// Copyright The OpenTelemetry 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 resource_test

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strings"
	"testing"

	"github.com/google/go-cmp/cmp"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	ottest "go.opentelemetry.io/otel/internal/internaltest"
	"go.opentelemetry.io/otel/sdk/resource"
	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
)

var (
	kv11 = attribute.String("k1", "v11")
	kv12 = attribute.String("k1", "v12")
	kv21 = attribute.String("k2", "v21")
	kv31 = attribute.String("k3", "v31")
	kv41 = attribute.String("k4", "v41")
	kv42 = attribute.String("k4", "")
)

func TestNewWithAttributes(t *testing.T) {
	cases := []struct {
		name string
		in   []attribute.KeyValue
		want []attribute.KeyValue
	}{
		{
			name: "Key with common key order1",
			in:   []attribute.KeyValue{kv12, kv11, kv21},
			want: []attribute.KeyValue{kv11, kv21},
		},
		{
			name: "Key with common key order2",
			in:   []attribute.KeyValue{kv11, kv12, kv21},
			want: []attribute.KeyValue{kv12, kv21},
		},
		{
			name: "Key with nil",
			in:   nil,
			want: nil,
		},
	}
	for _, c := range cases {
		t.Run(fmt.Sprintf("case-%s", c.name), func(t *testing.T) {
			res := resource.NewSchemaless(c.in...)
			if diff := cmp.Diff(
				res.Attributes(),
				c.want,
				cmp.AllowUnexported(attribute.Value{})); diff != "" {
				t.Fatalf("unwanted result: diff %+v,", diff)
			}
		})
	}
}

func TestMerge(t *testing.T) {
	cases := []struct {
		name      string
		a, b      *resource.Resource
		want      []attribute.KeyValue
		isErr     bool
		schemaURL string
	}{
		{
			name: "Merge 2 nils",
			a:    nil,
			b:    nil,
			want: nil,
		},
		{
			name: "Merge with no overlap, no nil",
			a:    resource.NewSchemaless(kv11, kv31),
			b:    resource.NewSchemaless(kv21, kv41),
			want: []attribute.KeyValue{kv11, kv21, kv31, kv41},
		},
		{
			name: "Merge with no overlap, no nil, not interleaved",
			a:    resource.NewSchemaless(kv11, kv21),
			b:    resource.NewSchemaless(kv31, kv41),
			want: []attribute.KeyValue{kv11, kv21, kv31, kv41},
		},
		{
			name: "Merge with common key order1",
			a:    resource.NewSchemaless(kv11),
			b:    resource.NewSchemaless(kv12, kv21),
			want: []attribute.KeyValue{kv12, kv21},
		},
		{
			name: "Merge with common key order2",
			a:    resource.NewSchemaless(kv12, kv21),
			b:    resource.NewSchemaless(kv11),
			want: []attribute.KeyValue{kv11, kv21},
		},
		{
			name: "Merge with common key order4",
			a:    resource.NewSchemaless(kv11, kv21, kv41),
			b:    resource.NewSchemaless(kv31, kv41),
			want: []attribute.KeyValue{kv11, kv21, kv31, kv41},
		},
		{
			name: "Merge with no keys",
			a:    resource.NewSchemaless(),
			b:    resource.NewSchemaless(),
			want: nil,
		},
		{
			name: "Merge with first resource no keys",
			a:    resource.NewSchemaless(),
			b:    resource.NewSchemaless(kv21),
			want: []attribute.KeyValue{kv21},
		},
		{
			name: "Merge with second resource no keys",
			a:    resource.NewSchemaless(kv11),
			b:    resource.NewSchemaless(),
			want: []attribute.KeyValue{kv11},
		},
		{
			name: "Merge with first resource nil",
			a:    nil,
			b:    resource.NewSchemaless(kv21),
			want: []attribute.KeyValue{kv21},
		},
		{
			name: "Merge with second resource nil",
			a:    resource.NewSchemaless(kv11),
			b:    nil,
			want: []attribute.KeyValue{kv11},
		},
		{
			name: "Merge with first resource value empty string",
			a:    resource.NewSchemaless(kv42),
			b:    resource.NewSchemaless(kv41),
			want: []attribute.KeyValue{kv41},
		},
		{
			name: "Merge with second resource value empty string",
			a:    resource.NewSchemaless(kv41),
			b:    resource.NewSchemaless(kv42),
			want: []attribute.KeyValue{kv42},
		},
		{
			name:      "Merge with first resource with schema",
			a:         resource.NewWithAttributes("https://opentelemetry.io/schemas/1.4.0", kv41),
			b:         resource.NewSchemaless(kv42),
			want:      []attribute.KeyValue{kv42},
			schemaURL: "https://opentelemetry.io/schemas/1.4.0",
		},
		{
			name:      "Merge with second resource with schema",
			a:         resource.NewSchemaless(kv41),
			b:         resource.NewWithAttributes("https://opentelemetry.io/schemas/1.4.0", kv42),
			want:      []attribute.KeyValue{kv42},
			schemaURL: "https://opentelemetry.io/schemas/1.4.0",
		},
		{
			name:  "Merge with different schemas",
			a:     resource.NewWithAttributes("https://opentelemetry.io/schemas/1.4.0", kv41),
			b:     resource.NewWithAttributes("https://opentelemetry.io/schemas/1.3.0", kv42),
			want:  nil,
			isErr: true,
		},
	}
	for _, c := range cases {
		t.Run(fmt.Sprintf("case-%s", c.name), func(t *testing.T) {
			res, err := resource.Merge(c.a, c.b)
			if c.isErr {
				assert.Error(t, err)
			} else {
				assert.NoError(t, err)
			}
			assert.EqualValues(t, c.schemaURL, res.SchemaURL())
			if diff := cmp.Diff(
				res.Attributes(),
				c.want,
				cmp.AllowUnexported(attribute.Value{})); diff != "" {
				t.Fatalf("unwanted result: diff %+v,", diff)
			}
		})
	}
}

func TestDefault(t *testing.T) {
	res := resource.Default()
	require.False(t, res.Equal(resource.Empty()))
	require.True(t, res.Set().HasValue(semconv.ServiceNameKey))

	serviceName, _ := res.Set().Value(semconv.ServiceNameKey)
	require.True(t, strings.HasPrefix(serviceName.AsString(), "unknown_service:"))
	require.Greaterf(t, len(serviceName.AsString()), len("unknown_service:"),
		"default service.name should include executable name")

	require.Contains(t, res.Attributes(), semconv.TelemetrySDKLanguageGo)
	require.Contains(t, res.Attributes(), semconv.TelemetrySDKVersionKey.String(otel.Version()))
	require.Contains(t, res.Attributes(), semconv.TelemetrySDKNameKey.String("opentelemetry"))
}

func TestString(t *testing.T) {
	for _, test := range []struct {
		kvs  []attribute.KeyValue
		want string
	}{
		{
			kvs:  nil,
			want: "",
		},
		{
			kvs:  []attribute.KeyValue{},
			want: "",
		},
		{
			kvs:  []attribute.KeyValue{kv11},
			want: "k1=v11",
		},
		{
			kvs:  []attribute.KeyValue{kv11, kv12},
			want: "k1=v12",
		},
		{
			kvs:  []attribute.KeyValue{kv11, kv21},
			want: "k1=v11,k2=v21",
		},
		{
			kvs:  []attribute.KeyValue{kv21, kv11},
			want: "k1=v11,k2=v21",
		},
		{
			kvs:  []attribute.KeyValue{kv11, kv21, kv31},
			want: "k1=v11,k2=v21,k3=v31",
		},
		{
			kvs:  []attribute.KeyValue{kv31, kv11, kv21},
			want: "k1=v11,k2=v21,k3=v31",
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("A", "a"), attribute.String("B", "b")},
			want: "A=a,B=b",
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("A", "a,B=b")},
			want: `A=a\,B\=b`,
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("A", `a,B\=b`)},
			want: `A=a\,B\\\=b`,
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("A=a,B", `b`)},
			want: `A\=a\,B=b`,
		},
		{
			kvs:  []attribute.KeyValue{attribute.String(`A=a\,B`, `b`)},
			want: `A\=a\\\,B=b`,
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("", "invalid")},
			want: "",
		},
		{
			kvs:  []attribute.KeyValue{attribute.String("", "invalid"), attribute.String("B", "b")},
			want: "B=b",
		},
	} {
		if got := resource.NewSchemaless(test.kvs...).String(); got != test.want {
			t.Errorf("Resource(%v).String() = %q, want %q", test.kvs, got, test.want)
		}
	}
}

const envVar = "OTEL_RESOURCE_ATTRIBUTES"

func TestMarshalJSON(t *testing.T) {
	r := resource.NewSchemaless(attribute.Int64("A", 1), attribute.String("C", "D"))
	data, err := json.Marshal(r)
	require.NoError(t, err)
	require.Equal(t,
		`[{"Key":"A","Value":{"Type":"INT64","Value":1}},{"Key":"C","Value":{"Type":"STRING","Value":"D"}}]`,
		string(data))
}

func TestNew(t *testing.T) {
	tc := []struct {
		name      string
		envars    string
		detectors []resource.Detector
		options   []resource.Option

		resourceValues map[string]string
		schemaURL      string
		isErr          bool
	}{
		{
			name:           "No Options returns empty resource",
			envars:         "key=value,other=attr",
			options:        nil,
			resourceValues: map[string]string{},
		},
		{
			name:   "Nil Detectors works",
			envars: "key=value,other=attr",
			options: []resource.Option{
				resource.WithDetectors(),
			},
			resourceValues: map[string]string{},
		},
		{
			name:   "Only Host",
			envars: "from=here",
			options: []resource.Option{
				resource.WithHost(),
			},
			resourceValues: map[string]string{
				"host.name": hostname(),
			},
			schemaURL: semconv.SchemaURL,
		},
		{
			name:   "Only Env",
			envars: "key=value,other=attr",
			options: []resource.Option{
				resource.WithFromEnv(),
			},
			resourceValues: map[string]string{
				"key":   "value",
				"other": "attr",
			},
		},
		{
			name:   "Only TelemetrySDK",
			envars: "",
			options: []resource.Option{
				resource.WithTelemetrySDK(),
			},
			resourceValues: map[string]string{
				"telemetry.sdk.name":     "opentelemetry",
				"telemetry.sdk.language": "go",
				"telemetry.sdk.version":  otel.Version(),
			},
			schemaURL: semconv.SchemaURL,
		},
		{
			name:   "WithAttributes",
			envars: "key=value,other=attr",
			options: []resource.Option{
				resource.WithAttributes(attribute.String("A", "B")),
			},
			resourceValues: map[string]string{
				"A": "B",
			},
		},
		{
			name:   "Builtins",
			envars: "key=value,other=attr",
			options: []resource.Option{
				resource.WithBuiltinDetectors(),
			},
			resourceValues: map[string]string{
				"host.name":              hostname(),
				"telemetry.sdk.name":     "opentelemetry",
				"telemetry.sdk.language": "go",
				"telemetry.sdk.version":  otel.Version(),
				"key":                    "value",
				"other":                  "attr",
			},
			schemaURL: semconv.SchemaURL,
		},
		{
			name:   "With schema url",
			envars: "",
			options: []resource.Option{
				resource.WithAttributes(attribute.String("A", "B")),
				resource.WithSchemaURL("https://opentelemetry.io/schemas/1.0.0"),
			},
			resourceValues: map[string]string{
				"A": "B",
			},
			schemaURL: "https://opentelemetry.io/schemas/1.0.0",
		},
		{
			name:   "With conflicting schema urls",
			envars: "",
			options: []resource.Option{
				resource.WithDetectors(
					resource.StringDetector("https://opentelemetry.io/schemas/1.0.0", semconv.HostNameKey, os.Hostname),
				),
				resource.WithSchemaURL("https://opentelemetry.io/schemas/1.1.0"),
			},
			resourceValues: map[string]string{},
			schemaURL:      "",
			isErr:          true,
		},
		{
			name:   "With conflicting detector schema urls",
			envars: "",
			options: []resource.Option{
				resource.WithDetectors(
					resource.StringDetector("https://opentelemetry.io/schemas/1.0.0", semconv.HostNameKey, os.Hostname),
					resource.StringDetector("https://opentelemetry.io/schemas/1.1.0", semconv.HostNameKey, func() (string, error) { return "", errors.New("fail") }),
				),
				resource.WithSchemaURL("https://opentelemetry.io/schemas/1.2.0"),
			},
			resourceValues: map[string]string{},
			schemaURL:      "",
			isErr:          true,
		},
	}
	for _, tt := range tc {
		t.Run(tt.name, func(t *testing.T) {
			store, err := ottest.SetEnvVariables(map[string]string{
				envVar: tt.envars,
			})
			require.NoError(t, err)
			defer func() { require.NoError(t, store.Restore()) }()

			ctx := context.Background()
			res, err := resource.New(ctx, tt.options...)

			if tt.isErr {
				require.Error(t, err)
			} else {
				require.NoError(t, err)
			}

			require.EqualValues(t, tt.resourceValues, toMap(res))

			// TODO: do we need to ensure that resource is never nil and eliminate the
			// following if?
			if res != nil {
				assert.EqualValues(t, tt.schemaURL, res.SchemaURL())
			}
		})
	}
}

func TestNewWithBuiltinDetectors(t *testing.T) {
	tc := []struct {
		name      string
		envars    string
		detectors []resource.Detector
		options   []resource.Option

		resourceValues map[string]string
	}{
		{
			name:    "No Options returns builtin",
			envars:  "key=value,other=attr",
			options: nil,
			resourceValues: map[string]string{
				"host.name":              hostname(),
				"telemetry.sdk.name":     "opentelemetry",
				"telemetry.sdk.language": "go",
				"telemetry.sdk.version":  otel.Version(),
				"key":                    "value",
				"other":                  "attr",
			},
		},
		{
			name:   "WithAttributes",
			envars: "key=value,other=attr",
			options: []resource.Option{
				resource.WithAttributes(attribute.String("A", "B")),
			},
			resourceValues: map[string]string{
				"host.name":              hostname(),
				"telemetry.sdk.name":     "opentelemetry",
				"telemetry.sdk.language": "go",
				"telemetry.sdk.version":  otel.Version(),
				"key":                    "value",
				"other":                  "attr",
				"A":                      "B",
			},
		},
	}
	for _, tt := range tc {
		t.Run(tt.name, func(t *testing.T) {
			store, err := ottest.SetEnvVariables(map[string]string{
				envVar: tt.envars,
			})
			require.NoError(t, err)
			defer func() { require.NoError(t, store.Restore()) }()

			ctx := context.Background()
			options := append([]resource.Option{resource.WithBuiltinDetectors()}, tt.options...)
			res, err := resource.New(ctx, options...)

			require.NoError(t, err)
			require.EqualValues(t, tt.resourceValues, toMap(res))
		})
	}
}

func toMap(res *resource.Resource) map[string]string {
	m := map[string]string{}
	for _, attr := range res.Attributes() {
		m[string(attr.Key)] = attr.Value.Emit()
	}
	return m
}

func hostname() string {
	hn, err := os.Hostname()
	if err != nil {
		return fmt.Sprintf("hostname(%s)", err)
	}
	return hn
}