/*
Copyright 2020 KubeSphere 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 prometheus

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"
	jsoniter "github.com/json-iterator/go"

	"kubesphere.io/kubesphere/pkg/simple/client/monitoring"
)

func TestGetNamedMetrics(t *testing.T) {
	tests := []struct {
		fakeResp string
		expected string
	}{
		{
			fakeResp: "metrics-vector-type-prom.json",
			expected: "metrics-vector-type-res.json",
		},
		{
			fakeResp: "metrics-error-prom.json",
			expected: "metrics-error-res.json",
		},
	}

	for i, tt := range tests {
		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
			expected := make([]monitoring.Metric, 0)
			err := jsonFromFile(tt.expected, &expected)
			if err != nil {
				t.Fatal(err)
			}

			srv := mockPrometheusService("/api/v1/query", tt.fakeResp)
			defer srv.Close()

			client, _ := NewPrometheus(&Options{Endpoint: srv.URL})
			result := client.GetNamedMetrics([]string{"cluster_cpu_utilisation"}, time.Now(), monitoring.ClusterOption{})
			if diff := cmp.Diff(result, expected); diff != "" {
				t.Fatalf("%T differ (-got, +want): %s", expected, diff)
			}
		})
	}
}

func TestGetNamedMetricsOverTime(t *testing.T) {
	tests := []struct {
		fakeResp string
		expected string
	}{
		{
			fakeResp: "metrics-matrix-type-prom.json",
			expected: "metrics-matrix-type-res.json",
		},
		{
			fakeResp: "metrics-error-prom.json",
			expected: "metrics-error-res.json",
		},
	}

	for i, tt := range tests {
		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
			expected := make([]monitoring.Metric, 0)
			err := jsonFromFile(tt.expected, &expected)
			if err != nil {
				t.Fatal(err)
			}

			srv := mockPrometheusService("/api/v1/query_range", tt.fakeResp)
			defer srv.Close()

			client, _ := NewPrometheus(&Options{Endpoint: srv.URL})
			result := client.GetNamedMetricsOverTime([]string{"cluster_cpu_utilisation"}, time.Now().Add(-time.Minute*3), time.Now(), time.Minute, monitoring.ClusterOption{})
			if diff := cmp.Diff(result, expected); diff != "" {
				t.Fatalf("%T differ (-got, +want): %s", expected, diff)
			}
		})
	}
}

func TestGetMetadata(t *testing.T) {
	tests := []struct {
		fakeResp string
		expected string
	}{
		{
			fakeResp: "metadata-prom.json",
			expected: "metadata-res.json",
		},
		{
			fakeResp: "metadata-notfound-prom.json",
			expected: "metadata-notfound-res.json",
		},
	}

	for i, tt := range tests {
		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
			expected := make([]monitoring.Metadata, 0)
			err := jsonFromFile(tt.expected, &expected)
			if err != nil {
				t.Fatal(err)
			}
			if len(expected) == 0 {
				expected = nil
			}

			srv := mockPrometheusService("/api/v1/targets/metadata", tt.fakeResp)
			defer srv.Close()

			client, _ := NewPrometheus(&Options{Endpoint: srv.URL})
			result := client.GetMetadata("default")
			if diff := cmp.Diff(result, expected); diff != "" {
				t.Fatalf("%T differ (-got, +want): %s", expected, diff)
			}
		})
	}
}

func TestGetMetricLabelSet(t *testing.T) {
	tests := []struct {
		fakeResp string
		expected string
	}{
		{
			fakeResp: "labels-prom.json",
			expected: "labels-res.json",
		},
		{
			fakeResp: "labels-error-prom.json",
			expected: "labels-error-res.json",
		},
	}

	for i, tt := range tests {
		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
			var expected []map[string]string
			err := jsonFromFile(tt.expected, &expected)
			if err != nil {
				t.Fatal(err)
			}

			srv := mockPrometheusService("/api/v1/series", tt.fakeResp)
			defer srv.Close()

			client, _ := NewPrometheus(&Options{Endpoint: srv.URL})
			result := client.GetMetricLabelSet("default", time.Now(), time.Now())
			if diff := cmp.Diff(result, expected); diff != "" {
				t.Fatalf("%T differ (-got, +want): %s", expected, diff)
			}
		})
	}
}

func mockPrometheusService(pattern, fakeResp string) *httptest.Server {
	mux := http.NewServeMux()
	mux.HandleFunc(pattern, func(res http.ResponseWriter, req *http.Request) {
		b, _ := ioutil.ReadFile(fmt.Sprintf("./testdata/%s", fakeResp))
		res.Write(b)
	})
	return httptest.NewServer(mux)
}

func jsonFromFile(expectedFile string, expectedJsonPtr interface{}) error {
	json, err := ioutil.ReadFile(fmt.Sprintf("./testdata/%s", expectedFile))
	if err != nil {
		return err
	}
	err = jsoniter.Unmarshal(json, expectedJsonPtr)
	if err != nil {
		return err
	}

	return nil
}