/*
 *     Copyright 2020 The Dragonfly 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 cache

import (
	"bytes"
	"os"
	"runtime"
	"strconv"
	"sync"
	"testing"
	"time"

	testifyassert "github.com/stretchr/testify/assert"
)

var (
	v1 = "foo"
	v2 = "bar"
	v3 = "baz"
	v4 = "yes"
)

type TestStruct struct {
	Num      int
	Children []*TestStruct
}

func TestCache(t *testing.T) {
	tc := New(DefaultExpiration, 0)

	a, found := tc.Get("a")
	if found || a != nil {
		t.Error("Getting A found value that shouldn't exist:", a)
	}

	b, found := tc.Get("b")
	if found || b != nil {
		t.Error("Getting B found value that shouldn't exist:", b)
	}

	c, found := tc.Get("c")
	if found || c != nil {
		t.Error("Getting C found value that shouldn't exist:", c)
	}

	tc.Set("a", 1, DefaultExpiration)
	tc.Set("b", "b", DefaultExpiration)
	tc.Set("c", 3.5, DefaultExpiration)

	x, found := tc.Get("a")
	if !found {
		t.Error("a was not found while getting a2")
	}
	if x == nil {
		t.Error("x for a is nil")
	} else if a2 := x.(int); a2+2 != 3 {
		t.Error("a2 (which should be 1) plus 2 does not equal 3; value:", a2)
	}

	x, found = tc.Get("b")
	if !found {
		t.Error("b was not found while getting b2")
	}
	if x == nil {
		t.Error("x for b is nil")
	} else if b2 := x.(string); b2+"B" != "bB" {
		t.Error("b2 (which should be b) plus B does not equal bB; value:", b2)
	}

	x, found = tc.Get("c")
	if !found {
		t.Error("c was not found while getting c2")
	}
	if x == nil {
		t.Error("x for c is nil")
	} else if c2 := x.(float64); c2+1.2 != 4.7 {
		t.Error("c2 (which should be 3.5) plus 1.2 does not equal 4.7; value:", c2)
	}
}

func TestCacheTimes(t *testing.T) {
	var found bool

	tc := New(100*time.Millisecond, 1*time.Millisecond)
	tc.Set("a", 1, DefaultExpiration)
	tc.Set("b", 2, NoExpiration)
	tc.Set("c", 3, 40*time.Millisecond)
	tc.Set("d", 4, 140*time.Millisecond)

	<-time.After(50 * time.Millisecond)
	_, found = tc.Get("c")
	if found {
		t.Error("Found c when it should have been automatically deleted")
	}

	<-time.After(80 * time.Millisecond)
	_, found = tc.Get("a")
	if found {
		t.Error("Found a when it should have been automatically deleted")
	}

	_, found = tc.Get("b")
	if !found {
		t.Error("Did not find b even though it was set to never expire")
	}

	_, found = tc.Get("d")
	if !found {
		t.Error("Did not find d even though it was set to expire later than the default")
	}

	<-time.After(40 * time.Millisecond)
	_, found = tc.Get("d")
	if found {
		t.Error("Found d when it should have been automatically deleted (later than the default)")
	}
}

func TestStorePointerToStruct(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, &TestStruct{Num: 1}, DefaultExpiration)
	x, found := tc.Get(v1)
	if !found {
		t.Fatal("*TestStruct was not found for foo")
	}
	foo := x.(*TestStruct)
	foo.Num++

	y, found := tc.Get(v1)
	if !found {
		t.Fatal("*TestStruct was not found for foo (second time)")
	}
	bar := y.(*TestStruct)
	if bar.Num != 2 {
		t.Fatal("TestStruct.Num is not 2")
	}
}

func TestScan(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v2, v1, DefaultExpiration)
	tc.Set(v3, v1, DefaultExpiration)
	keys, err := tc.Scan("^b", 1)
	if err != nil {
		t.Error("Couldn't parse a regular expression and returns")
	}

	if len(keys) != 1 {
		t.Error("Invalid number of scaning cache keys")
	}

	keys, err = tc.Scan("^b", 2)
	if err != nil {
		t.Error("Couldn't parse a regular expression and returns")
	}

	if len(keys) != 2 {
		t.Error("Invalid number of scaning cache keys")
	}

	keys, err = tc.Scan("^b", 4)
	if err != nil {
		t.Error("Couldn't parse a regular expression and returns")
	}

	if len(keys) != 2 {
		t.Error("Invalid number of scaning cache keys")
	}

	keys, err = tc.Scan("^ba", 2)
	if err != nil {
		t.Error("Couldn't parse a regular expression and returns")
	}

	if len(keys) != 2 {
		t.Error("Invalid number of scaning cache keys")
	}

	keys, err = tc.Scan("^a", 2)
	if err != nil {
		t.Error("Couldn't parse a regular expression and returns")
	}

	if len(keys) != 0 {
		t.Error("Invalid number of scaning cache keys")
	}

	_, err = tc.Scan("(", 2)
	if err == nil {
		t.Error("Parse a fault regular expression")
	}
}

func TestAdd(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	err := tc.Add(v1, v2, DefaultExpiration)
	if err != nil {
		t.Error("Couldn't add foo even though it shouldn't exist")
	}
	err = tc.Add(v1, v3, DefaultExpiration)
	if err == nil {
		t.Error("Successfully added another foo when it should have returned an error")
	}
}

func TestDelete(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, v2, DefaultExpiration)
	tc.Delete(v1)
	x, found := tc.Get(v1)
	if found {
		t.Error("foo was found, but it should have been deleted")
	}
	if x != nil {
		t.Error("x is not nil:", x)
	}
}

func TestCacheKeys(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, 1, DefaultExpiration)
	tc.Set(v2, 2, DefaultExpiration)
	tc.Set(v3, 3, DefaultExpiration)
	keys := tc.Keys()
	if len(keys) != 3 {
		t.Error("invalid number of cache keys received")
	}
}

func TestItems(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, "1", 1)
	tc.Set(v2, "2", DefaultExpiration)
	tc.Set(v3, "3", DefaultExpiration)
	m := tc.Items()
	assert := testifyassert.New(t)
	assert.Equal(map[string]Item{"bar": {Object: "2", Expiration: 0}, "baz": {Object: "3", Expiration: 0}}, m)
}

func TestItemCount(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, "1", DefaultExpiration)
	tc.Set(v2, "2", DefaultExpiration)
	tc.Set(v3, "3", DefaultExpiration)
	if n := tc.ItemCount(); n != 3 {
		t.Errorf("Item count is not 3: %d", n)
	}
}

func TestFlush(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, v2, DefaultExpiration)
	tc.Set(v3, v4, DefaultExpiration)
	tc.Flush()
	x, found := tc.Get(v1)
	if found {
		t.Error("foo was found, but it should have been deleted")
	}
	if x != nil {
		t.Error("x is not nil:", x)
	}
	x, found = tc.Get(v3)
	if found {
		t.Error("baz was found, but it should have been deleted")
	}
	if x != nil {
		t.Error("x is not nil:", x)
	}
}

func TestOnEvicted(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	tc.Set(v1, 3, DefaultExpiration)
	works := false
	tc.OnEvicted(func(k string, v any) {
		if k == v1 && v.(int) == 3 {
			works = true
		}
		tc.Set(v2, 4, DefaultExpiration)
	})
	tc.Delete(v1)
	x, _ := tc.Get(v2)
	if !works {
		t.Error("works bool not true")
	}
	if x.(int) != 4 {
		t.Error("bar was not 4")
	}
}

func TestCacheSerialization(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	testFillAndSerialize(t, tc)

	// Check if gob.Register behaves properly even after multiple gob.Register
	// on c.Items (many of which will be the same type)
	testFillAndSerialize(t, tc)
}

func testFillAndSerialize(t *testing.T, tc Cache) {
	tc.Set("a", "a", DefaultExpiration)
	tc.Set("b", "b", DefaultExpiration)
	tc.Set("c", "c", DefaultExpiration)
	tc.Set("expired", "foo", 1*time.Millisecond)
	tc.Set("*struct", &TestStruct{Num: 1}, DefaultExpiration)
	tc.Set("[]struct", []TestStruct{
		{Num: 2},
		{Num: 3},
	}, DefaultExpiration)

	fp := &bytes.Buffer{}
	err := tc.Save(fp)
	if err != nil {
		t.Fatal("Couldn't save cache to fp:", err)
	}

	oc := New(DefaultExpiration, 0)
	err = oc.Load(fp)
	if err != nil {
		t.Fatal("Couldn't load cache from fp:", err)
	}

	a, found := oc.Get("a")
	if !found {
		t.Error("a was not found")
	}
	if a.(string) != "a" {
		t.Error("a is not a")
	}

	b, found := oc.Get("b")
	if !found {
		t.Error("b was not found")
	}
	if b.(string) != "b" {
		t.Error("b is not b")
	}

	c, found := oc.Get("c")
	if !found {
		t.Error("c was not found")
	}
	if c.(string) != "c" {
		t.Error("c is not c")
	}

	<-time.After(5 * time.Millisecond)
	_, found = oc.Get("expired")
	if !found {
		t.Error("expired was not found")
	}

	s1, found := oc.Get("*struct")
	if !found {
		t.Error("*struct was not found")
	}
	if s1.(*TestStruct).Num != 1 {
		t.Error("*struct.Num is not 1")
	}

	s2, found := oc.Get("[]struct")
	if !found {
		t.Error("[]struct was not found")
	}
	s2r := s2.([]TestStruct)
	if len(s2r) != 2 {
		t.Error("Length of s2r is not 2")
	}
	if s2r[0].Num != 2 {
		t.Error("s2r[0].Num is not 2")
	}
	if s2r[1].Num != 3 {
		t.Error("s2r[1].Num is not 3")
	}
}

func TestFileSerialization(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	if err := tc.Add("a", "a", DefaultExpiration); err != nil {
		t.Error(err)
	}
	if err := tc.Add("b", "b", DefaultExpiration); err != nil {
		t.Error(err)
	}

	f, err := os.CreateTemp("", "go-cache-cache.dat")
	if err != nil {
		t.Fatal("Couldn't create cache file:", err)
	}
	fname := f.Name()
	f.Close()

	if err := tc.SaveFile(fname); err != nil {
		t.Fatal(err)
	}

	oc := New(DefaultExpiration, 0)
	// this should not be overwritten
	if err := oc.Add("a", "aa", 0); err != nil {
		t.Error(err)
	}

	if err := oc.LoadFile(fname); err != nil {
		t.Fatal(err)
	}

	a, found := oc.Get("a")
	if !found {
		t.Error("a was not found")
	}

	astr := a.(string)
	if astr != "aa" {
		if astr == "a" {
			t.Error("a was overwritten")
		} else {
			t.Error("a is not aa")
		}
	}

	b, found := oc.Get("b")
	if !found {
		t.Error("b was not found")
	}

	if b.(string) != "b" {
		t.Error("b is not b")
	}
}

func TestSerializeUnserializable(t *testing.T) {
	tc := New(DefaultExpiration, 0)
	ch := make(chan bool, 1)
	ch <- true
	tc.Set("chan", ch, DefaultExpiration)
	fp := &bytes.Buffer{}
	err := tc.Save(fp) // this should fail gracefully
	if err.Error() != "gob NewTypeObject can't handle type: chan bool" {
		t.Error("Error from Save was not gob NewTypeObject can't handle type chan bool:", err)
	}
}

func BenchmarkCacheGetExpiring(b *testing.B) {
	benchmarkCacheGet(b, 5*time.Minute)
}

func BenchmarkCacheGetNotExpiring(b *testing.B) {
	benchmarkCacheGet(b, NoExpiration)
}

func benchmarkCacheGet(b *testing.B, exp time.Duration) {
	b.StopTimer()
	tc := New(exp, 0)
	tc.Set(v1, v2, DefaultExpiration)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		tc.Get(v1)
	}
}

func BenchmarkRWMutexMapGet(b *testing.B) {
	b.StopTimer()
	m := map[string]string{
		v1: v2,
	}
	var mu sync.RWMutex
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.RLock()
		_, _ = m[v1]
		mu.RUnlock()
	}
}

func BenchmarkRWMutexInterfaceMapGetStruct(b *testing.B) {
	b.StopTimer()
	s := struct{ name string }{name: v1}
	m := map[any]string{
		s: v2,
	}
	var mu sync.RWMutex
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.RLock()
		_, _ = m[s]
		mu.RUnlock()
	}
}

func BenchmarkRWMutexInterfaceMapGetString(b *testing.B) {
	b.StopTimer()
	m := map[any]string{
		v1: v2,
	}
	var mu sync.RWMutex
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.RLock()
		_, _ = m[v1]
		mu.RUnlock()
	}
}

func BenchmarkCacheGetConcurrentExpiring(b *testing.B) {
	benchmarkCacheGetConcurrent(b, 5*time.Minute)
}

func BenchmarkCacheGetConcurrentNotExpiring(b *testing.B) {
	benchmarkCacheGetConcurrent(b, NoExpiration)
}

func benchmarkCacheGetConcurrent(b *testing.B, exp time.Duration) {
	b.StopTimer()
	tc := New(exp, 0)
	tc.Set(v1, v2, DefaultExpiration)
	wg := new(sync.WaitGroup)
	workers := runtime.NumCPU()
	each := b.N / workers
	wg.Add(workers)
	b.StartTimer()
	for range workers {
		go func() {
			for range each {
				tc.Get(v1)
			}
			wg.Done()
		}()
	}
	wg.Wait()
}

func BenchmarkRWMutexMapGetConcurrent(b *testing.B) {
	b.StopTimer()
	m := map[string]string{
		v1: v2,
	}
	mu := sync.RWMutex{}
	wg := new(sync.WaitGroup)
	workers := runtime.NumCPU()
	each := b.N / workers
	wg.Add(workers)
	b.StartTimer()
	for range workers {
		go func() {
			for range each {
				mu.RLock()
				_, _ = m[v1]
				mu.RUnlock()
			}
			wg.Done()
		}()
	}
	wg.Wait()
}

func BenchmarkCacheGetManyConcurrentExpiring(b *testing.B) {
	benchmarkCacheGetManyConcurrent(b, 5*time.Minute)
}

func BenchmarkCacheGetManyConcurrentNotExpiring(b *testing.B) {
	benchmarkCacheGetManyConcurrent(b, NoExpiration)
}

func benchmarkCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
	// This is the same as BenchmarkCacheGetConcurrent, but its result
	// can be compared against BenchmarkShardedCacheGetManyConcurrent
	// in sharded_test.go.
	b.StopTimer()
	n := 10000
	tc := New(exp, 0)
	keys := make([]string, n)
	for i := range n {
		k := v1 + strconv.Itoa(i)
		keys[i] = k
		tc.Set(k, v2, DefaultExpiration)
	}
	each := b.N / n
	wg := new(sync.WaitGroup)
	wg.Add(n)
	for _, v := range keys {
		go func(k string) {
			for range each {
				tc.Get(k)
			}
			wg.Done()
		}(v)
	}
	b.StartTimer()
	wg.Wait()
}

func BenchmarkCacheSetExpiring(b *testing.B) {
	benchmarkCacheSet(b, 5*time.Minute)
}

func BenchmarkCacheSetNotExpiring(b *testing.B) {
	benchmarkCacheSet(b, NoExpiration)
}

func benchmarkCacheSet(b *testing.B, exp time.Duration) {
	b.StopTimer()
	tc := New(exp, 0)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		tc.Set(v1, v2, DefaultExpiration)
	}
}

func BenchmarkRWMutexMapSet(b *testing.B) {
	b.StopTimer()
	m := map[string]string{}
	mu := sync.RWMutex{}
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.Lock()
		m[v1] = v2
		mu.Unlock()
	}
}

func BenchmarkCacheSetDelete(b *testing.B) {
	b.StopTimer()
	tc := New(DefaultExpiration, 0)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		tc.Set(v1, v2, DefaultExpiration)
		tc.Delete(v1)
	}
}

func BenchmarkRWMutexMapSetDelete(b *testing.B) {
	b.StopTimer()
	m := map[string]string{}
	mu := sync.RWMutex{}
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.Lock()
		m[v1] = v2
		mu.Unlock()
		mu.Lock()
		delete(m, v1)
		mu.Unlock()
	}
}

func BenchmarkRWMutexMapSetDeleteSingleLock(b *testing.B) {
	b.StopTimer()
	m := map[string]string{}
	var mu sync.Mutex
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		mu.Lock()
		m[v1] = v2
		delete(m, v1)
		mu.Unlock()
	}
}

func TestGetWithExpiration(t *testing.T) {
	tc := New(DefaultExpiration, 0)

	a, expiration, found := tc.GetWithExpiration("a")
	if found || a != nil || !expiration.IsZero() {
		t.Error("Getting A found value that shouldn't exist:", a)
	}

	b, expiration, found := tc.GetWithExpiration("b")
	if found || b != nil || !expiration.IsZero() {
		t.Error("Getting B found value that shouldn't exist:", b)
	}

	c, expiration, found := tc.GetWithExpiration("c")
	if found || c != nil || !expiration.IsZero() {
		t.Error("Getting C found value that shouldn't exist:", c)
	}

	tc.Set("a", 1, DefaultExpiration)
	tc.Set("b", "b", DefaultExpiration)
	tc.Set("c", 3.5, DefaultExpiration)
	tc.Set("d", 1, NoExpiration)
	tc.Set("e", 1, 50*time.Millisecond)

	x, expiration, found := tc.GetWithExpiration("a")
	if !found {
		t.Error("a was not found while getting a2")
	}
	if x == nil {
		t.Error("x for a is nil")
	} else if a2 := x.(int); a2+2 != 3 {
		t.Error("a2 (which should be 1) plus 2 does not equal 3; value:", a2)
	}
	if !expiration.IsZero() {
		t.Error("expiration for a is not a zeroed time")
	}

	x, expiration, found = tc.GetWithExpiration("b")
	if !found {
		t.Error("b was not found while getting b2")
	}
	if x == nil {
		t.Error("x for b is nil")
	} else if b2 := x.(string); b2+"B" != "bB" {
		t.Error("b2 (which should be b) plus B does not equal bB; value:", b2)
	}
	if !expiration.IsZero() {
		t.Error("expiration for b is not a zeroed time")
	}

	x, expiration, found = tc.GetWithExpiration("c")
	if !found {
		t.Error("c was not found while getting c2")
	}
	if x == nil {
		t.Error("x for c is nil")
	} else if c2 := x.(float64); c2+1.2 != 4.7 {
		t.Error("c2 (which should be 3.5) plus 1.2 does not equal 4.7; value:", c2)
	}
	if !expiration.IsZero() {
		t.Error("expiration for c is not a zeroed time")
	}

	x, expiration, found = tc.GetWithExpiration("d")
	if !found {
		t.Error("d was not found while getting d2")
	}
	if x == nil {
		t.Error("x for d is nil")
	} else if d2 := x.(int); d2+2 != 3 {
		t.Error("d (which should be 1) plus 2 does not equal 3; value:", d2)
	}
	if !expiration.IsZero() {
		t.Error("expiration for d is not a zeroed time")
	}

	x, expiration, found = tc.GetWithExpiration("e")
	if !found {
		t.Error("e was not found while getting e2")
	}
	if x == nil {
		t.Error("x for e is nil")
	} else if e2 := x.(int); e2+2 != 3 {
		t.Error("e (which should be 1) plus 2 does not equal 3; value:", e2)
	}
	if expiration.UnixNano() < time.Now().UnixNano() {
		t.Error("expiration for e is in the past")
	}
}