package server

import (
	"context"
	"crypto/sha256"
	"fmt"
	"hash"
	"log"
	"net/http"
	"os"
	"regexp"
	"time"

	"github.com/ReneKroon/ttlcache/v2"
	"github.com/lbryio/hub/internal/metrics"
	"github.com/lbryio/hub/meta"
	pb "github.com/lbryio/hub/protobuf/go"
	"github.com/olivere/elastic/v7"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"google.golang.org/grpc"
)

type Server struct {
	GrpcServer   	 *grpc.Server
	Args         	 *Args
	MultiSpaceRe 	 *regexp.Regexp
	WeirdCharsRe 	 *regexp.Regexp
	EsClient     	 *elastic.Client
	Servers      	 []*FederatedServer
	QueryCache   	 *ttlcache.Cache
	S256		 	 *hash.Hash
	LastRefreshCheck time.Time
	RefreshDelta     time.Duration
	NumESRefreshes   int64
	pb.UnimplementedHubServer
}

type FederatedServer struct {
	Address string
	Port    string
	Ts      time.Time
	Ping    int //?
}

const (
	ServeCmd  = iota
	SearchCmd = iota
)

type Args struct {
	// TODO Make command types an enum
	CmdType      int
	Host         string
	Port         string
	EsHost       string
	EsPort       string
	EsIndex      string
	Debug        bool
	RefreshDelta int
	CacheTTL     int
}

func getVersion() string {
	return meta.Version
}

/*
	'blockchain.block.get_chunk'
	'blockchain.block.get_header'
	'blockchain.estimatefee'
	'blockchain.relayfee'
	'blockchain.scripthash.get_balance'
	'blockchain.scripthash.get_history'
	'blockchain.scripthash.get_mempool'
	'blockchain.scripthash.listunspent'
	'blockchain.scripthash.subscribe'
	'blockchain.transaction.broadcast'
	'blockchain.transaction.get'
	'blockchain.transaction.get_batch'
	'blockchain.transaction.info'
	'blockchain.transaction.get_merkle'
	'server.add_peer'
	'server.banner'
	'server.payment_address'
	'server.donation_address'
	'server.features'
	'server.peers.subscribe'
	'server.version'
	'blockchain.transaction.get_height'
	'blockchain.claimtrie.search'
	'blockchain.claimtrie.resolve'
	'blockchain.claimtrie.getclaimsbyids'
	'blockchain.block.get_server_height'
	'mempool.get_fee_histogram'
	'blockchain.block.headers'
	'server.ping'
	'blockchain.headers.subscribe'
	'blockchain.address.get_balance'
	'blockchain.address.get_history'
	'blockchain.address.get_mempool'
	'blockchain.address.listunspent'
	'blockchain.address.subscribe'
	'blockchain.address.unsubscribe'
*/

func MakeHubServer(args *Args) *Server {
	grpcServer := grpc.NewServer(grpc.NumStreamWorkers(10))

	multiSpaceRe, err := regexp.Compile(`\s{2,}`)
	if err != nil {
		log.Fatal(err)
	}

	weirdCharsRe, err := regexp.Compile("[#!~]")
	if err != nil {
		log.Fatal(err)
	}
	self := &FederatedServer{
		Address: "127.0.0.1",
		Port:    args.Port,
		Ts:      time.Now(),
		Ping:    0,
	}
	servers := make([]*FederatedServer, 10)
	servers = append(servers, self)

	esUrl := args.EsHost + ":" + args.EsPort
	opts := []elastic.ClientOptionFunc{elastic.SetSniff(false), elastic.SetURL(esUrl)}
	if args.Debug {
		opts = append(opts, elastic.SetTraceLog(log.New(os.Stderr, "[[ELASTIC]]", 0)))
	}
	client, err := elastic.NewClient(opts...)
	if err != nil {
		log.Fatal(err)
	}

	cache := ttlcache.NewCache()
	err = cache.SetTTL(time.Duration(args.CacheTTL) * time.Minute)
	if err != nil {
		log.Fatal(err)
	}
	s256 := sha256.New()
	var refreshDelta = time.Second * time.Duration(args.RefreshDelta)
	if args.Debug {
		refreshDelta = time.Second * 0
	}

	s := &Server{
		GrpcServer:       grpcServer,
		Args:         	  args,
		MultiSpaceRe: 	  multiSpaceRe,
		WeirdCharsRe: 	  weirdCharsRe,
		EsClient:     	  client,
		QueryCache:   	  cache,
		S256:         	  &s256,
		LastRefreshCheck: time.Now(),
		RefreshDelta: 	  refreshDelta,
		NumESRefreshes:   0,
	}

	return s
}

func (s *Server) PromethusEndpoint(port string, endpoint string) error {
	http.Handle("/"+endpoint, promhttp.Handler())
	log.Println(fmt.Sprintf("listening on :%s /%s", port, endpoint))
	err := http.ListenAndServe(":"+port, nil)
	if err != nil {
		return err
	}
	log.Fatalln("Shouldn't happen??!?!")
	return nil
}

func (s *Server) Hello(context context.Context, args *FederatedServer) (*FederatedServer, error) {
	s.Servers = append(s.Servers, args)

	return s.Servers[0], nil
}

func (s *Server) Ping(context context.Context, args *pb.EmptyMessage) (*pb.StringValue, error) {
	metrics.RequestsCount.With(prometheus.Labels{"method": "ping"}).Inc()
	return &pb.StringValue{Value: "Hello, world!"}, nil
}

func (s *Server) Version(context context.Context, args *pb.EmptyMessage) (*pb.StringValue, error) {
	metrics.RequestsCount.With(prometheus.Labels{"method": "version"}).Inc()
	return &pb.StringValue{Value: getVersion()}, nil
}