package server

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

)

// this package creates coordinators responsible for keeping track of active clients and invoking managers
type SubCoordinator interface {
    Start()
    NewManager(*Client,*SystemViewer, chan error) GeneralManager
    GetManager(uint32) (GeneralManager, bool)
    AddManager(uint32, GeneralManager)
    Register()
}

type GeneralManager interface {
    Start()
    UpdateClient(*Client)
    ReactorStatusHandler(context.Context,*pb.ReactorStatusPing) (*pb.ReactorStatusResponse, error)
    GetDevices(context.Context, *pb.GetDevicesRequest) (*pb.GetDevicesResponse, error)
}

type Coordinator struct {
    Port int                // port that we set up gRPC endpoint on
    //*Managers     going to embed this in subcoordinator
    SubCoordinator
    *SystemViewer
    Err chan error
}

type Managers struct {
    Directory map[uint32]GeneralManager
    sync.RWMutex                        // potential perf
}

// interface stuff
func NewCoordinator(clientType string, sys *SystemViewer, err chan error) *Coordinator {
    d := make(map[uint32]GeneralManager)
    m := &Managers{Directory:d}
    c := &Coordinator{Err:err}
    c.Port = 2023
    sub, errs := NewSubCoordinator(clientType, m, err)
    if errs != nil {
        err <-errs
    }
    c.SubCoordinator = sub
    c.SystemViewer = sys
    //c.Managers = m
    go c.Register()
    return c
}

func (c *Coordinator) Start() {
    // on start we need to create channel listener
    // on each new connection we want to check its id against our mapping
    c.SubCoordinator.Start()
}

func (c *Coordinator) ClientHandler(cl *Client) int {
    // (creates and) notifies manager of client connection
    go c.UpdateManager(cl)
    return c.Port
}

func (c *Coordinator) UpdateManager(cl *Client) {
    // shouldn't happen all that often so should be fine to lock
    m, exists := c.GetManager(cl.Id)
    if !exists {
        m = c.NewManager(cl, c.SystemViewer, c.Err)
        m.UpdateClient(cl)
        go c.AddManager(cl.Id, m)
        go m.Start()
    }
    go m.UpdateClient(cl)
}

func (m *Managers) AddManager(id uint32, man GeneralManager) {
    m.Lock()
    defer m.Unlock()
    m.Directory[id] = man
}

func (m *Managers) GetManager(id uint32) (GeneralManager, bool) {
    // just read locks and reuturns
    m.RLock()
    defer m.RUnlock()
    man, exists := m.Directory[id]
    return man, exists
}

func NewSubCoordinator(clientType string, m *Managers, err chan error) (SubCoordinator, error) {

    if clientType == "reactor" {
        c := &reactorCoordinator{}
        c.Managers = m
        return c, nil
    } else if clientType == "tui" {
        c := &tuiCoordinator{}
        c.Managers = m
        return c, nil
    }
    return &reactorCoordinator{}, errors.New("Unrecognized client type")
}

// creating sub coordinators for associated gRPC handlers
// reactor coordinator
type reactorCoordinator struct {
    *Managers
    pb.UnimplementedMonitoringServer
}

func (r *reactorCoordinator) Start() {
    logging.Debug(logging.DStart,"RCO 01 Starting!")
}

func (r *reactorCoordinator) NewManager(cl *Client, sys *SystemViewer, err chan error) GeneralManager {
    logging.Debug(logging.DClient, "RCO 01 starting manager for %v client %v",cl.Type,cl.Id)
    return NewReactorManager(cl,sys,err)
}

func (r *reactorCoordinator) Register() {
    lis, err := net.Listen("tcp", ":2023")
    if err != nil {
        // rip
    }
    grpcServer := grpc.NewServer()
    pb.RegisterMonitoringServer(grpcServer,r)
    go grpcServer.Serve(lis)
    logging.Debug(logging.DClient, "RCO ready for client requests")
}

func (r *reactorCoordinator) ReactorStatusHandler(ctx context.Context, req *pb.ReactorStatusPing) (*pb.ReactorStatusResponse, error) {
    m, exists := r.GetManager(req.GetId())
    if !exists {
        return &pb.ReactorStatusResponse{}, errors.New("Manager doesn't exists for that client")
    }
    return m.ReactorStatusHandler(ctx, req)
}

//tui coordinator
type tuiCoordinator struct {
    *Managers
    pb.UnimplementedManagementServer
}

func (t *tuiCoordinator) Start() {
    logging.Debug(logging.DStart,"TCO 01 Starting!")
}

func (t *tuiCoordinator) NewManager(cl *Client, sys *SystemViewer, err chan error) GeneralManager {
    logging.Debug(logging.DClient, "TCO 01 starting manager for %v client %v",cl.Type,cl.Id)
    return NewTUIManager(cl,sys,err)
}

func (t *tuiCoordinator) Register() {
    lis, err := net.Listen("tcp", ":2024")
    if err != nil {
        // rip
    }
    grpcServer := grpc.NewServer()
    pb.RegisterManagementServer(grpcServer,t)
    go grpcServer.Serve(lis)
    logging.Debug(logging.DClient, "TCO ready for client requests")
}

func (t *tuiCoordinator) GetDevices(ctx context.Context, req *pb.GetDevicesRequest) (*pb.GetDevicesResponse, error) {
    // grpc handler to fwd to manager
    m, exists := t.GetManager(req.GetClientId())
    if !exists {
        // doesnt exist for some reason
        return &pb.GetDevicesResponse{}, errors.New("Manager doesn't exists for client")
    }
    return m.GetDevices(ctx,req)
}

// unimplemented bs for grpc
func (t *tuiCoordinator) DeleteReactor(ctx context.Context, req *pb.DeleteReactorRequest) (*pb.DeleteReactorResponse, error) {
    // TODO
    return &pb.DeleteReactorResponse{}, nil
}

func (t *tuiCoordinator) DeleteReactorDevice(ctx context.Context, req *pb.DeleteReactorDeviceRequest) (*pb.DeleteReactorDeviceResponse, error) {
    // TODO
    return &pb.DeleteReactorDeviceResponse{}, nil
}