// Copyright 2021 ByteDance Inc.
//
// 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 circuitbreaker

import (
	"math/rand"
	"testing"
	"time"
)

func BenchmarkBuckets(b *testing.B) {
	bk := bucket{}
	bk.Reset()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		bk.Fail()
		bk.Timeout()
		bk.Succeed()
	}
}

// TestMetricser1 tests basic functions
func TestMetricser1(t *testing.T) {
	m := newWindow()

	// no data
	deepEqual(t, m.ErrorRate(), float64(0))
	deepEqual(t, m.ConseErrors(), int64(0))
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(0))
	deepEqual(t, m.Timeouts(), int64(0))

	m.Fail()
	m.Timeout()
	m.Fail()
	m.Timeout()
	deepEqual(t, m.Failures(), int64(2))
	deepEqual(t, m.Timeouts(), int64(2))
	deepEqual(t, m.ErrorRate(), float64(1))
	deepEqual(t, m.ConseErrors(), int64(4))
	deepEqual(t, m.Successes(), int64(0))

	m.Succeed()
	deepEqual(t, m.ErrorRate(), float64(.8))
	deepEqual(t, m.ConseErrors(), int64(0))
	deepEqual(t, m.Successes(), int64(1))
	deepEqual(t, m.Failures(), int64(2))
	deepEqual(t, m.Timeouts(), int64(2))

	s, f, tm := m.Counts()
	deepEqual(t, s, int64(1))
	deepEqual(t, f, int64(2))
	deepEqual(t, tm, int64(2))

	tot := 1000000
	for i := 0; i < tot; i++ {
		t := rand.Intn(3)
		if t == 0 { // fail
			m.Fail()
		} else if t == 1 { // timeout
			m.Timeout()
		} else { // succeed
			m.Succeed()
		}
	}

	rate := m.ErrorRate()
	assert(t, rate > .6 && rate < .7)
	// it's not guaranteed in unstable ci env
	//s = m.Successes()
	//assert(t, s > int64(tot/3-1000) && s < int64(tot/3+1000))
	//f = m.Failures()
	//assert(t, f > int64(tot/3-1000) && f < int64(tot/3+1000))
	//ts := m.Timeouts()
	//assert(t, ts > int64(tot/3-1000) && ts < int64(tot/3+1000))
}

// TestMetricser2 tests functions about time
func TestMetricser2(t *testing.T) {
	t.Skipf("it's not a stable unit tests since depend time stricly")
	p, _ := NewPanel(nil, Options{BucketTime: time.Millisecond * 10, BucketNums: 100})
	b := p.(*panel).getBreaker("test")
	m := b.metricer
	expire := time.Millisecond * 10 * 100

	m.Succeed()
	deepEqual(t, m.Successes(), int64(1))
	deepEqual(t, m.Failures(), int64(0))
	deepEqual(t, m.Timeouts(), int64(0))

	time.Sleep(expire + time.Millisecond*10)
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(0))
	deepEqual(t, m.Timeouts(), int64(0))

	for i := 0; i < 10; i++ {
		m.Fail()
	}
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(10))
	deepEqual(t, m.Timeouts(), int64(0))
	deepEqual(t, m.ConseErrors(), int64(10))

	time.Sleep(expire / 2)
	for i := 0; i < 100; i++ {
		m.Fail()
	}
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(110))
	deepEqual(t, m.Timeouts(), int64(0))
	deepEqual(t, m.ConseErrors(), int64(110))

	time.Sleep(expire / 2)
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(100))
	deepEqual(t, m.Timeouts(), int64(0))
	deepEqual(t, m.ConseErrors(), int64(110))

	time.Sleep(expire / 2)
	deepEqual(t, m.Successes(), int64(0))
	deepEqual(t, m.Failures(), int64(0))
	deepEqual(t, m.Timeouts(), int64(0))
	deepEqual(t, m.ConseErrors(), int64(110))

	m.Succeed()
	deepEqual(t, m.Successes(), int64(1))
	deepEqual(t, m.Failures(), int64(0))
	deepEqual(t, m.Timeouts(), int64(0))
	deepEqual(t, m.ConseErrors(), int64(0))
}

func BenchmarkWindow(b *testing.B) {
	m := newWindow()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		m.Succeed()
	}
}

func BenchmarkWindowParallel(b *testing.B) {
	m := newWindow()
	b.ResetTimer()
	b.RunParallel(func(pb *testing.PB) {
		for pb.Next() {
			m.Succeed()
		}
	})
}

func BenchmarkWindowParallel2Cores(b *testing.B) {
	b.SetParallelism(2)
	m := newWindow()
	b.ResetTimer()
	b.RunParallel(func(pb *testing.PB) {
		for pb.Next() {
			m.Succeed()
		}
	})
}