// Copyright 2020 Google LLC
//
// 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 prf_test

import (
	"bytes"
	"testing"

	"github.com/google/tink/go/keyset"
	"github.com/google/tink/go/prf"
	tinkpb "github.com/google/tink/go/proto/tink_go_proto"
)

func TestKeyTemplates(t *testing.T) {
	var testCases = []struct {
		name     string
		template *tinkpb.KeyTemplate
	}{
		{name: "HMAC_SHA256_PRF",
			template: prf.HMACSHA256PRFKeyTemplate()},
		{name: "HMAC_SHA512_PRF",
			template: prf.HMACSHA512PRFKeyTemplate()},
		{name: "HKDF_SHA256",
			template: prf.HKDFSHA256PRFKeyTemplate()},
		{name: "AES_CMAC_PRF",
			template: prf.AESCMACPRFKeyTemplate()},
	}
	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			handle, err := keyset.NewHandle(tc.template)
			if err != nil {
				t.Errorf("keyset.NewHandle(tc.template) failed: %s", err)
			}
			prfset, err := prf.NewPRFSet(handle)
			if err != nil {
				t.Errorf("prf.NewPRFSet(handle) failed: %s", err)
			}

			var testInputs = []struct {
				message1 []byte
				message2 []byte
			}{
				{
					message1: []byte("this data needs to be authenticated"),
					message2: []byte("this data needs to be authenticated"),
				}, {
					message1: []byte(""),
					message2: []byte(""),
				}, {
					message1: []byte(""),
					message2: nil,
				}, {
					message1: nil,
					message2: []byte(""),
				}, {
					message1: nil,
					message2: nil,
				},
			}
			for _, ti := range testInputs {
				output, err := prfset.ComputePrimaryPRF(ti.message1, 16)
				if err != nil {
					t.Errorf("prfset.ComputePrimaryPRF(ti.message1, 16) failed: %s", err)
				}
				if len(output) != 16 {
					t.Errorf("len(output) = %d, want 16", len(output))
				}
				output2, err := prfset.ComputePrimaryPRF(ti.message2, 16)
				if err != nil {
					t.Errorf("prfset.ComputePrimaryPRF(ti.message2, 16) failed: %s", err)
				}
				if !bytes.Equal(output2, output) {
					t.Errorf("equivalent inputs did not produce equivalent outputs, got: %q, want: %q", output2, output)
				}
			}
		})
	}
}