package server

import (
    "fmt"
    "sync"
    "net"
    "context"
    "google.golang.org/grpc"
    pb "FRMS/internal/pkg/grpc"
)

// the goal here is to set up a gRPC handler to respond to reactor pings with their IP and to establish a new coordinator for that specific reactor

type ReactorListener struct { // exporting for easy use in the short term
    Reactor map[uint32]*ReactorCoordinator
    Ip string
    Port int
    Err chan error
    mu sync.Mutex
    pb.UnimplementedHandshakeServer
}

func NewReactorListener(ch chan error) *ReactorListener {
    m := make(map[uint32]*ReactorCoordinator)
    ip := "192.1.168.136"
    port := 2000
    return &ReactorListener{Err:ch, Reactor:m, Port:port, Ip:ip}
}

func (r *ReactorListener) GetIp() string {
    r.mu.Lock()
    defer r.mu.Unlock()
    return r.Ip
}

func (r *ReactorListener) GetPort() int {
    r.mu.Lock()
    defer r.mu.Unlock()
    return r.Port
}

func (r *ReactorListener) Start() {
    // start grpc server and implement reciever
    err := r.Register()
    if err != nil {
        r.Err <- err
    }
    // reactor listener started and grpc library will execute listener
    fmt.Printf("Started listener on %v:%v\n",r.Ip,r.Port)
}

func (r *ReactorListener) Register() error {
    // creates a gRPC service and binds it to our handler
    lis, err := net.Listen("tcp", fmt.Sprintf("%v:%v",r.Ip,r.Port))
    if err != nil {
        return err
    }
    grpcServer := grpc.NewServer()
    pb.RegisterHandshakeServer(grpcServer, r)
    go grpcServer.Serve(lis)
    return nil
}

func (r *ReactorListener) ReactorDiscoveryHandler(ctx context.Context, ping *pb.ReactorDiscoveryRequest) (*pb.ReactorDiscoveryResponse, error) {
    // incoming reactor ping need to spawn coord
    r.mu.Lock()
    rc, ok := r.Reactor[ping.GetId()]
    fmt.Printf("Reactor %v has connected from addr %v and provided port %v\n",ping.GetId(),ping.GetIp(),ping.GetPort())
    // if reactor exists
    if ok {
        go rc.Start()
    } else {
        rc := NewReactorCoordinator(r,ping.GetIp(),ping.GetModel(),int(ping.GetPort()),ping.GetId())
        go rc.Start()
        r.Reactor[ping.GetId()] = rc
    }
    return &pb.ReactorDiscoveryResponse{Success:true}, nil
}