/*
Copyright 2013 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"
	"sync/atomic"
)

const (
	SetSuccess = iota
	SetFail
	DeleteSuccess
	DeleteFail
	CreateSuccess
	CreateFail
	UpdateSuccess
	UpdateFail
	CompareAndSwapSuccess
	CompareAndSwapFail
	GetSuccess
	GetFail
	ExpireCount
	CompareAndDeleteSuccess
	CompareAndDeleteFail
)

type Stats struct {

	// Number of get requests
	GetSuccess uint64 `json:"getsSuccess"`
	GetFail    uint64 `json:"getsFail"`

	// Number of sets requests
	SetSuccess uint64 `json:"setsSuccess"`
	SetFail    uint64 `json:"setsFail"`

	// Number of delete requests
	DeleteSuccess uint64 `json:"deleteSuccess"`
	DeleteFail    uint64 `json:"deleteFail"`

	// Number of update requests
	UpdateSuccess uint64 `json:"updateSuccess"`
	UpdateFail    uint64 `json:"updateFail"`

	// Number of create requests
	CreateSuccess uint64 `json:"createSuccess"`
	CreateFail    uint64 `json:"createFail"`

	// Number of testAndSet requests
	CompareAndSwapSuccess uint64 `json:"compareAndSwapSuccess"`
	CompareAndSwapFail    uint64 `json:"compareAndSwapFail"`

	// Number of compareAndDelete requests
	CompareAndDeleteSuccess uint64 `json:"compareAndDeleteSuccess"`
	CompareAndDeleteFail    uint64 `json:"compareAndDeleteFail"`

	ExpireCount uint64 `json:"expireCount"`

	Watchers uint64 `json:"watchers"`
}

func newStats() *Stats {
	s := new(Stats)
	return s
}

func (s *Stats) clone() *Stats {
	return &Stats{s.GetSuccess, s.GetFail, s.SetSuccess, s.SetFail,
		s.DeleteSuccess, s.DeleteFail, s.UpdateSuccess, s.UpdateFail, s.CreateSuccess,
		s.CreateFail, s.CompareAndSwapSuccess, s.CompareAndSwapFail,
		s.CompareAndDeleteSuccess, s.CompareAndDeleteFail, s.Watchers, s.ExpireCount}
}

// Status() return the statistics info of etcd storage its recent start
func (s *Stats) toJson() []byte {
	b, _ := json.Marshal(s)
	return b
}

func (s *Stats) TotalReads() uint64 {
	return s.GetSuccess + s.GetFail
}

func (s *Stats) TotalTranscations() uint64 {
	return s.SetSuccess + s.SetFail +
		s.DeleteSuccess + s.DeleteFail +
		s.CompareAndSwapSuccess + s.CompareAndSwapFail +
		s.CompareAndDeleteSuccess + s.CompareAndDeleteFail +
		s.UpdateSuccess + s.UpdateFail
}

func (s *Stats) Inc(field int) {
	switch field {
	case SetSuccess:
		atomic.AddUint64(&s.SetSuccess, 1)
	case SetFail:
		atomic.AddUint64(&s.SetFail, 1)
	case CreateSuccess:
		atomic.AddUint64(&s.CreateSuccess, 1)
	case CreateFail:
		atomic.AddUint64(&s.CreateFail, 1)
	case DeleteSuccess:
		atomic.AddUint64(&s.DeleteSuccess, 1)
	case DeleteFail:
		atomic.AddUint64(&s.DeleteFail, 1)
	case GetSuccess:
		atomic.AddUint64(&s.GetSuccess, 1)
	case GetFail:
		atomic.AddUint64(&s.GetFail, 1)
	case UpdateSuccess:
		atomic.AddUint64(&s.UpdateSuccess, 1)
	case UpdateFail:
		atomic.AddUint64(&s.UpdateFail, 1)
	case CompareAndSwapSuccess:
		atomic.AddUint64(&s.CompareAndSwapSuccess, 1)
	case CompareAndSwapFail:
		atomic.AddUint64(&s.CompareAndSwapFail, 1)
	case CompareAndDeleteSuccess:
		atomic.AddUint64(&s.CompareAndDeleteSuccess, 1)
	case CompareAndDeleteFail:
		atomic.AddUint64(&s.CompareAndDeleteFail, 1)
	case ExpireCount:
		atomic.AddUint64(&s.ExpireCount, 1)
	}
}
