// Copyright 2018 The etcd 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 tester

import (
	"fmt"
	"os"
	"testing"
	"time"

	"go.etcd.io/etcd/client/pkg/v3/fileutil"
	"go.etcd.io/etcd/tests/v3/functional/rpcpb"

	"go.uber.org/zap"
)

// compactQPS is rough number of compact requests per second.
// Previous tests showed etcd can compact about 60,000 entries per second.
const compactQPS = 50000

// Run starts tester.
func (clus *Cluster) Run(t *testing.T) error {
	defer printReport()

	// updateCases must be executed after etcd is started, because the FAILPOINTS case
	// needs to obtain all the failpoints from the etcd member.
	clus.updateCases()

	if err := fileutil.TouchDirAll(clus.lg, clus.Tester.DataDir); err != nil {
		clus.lg.Panic(
			"failed to create test data directory",
			zap.String("dir", clus.Tester.DataDir),
			zap.Error(err),
		)
	}

	var (
		preModifiedKey int64
		err            error
	)
	for round := 0; round < int(clus.Tester.RoundLimit) || clus.Tester.RoundLimit == -1; round++ {
		t.Run(fmt.Sprintf("round-%d", round), func(t *testing.T) {
			preModifiedKey, err = clus.doRoundAndCompact(t, round, preModifiedKey)
		})

		if err != nil {
			clus.failed(t, err)
			return err
		}

		if round > 0 && round%500 == 0 { // every 500 rounds
			t.Logf("Defragmenting in round: %v", round)
			if err := clus.defrag(); err != nil {
				clus.failed(t, err)
				return err
			}
		}
	}

	clus.lg.Info(
		"functional-tester PASS",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
	)
	return nil
}

func (clus *Cluster) doRoundAndCompact(t *testing.T, round int, preModifiedKey int64) (postModifiedKey int64, err error) {
	roundTotalCounter.Inc()
	clus.rd = round

	if err = clus.doRound(t); err != nil {
		clus.failed(t, fmt.Errorf("doRound FAIL: %w", err))
		return
	}

	// -1 so that logPrefix doesn't print out 'case'
	clus.cs = -1

	revToCompact := max(0, clus.currentRevision-10000)
	currentModifiedKey := clus.stresser.ModifiedKeys()
	modifiedKey := currentModifiedKey - preModifiedKey
	timeout := 10 * time.Second
	timeout += time.Duration(modifiedKey/compactQPS) * time.Second
	clus.lg.Info(
		"compact START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.Duration("timeout", timeout),
	)
	if err = clus.compact(revToCompact, timeout); err != nil {
		clus.failed(t, fmt.Errorf("compact FAIL: %w", err))
	} else {
		postModifiedKey = currentModifiedKey
	}
	return
}

func (clus *Cluster) doRound(t *testing.T) error {
	if clus.Tester.CaseShuffle {
		clus.shuffleCases()
	}

	roundNow := time.Now()
	clus.lg.Info(
		"round START",
		zap.Int("round", clus.rd),
		zap.Int("case-total", len(clus.cases)),
		zap.Strings("cases", clus.listCases()),
	)
	for i, fa := range clus.cases {
		clus.cs = i
		t.Run(fmt.Sprintf("%v_%s", i, fa.TestCase()),
			func(t *testing.T) {
				clus.doTestCase(t, fa)
			})
	}

	clus.lg.Info(
		"round ALL PASS",
		zap.Int("round", clus.rd),
		zap.Strings("cases", clus.listCases()),
		zap.Int("case-total", len(clus.cases)),
		zap.Duration("took", time.Since(roundNow)),
	)
	return nil
}

func (clus *Cluster) doTestCase(t *testing.T, fa Case) {
	caseTotal[fa.Desc()]++
	caseTotalCounter.WithLabelValues(fa.Desc()).Inc()

	caseNow := time.Now()
	clus.lg.Info(
		"case START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
	)

	clus.lg.Info("wait health before injecting failures")
	if err := clus.WaitHealth(); err != nil {
		clus.failed(t, fmt.Errorf("wait full health error before starting test case: %w", err))
	}

	stressStarted := false
	fcase := fa.TestCase()
	if fcase != rpcpb.Case_NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS {
		clus.lg.Info(
			"stress START",
			zap.Int("round", clus.rd),
			zap.Int("case", clus.cs),
			zap.Int("case-total", len(clus.cases)),
			zap.String("desc", fa.Desc()),
		)
		if err := clus.stresser.Stress(); err != nil {
			clus.failed(t, fmt.Errorf("start stresser error: %w", err))
		}
		stressStarted = true
	}

	clus.lg.Info(
		"inject START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
	)
	if err := fa.Inject(clus); err != nil {
		clus.failed(t, fmt.Errorf("injection error: %w", err))
	}

	// if run local, recovering server may conflict
	// with stressing client ports
	// TODO: use unix for local tests
	clus.lg.Info(
		"recover START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
	)
	if err := fa.Recover(clus); err != nil {
		clus.failed(t, fmt.Errorf("recovery error: %w", err))
	}

	if stressStarted {
		clus.lg.Info(
			"stress PAUSE",
			zap.Int("round", clus.rd),
			zap.Int("case", clus.cs),
			zap.Int("case-total", len(clus.cases)),
			zap.String("desc", fa.Desc()),
		)
		ems := clus.stresser.Pause()
		if fcase == rpcpb.Case_NO_FAIL_WITH_STRESS && len(ems) > 0 {
			ess := make([]string, 0, len(ems))
			cnt := 0
			for k, v := range ems {
				ess = append(ess, fmt.Sprintf("%s (count: %d)", k, v))
				cnt += v
			}
			clus.lg.Warn(
				"expected no errors",
				zap.String("desc", fa.Desc()),
				zap.Strings("errors", ess),
			)

			// with network delay, some ongoing requests may fail
			// only return error, if more than 30% of QPS requests fail
			if cnt > int(float64(clus.Tester.StressQPS)*0.3) {
				clus.failed(t, fmt.Errorf("expected no error in %q, got %q", fcase.String(), ess))
			}
		}
	}

	clus.lg.Info(
		"health check START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
	)
	if err := clus.WaitHealth(); err != nil {
		clus.failed(t, fmt.Errorf("wait full health error after test finished: %w", err))
	}

	var checkerFailExceptions []rpcpb.Checker
	switch fcase {
	case rpcpb.Case_SIGQUIT_AND_REMOVE_QUORUM_AND_RESTORE_LEADER_SNAPSHOT_FROM_SCRATCH:
		// TODO: restore from snapshot
		checkerFailExceptions = append(checkerFailExceptions, rpcpb.Checker_LEASE_EXPIRE)
	}

	clus.lg.Info(
		"consistency check START",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
	)
	if err := clus.runCheckers(checkerFailExceptions...); err != nil {
		clus.failed(t, fmt.Errorf("consistency check error: %w", err))
	}
	clus.lg.Info(
		"consistency check PASS",
		zap.Int("round", clus.rd),
		zap.Int("case", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.String("desc", fa.Desc()),
		zap.Duration("took", time.Since(caseNow)),
	)
}

func (clus *Cluster) updateRevision() error {
	revs, _, err := clus.getRevisionHash()
	for _, rev := range revs {
		clus.currentRevision = rev
		break // just need get one of the current revisions
	}

	clus.lg.Info(
		"updated current revision",
		zap.Int64("current-revision", clus.currentRevision),
	)
	return err
}

func (clus *Cluster) compact(rev int64, timeout time.Duration) (err error) {
	if err = clus.compactKV(rev, timeout); err != nil {
		clus.lg.Warn(
			"compact FAIL",
			zap.Int64("current-revision", clus.currentRevision),
			zap.Int64("compact-revision", rev),
			zap.Error(err),
		)
		return err
	}
	clus.lg.Info(
		"compact DONE",
		zap.Int64("current-revision", clus.currentRevision),
		zap.Int64("compact-revision", rev),
	)

	if err = clus.checkCompact(rev); err != nil {
		clus.lg.Warn(
			"check compact FAIL",
			zap.Int64("current-revision", clus.currentRevision),
			zap.Int64("compact-revision", rev),
			zap.Error(err),
		)
		return err
	}
	clus.lg.Info(
		"check compact DONE",
		zap.Int64("current-revision", clus.currentRevision),
		zap.Int64("compact-revision", rev),
	)

	return nil
}

func (clus *Cluster) failed(t *testing.T, err error) {
	clus.lg.Error(
		"functional-tester FAIL",
		zap.Int("round", clus.rd),
		zap.String("case-name", t.Name()),
		zap.Int("case-number", clus.cs),
		zap.Int("case-total", len(clus.cases)),
		zap.Error(err),
	)

	os.Exit(2)
}