/*
 * 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 main

import (
    "context"
    "errors"
    "fmt"
    "github.com/opencord/voltha-go/adapters"
    com "github.com/opencord/voltha-go/adapters/common"
    ac "github.com/opencord/voltha-go/adapters/openolt/adaptercore"
    "github.com/opencord/voltha-go/adapters/openolt/config"
    "github.com/opencord/voltha-go/common/log"
    "github.com/opencord/voltha-go/db/kvstore"
    "github.com/opencord/voltha-go/kafka"
    ic "github.com/opencord/voltha-go/protos/inter_container"
    "github.com/opencord/voltha-go/protos/voltha"
    "os"
    "os/signal"
    "strconv"
    "syscall"
    "time"
)

type adapter struct {
    instanceId       string
    config           *config.AdapterFlags
    iAdapter         adapters.IAdapter
    kafkaClient      kafka.Client
    kvClient         kvstore.Client
    kip              *kafka.InterContainerProxy
    coreProxy        *com.CoreProxy
    halted           bool
    exitChannel      chan int
    receiverChannels []<-chan *ic.InterContainerMessage
}

func init() {
    log.AddPackage(log.JSON, log.DebugLevel, nil)
}

func newAdapter(cf *config.AdapterFlags) *adapter {
    var a adapter
    a.instanceId = cf.InstanceID
    a.config = cf
    a.halted = false
    a.exitChannel = make(chan int, 1)
    a.receiverChannels = make([]<-chan *ic.InterContainerMessage, 0)
    return &a
}

func (a *adapter) start(ctx context.Context) {
    log.Info("Starting Core Adapter components")
    var err error

    // Setup KV Client
    log.Debugw("create-kv-client", log.Fields{"kvstore": a.config.KVStoreType})
    if err := a.setKVClient(); err != nil {
        log.Fatal("error-setting-kv-client")
    }

    // Setup Kafka Client
    if a.kafkaClient, err = newKafkaClient("sarama", a.config.KafkaAdapterHost, a.config.KafkaAdapterPort); err != nil {
        log.Fatal("Unsupported-common-client")
    }

    // Start the common InterContainer Proxy - retries indefinitely
    if a.kip, err = a.startInterContainerProxy(-1); err != nil {
        log.Fatal("error-starting-inter-container-proxy")
    }

    // Create the core proxy to handle requests to the Core
    a.coreProxy = com.NewCoreProxy(a.kip, a.config.Topic, a.config.CoreTopic)

    // Create the open OLT adapter
    if a.iAdapter, err = a.startOpenOLT(ctx, a.kip, a.coreProxy, a.config.OnuNumber); err != nil {
        log.Fatal("error-starting-inter-container-proxy")
    }

    // Register the core request handler
    if err = a.setupRequestHandler(a.instanceId, a.iAdapter); err != nil {
        log.Fatal("error-setting-core-request-handler")
    }

    //    Register this adapter to the Core - retries indefinitely
    if err = a.registerWithCore(-1); err != nil {
        log.Fatal("error-registering-with-core")
    }
}

func (rw *adapter) stop() {
    // Stop leadership tracking
    rw.halted = true

    // send exit signal
    rw.exitChannel <- 0

    // Cleanup - applies only if we had a kvClient
    if rw.kvClient != nil {
        // Release all reservations
        if err := rw.kvClient.ReleaseAllReservations(); err != nil {
            log.Infow("fail-to-release-all-reservations", log.Fields{"error": err})
        }
        // Close the DB connection
        rw.kvClient.Close()
    }

    // TODO:  More cleanup
}

func newKVClient(storeType string, address string, timeout int) (kvstore.Client, error) {

    log.Infow("kv-store-type", log.Fields{"store": storeType})
    switch storeType {
    case "consul":
        return kvstore.NewConsulClient(address, timeout)
    case "etcd":
        return kvstore.NewEtcdClient(address, timeout)
    }
    return nil, errors.New("unsupported-kv-store")
}

func newKafkaClient(clientType string, host string, port int) (kafka.Client, error) {

    log.Infow("common-client-type", log.Fields{"client": clientType})
    switch clientType {
    case "sarama":
        return kafka.NewSaramaClient(
            kafka.Host(host),
            kafka.Port(port),
            kafka.ProducerReturnOnErrors(true),
            kafka.ProducerReturnOnSuccess(true),
            kafka.ProducerMaxRetries(6),
            kafka.ProducerRetryBackoff(time.Millisecond*30)), nil
    }
    return nil, errors.New("unsupported-client-type")
}

func (a *adapter) setKVClient() error {
    addr := a.config.KVStoreHost + ":" + strconv.Itoa(a.config.KVStorePort)
    client, err := newKVClient(a.config.KVStoreType, addr, a.config.KVStoreTimeout)
    if err != nil {
        a.kvClient = nil
        log.Error(err)
        return err
    }
    a.kvClient = client
    return nil
}

func toString(value interface{}) (string, error) {
    switch t := value.(type) {
    case []byte:
        return string(value.([]byte)), nil
    case string:
        return value.(string), nil
    default:
        return "", fmt.Errorf("unexpected-type-%T", t)
    }
}

func (a *adapter) startInterContainerProxy(retries int) (*kafka.InterContainerProxy, error) {
    log.Infow("starting-intercontainer-messaging-proxy", log.Fields{"host": a.config.KafkaAdapterHost,
        "port": a.config.KafkaAdapterPort, "topic": a.config.Topic})
    var err error
    var kip *kafka.InterContainerProxy
    if kip, err = kafka.NewInterContainerProxy(
        kafka.InterContainerHost(a.config.KafkaAdapterHost),
        kafka.InterContainerPort(a.config.KafkaAdapterPort),
        kafka.MsgClient(a.kafkaClient),
        kafka.DefaultTopic(&kafka.Topic{Name: a.config.Topic})); err != nil {
        log.Errorw("fail-to-create-common-proxy", log.Fields{"error": err})
        return nil, err
    }
    count := 0
    for {
        if err = kip.Start(); err != nil {
            log.Warnw("error-starting-messaging-proxy", log.Fields{"error": err})
            if retries == count {
                return nil, err
            }
            count = +1
            //    Take a nap before retrying
            time.Sleep(2 * time.Second)
        } else {
            break
        }
    }

    log.Info("common-messaging-proxy-created")
    return kip, nil
}

func (a *adapter) startOpenOLT(ctx context.Context, kip *kafka.InterContainerProxy, cp *com.CoreProxy, onuNumber int) (*ac.OpenOLT, error) {
    log.Info("starting-open-olt")
    var err error
    sOLT := ac.NewOpenOLT(ctx, a.kip, cp, onuNumber)

    if err = sOLT.Start(ctx); err != nil {
        log.Fatalw("error-starting-messaging-proxy", log.Fields{"error": err})
        return nil, err
    }

    log.Info("open-olt-started")
    return sOLT, nil
}

func (a *adapter) setupRequestHandler(coreInstanceId string, iadapter adapters.IAdapter) error {
    log.Info("setting-request-handler")
    requestProxy := com.NewRequestHandlerProxy(coreInstanceId, iadapter, a.coreProxy)
    if err := a.kip.SubscribeWithRequestHandlerInterface(kafka.Topic{Name: a.config.Topic}, requestProxy); err != nil {
        log.Errorw("request-handler-setup-failed", log.Fields{"error": err})
        return err

    }
    log.Info("request-handler-setup-done")
    return nil
}

func (a *adapter) registerWithCore(retries int) error {
    log.Info("registering-with-core")
    adapterDescription := &voltha.Adapter{Id: "openolt", Vendor: "simulation Enterprise Inc"}
    types := []*voltha.DeviceType{{Id: "openolt", Adapter: "openolt"}}
    deviceTypes := &voltha.DeviceTypes{Items: types}
    count := 0
    for {
        if err := a.coreProxy.RegisterAdapter(nil, adapterDescription, deviceTypes); err != nil {
            log.Warnw("registering-with-core-failed", log.Fields{"error": err})
            if retries == count {
                return err
            }
            count += 1
            //    Take a nap before retrying
            time.Sleep(2 * time.Second)
        } else {
            break
        }
    }
    log.Info("registered-with-core")
    return nil
}

func waitForExit() int {
    signalChannel := make(chan os.Signal, 1)
    signal.Notify(signalChannel,
        syscall.SIGHUP,
        syscall.SIGINT,
        syscall.SIGTERM,
        syscall.SIGQUIT)

    exitChannel := make(chan int)

    go func() {
        s := <-signalChannel
        switch s {
        case syscall.SIGHUP,
            syscall.SIGINT,
            syscall.SIGTERM,
            syscall.SIGQUIT:
            log.Infow("closing-signal-received", log.Fields{"signal": s})
            exitChannel <- 0
        default:
            log.Infow("unexpected-signal-received", log.Fields{"signal": s})
            exitChannel <- 1
        }
    }()

    code := <-exitChannel
    return code
}

func printBanner() {
    fmt.Println("   ____                     ____  _   _______ ")
    fmt.Println("  / _ \\                   / __\\| | |__   __|")
    fmt.Println(" | |  | |_ __   ___ _ __  | |  | | |    | |   ")
    fmt.Println(" | |  | | '_\\ / _\\ '_\\ | |  | | |    | |   ")
    fmt.Println(" | |__| | |_) |  __/ | | || |__| | |____| |   ")
    fmt.Println(" \\____/| .__/\\___|_| |_|\\____/|______|_|   ")
    fmt.Println("        | |                                   ")
    fmt.Println("        |_|                                   ")
    fmt.Println("                                              ")
}

func main() {
    start := time.Now()

    cf := config.NewAdapterFlags()
    cf.ParseCommandArguments()

    //// Setup logging

    //Setup default logger - applies for packages that do not have specific logger set
    if _, err := log.SetDefaultLogger(log.JSON, cf.LogLevel, log.Fields{"instanceId": cf.InstanceID}); err != nil {
        log.With(log.Fields{"error": err}).Fatal("Cannot setup logging")
    }

    // Update all loggers (provisionned via init) with a common field
    if err := log.UpdateAllLoggers(log.Fields{"instanceId": cf.InstanceID}); err != nil {
        log.With(log.Fields{"error": err}).Fatal("Cannot setup logging")
    }

    log.SetPackageLogLevel("github.com/opencord/voltha-go/adapters/common", log.DebugLevel)

    defer log.CleanUp()

    // Print banner if specified
    if cf.Banner {
        printBanner()
    }

    log.Infow("config", log.Fields{"config": *cf})

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    ad := newAdapter(cf)
    go ad.start(ctx)

    code := waitForExit()
    log.Infow("received-a-closing-signal", log.Fields{"code": code})

    // Cleanup before leaving
    ad.stop()

    elapsed := time.Since(start)
    log.Infow("run-time", log.Fields{"instanceId": ad.config.InstanceID, "time": elapsed / time.Second})
}