/*
   Copyright 2014 CoreOS, 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 store

import (
	"encoding/json"
	"fmt"
	"runtime"
	"testing"
)

func BenchmarkStoreSet128Bytes(b *testing.B) {
	benchStoreSet(b, 128, nil)
}

func BenchmarkStoreSet1024Bytes(b *testing.B) {
	benchStoreSet(b, 1024, nil)
}

func BenchmarkStoreSet4096Bytes(b *testing.B) {
	benchStoreSet(b, 4096, nil)
}

func BenchmarkStoreSetWithJson128Bytes(b *testing.B) {
	benchStoreSet(b, 128, json.Marshal)
}

func BenchmarkStoreSetWithJson1024Bytes(b *testing.B) {
	benchStoreSet(b, 1024, json.Marshal)
}

func BenchmarkStoreSetWithJson4096Bytes(b *testing.B) {
	benchStoreSet(b, 4096, json.Marshal)
}

func BenchmarkStoreDelete(b *testing.B) {
	b.StopTimer()

	s := newStore()
	kvs, _ := generateNRandomKV(b.N, 128)

	memStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(memStats)

	for i := 0; i < b.N; i++ {
		_, err := s.Set(kvs[i][0], false, kvs[i][1], Permanent)
		if err != nil {
			panic(err)
		}
	}

	setMemStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(setMemStats)

	b.StartTimer()

	for i := range kvs {
		s.Delete(kvs[i][0], false, false)
	}

	b.StopTimer()

	// clean up
	e, err := s.Get("/", false, false)
	if err != nil {
		panic(err)
	}

	for _, n := range e.Node.Nodes {
		_, err := s.Delete(n.Key, true, true)
		if err != nil {
			panic(err)
		}
	}
	s.WatcherHub.EventHistory = nil

	deleteMemStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(deleteMemStats)

	fmt.Printf("\nBefore set Alloc: %v; After set Alloc: %v, After delete Alloc: %v\n",
		memStats.Alloc/1000, setMemStats.Alloc/1000, deleteMemStats.Alloc/1000)
}

func BenchmarkWatch(b *testing.B) {
	b.StopTimer()
	s := newStore()
	kvs, _ := generateNRandomKV(b.N, 128)
	b.StartTimer()

	memStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(memStats)

	for i := 0; i < b.N; i++ {
		w, _ := s.Watch(kvs[i][0], false, false, 0)

		e := newEvent("set", kvs[i][0], uint64(i+1), uint64(i+1))
		s.WatcherHub.notify(e)
		<-w.EventChan()
		s.CurrentIndex++
	}

	s.WatcherHub.EventHistory = nil
	afterMemStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(afterMemStats)
	fmt.Printf("\nBefore Alloc: %v; After Alloc: %v\n",
		memStats.Alloc/1000, afterMemStats.Alloc/1000)
}

func BenchmarkWatchWithSet(b *testing.B) {
	b.StopTimer()
	s := newStore()
	kvs, _ := generateNRandomKV(b.N, 128)
	b.StartTimer()

	for i := 0; i < b.N; i++ {
		w, _ := s.Watch(kvs[i][0], false, false, 0)

		s.Set(kvs[i][0], false, "test", Permanent)
		<-w.EventChan()
	}
}

func BenchmarkWatchWithSetBatch(b *testing.B) {
	b.StopTimer()
	s := newStore()
	kvs, _ := generateNRandomKV(b.N, 128)
	b.StartTimer()

	watchers := make([]Watcher, b.N)

	for i := 0; i < b.N; i++ {
		watchers[i], _ = s.Watch(kvs[i][0], false, false, 0)
	}

	for i := 0; i < b.N; i++ {
		s.Set(kvs[i][0], false, "test", Permanent)
	}

	for i := 0; i < b.N; i++ {
		<-watchers[i].EventChan()
	}

}

func BenchmarkWatchOneKey(b *testing.B) {
	s := newStore()
	watchers := make([]Watcher, b.N)

	for i := 0; i < b.N; i++ {
		watchers[i], _ = s.Watch("/foo", false, false, 0)
	}

	s.Set("/foo", false, "", Permanent)

	for i := 0; i < b.N; i++ {
		<-watchers[i].EventChan()
	}
}

func benchStoreSet(b *testing.B, valueSize int, process func(interface{}) ([]byte, error)) {
	s := newStore()
	b.StopTimer()
	kvs, size := generateNRandomKV(b.N, valueSize)
	b.StartTimer()

	for i := 0; i < b.N; i++ {
		resp, err := s.Set(kvs[i][0], false, kvs[i][1], Permanent)
		if err != nil {
			panic(err)
		}

		if process != nil {
			_, err = process(resp)
			if err != nil {
				panic(err)
			}
		}
	}

	kvs = nil
	b.StopTimer()
	memStats := new(runtime.MemStats)
	runtime.GC()
	runtime.ReadMemStats(memStats)
	fmt.Printf("\nAlloc: %vKB; Data: %vKB; Kvs: %v; Alloc/Data:%v\n",
		memStats.Alloc/1000, size/1000, b.N, memStats.Alloc/size)
}

func generateNRandomKV(n int, valueSize int) ([][]string, uint64) {
	var size uint64
	kvs := make([][]string, n)
	bytes := make([]byte, valueSize)

	for i := 0; i < n; i++ {
		kvs[i] = make([]string, 2)
		kvs[i][0] = fmt.Sprintf("/%010d/%010d/%010d", n, n, n)
		kvs[i][1] = string(bytes)
		size = size + uint64(len(kvs[i][0])) + uint64(len(kvs[i][1]))
	}

	return kvs, size
}