// Copyright 2018 Google LLC All Rights Reserved.
//
// 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 random

import (
	"math/rand"
	"testing"

	v1 "github.com/google/go-containerregistry/pkg/v1"
	"github.com/google/go-containerregistry/pkg/v1/types"
	"github.com/google/go-containerregistry/pkg/v1/validate"
)

func TestRandomIndex(t *testing.T) {
	ii, err := Index(1024, 5, 3)
	if err != nil {
		t.Fatalf("Error loading index: %v", err)
	}

	if err := validate.Index(ii); err != nil {
		t.Errorf("validate.Index() = %v", err)
	}

	digest, err := ii.Digest()
	if err != nil {
		t.Fatalf("Digest(): unexpected err: %v", err)
	}

	if _, err := ii.Image(digest); err == nil {
		t.Errorf("Image(%s): expected err, got nil", digest)
	}

	if _, err := ii.ImageIndex(digest); err == nil {
		t.Errorf("ImageIndex(%s): expected err, got nil", digest)
	}

	mt, err := ii.MediaType()
	if err != nil {
		t.Errorf("MediaType(): unexpected err: %v", err)
	}

	if got, want := mt, types.OCIImageIndex; got != want {
		t.Errorf("MediaType(): got: %v, want: %v", got, want)
	}

	man, err := ii.IndexManifest()
	if err != nil {
		t.Errorf("IndexManifest(): unexpected err: %v", err)
	}

	if got, want := man.MediaType, types.OCIImageIndex; got != want {
		t.Errorf("MediaType: got: %v, want: %v", got, want)
	}
}

func TestRandomIndexSource(t *testing.T) {
	indexDigest := func(o ...Option) v1.Hash {
		img, err := Index(1024, 2, 2, o...)
		if err != nil {
			t.Fatalf("Image: %v", err)
		}

		h, err := img.Digest()
		if err != nil {
			t.Fatalf("Digest(): %v", err)
		}
		return h
	}

	digest0a := indexDigest(WithSource(rand.NewSource(0)))
	digest0b := indexDigest(WithSource(rand.NewSource(0)))
	digest1 := indexDigest(WithSource(rand.NewSource(1)))

	if digest0a != digest0b {
		t.Error("Expected the index digest to be the same with the same seed")
	}

	if digest0a == digest1 {
		t.Error("Expected the index digest to be different with different seeds")
	}

	digestA := indexDigest()
	digestB := indexDigest()

	if digestA == digestB {
		t.Error("Expected the index digest to be different with different random seeds")
	}
}