/*
 *
 * Copyright 2020 gRPC 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 keys

import (
	"fmt"
	"strings"
	"testing"

	"github.com/google/go-cmp/cmp"
	rlspb "google.golang.org/grpc/balancer/rls/internal/proto/grpc_lookup_v1"
	"google.golang.org/grpc/metadata"
)

var (
	goodKeyBuilder1 = &rlspb.GrpcKeyBuilder{
		Names: []*rlspb.GrpcKeyBuilder_Name{
			{Service: "gFoo"},
		},
		Headers: []*rlspb.NameMatcher{
			{Key: "k1", Names: []string{"n1"}},
			{Key: "k2", Names: []string{"n1"}},
		},
	}
	goodKeyBuilder2 = &rlspb.GrpcKeyBuilder{
		Names: []*rlspb.GrpcKeyBuilder_Name{
			{Service: "gBar", Method: "method1"},
			{Service: "gFoobar"},
		},
		Headers: []*rlspb.NameMatcher{
			{Key: "k1", Names: []string{"n1", "n2"}},
		},
	}
)

func TestMakeBuilderMap(t *testing.T) {
	wantBuilderMap1 := map[string]builder{
		"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}, {key: "k2", names: []string{"n1"}}}},
	}
	wantBuilderMap2 := map[string]builder{
		"/gFoo/":        {matchers: []matcher{{key: "k1", names: []string{"n1"}}, {key: "k2", names: []string{"n1"}}}},
		"/gBar/method1": {matchers: []matcher{{key: "k1", names: []string{"n1", "n2"}}}},
		"/gFoobar/":     {matchers: []matcher{{key: "k1", names: []string{"n1", "n2"}}}},
	}

	tests := []struct {
		desc           string
		cfg            *rlspb.RouteLookupConfig
		wantBuilderMap BuilderMap
	}{
		{
			desc: "One good GrpcKeyBuilder",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{goodKeyBuilder1},
			},
			wantBuilderMap: wantBuilderMap1,
		},
		{
			desc: "Two good GrpcKeyBuilders",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{goodKeyBuilder1, goodKeyBuilder2},
			},
			wantBuilderMap: wantBuilderMap2,
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			builderMap, err := MakeBuilderMap(test.cfg)
			if err != nil || !builderMap.Equal(test.wantBuilderMap) {
				t.Errorf("MakeBuilderMap(%+v) returned {%v, %v}, want: {%v, nil}", test.cfg, builderMap, err, test.wantBuilderMap)
			}
		})
	}
}

func TestMakeBuilderMapErrors(t *testing.T) {
	emptyServiceKeyBuilder := &rlspb.GrpcKeyBuilder{
		Names: []*rlspb.GrpcKeyBuilder_Name{
			{Service: "bFoo", Method: "method1"},
			{Service: "bBar"},
			{Method: "method1"},
		},
		Headers: []*rlspb.NameMatcher{{Key: "k1", Names: []string{"n1", "n2"}}},
	}
	requiredMatchKeyBuilder := &rlspb.GrpcKeyBuilder{
		Names:   []*rlspb.GrpcKeyBuilder_Name{{Service: "bFoo", Method: "method1"}},
		Headers: []*rlspb.NameMatcher{{Key: "k1", Names: []string{"n1", "n2"}, RequiredMatch: true}},
	}
	repeatedHeadersKeyBuilder := &rlspb.GrpcKeyBuilder{
		Names: []*rlspb.GrpcKeyBuilder_Name{
			{Service: "gBar", Method: "method1"},
			{Service: "gFoobar"},
		},
		Headers: []*rlspb.NameMatcher{
			{Key: "k1", Names: []string{"n1", "n2"}},
			{Key: "k1", Names: []string{"n1", "n2"}},
		},
	}
	methodNameWithSlashKeyBuilder := &rlspb.GrpcKeyBuilder{
		Names:   []*rlspb.GrpcKeyBuilder_Name{{Service: "gBar", Method: "method1/foo"}},
		Headers: []*rlspb.NameMatcher{{Key: "k1", Names: []string{"n1", "n2"}}},
	}

	tests := []struct {
		desc          string
		cfg           *rlspb.RouteLookupConfig
		wantErrPrefix string
	}{
		{
			desc:          "No GrpcKeyBuilder",
			cfg:           &rlspb.RouteLookupConfig{},
			wantErrPrefix: "rls: RouteLookupConfig does not contain any GrpcKeyBuilder",
		},
		{
			desc: "Two GrpcKeyBuilders with same Name",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{goodKeyBuilder1, goodKeyBuilder1},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig contains repeated Name field",
		},
		{
			desc: "GrpcKeyBuilder with empty Service field",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{emptyServiceKeyBuilder, goodKeyBuilder1},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig contains a Name field with no Service",
		},
		{
			desc: "GrpcKeyBuilder with no Name",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{{}, goodKeyBuilder1},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig does not contain any Name",
		},
		{
			desc: "GrpcKeyBuilder with requiredMatch field set",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{requiredMatchKeyBuilder, goodKeyBuilder1},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig has required_match field set",
		},
		{
			desc: "GrpcKeyBuilder two headers with same key",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{repeatedHeadersKeyBuilder, goodKeyBuilder1},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig contains repeated Key field in headers",
		},
		{
			desc: "GrpcKeyBuilder with slash in method name",
			cfg: &rlspb.RouteLookupConfig{
				GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{methodNameWithSlashKeyBuilder},
			},
			wantErrPrefix: "rls: GrpcKeyBuilder in RouteLookupConfig contains a method with a slash",
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			builderMap, err := MakeBuilderMap(test.cfg)
			if builderMap != nil || !strings.HasPrefix(fmt.Sprint(err), test.wantErrPrefix) {
				t.Errorf("MakeBuilderMap(%+v) returned {%v, %v}, want: {nil, %v}", test.cfg, builderMap, err, test.wantErrPrefix)
			}
		})
	}
}

func TestRLSKey(t *testing.T) {
	bm, err := MakeBuilderMap(&rlspb.RouteLookupConfig{
		GrpcKeybuilders: []*rlspb.GrpcKeyBuilder{goodKeyBuilder1, goodKeyBuilder2},
	})
	if err != nil {
		t.Fatalf("MakeBuilderMap() failed: %v", err)
	}

	tests := []struct {
		desc   string
		path   string
		md     metadata.MD
		wantKM KeyMap
	}{
		{
			// No keyBuilder is found for the provided service.
			desc:   "service not found in key builder map",
			path:   "/notFoundService/method",
			md:     metadata.Pairs("n1", "v1", "n2", "v2"),
			wantKM: KeyMap{},
		},
		{
			// No keyBuilder is found for the provided method.
			desc:   "method not found in key builder map",
			path:   "/gBar/notFoundMethod",
			md:     metadata.Pairs("n1", "v1", "n2", "v2"),
			wantKM: KeyMap{},
		},
		{
			// A keyBuilder is found, but none of the headers match.
			desc:   "directPathMatch-NoMatchingKey",
			path:   "/gBar/method1",
			md:     metadata.Pairs("notMatchingKey", "v1"),
			wantKM: KeyMap{Map: map[string]string{}, Str: ""},
		},
		{
			// A keyBuilder is found, and a single headers matches.
			desc:   "directPathMatch-SingleKey",
			path:   "/gBar/method1",
			md:     metadata.Pairs("n1", "v1"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1"}, Str: "k1=v1"},
		},
		{
			// A keyBuilder is found, and multiple headers match, but the first
			// match is chosen.
			desc:   "directPathMatch-FirstMatchingKey",
			path:   "/gBar/method1",
			md:     metadata.Pairs("n2", "v2", "n1", "v1"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1"}, Str: "k1=v1"},
		},
		{
			// A keyBuilder is found as a wildcard match, but none of the
			// headers match.
			desc:   "wildcardPathMatch-NoMatchingKey",
			path:   "/gFoobar/method1",
			md:     metadata.Pairs("notMatchingKey", "v1"),
			wantKM: KeyMap{Map: map[string]string{}, Str: ""},
		},
		{
			// A keyBuilder is found as a wildcard match, and a single headers
			// matches.
			desc:   "wildcardPathMatch-SingleKey",
			path:   "/gFoobar/method1",
			md:     metadata.Pairs("n1", "v1"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1"}, Str: "k1=v1"},
		},
		{
			// A keyBuilder is found as a wildcard match, and multiple headers
			// match, but the first match is chosen.
			desc:   "wildcardPathMatch-FirstMatchingKey",
			path:   "/gFoobar/method1",
			md:     metadata.Pairs("n2", "v2", "n1", "v1"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1"}, Str: "k1=v1"},
		},
		{
			// Multiple matchers find hits in the provided request headers.
			desc:   "multipleMatchers",
			path:   "/gFoo/method1",
			md:     metadata.Pairs("n2", "v2", "n1", "v1"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1", "k2": "v1"}, Str: "k1=v1,k2=v1"},
		},
		{
			// A match is found for a header which is specified multiple times.
			// So, the values are joined with commas separating them.
			desc:   "commaSeparated",
			path:   "/gBar/method1",
			md:     metadata.Pairs("n1", "v1", "n1", "v2", "n1", "v3"),
			wantKM: KeyMap{Map: map[string]string{"k1": "v1,v2,v3"}, Str: "k1=v1,v2,v3"},
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			if gotKM := bm.RLSKey(test.md, test.path); !cmp.Equal(gotKM, test.wantKM) {
				t.Errorf("RLSKey(%+v, %s) = %+v, want %+v", test.md, test.path, gotKM, test.wantKM)
			}
		})
	}
}

func TestMapToString(t *testing.T) {
	tests := []struct {
		desc    string
		input   map[string]string
		wantStr string
	}{
		{
			desc:    "empty map",
			input:   nil,
			wantStr: "",
		},
		{
			desc: "one key",
			input: map[string]string{
				"k1": "v1",
			},
			wantStr: "k1=v1",
		},
		{
			desc: "sorted keys",
			input: map[string]string{
				"k1": "v1",
				"k2": "v2",
				"k3": "v3",
			},
			wantStr: "k1=v1,k2=v2,k3=v3",
		},
		{
			desc: "unsorted keys",
			input: map[string]string{
				"k3": "v3",
				"k1": "v1",
				"k2": "v2",
			},
			wantStr: "k1=v1,k2=v2,k3=v3",
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			if gotStr := mapToString(test.input); gotStr != test.wantStr {
				t.Errorf("mapToString(%v) = %s, want %s", test.input, gotStr, test.wantStr)
			}
		})
	}
}

func TestBuilderMapEqual(t *testing.T) {
	tests := []struct {
		desc      string
		a         BuilderMap
		b         BuilderMap
		wantEqual bool
	}{
		{
			desc:      "nil builder maps",
			a:         nil,
			b:         nil,
			wantEqual: true,
		},
		{
			desc:      "empty builder maps",
			a:         make(map[string]builder),
			b:         make(map[string]builder),
			wantEqual: true,
		},
		{
			desc:      "nil and non-nil builder maps",
			a:         nil,
			b:         map[string]builder{"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}}},
			wantEqual: false,
		},
		{
			desc:      "empty and non-empty builder maps",
			a:         make(map[string]builder),
			b:         map[string]builder{"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}}},
			wantEqual: false,
		},
		{
			desc: "different number of map keys",
			a: map[string]builder{
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			b: map[string]builder{
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			wantEqual: false,
		},
		{
			desc: "different map keys",
			a: map[string]builder{
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			b: map[string]builder{
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			wantEqual: false,
		},
		{
			desc: "equal keys different values",
			a: map[string]builder{
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1", "n2"}}}},
			},
			b: map[string]builder{
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			wantEqual: false,
		},
		{
			desc: "good match",
			a: map[string]builder{
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			b: map[string]builder{
				"/gBar/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
				"/gFoo/": {matchers: []matcher{{key: "k1", names: []string{"n1"}}}},
			},
			wantEqual: true,
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			if gotEqual := test.a.Equal(test.b); gotEqual != test.wantEqual {
				t.Errorf("BuilderMap.Equal(%v, %v) = %v, want %v", test.a, test.b, gotEqual, test.wantEqual)
			}
		})
	}
}

func TestBuilderEqual(t *testing.T) {
	tests := []struct {
		desc      string
		a         builder
		b         builder
		wantEqual bool
	}{
		{
			desc:      "nil builders",
			a:         builder{matchers: nil},
			b:         builder{matchers: nil},
			wantEqual: true,
		},
		{
			desc:      "empty builders",
			a:         builder{matchers: []matcher{}},
			b:         builder{matchers: []matcher{}},
			wantEqual: true,
		},
		{
			desc:      "nil and non-nil builders",
			a:         builder{matchers: nil},
			b:         builder{matchers: []matcher{}},
			wantEqual: false,
		},
		{
			desc:      "empty and non-empty builders",
			a:         builder{matchers: []matcher{}},
			b:         builder{matchers: []matcher{{key: "foo"}}},
			wantEqual: false,
		},
		{
			desc:      "different number of matchers",
			a:         builder{matchers: []matcher{{key: "foo"}, {key: "bar"}}},
			b:         builder{matchers: []matcher{{key: "foo"}}},
			wantEqual: false,
		},
		{
			desc:      "equal number but differing matchers",
			a:         builder{matchers: []matcher{{key: "bar"}}},
			b:         builder{matchers: []matcher{{key: "foo"}}},
			wantEqual: false,
		},
		{
			desc:      "good match",
			a:         builder{matchers: []matcher{{key: "foo"}}},
			b:         builder{matchers: []matcher{{key: "foo"}}},
			wantEqual: true,
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			t.Run(test.desc, func(t *testing.T) {
				if gotEqual := test.a.Equal(test.b); gotEqual != test.wantEqual {
					t.Errorf("builder.Equal(%v, %v) = %v, want %v", test.a, test.b, gotEqual, test.wantEqual)
				}
			})
		})
	}
}

// matcher helps extract a key from request headers based on a given name.
func TestMatcherEqual(t *testing.T) {
	tests := []struct {
		desc      string
		a         matcher
		b         matcher
		wantEqual bool
	}{
		{
			desc:      "different keys",
			a:         matcher{key: "foo"},
			b:         matcher{key: "bar"},
			wantEqual: false,
		},
		{
			desc:      "different number of names",
			a:         matcher{key: "foo", names: []string{"v1", "v2"}},
			b:         matcher{key: "foo", names: []string{"v1"}},
			wantEqual: false,
		},
		{
			desc:      "equal number but differing names",
			a:         matcher{key: "foo", names: []string{"v1", "v2"}},
			b:         matcher{key: "foo", names: []string{"v1", "v22"}},
			wantEqual: false,
		},
		{
			desc:      "same names in different order",
			a:         matcher{key: "foo", names: []string{"v2", "v1"}},
			b:         matcher{key: "foo", names: []string{"v1", "v3"}},
			wantEqual: false,
		},
		{
			desc:      "good match",
			a:         matcher{key: "foo", names: []string{"v1", "v2"}},
			b:         matcher{key: "foo", names: []string{"v1", "v2"}},
			wantEqual: true,
		},
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			if gotEqual := test.a.Equal(test.b); gotEqual != test.wantEqual {
				t.Errorf("matcher.Equal(%v, %v) = %v, want %v", test.a, test.b, gotEqual, test.wantEqual)
			}
		})
	}
}