package scsi

import (
	"github.com/gostor/gotgt/pkg/api"
	"github.com/satori/go.uuid"
)

type SCSIReservationOperator interface {
	GetCurrentReservation(tgtName string, devUUID uint64) *api.SCSIReservation
	SetCurrentReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool
	IsCurrentReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool

	GetPRGeneration(tgtName string, devUUID uint64) (uint32, bool)
	IncPRGeneration(tgtName string, devUUID uint64) bool

	AddReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool
	GetReservation(tgtName string, devUUID uint64, ITNexusID uuid.UUID) *api.SCSIReservation
	GetReservationList(tgtName string, devUUID uint64) []*api.SCSIReservation
	DeleteAndRemoveReservation(tgtName string, devUUID uint64, res *api.SCSIReservation)
	RemoveReservation(tgtName string, devUUID uint64, res *api.SCSIReservation)
	RemoveAllReservation(tgtName string, devUUID uint64)

	IsKeyExists(tgtName string, devUUID uint64, key uint64) bool

	Save(tgtName string, devUUID uint64) bool
}

var onePROperator SCSIReservationOperator

func GetSCSIReservationOperator() SCSIReservationOperator {
	if onePROperator == nil {
		onePROperator = &SCSISimpleReservationOperator{
			targetReservations: make(map[string]SCSILUReservationMap),
		}
	}
	return onePROperator
}

type SCSILUReservation struct {
	TargetName         string
	DeviceUUID         uint64
	PRGeneration       uint32
	Reservations       []*api.SCSIReservation
	CurrentReservation *api.SCSIReservation
}

type SCSILUReservationMap map[uint64]*SCSILUReservation /* device uuid as the key */

type SCSISimpleReservationOperator struct {
	SCSIReservationOperator
	targetReservations map[string]SCSILUReservationMap /* target name as the key*/
}

func (op *SCSISimpleReservationOperator) InitLUReservation(tgtName string, devUUID uint64) {
	var (
		targetRes SCSILUReservationMap
		ok        bool
	)

	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		op.targetReservations[tgtName] = make(SCSILUReservationMap)
		targetRes = op.targetReservations[tgtName]
	}
	if _, ok = targetRes[devUUID]; !ok {
		targetRes[devUUID] = &SCSILUReservation{TargetName: tgtName,
			DeviceUUID:         devUUID,
			PRGeneration:       0,
			Reservations:       []*api.SCSIReservation{},
			CurrentReservation: nil,
		}
	}
}

func (op *SCSISimpleReservationOperator) GetReservation(tgtName string, devUUID uint64, ITNexusID uuid.UUID) *api.SCSIReservation {
	var (
		LURes     *SCSILUReservation
		SCSIRes   *api.SCSIReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return nil
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return nil
	}
	for _, SCSIRes = range LURes.Reservations {
		if uuid.Equal(SCSIRes.ITNexusID, ITNexusID) {
			return SCSIRes
		}
	}

	return nil
}

func (op *SCSISimpleReservationOperator) GetPRGeneration(tgtName string, devUUID uint64) (uint32, bool) {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return 0, false
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return 0, false
	}

	return LURes.PRGeneration, true
}

func (op *SCSISimpleReservationOperator) IncPRGeneration(tgtName string, devUUID uint64) bool {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return false
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return false
	}
	LURes.PRGeneration++
	return true
}

func (op *SCSISimpleReservationOperator) GetCurrentReservation(tgtName string, devUUID uint64) *api.SCSIReservation {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return nil
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return nil
	}
	return LURes.CurrentReservation
}

func (op *SCSISimpleReservationOperator) SetCurrentReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return false
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return false
	}
	LURes.CurrentReservation = res
	return true
}

func (op *SCSISimpleReservationOperator) GetReservationList(tgtName string, devUUID uint64) []*api.SCSIReservation {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return nil
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return nil
	}
	return LURes.Reservations
}

func (op *SCSISimpleReservationOperator) DeleteAndRemoveReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) {
	var (
		i         int = -1
		ok        bool
		tmpRes    *api.SCSIReservation
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return
	}

	resArray := LURes.Reservations
	curRes := LURes.CurrentReservation

	for i, tmpRes = range resArray {
		if tmpRes == res {
			break
		}
	}

	if i >= 0 {
		resArray[i] = resArray[len(resArray)-1]
		resArray[len(resArray)-1] = nil
		resArray = resArray[:len(resArray)-1]
	}

	if curRes == nil {
		return
	}

	if !op.IsCurrentReservation(tgtName, devUUID, res) {
		return
	}

	if (curRes.Type != PR_TYPE_WRITE_EXCLUSIVE_ALLREG &&
		curRes.Type != PR_TYPE_EXCLUSIVE_ACCESS_ALLREG) ||
		len(resArray) == 0 {
		curRes.Scope = 0
		curRes.Type = 0
		LURes.CurrentReservation = nil
		for i, tmpRes = range resArray {
			if tmpRes == res {
				continue
			}
			//TODO send sense code
		}
		LURes.PRGeneration++
	} else {
		for i, tmpRes = range resArray {
			if tmpRes != res {
				//kep scope and type
				LURes.CurrentReservation = tmpRes
				tmpRes.Scope = curRes.Scope
				tmpRes.Type = curRes.Type
				break
			}
		}
		LURes.PRGeneration++
	}

}

func (op *SCSISimpleReservationOperator) RemoveReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) {
	var (
		i      int = -1
		tmpRes *api.SCSIReservation
	)

	resArray := op.GetReservationList(tgtName, devUUID)

	for i, tmpRes = range resArray {
		if tmpRes == res {
			break
		}
	}

	if i >= 0 {
		resArray[i] = resArray[len(resArray)-1]
		resArray[len(resArray)-1] = nil
		resArray = resArray[:len(resArray)-1]
	}
}

func (op *SCSISimpleReservationOperator) AddReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return false
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return false
	}
	LURes.Reservations = append(LURes.Reservations, res)
	return true
}

func (op *SCSISimpleReservationOperator) IsKeyExists(tgtName string, devUUID uint64, key uint64) bool {

	resList := op.GetReservationList(tgtName, devUUID)
	for _, tmpRes := range resList {
		if tmpRes.Key == key {
			return true
		}
	}

	return false
}

func (op *SCSISimpleReservationOperator) IsCurrentReservation(tgtName string, devUUID uint64, res *api.SCSIReservation) bool {
	curRes := op.GetCurrentReservation(tgtName, devUUID)
	if curRes == nil {
		return false
	}
	if curRes.Type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG ||
		curRes.Type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG {
		return true
	}

	if curRes == res {
		return true
	}

	return false
}

func (op *SCSISimpleReservationOperator) RemoveAllReservation(tgtName string, devUUID uint64) {
	var (
		LURes     *SCSILUReservation
		targetRes SCSILUReservationMap
		ok        bool
	)
	if targetRes, ok = op.targetReservations[tgtName]; !ok {
		return
	}
	if LURes, ok = targetRes[devUUID]; !ok {
		return
	}
	LURes.Reservations = []*api.SCSIReservation{}

}

func (op *SCSISimpleReservationOperator) Save(tgtName string, devUUID uint64) bool {
	return true
}