/*
 * Copyright 2018-present Open Networking Foundation

 * 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 core

import (
	"context"
	"errors"
	"github.com/gogo/protobuf/proto"
	"github.com/opencord/voltha-go/common/log"
	"github.com/opencord/voltha-go/db/model"
	"github.com/opencord/voltha-go/kafka"
	"github.com/opencord/voltha-go/protos/core_adapter"
	ofp "github.com/opencord/voltha-go/protos/openflow_13"
	"github.com/opencord/voltha-go/protos/voltha"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"reflect"
	"runtime"
	"sync"
)

type DeviceManager struct {
	deviceAgents        map[string]*DeviceAgent
	adapterProxy        *AdapterProxy
	logicalDeviceMgr    *LogicalDeviceManager
	kafkaProxy          *kafka.KafkaMessagingProxy
	stateTransitions    *TransitionMap
	clusterDataProxy    *model.Proxy
	exitChannel         chan int
	lockDeviceAgentsMap sync.RWMutex
}

func newDeviceManager(kafkaProxy *kafka.KafkaMessagingProxy, cdProxy *model.Proxy) *DeviceManager {
	var deviceMgr DeviceManager
	deviceMgr.exitChannel = make(chan int, 1)
	deviceMgr.deviceAgents = make(map[string]*DeviceAgent)
	deviceMgr.adapterProxy = NewAdapterProxy(kafkaProxy)
	deviceMgr.kafkaProxy = kafkaProxy
	deviceMgr.clusterDataProxy = cdProxy
	deviceMgr.lockDeviceAgentsMap = sync.RWMutex{}
	return &deviceMgr
}

func (dMgr *DeviceManager) start(ctx context.Context, logicalDeviceMgr *LogicalDeviceManager) {
	log.Info("starting-device-manager")
	dMgr.logicalDeviceMgr = logicalDeviceMgr
	dMgr.stateTransitions = NewTransitionMap(dMgr)
	log.Info("device-manager-started")
}

func (dMgr *DeviceManager) stop(ctx context.Context) {
	log.Info("stopping-device-manager")
	dMgr.exitChannel <- 1
	log.Info("device-manager-stopped")
}

func sendResponse(ctx context.Context, ch chan interface{}, result interface{}) {
	if ctx.Err() == nil {
		// Returned response only of the ctx has not been cancelled/timeout/etc
		// Channel is automatically closed when a context is Done
		ch <- result
		log.Debugw("sendResponse", log.Fields{"result": result})
	} else {
		// Should the transaction be reverted back?
		log.Debugw("sendResponse-context-error", log.Fields{"context-error": ctx.Err()})
	}
}

func (dMgr *DeviceManager) addDeviceAgentToMap(agent *DeviceAgent) {
	dMgr.lockDeviceAgentsMap.Lock()
	defer dMgr.lockDeviceAgentsMap.Unlock()
	if _, exist := dMgr.deviceAgents[agent.deviceId]; !exist {
		dMgr.deviceAgents[agent.deviceId] = agent
	}
}

func (dMgr *DeviceManager) deleteDeviceAgentToMap(agent *DeviceAgent) {
	dMgr.lockDeviceAgentsMap.Lock()
	defer dMgr.lockDeviceAgentsMap.Unlock()
	delete(dMgr.deviceAgents, agent.deviceId)
}

func (dMgr *DeviceManager) getDeviceAgent(deviceId string) *DeviceAgent {
	// TODO If the device is not in memory it needs to be loaded first
	dMgr.lockDeviceAgentsMap.Lock()
	defer dMgr.lockDeviceAgentsMap.Unlock()
	if agent, ok := dMgr.deviceAgents[deviceId]; ok {
		return agent
	}
	return nil
}

func (dMgr *DeviceManager) createDevice(ctx context.Context, device *voltha.Device, ch chan interface{}) {
	log.Debugw("createDevice", log.Fields{"device": device, "aproxy": dMgr.adapterProxy})

	// Create and start a device agent for that device
	agent := newDeviceAgent(dMgr.adapterProxy, device, dMgr, dMgr.clusterDataProxy)
	dMgr.addDeviceAgentToMap(agent)
	agent.start(ctx)

	sendResponse(ctx, ch, agent.lastData)
}

func (dMgr *DeviceManager) enableDevice(ctx context.Context, id *voltha.ID, ch chan interface{}) {
	log.Debugw("enableDevice", log.Fields{"deviceid": id})
	var res interface{}
	if agent := dMgr.getDeviceAgent(id.Id); agent != nil {
		res = agent.enableDevice(ctx)
		log.Debugw("EnableDevice-result", log.Fields{"result": res})
	} else {
		res = status.Errorf(codes.NotFound, "%s", id.Id)
	}

	sendResponse(ctx, ch, res)
}

func (dMgr *DeviceManager) disableDevice(ctx context.Context, id *voltha.ID, ch chan interface{}) {
	log.Debugw("disableDevice", log.Fields{"deviceid": id})
	var res interface{}
	if agent := dMgr.getDeviceAgent(id.Id); agent != nil {
		res = agent.disableDevice(ctx)
		log.Debugw("disableDevice-result", log.Fields{"result": res})
	} else {
		res = status.Errorf(codes.NotFound, "%s", id.Id)
	}

	sendResponse(ctx, ch, res)
}

func (dMgr *DeviceManager) rebootDevice(ctx context.Context, id *voltha.ID, ch chan interface{}) {
	log.Debugw("rebootDevice", log.Fields{"deviceid": id})
	var res interface{}
	if agent := dMgr.getDeviceAgent(id.Id); agent != nil {
		res = agent.rebootDevice(ctx)
		log.Debugw("rebootDevice-result", log.Fields{"result": res})
	} else {
		res = status.Errorf(codes.NotFound, "%s", id.Id)
	}
	sendResponse(ctx, ch, res)
}

func (dMgr *DeviceManager) deleteDevice(ctx context.Context, id *voltha.ID, ch chan interface{}) {
	log.Debugw("deleteDevice", log.Fields{"deviceid": id})
	var res interface{}
	if agent := dMgr.getDeviceAgent(id.Id); agent != nil {
		res = agent.deleteDevice(ctx)
		if res == nil { //Success
			agent.stop(ctx)
			dMgr.deleteDeviceAgentToMap(agent)
		}
		log.Debugw("deleteDevice-result", log.Fields{"result": res})
	} else {
		res = status.Errorf(codes.NotFound, "%s", id.Id)
	}
	sendResponse(ctx, ch, res)
}

func (dMgr *DeviceManager) GetDevice(id string) (*voltha.Device, error) {
	log.Debugw("GetDevice", log.Fields{"deviceid": id})
	if agent := dMgr.getDeviceAgent(id); agent != nil {
		return agent.getDevice()
	}
	return nil, status.Errorf(codes.NotFound, "%s", id)
}

func (dMgr *DeviceManager) IsRootDevice(id string) (bool, error) {
	device, err := dMgr.GetDevice(id)
	if err != nil {
		return false, err
	}
	return device.Root, nil
}

func (dMgr *DeviceManager) ListDevices() (*voltha.Devices, error) {
	log.Debug("ListDevices")
	result := &voltha.Devices{}
	dMgr.lockDeviceAgentsMap.Lock()
	defer dMgr.lockDeviceAgentsMap.Unlock()
	for _, agent := range dMgr.deviceAgents {
		if device, err := agent.getDevice(); err == nil {
			cloned := proto.Clone(device).(*voltha.Device)
			result.Items = append(result.Items, cloned)
		}
	}
	return result, nil
}

func (dMgr *DeviceManager) updateDevice(device *voltha.Device) error {
	log.Debugw("updateDevice", log.Fields{"deviceid": device.Id, "device": device})
	if agent := dMgr.getDeviceAgent(device.Id); agent != nil {
		return agent.updateDevice(device)
	}
	return status.Errorf(codes.NotFound, "%s", device.Id)
}

func (dMgr *DeviceManager) addPort(deviceId string, port *voltha.Port) error {
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		if err := agent.addPort(port); err != nil {
			return err
		}
		//	Setup peer ports
		meAsPeer := &voltha.Port_PeerPort{DeviceId: deviceId, PortNo: port.PortNo}
		for _, peerPort := range port.Peers {
			if agent := dMgr.getDeviceAgent(peerPort.DeviceId); agent != nil {
				if err := agent.addPeerPort(meAsPeer); err != nil {
					log.Errorw("failed-to-add-peer", log.Fields{"peer-device-id": peerPort.DeviceId})
					return err
				}
			}
		}
		return nil
	} else {
		return status.Errorf(codes.NotFound, "%s", deviceId)
	}
}

func (dMgr *DeviceManager) updateFlows(deviceId string, flows []*ofp.OfpFlowStats) error {
	log.Debugw("updateFlows", log.Fields{"deviceid": deviceId})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.updateFlows(flows)
	}
	return status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) updateGroups(deviceId string, groups []*ofp.OfpGroupEntry) error {
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.updateGroups(groups)
	}
	return status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) updatePmConfigs(deviceId string, pmConfigs *voltha.PmConfigs) error {
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.updatePmConfigs(pmConfigs)
	}
	return status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) getSwitchCapability(ctx context.Context, deviceId string) (*core_adapter.SwitchCapability, error) {
	log.Debugw("getSwitchCapability", log.Fields{"deviceid": deviceId})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.getSwitchCapability(ctx)
	}
	return nil, status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) getPorts(ctx context.Context, deviceId string, portType voltha.Port_PortType) (*voltha.Ports, error) {
	log.Debugw("getPorts", log.Fields{"deviceid": deviceId, "portType": portType})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.getPorts(ctx, portType), nil
	}
	return nil, status.Errorf(codes.NotFound, "%s", deviceId)

}

func (dMgr *DeviceManager) getPortCapability(ctx context.Context, deviceId string, portNo uint32) (*core_adapter.PortCapability, error) {
	log.Debugw("getPortCapability", log.Fields{"deviceid": deviceId})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.getPortCapability(ctx, portNo)
	}
	return nil, status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) updateDeviceStatus(deviceId string, operStatus voltha.OperStatus_OperStatus, connStatus voltha.ConnectStatus_ConnectStatus) error {
	log.Debugw("updateDeviceStatus", log.Fields{"deviceid": deviceId, "operStatus": operStatus, "connStatus": connStatus})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.updateDeviceStatus(operStatus, connStatus)
	}
	return status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) updateChildrenStatus(deviceId string, operStatus voltha.OperStatus_OperStatus, connStatus voltha.ConnectStatus_ConnectStatus) error {
	log.Debugw("updateChildrenStatus", log.Fields{"parentDeviceid": deviceId, "operStatus": operStatus, "connStatus": connStatus})
	var parentDevice *voltha.Device
	var err error
	if parentDevice, err = dMgr.GetDevice(deviceId); err != nil {
		return status.Errorf(codes.Aborted, "%s", err.Error())
	}
	var childDeviceIds []string
	if childDeviceIds, err = dMgr.getAllChildDeviceIds(parentDevice); err != nil {
		return status.Errorf(codes.Aborted, "%s", err.Error())
	}
	if len(childDeviceIds) == 0 {
		log.Debugw("no-child-device", log.Fields{"parentDeviceId": parentDevice.Id})
	}
	for _, childDeviceId := range childDeviceIds {
		if agent := dMgr.getDeviceAgent(childDeviceId); agent != nil {
			if err = agent.updateDeviceStatus(operStatus, connStatus); err != nil {
				return status.Errorf(codes.Aborted, "childDevice:%s, error:%s", childDeviceId, err.Error())
			}
		}
	}
	return nil
}

func (dMgr *DeviceManager) updatePortState(deviceId string, portType voltha.Port_PortType, portNo uint32, operStatus voltha.OperStatus_OperStatus) error {
	log.Debugw("updatePortState", log.Fields{"deviceid": deviceId, "portType": portType, "portNo": portNo, "operStatus": operStatus})
	if agent := dMgr.getDeviceAgent(deviceId); agent != nil {
		return agent.updatePortState(portType, portNo, operStatus)
	}
	return status.Errorf(codes.NotFound, "%s", deviceId)
}

func (dMgr *DeviceManager) childDeviceDetected(parentDeviceId string, parentPortNo int64, deviceType string, channelId int64) error {
	log.Debugw("childDeviceDetected", log.Fields{"parentDeviceId": parentDeviceId})

	// Create the ONU device
	childDevice := &voltha.Device{}
	childDevice.Type = deviceType
	childDevice.ParentId = parentDeviceId
	childDevice.ParentPortNo = uint32(parentPortNo)
	childDevice.Root = false
	childDevice.ProxyAddress = &voltha.Device_ProxyAddress{ChannelId: uint32(channelId)}

	// Create and start a device agent for that device
	agent := newDeviceAgent(dMgr.adapterProxy, childDevice, dMgr, dMgr.clusterDataProxy)
	dMgr.addDeviceAgentToMap(agent)
	agent.start(nil)

	// Activate the child device
	if agent := dMgr.getDeviceAgent(agent.deviceId); agent != nil {
		return agent.enableDevice(nil)
	}

	return nil
}

func (dMgr *DeviceManager) processTransition(previous *voltha.Device, current *voltha.Device) error {
	// This will be triggered on every update to the device.
	handlers := dMgr.stateTransitions.GetTransitionHandler(previous, current)
	if handlers == nil {
		log.Debugw("handlers-not-found", log.Fields{"deviceId": current.Id})
		return nil
	}
	for _, handler := range handlers {
		log.Debugw("running-handler", log.Fields{"handler": funcName(handler)})
		if err := handler(current); err != nil {
			return err
		}
	}
	return nil
}

func (dMgr *DeviceManager) createLogicalDevice(cDevice *voltha.Device) error {
	log.Info("createLogicalDevice")
	var logicalId *string
	var err error
	if logicalId, err = dMgr.logicalDeviceMgr.createLogicalDevice(nil, cDevice); err != nil {
		log.Warnw("createlogical-device-error", log.Fields{"device": cDevice})
		return err
	}
	// Update the parent device with the logical id
	dMgr.UpdateDeviceAttribute(cDevice.Id, "ParentId", *logicalId)
	return nil
}

func (dMgr *DeviceManager) deleteLogicalDevice(cDevice *voltha.Device) error {
	log.Info("deleteLogicalDevice")
	var err error
	if err = dMgr.logicalDeviceMgr.deleteLogicalDevice(nil, cDevice); err != nil {
		log.Warnw("deleteLogical-device-error", log.Fields{"deviceId": cDevice.Id})
		return err
	}
	// Remove the logical device Id from the parent device
	logicalId := ""
	dMgr.UpdateDeviceAttribute(cDevice.Id, "ParentId", logicalId)
	return nil
}

func (dMgr *DeviceManager) deleteLogicalPort(device *voltha.Device) error {
	log.Info("deleteLogicalPort")
	var err error
	// Get the logical port associated with this device
	var lPortId *voltha.LogicalPortId
	if lPortId, err = dMgr.logicalDeviceMgr.getLogicalPortId(device); err != nil {
		log.Warnw("getLogical-port-error", log.Fields{"deviceId": device.Id})
		return err
	}
	if err = dMgr.logicalDeviceMgr.deleteLogicalPort(nil, lPortId); err != nil {
		log.Warnw("deleteLogical-port-error", log.Fields{"deviceId": device.Id})
		return err
	}
	return nil
}

func (dMgr *DeviceManager) getParentDevice(childDevice *voltha.Device) *voltha.Device {
	//	Sanity check
	if childDevice.Root {
		// childDevice is the parent device
		return childDevice
	}
	parentDevice, _ := dMgr.GetDevice(childDevice.ParentId)
	return parentDevice
}

/*
All the functions below are callback functions where they are invoked with the latest and previous data.  We can
therefore use the data as is without trying to get the latest from the model.
*/

//disableAllChildDevices is invoked as a callback when the parent device is disabled
func (dMgr *DeviceManager) disableAllChildDevices(parentDevice *voltha.Device) error {
	log.Debug("disableAllChildDevices")
	var childDeviceIds []string
	var err error
	if childDeviceIds, err = dMgr.getAllChildDeviceIds(parentDevice); err != nil {
		return status.Errorf(codes.NotFound, "%s", parentDevice.Id)
	}
	if len(childDeviceIds) == 0 {
		log.Debugw("no-child-device", log.Fields{"parentDeviceId": parentDevice.Id})
	}
	allChildDisable := true
	for _, childDeviceId := range childDeviceIds {
		if agent := dMgr.getDeviceAgent(childDeviceId); agent != nil {
			if err = agent.disableDevice(nil); err != nil {
				log.Errorw("failure-disable-device", log.Fields{"deviceId": childDeviceId, "error": err.Error()})
				allChildDisable = false
			}
		}
	}
	if !allChildDisable {
		return err
	}
	return nil
}

//deleteAllChildDevices is invoked as a callback when the parent device is deleted
func (dMgr *DeviceManager) deleteAllChildDevices(parentDevice *voltha.Device) error {
	log.Debug("deleteAllChildDevices")
	var childDeviceIds []string
	var err error
	if childDeviceIds, err = dMgr.getAllChildDeviceIds(parentDevice); err != nil {
		return status.Errorf(codes.NotFound, "%s", parentDevice.Id)
	}
	if len(childDeviceIds) == 0 {
		log.Debugw("no-child-device", log.Fields{"parentDeviceId": parentDevice.Id})
	}
	allChildDeleted := true
	for _, childDeviceId := range childDeviceIds {
		if agent := dMgr.getDeviceAgent(childDeviceId); agent != nil {
			if err = agent.deleteDevice(nil); err != nil {
				log.Errorw("failure-delete-device", log.Fields{"deviceId": childDeviceId, "error": err.Error()})
				allChildDeleted = false
			} else {
				agent.stop(nil)
				dMgr.deleteDeviceAgentToMap(agent)
			}
		}
	}
	if !allChildDeleted {
		return err
	}
	return nil
}

//getAllChildDeviceIds is a helper method to get all the child device IDs from the device passed as parameter
func (dMgr *DeviceManager) getAllChildDeviceIds(parentDevice *voltha.Device) ([]string, error) {
	log.Debugw("getAllChildDeviceIds", log.Fields{"parentDeviceId": parentDevice.Id})
	childDeviceIds := make([]string, 0)
	if parentDevice != nil {
		for _, port := range parentDevice.Ports {
			for _, peer := range port.Peers {
				childDeviceIds = append(childDeviceIds, peer.DeviceId)
			}
		}
	}
	return childDeviceIds, nil
}

func (dMgr *DeviceManager) addUNILogicalPort(cDevice *voltha.Device) error {
	log.Info("addUNILogicalPort")
	if err := dMgr.logicalDeviceMgr.addUNILogicalPort(nil, cDevice); err != nil {
		log.Warnw("addUNILogicalPort-error", log.Fields{"device": cDevice, "err": err})
		return err
	}
	return nil
}

func (dMgr *DeviceManager) activateDevice(cDevice *voltha.Device) error {
	log.Info("activateDevice")
	return nil
}

func (dMgr *DeviceManager) disableDeviceHandler(cDevice *voltha.Device) error {
	log.Info("disableDevice-donothing")
	return nil
}

func (dMgr *DeviceManager) abandonDevice(cDevice *voltha.Device) error {
	log.Info("abandonDevice")
	return nil
}

func (dMgr *DeviceManager) reEnableDevice(cDevice *voltha.Device) error {
	log.Info("reEnableDevice")
	return nil
}

func (dMgr *DeviceManager) noOp(cDevice *voltha.Device) error {
	log.Info("noOp")
	return nil
}

func (dMgr *DeviceManager) notAllowed(pcDevice *voltha.Device) error {
	log.Info("notAllowed")
	return errors.New("Transition-not-allowed")
}

func funcName(f interface{}) string {
	p := reflect.ValueOf(f).Pointer()
	rf := runtime.FuncForPC(p)
	return rf.Name()
}

func (dMgr *DeviceManager) UpdateDeviceAttribute(deviceId string, attribute string, value interface{}) {
	if agent, ok := dMgr.deviceAgents[deviceId]; ok {
		agent.updateDeviceAttribute(attribute, value)
	}
}

func (dMgr *DeviceManager) GetParentDeviceId(deviceId string) *string {
	if device, _ := dMgr.GetDevice(deviceId); device != nil {
		log.Infow("GetParentDeviceId", log.Fields{"deviceId": device.Id, "parentId": device.ParentId})
		return &device.ParentId
	}
	return nil
}