/*
 * 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.
 */
// gRPC affinity router with active/active backends

package afrouter

import (
	"net"
	"fmt"
	"errors"
	"runtime"
	"strconv"
	"google.golang.org/grpc"
	"golang.org/x/net/context"
	"github.com/opencord/voltha-go/common/log"
	pb "github.com/opencord/voltha-protos/go/afrouter"
)


type ArouterApi struct {
	addr string
	port int
	apiListener net.Listener
	apiServer * grpc.Server
	running bool
	ar *ArouterProxy
}

func newApi(config *ApiConfig, ar *ArouterProxy) (*ArouterApi, error) {
	var rtrn_err bool
	// Create a seperate server and listener for the API
	// Validate the ip address if one is provided
	if ip := net.ParseIP(config.Addr); config.Addr != "" && ip == nil {
		log.Errorf("Invalid address '%s' provided for API server", config.Addr)
		rtrn_err = true
	}
	if rtrn_err == true {
		return nil, errors.New("Errors in API configuration")
	} else {
		var err error = nil
		aa := &ArouterApi{addr:config.Addr,port:int(config.Port),ar:ar}
		// Create the listener for the API server
		if aa.apiListener, err =
			net.Listen("tcp", config.Addr + ":"+
			strconv.Itoa(int(config.Port))); err != nil {
			log.Error(err)
			return nil, err
		}
		// Create the API server
		aa.apiServer = grpc.NewServer()
		pb.RegisterConfigurationServer(aa.apiServer, *aa)
		return aa,err
	}
}

func (aa *ArouterApi) getServer(srvr string) (*server, error) {
	if s,ok := aa.ar.servers[srvr]; ok == false {
		err := errors.New(fmt.Sprintf("Server '%s' doesn't exist", srvr))
		return nil, err
	} else {
		return s, nil
	}
}

func (aa *ArouterApi) getRouter(s *server, clstr string) (Router, error) {
	for _,pkg := range s.routers {
		for  _,r := range pkg {
			if c := r.FindBackendCluster(clstr); c != nil {
				return r, nil
			}
		}
	}
	err := errors.New(fmt.Sprintf("Cluster '%s' doesn't exist", clstr))
	return nil, err
}

func (aa *ArouterApi) getCluster(s *server, clstr string) (*backendCluster, error) {
	for _,pkg := range s.routers {
		for  _,r := range pkg {
			if c := r.FindBackendCluster(clstr); c != nil {
				return c, nil
			}
		}
	}
	err := errors.New(fmt.Sprintf("Cluster '%s' doesn't exist", clstr))
	return nil, err
}

func (aa *ArouterApi) getBackend(c *backendCluster, bknd string) (*backend, error) {
	for _,b := range c.backends {
		if b.name == bknd {
			return b,nil
		}
	}
	err := errors.New(fmt.Sprintf("Backend '%s' doesn't exist in cluster %s",
						bknd, c.name))
	return nil, err
}

func (aa *ArouterApi) getConnection(b *backend, con string) (*beConnection, error) {
	if c,ok := b.connections[con]; ok == false {
		err := errors.New(fmt.Sprintf("Connection '%s' doesn't exist", con))
		return nil, err
	} else {
		return c, nil
	}
}

func (aa * ArouterApi) updateConnection(in *pb.Conn, cn *beConnection, b *backend) error {
	sPort := strconv.FormatUint(in.Port,10)
	// Check that the ip address and or port are different
	if in.Addr == cn.addr && sPort == cn.port {
		err := errors.New(fmt.Sprintf("Refusing to change connection '%s' to identical values", in.Connection))
		return err
	}
	//log.Debugf("BEFORE: Be1: %v Be2 %v", cn.bknd, b)
	cn.close()
	cn.addr = in.Addr
	cn.port = sPort
	cn.connect()
	return nil
}

func (aa ArouterApi) SetAffinity(ctx context.Context, in *pb.Affinity) (*pb.Result, error) {
	log.Debugf("SetAffinity called! %v",in);
	//return &pb.Result{Success:true,Error:""},nil
	// Navigate down tot he connection and compare IP addresses and ports if they're
	// not the same then close the existing connection. If they are bothe the same
	// then return an error describing the situation.
	var err error

	aap := &aa

	_=aap

	log.Debugf("Getting router %s and route %s", in.Router, in.Route)
	if r,ok := allRouters[in.Router+in.Route]; ok == true {
		switch rr := r.(type) {
			case AffinityRouter:
				log.Debug("Affinity router found")
				b := rr.FindBackendCluster(in.Cluster).getBackend(in.Backend)
				if b != nil {
					rr.setAffinity(in.Id, b)
				} else {
					log.Errorf("Requested backend '%s' not found", in.Backend)
				}
				_ = rr
			case MethodRouter:
				log.Debug("Method router found")
				_ = rr
			default:
				log.Debug("Some other router found")
				_ = rr
		}
	} else {
		log.Debugf("Couldn't get router type")
		return &pb.Result{Success:false,Error:err.Error()}, err
	}

	return &pb.Result{Success:true,Error:""},nil
}

func (aa ArouterApi) SetConnection(ctx context.Context, in *pb.Conn) (*pb.Result, error) {
	// Navigate down tot he connection and compare IP addresses and ports if they're
	// not the same then close the existing connection. If they are bothe the same
	// then return an error describing the situation.
	var s *server
	var c *backendCluster
	var b * backend
	var cn * beConnection
	var err error

	log.Debugf("SetConnection called! %v",in);

	aap := &aa
	if s,err = (aap).getServer(in.Server); err != nil {
		err := errors.New(fmt.Sprintf("Server '%s' doesn't exist", in.Server))
		log.Error(err)
		return &pb.Result{Success:false,Error:err.Error()}, err
	}
	// The cluster is usually accessed via tha router but since each
	// cluster is unique it's good enough to find the router that
	// has the cluster we're looking for rather than fully keying
	// the path
	if c,err = aap.getCluster(s, in.Cluster); err != nil {
		log.Error(err)
		return &pb.Result{Success:false,Error:err.Error()}, err
	}

	if b,err = aap.getBackend(c, in.Backend); err != nil {
		log.Error(err)
		return &pb.Result{Success:false,Error:err.Error()}, err
	}

	if cn,err = aap.getConnection(b, in.Connection); err != nil {
		log.Error(err)
		return &pb.Result{Success:false,Error:err.Error()}, err
	}

	if err = aap.updateConnection(in, cn, b); err != nil {
		log.Error(err)
		return &pb.Result{Success:false,Error:err.Error()}, err
	}

	return &pb.Result{Success:true,Error:""},nil
}

func (aa ArouterApi) GetGoroutineCount(ctx context.Context, in *pb.Empty) (*pb.Count, error) {
	return &pb.Count{Count:uint32(runtime.NumGoroutine())}, nil
}

func (aa *ArouterApi) serve() {
	// Start a serving thread
	go func() {
		aa.running = true
		if err := aa.apiServer.Serve(aa.apiListener); err != nil {
			aa.running = false
			log.Error(err)
			errChan <- err
		}
	}()
}