// Copyright 2015 flannel authors
//
// 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 network

import (
	"net"
	"sync"
	"time"

	log "github.com/coreos/flannel/Godeps/_workspace/src/github.com/golang/glog"
	"github.com/coreos/flannel/Godeps/_workspace/src/golang.org/x/net/context"
	"github.com/coreos/flannel/backend"
	"github.com/coreos/flannel/subnet"
)

type Network struct {
	Name       string
	Config     *subnet.Config
	ctx        context.Context
	cancelFunc context.CancelFunc

	sm     subnet.Manager
	ipMasq bool
	be     backend.Backend
	lease  *subnet.Lease
}

func NewNetwork(ctx context.Context, sm subnet.Manager, name string, ipMasq bool) *Network {
	ctx, cancel := context.WithCancel(ctx)

	return &Network{
		Name:       name,
		ctx:        ctx,
		cancelFunc: cancel,
		sm:         sm,
		ipMasq:     ipMasq,
	}
}

func (n *Network) Init(iface *net.Interface, iaddr net.IP, eaddr net.IP) *backend.SubnetDef {
	var be backend.Backend
	var sn *backend.SubnetDef

	steps := []func() error{
		func() (err error) {
			n.Config, err = n.sm.GetNetworkConfig(n.ctx, n.Name)
			if err != nil {
				log.Error("Failed to retrieve network config: ", err)
			}
			return
		},

		func() (err error) {
			be, err = newBackend(n.sm, n.Config.BackendType, iface, iaddr, eaddr)
			if err != nil {
				log.Errorf("Failed to create and initialize network %v (type %v): %v", n.Name, n.Config.BackendType, err)
			} else {
				n.be = be
			}
			return
		},

		func() (err error) {
			sn, err = be.RegisterNetwork(n.ctx, n.Name, n.Config)
			if err != nil {
				log.Errorf("Failed register network %v (type %v): %v", n.Name, n.Config.BackendType, err)
			} else {
				n.lease = sn.Lease
			}
			return
		},

		func() (err error) {
			if n.ipMasq {
				flannelNet := n.Config.Network
				if err = setupIPMasq(flannelNet); err != nil {
					log.Errorf("Failed to set up IP Masquerade for network %v: %v", n.Name, err)
				}
			}
			return
		},
	}

	for _, s := range steps {
		for {
			if err := s(); err == nil {
				break
			}

			select {
			case <-time.After(time.Second):

			case <-n.ctx.Done():
				return nil
			}
		}
	}

	return sn
}

func (n *Network) Run() {
	wg := sync.WaitGroup{}
	wg.Add(1)
	go func() {
		n.be.Run(n.ctx)
		wg.Done()
	}()

	wg.Add(1)
	go func() {
		subnet.LeaseRenewer(n.ctx, n.sm, n.Name, n.lease)
		wg.Done()
	}()

	<-n.ctx.Done()
	n.be.UnregisterNetwork(n.ctx, n.Name)

	wg.Wait()
}

func (n *Network) Cancel() {
	n.cancelFunc()
}