/*
 * 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 device

import (
	"context"
	"encoding/hex"
	"fmt"
	"sync"
	"time"

	"github.com/gogo/protobuf/proto"
	"github.com/opencord/voltha-go/db/model"
	fd "github.com/opencord/voltha-go/rw_core/flowdecomposition"
	"github.com/opencord/voltha-go/rw_core/route"
	coreutils "github.com/opencord/voltha-go/rw_core/utils"
	fu "github.com/opencord/voltha-lib-go/v3/pkg/flows"
	"github.com/opencord/voltha-lib-go/v3/pkg/log"
	ic "github.com/opencord/voltha-protos/v3/go/inter_container"
	ofp "github.com/opencord/voltha-protos/v3/go/openflow_13"
	"github.com/opencord/voltha-protos/v3/go/voltha"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

// LogicalAgent represent attributes of logical device agent
type LogicalAgent struct {
	logicalDeviceID    string
	serialNumber       string
	rootDeviceID       string
	deviceMgr          *Manager
	ldeviceMgr         *LogicalManager
	clusterDataProxy   *model.Proxy
	stopped            bool
	deviceRoutes       *route.DeviceRoutes
	logicalPortsNo     map[uint32]bool //value is true for NNI port
	lockLogicalPortsNo sync.RWMutex
	flowDecomposer     *fd.FlowDecomposer
	defaultTimeout     time.Duration
	logicalDevice      *voltha.LogicalDevice
	requestQueue       *coreutils.RequestQueue
	startOnce          sync.Once
	stopOnce           sync.Once

	meters    map[uint32]*MeterChunk
	meterLock sync.RWMutex
	flows     map[uint64]*FlowChunk
	flowLock  sync.RWMutex
	groups    map[uint32]*GroupChunk
	groupLock sync.RWMutex
}

func newLogicalDeviceAgent(id string, sn string, deviceID string, ldeviceMgr *LogicalManager,
	deviceMgr *Manager, cdProxy *model.Proxy, defaultTimeout time.Duration) *LogicalAgent {
	var agent LogicalAgent
	agent.logicalDeviceID = id
	agent.serialNumber = sn
	agent.rootDeviceID = deviceID
	agent.deviceMgr = deviceMgr
	agent.clusterDataProxy = cdProxy
	agent.ldeviceMgr = ldeviceMgr
	agent.flowDecomposer = fd.NewFlowDecomposer(agent.deviceMgr)
	agent.logicalPortsNo = make(map[uint32]bool)
	agent.defaultTimeout = defaultTimeout
	agent.requestQueue = coreutils.NewRequestQueue()
	agent.meters = make(map[uint32]*MeterChunk)
	agent.flows = make(map[uint64]*FlowChunk)
	agent.groups = make(map[uint32]*GroupChunk)
	agent.deviceRoutes = route.NewDeviceRoutes(agent.logicalDeviceID, agent.deviceMgr.getDevice)
	return &agent
}

// start creates the logical device and add it to the data model
func (agent *LogicalAgent) start(ctx context.Context, loadFromDB bool) error {
	needToStart := false
	if agent.startOnce.Do(func() { needToStart = true }); !needToStart {
		return nil
	}

	logger.Infow("starting-logical_device-agent", log.Fields{"logical-device-id": agent.logicalDeviceID, "load-from-db": loadFromDB})

	var startSucceeded bool
	defer func() {
		if !startSucceeded {
			if err := agent.stop(ctx); err != nil {
				logger.Errorw("failed-to-cleanup-after-unsuccessful-start", log.Fields{"logical-device-id": agent.logicalDeviceID, "error": err})
			}
		}
	}()

	var ld *voltha.LogicalDevice
	if !loadFromDB {
		//Build the logical device based on information retrieved from the device adapter
		var switchCap *ic.SwitchCapability
		var err error
		if switchCap, err = agent.deviceMgr.getSwitchCapability(ctx, agent.rootDeviceID); err != nil {
			return err
		}
		ld = &voltha.LogicalDevice{Id: agent.logicalDeviceID, RootDeviceId: agent.rootDeviceID}

		// Create the datapath ID (uint64) using the logical device ID (based on the MAC Address)
		var datapathID uint64
		if datapathID, err = coreutils.CreateDataPathID(agent.serialNumber); err != nil {
			return err
		}
		ld.DatapathId = datapathID
		ld.Desc = (proto.Clone(switchCap.Desc)).(*ofp.OfpDesc)
		logger.Debugw("Switch-capability", log.Fields{"Desc": ld.Desc, "fromAd": switchCap.Desc})
		ld.SwitchFeatures = (proto.Clone(switchCap.SwitchFeatures)).(*ofp.OfpSwitchFeatures)
		ld.Flows = &ofp.Flows{Items: nil}
		ld.FlowGroups = &ofp.FlowGroups{Items: nil}
		ld.Ports = []*voltha.LogicalPort{}

		// Save the logical device
		if err := agent.clusterDataProxy.AddWithID(ctx, "logical_devices", ld.Id, ld); err != nil {
			logger.Errorw("failed-to-add-logical-device", log.Fields{"logical-device-id": agent.logicalDeviceID})
			return err
		}
		logger.Debugw("logicaldevice-created", log.Fields{"logical-device-id": agent.logicalDeviceID, "root-id": ld.RootDeviceId})

		agent.logicalDevice = proto.Clone(ld).(*voltha.LogicalDevice)

		// Setup the logicalports - internal processing, no need to propagate the client context
		go func() {
			err := agent.setupLogicalPorts(context.Background())
			if err != nil {
				logger.Errorw("unable-to-setup-logical-ports", log.Fields{"error": err})
			}
		}()
	} else {
		//	load from dB - the logical may not exist at this time.  On error, just return and the calling function
		// will destroy this agent.
		ld := &voltha.LogicalDevice{}
		have, err := agent.clusterDataProxy.Get(ctx, "logical_devices/"+agent.logicalDeviceID, ld)
		if err != nil {
			return err
		} else if !have {
			return status.Errorf(codes.NotFound, "logical_device-%s", agent.logicalDeviceID)
		}

		// Update the root device Id
		agent.rootDeviceID = ld.RootDeviceId

		// Update the last data
		agent.logicalDevice = proto.Clone(ld).(*voltha.LogicalDevice)

		// Setup the local list of logical ports
		agent.addLogicalPortsToMap(ld.Ports)
		// load the flows, meters and groups from KV to cache
		agent.loadFlows(ctx)
		agent.loadMeters(ctx)
		agent.loadGroups(ctx)
	}

	// Setup the device routes. Building routes may fail if the pre-conditions are not satisfied (e.g. no PON ports present)
	if loadFromDB {
		go func() {
			if err := agent.buildRoutes(context.Background()); err != nil {
				logger.Warn("routes-not-ready", log.Fields{"logical-device-id": agent.logicalDeviceID, "error": err})
			}
		}()
	}
	startSucceeded = true

	return nil
}

// stop stops the logical device agent.  This removes the logical device from the data model.
func (agent *LogicalAgent) stop(ctx context.Context) error {
	var returnErr error
	agent.stopOnce.Do(func() {
		logger.Info("stopping-logical_device-agent")

		if err := agent.requestQueue.WaitForGreenLight(ctx); err != nil {
			// This should never happen - an error is returned only if the agent is stopped and an agent is only stopped once.
			returnErr = err
			return
		}
		defer agent.requestQueue.RequestComplete()

		//Remove the logical device from the model
		if err := agent.clusterDataProxy.Remove(ctx, "logical_devices/"+agent.logicalDeviceID); err != nil {
			returnErr = err
		} else {
			logger.Debugw("logicaldevice-removed", log.Fields{"logicaldeviceId": agent.logicalDeviceID})
		}

		agent.stopped = true

		logger.Info("logical_device-agent-stopped")
	})
	return returnErr
}

// GetLogicalDevice returns the latest logical device data
func (agent *LogicalAgent) GetLogicalDevice(ctx context.Context) (*voltha.LogicalDevice, error) {
	if err := agent.requestQueue.WaitForGreenLight(ctx); err != nil {
		return nil, err
	}
	defer agent.requestQueue.RequestComplete()
	return proto.Clone(agent.logicalDevice).(*voltha.LogicalDevice), nil
}

// getLogicalDeviceWithoutLock returns a cloned logical device to a function that already holds the agent lock.
func (agent *LogicalAgent) getLogicalDeviceWithoutLock() *voltha.LogicalDevice {
	logger.Debug("getLogicalDeviceWithoutLock")
	return proto.Clone(agent.logicalDevice).(*voltha.LogicalDevice)
}

//updateLogicalDeviceWithoutLock updates the model with the logical device.  It clones the logicaldevice before saving it
func (agent *LogicalAgent) updateLogicalDeviceWithoutLock(ctx context.Context, logicalDevice *voltha.LogicalDevice) error {
	if agent.stopped {
		return fmt.Errorf("logical device agent stopped-%s", logicalDevice.Id)
	}

	updateCtx := context.WithValue(ctx, model.RequestTimestamp, time.Now().UnixNano())
	if err := agent.clusterDataProxy.Update(updateCtx, "logical_devices/"+agent.logicalDeviceID, logicalDevice); err != nil {
		logger.Errorw("failed-to-update-logical-devices-to-cluster-proxy", log.Fields{"error": err})
		return err
	}

	agent.logicalDevice = logicalDevice

	return nil
}

func (agent *LogicalAgent) deleteFlowAndUpdateMeterStats(ctx context.Context, mod *ofp.OfpFlowMod, chunk *FlowChunk) error {
	chunk.lock.Lock()
	defer chunk.lock.Unlock()
	if changedMeter := agent.updateFlowCountOfMeterStats(ctx, mod, chunk.flow, false); !changedMeter {
		return fmt.Errorf("Cannot-delete-flow-%s. Meter-update-failed", chunk.flow)
	}
	// Update store and cache
	if err := agent.removeLogicalDeviceFlow(ctx, chunk.flow.Id); err != nil {
		return fmt.Errorf("Cannot-delete-flows-%s. Delete-from-store-failed", chunk.flow)
	}
	return nil
}

func (agent *LogicalAgent) addFlowsAndGroupsToDevices(deviceRules *fu.DeviceRules, flowMetadata *voltha.FlowMetadata) []coreutils.Response {
	logger.Debugw("send-add-flows-to-device-manager", log.Fields{"logicalDeviceID": agent.logicalDeviceID, "deviceRules": deviceRules, "flowMetadata": flowMetadata})

	responses := make([]coreutils.Response, 0)
	for deviceID, value := range deviceRules.GetRules() {
		response := coreutils.NewResponse()
		responses = append(responses, response)
		go func(deviceId string, value *fu.FlowsAndGroups) {
			subCtx, cancel := context.WithTimeout(context.Background(), agent.defaultTimeout)
			defer cancel()
			start := time.Now()
			if err := agent.deviceMgr.addFlowsAndGroups(subCtx, deviceId, value.ListFlows(), value.ListGroups(), flowMetadata); err != nil {
				logger.Errorw("flow-add-failed", log.Fields{"deviceID": deviceId, "error": err, "wait-time": time.Since(start)})
				response.Error(status.Errorf(codes.Internal, "flow-add-failed: %s", deviceId))
			}
			response.Done()
		}(deviceID, value)
	}
	// Return responses (an array of channels) for the caller to wait for a response from the far end.
	return responses
}

func (agent *LogicalAgent) deleteFlowsAndGroupsFromDevices(deviceRules *fu.DeviceRules, flowMetadata *voltha.FlowMetadata) []coreutils.Response {
	logger.Debugw("send-delete-flows-to-device-manager", log.Fields{"logicalDeviceID": agent.logicalDeviceID})

	responses := make([]coreutils.Response, 0)
	for deviceID, value := range deviceRules.GetRules() {
		response := coreutils.NewResponse()
		responses = append(responses, response)
		go func(deviceId string, value *fu.FlowsAndGroups) {
			subCtx, cancel := context.WithTimeout(context.Background(), agent.defaultTimeout)
			defer cancel()
			start := time.Now()
			if err := agent.deviceMgr.deleteFlowsAndGroups(subCtx, deviceId, value.ListFlows(), value.ListGroups(), flowMetadata); err != nil {
				logger.Errorw("flow-delete-failed", log.Fields{"deviceID": deviceId, "error": err, "wait-time": time.Since(start)})
				response.Error(status.Errorf(codes.Internal, "flow-delete-failed: %s", deviceId))
			}
			response.Done()
		}(deviceID, value)
	}
	return responses
}

func (agent *LogicalAgent) updateFlowsAndGroupsOfDevice(deviceRules *fu.DeviceRules, flowMetadata *voltha.FlowMetadata) []coreutils.Response {
	logger.Debugw("send-update-flows-to-device-manager", log.Fields{"logicalDeviceID": agent.logicalDeviceID})

	responses := make([]coreutils.Response, 0)
	for deviceID, value := range deviceRules.GetRules() {
		response := coreutils.NewResponse()
		responses = append(responses, response)
		go func(deviceId string, value *fu.FlowsAndGroups) {
			subCtx, cancel := context.WithTimeout(context.Background(), agent.defaultTimeout)
			defer cancel()
			if err := agent.deviceMgr.updateFlowsAndGroups(subCtx, deviceId, value.ListFlows(), value.ListGroups(), flowMetadata); err != nil {
				logger.Errorw("flow-update-failed", log.Fields{"deviceID": deviceId, "error": err})
				response.Error(status.Errorf(codes.Internal, "flow-update-failed: %s", deviceId))
			}
			response.Done()
		}(deviceID, value)
	}
	return responses
}

func (agent *LogicalAgent) deleteFlowsFromParentDevice(flows ofp.Flows, metadata *voltha.FlowMetadata) []coreutils.Response {
	logger.Debugw("deleting-flows-from-parent-device", log.Fields{"logical-device-id": agent.logicalDeviceID, "flows": flows})
	responses := make([]coreutils.Response, 0)
	for _, flow := range flows.Items {
		response := coreutils.NewResponse()
		responses = append(responses, response)
		uniPort, err := agent.getUNILogicalPortNo(flow)
		if err != nil {
			logger.Error("no-uni-port-in-flow", log.Fields{"deviceID": agent.rootDeviceID, "flow": flow, "error": err})
			response.Error(err)
			response.Done()
			continue
		}
		logger.Debugw("uni-port", log.Fields{"flows": flows, "uni-port": uniPort})
		go func(uniPort uint32, metadata *voltha.FlowMetadata) {
			subCtx, cancel := context.WithTimeout(context.Background(), agent.defaultTimeout)
			defer cancel()
			if err := agent.deviceMgr.deleteParentFlows(subCtx, agent.rootDeviceID, uniPort, metadata); err != nil {
				logger.Error("flow-delete-failed", log.Fields{"device-id": agent.rootDeviceID, "error": err})
				response.Error(status.Errorf(codes.Internal, "flow-delete-failed: %s %v", agent.rootDeviceID, err))
			}
			response.Done()
		}(uniPort, metadata)
	}
	return responses
}

func (agent *LogicalAgent) packetOut(ctx context.Context, packet *ofp.OfpPacketOut) {
	logger.Debugw("packet-out", log.Fields{
		"packet": hex.EncodeToString(packet.Data),
		"inPort": packet.GetInPort(),
	})
	outPort := fu.GetPacketOutPort(packet)
	//frame := packet.GetData()
	//TODO: Use a channel between the logical agent and the device agent
	if err := agent.deviceMgr.packetOut(ctx, agent.rootDeviceID, outPort, packet); err != nil {
		logger.Error("packetout-failed", log.Fields{"logicalDeviceID": agent.rootDeviceID})
	}
}

func (agent *LogicalAgent) packetIn(port uint32, transactionID string, packet []byte) {
	logger.Debugw("packet-in", log.Fields{
		"port":          port,
		"packet":        hex.EncodeToString(packet),
		"transactionId": transactionID,
	})
	packetIn := fu.MkPacketIn(port, packet)
	agent.ldeviceMgr.SendPacketIn(agent.logicalDeviceID, transactionID, packetIn)
	logger.Debugw("sending-packet-in", log.Fields{"packet": hex.EncodeToString(packetIn.Data)})
}