog: nil, // set this to log to a transparency log
	}

	ref := "docker/image-signer-verifier:latest"

	digest, err := v1.NewHash("sha256:7ae6b41655929ad8e1848064874a98ac3f68884996c79907f6525e3045f75390")
	if err != nil {
		panic(err)
	}
	desc := &v1.Descriptor{
		Digest:    digest,
		Size:      1234,
		MediaType: "application/vnd.oci.image.manifest.v1+json",
	}

	// the in-toto statement to be signed
	statement := &intoto.Statement{
		StatementHeader: intoto.StatementHeader{
			PredicateType: attestation.VSAPredicateType,
			Subject:       []intoto.Subject{{Name: ref, Digest: common.DigestSet{digest.Algorithm: digest.Hex}}},
			Type:          intoto.StatementInTotoV01,
		},
		Predicate: attestation.VSAPredicate{
			Verifier: attestation.VSAVerifier{
				ID: "test-verifier",
			},
			TimeVerified:       time.Now().UTC().Format(time.RFC3339),
			ResourceURI:        "some-uri",
			Policy:             attestation.VSAPolicy{URI: "some-uri"},
			VerificationResult: "PASSED",
			VerifiedLevels:     []string{"SLSA_BUILD_LEVEL_1"},
		},
	}

	// create a new manifest to hold the attestation
	manifest, err := attestation.NewManifest(desc)
	if err != nil {
		panic(err)
	}

	// sign and add the attestation to the manifest
	err = manifest.Add(context.Background(), signer, statement, opts)
	if err != nil {
		panic(err)
	}

	output, err := oci.ParseImageSpecs("docker/image-signer-verifier-referrers:latest")
	if err != nil {
		panic(err)
	}

	// save the manifest to the registry as a referrers artifact
	artifacts, err := manifest.BuildReferringArtifacts()
	if err != nil {
		panic(err)
	}
	ctx := context.Background()
	err = oci.SaveImagesNoTag(ctx, artifacts, output)
	if err != nil {
		panic(err)
	}
}