// Copyright 2018 The Prometheus 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 graphite

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"io"
	"log"
	"net"
	"os"
	"reflect"
	"regexp"
	"sort"
	"strings"
	"testing"
	"time"

	"github.com/prometheus/common/model"

	"git.internal/re/client_golang/prometheus"
)

func TestSanitize(t *testing.T) {
	testCases := []struct {
		in, out string
	}{
		{in: "hello", out: "hello"},
		{in: "hE/l1o", out: "hE_l1o"},
		{in: "he,*ll(.o", out: "he_ll_o"},
		{in: "hello_there%^&", out: "hello_there_"},
		{in: "hell-.o", out: "hell-_o"},
	}

	var buf bytes.Buffer
	w := bufio.NewWriter(&buf)

	for i, tc := range testCases {
		if err := writeSanitized(w, tc.in); err != nil {
			t.Fatalf("write failed: %v", err)
		}
		if err := w.Flush(); err != nil {
			t.Fatalf("flush failed: %v", err)
		}

		if want, got := tc.out, buf.String(); want != got {
			t.Fatalf("test case index %d: got sanitized string %s, want %s", i, got, want)
		}

		buf.Reset()
	}
}

func TestWriteSummary(t *testing.T) {
	testWriteSummary(t, false)
	testWriteSummary(t, true)
}

func testWriteSummary(t *testing.T, useTags bool) {
	sumVec := prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Name:        "name",
			Help:        "docstring",
			ConstLabels: prometheus.Labels{"constname": "constvalue"},
			Objectives:  map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
		},
		[]string{"labelname"},
	)

	sumVec.WithLabelValues("val1").Observe(float64(10))
	sumVec.WithLabelValues("val1").Observe(float64(20))
	sumVec.WithLabelValues("val1").Observe(float64(30))
	sumVec.WithLabelValues("val2").Observe(float64(20))
	sumVec.WithLabelValues("val2").Observe(float64(30))
	sumVec.WithLabelValues("val2").Observe(float64(40))

	reg := prometheus.NewRegistry()
	reg.MustRegister(sumVec)

	mfs, err := reg.Gather()
	if err != nil {
		t.Fatalf("error: %v", err)
	}

	testCases := []struct {
		prefix string
	}{
		{prefix: "prefix"},
		{prefix: "pre/fix"},
		{prefix: "pre.fix"},
		{prefix: ""},
	}

	var (
		want = `%s.name.constname.constvalue.labelname.val1.quantile.0_5 20 1477043
%s.name.constname.constvalue.labelname.val1.quantile.0_9 30 1477043
%s.name.constname.constvalue.labelname.val1.quantile.0_99 30 1477043
%s.name_sum.constname.constvalue.labelname.val1 60 1477043
%s.name_count.constname.constvalue.labelname.val1 3 1477043
%s.name.constname.constvalue.labelname.val2.quantile.0_5 30 1477043
%s.name.constname.constvalue.labelname.val2.quantile.0_9 40 1477043
%s.name.constname.constvalue.labelname.val2.quantile.0_99 40 1477043
%s.name_sum.constname.constvalue.labelname.val2 90 1477043
%s.name_count.constname.constvalue.labelname.val2 3 1477043
`
		wantTagged = `%s.name;constname=constvalue;labelname=val1;quantile=0.5 20 1477043
%s.name;constname=constvalue;labelname=val1;quantile=0.9 30 1477043
%s.name;constname=constvalue;labelname=val1;quantile=0.99 30 1477043
%s.name_sum;constname=constvalue;labelname=val1 60 1477043
%s.name_count;constname=constvalue;labelname=val1 3 1477043
%s.name;constname=constvalue;labelname=val2;quantile=0.5 30 1477043
%s.name;constname=constvalue;labelname=val2;quantile=0.9 40 1477043
%s.name;constname=constvalue;labelname=val2;quantile=0.99 40 1477043
%s.name_sum;constname=constvalue;labelname=val2 90 1477043
%s.name_count;constname=constvalue;labelname=val2 3 1477043
`
	)

	if useTags {
		want = wantTagged
	}

	for i, tc := range testCases {

		now := model.Time(1477043083)
		var buf bytes.Buffer
		err = writeMetrics(&buf, mfs, useTags, tc.prefix, now)
		if err != nil {
			t.Fatalf("error: %v", err)
		}

		var wantWithPrefix string
		if tc.prefix == "" {
			wantWithPrefix = strings.ReplaceAll(want, "%s.", "")
		} else {
			wantWithPrefix = fmt.Sprintf(want,
				tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
				tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
			)
		}

		got := buf.String()

		if err := checkLinesAreEqual(wantWithPrefix, got, useTags); err != nil {
			t.Fatalf("test case index %d:\n%s", i, err.Error())
		}
	}
}

func TestWriteHistogram(t *testing.T) {
	testWriteHistogram(t, false)
	testWriteHistogram(t, true)
}

func testWriteHistogram(t *testing.T, useTags bool) {
	histVec := prometheus.NewHistogramVec(
		prometheus.HistogramOpts{
			Name:        "name",
			Help:        "docstring",
			ConstLabels: prometheus.Labels{"constname": "constvalue"},
			Buckets:     []float64{0.01, 0.02, 0.05, 0.1},
		},
		[]string{"labelname"},
	)

	histVec.WithLabelValues("val1").Observe(float64(10))
	histVec.WithLabelValues("val1").Observe(float64(20))
	histVec.WithLabelValues("val1").Observe(float64(30))
	histVec.WithLabelValues("val2").Observe(float64(20))
	histVec.WithLabelValues("val2").Observe(float64(30))
	histVec.WithLabelValues("val2").Observe(float64(40))

	reg := prometheus.NewRegistry()
	reg.MustRegister(histVec)

	mfs, err := reg.Gather()
	if err != nil {
		t.Fatalf("error: %v", err)
	}

	now := model.Time(1477043083)
	var buf bytes.Buffer
	err = writeMetrics(&buf, mfs, useTags, "prefix", now)
	if err != nil {
		t.Fatalf("error: %v", err)
	}

	var (
		want = `prefix.name_bucket.constname.constvalue.labelname.val1.le.0_01 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val1.le.0_02 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val1.le.0_05 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val1.le.0_1 0 1477043
prefix.name_sum.constname.constvalue.labelname.val1 60 1477043
prefix.name_count.constname.constvalue.labelname.val1 3 1477043
prefix.name_bucket.constname.constvalue.labelname.val1.le._Inf 3 1477043
prefix.name_bucket.constname.constvalue.labelname.val2.le.0_01 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val2.le.0_02 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val2.le.0_05 0 1477043
prefix.name_bucket.constname.constvalue.labelname.val2.le.0_1 0 1477043
prefix.name_sum.constname.constvalue.labelname.val2 90 1477043
prefix.name_count.constname.constvalue.labelname.val2 3 1477043
prefix.name_bucket.constname.constvalue.labelname.val2.le._Inf 3 1477043
`
		wantTagged = `prefix.name_bucket;constname=constvalue;labelname=val1;le=0.01 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val1;le=0.02 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val1;le=0.05 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val1;le=0.1 0 1477043
prefix.name_sum;constname=constvalue;labelname=val1 60 1477043
prefix.name_count;constname=constvalue;labelname=val1 3 1477043
prefix.name_bucket;constname=constvalue;labelname=val1;le=+Inf 3 1477043
prefix.name_bucket;constname=constvalue;labelname=val2;le=0.01 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val2;le=0.02 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val2;le=0.05 0 1477043
prefix.name_bucket;constname=constvalue;labelname=val2;le=0.1 0 1477043
prefix.name_sum;constname=constvalue;labelname=val2 90 1477043
prefix.name_count;constname=constvalue;labelname=val2 3 1477043
prefix.name_bucket;constname=constvalue;labelname=val2;le=+Inf 3 1477043
`
	)

	if useTags {
		want = wantTagged
	}

	got := buf.String()

	if err := checkLinesAreEqual(want, got, useTags); err != nil {
		t.Fatalf(err.Error())
	}
}

func TestToReader(t *testing.T) {
	testToReader(t, false)
	testToReader(t, true)
}

func testToReader(t *testing.T, useTags bool) {
	cntVec := prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Name:        "name",
			Help:        "docstring",
			ConstLabels: prometheus.Labels{"constname": "constvalue"},
		},
		[]string{"labelname"},
	)
	cntVec.WithLabelValues("val1").Inc()
	cntVec.WithLabelValues("val2").Inc()

	reg := prometheus.NewRegistry()
	reg.MustRegister(cntVec)

	var (
		want = `prefix.name.constname.constvalue.labelname.val1 1 1477043
prefix.name.constname.constvalue.labelname.val2 1 1477043
`
		wantTagged = `prefix.name;constname=constvalue;labelname=val1 1 1477043
prefix.name;constname=constvalue;labelname=val2 1 1477043
`
	)

	if useTags {
		want = wantTagged
	}

	mfs, err := reg.Gather()
	if err != nil {
		t.Fatalf("error: %v", err)
	}

	now := model.Time(1477043083)
	var buf bytes.Buffer
	err = writeMetrics(&buf, mfs, useTags, "prefix", now)
	if err != nil {
		t.Fatalf("error: %v", err)
	}

	got := buf.String()

	if err := checkLinesAreEqual(want, got, useTags); err != nil {
		t.Fatalf(err.Error())
	}
}

func checkLinesAreEqual(w, g string, useTags bool) error {
	if useTags {
		taggedLineRegexp := regexp.MustCompile(`;| `)

		wantLines, err := stringToLines(w)
		if err != nil {
			return err
		}

		gotLines, err := stringToLines(g)
		if err != nil {
			return err
		}

		for lineInd := range gotLines {
			var log string
			// Tagged metric, order of tags doesn't matter
			// m1 := "prefix.name;tag1=val1;tag2=val2 3 1477043"
			// m2 := "prefix.name;tag2=val2;tag1=val1 3 1477043"
			// m1 should be equal to m2
			wantSplit := taggedLineRegexp.Split(wantLines[lineInd], -1)
			gotSplit := taggedLineRegexp.Split(gotLines[lineInd], -1)
			sort.Strings(wantSplit)
			sort.Strings(gotSplit)

			log += fmt.Sprintf("want: %v\ngot: %v\n\n", wantSplit, gotSplit)

			if !reflect.DeepEqual(wantSplit, gotSplit) {
				return fmt.Errorf(log)
			}
		}
		return nil
	}

	if w != g {
		return fmt.Errorf("wanted:\n\n%s\ngot:\n\n%s", w, g)
	}

	return nil
}

func stringToLines(s string) (lines []string, err error) {
	scanner := bufio.NewScanner(strings.NewReader(s))
	for scanner.Scan() {
		lines = append(lines, scanner.Text())
	}
	err = scanner.Err()
	return
}

func TestPush(t *testing.T) {
	reg := prometheus.NewRegistry()
	cntVec := prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Name:        "name",
			Help:        "docstring",
			ConstLabels: prometheus.Labels{"constname": "constvalue"},
		},
		[]string{"labelname"},
	)
	cntVec.WithLabelValues("val1").Inc()
	cntVec.WithLabelValues("val2").Inc()
	reg.MustRegister(cntVec)

	host := "localhost"
	port := ":56789"
	b, err := NewBridge(&Config{
		URL:      host + port,
		Gatherer: reg,
		Prefix:   "prefix",
	})
	if err != nil {
		t.Fatalf("error creating bridge: %v", err)
	}

	nmg, err := newMockGraphite(port)
	if err != nil {
		t.Fatalf("error creating mock graphite: %v", err)
	}
	defer nmg.Close()

	err = b.Push()
	if err != nil {
		t.Fatalf("error pushing: %v", err)
	}

	wants := []string{
		"prefix.name.constname.constvalue.labelname.val1 1",
		"prefix.name.constname.constvalue.labelname.val2 1",
	}

	select {
	case got := <-nmg.readc:
		for _, want := range wants {
			matched, err := regexp.MatchString(want, got)
			if err != nil {
				t.Fatalf("error pushing: %v", err)
			}
			if !matched {
				t.Fatalf("missing metric:\nno match for %s received by server:\n%s", want, got)
			}
		}
		return
	case err := <-nmg.errc:
		t.Fatalf("error reading push: %v", err)
	case <-time.After(50 * time.Millisecond):
		t.Fatalf("no result from graphite server")
	}
}

func newMockGraphite(port string) (*mockGraphite, error) {
	readc := make(chan string)
	errc := make(chan error)
	ln, err := net.Listen("tcp", port)
	if err != nil {
		return nil, err
	}

	go func() {
		conn, err := ln.Accept()
		if err != nil {
			errc <- err
		}
		var b bytes.Buffer
		io.Copy(&b, conn)
		readc <- b.String()
	}()

	return &mockGraphite{
		readc:    readc,
		errc:     errc,
		Listener: ln,
	}, nil
}

type mockGraphite struct {
	readc chan string
	errc  chan error

	net.Listener
}

func ExampleBridge() {
	b, err := NewBridge(&Config{
		URL:           "graphite.example.org:3099",
		Gatherer:      prometheus.DefaultGatherer,
		Prefix:        "prefix",
		Interval:      15 * time.Second,
		Timeout:       10 * time.Second,
		ErrorHandling: AbortOnError,
		Logger:        log.New(os.Stdout, "graphite bridge: ", log.Lshortfile),
	})
	if err != nil {
		panic(err)
	}

	go func() {
		// Start something in a goroutine that uses metrics.
	}()

	// Push initial metrics to Graphite. Fail fast if the push fails.
	if err := b.Push(); err != nil {
		panic(err)
	}

	// Create a Context to control stopping the Run() loop that pushes
	// metrics to Graphite.
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Start pushing metrics to Graphite in the Run() loop.
	b.Run(ctx)
}