package foundry

import (
	"context"
	"errors"
	"sync"
	"time"

	"gitea.local.lab/Lbenedar/foundry_helper_service/internal/foundry/actions"
	"gitea.local.lab/Lbenedar/foundry_helper_service/internal/foundry/requests"
	"gitea.local.lab/Lbenedar/foundry_helper_service/internal/foundry/transport"
	"gitea.local.lab/Lbenedar/foundry_helper_service/internal/foundry/types"
)

var (
	ListenIsDone         = errors.New("Listen for websocket data in foundry is stopped")
	ReconnectToWebSocket = errors.New("Reconnect to websocket")
	ChannelIsClosed      = errors.New("Channel is closed")

	CloseTimeoutExceed = errors.New("Timeout of websocket close is exceed")
)

type FoundryApi struct {
	//TODO: make check of admin's authentication
	transport   *transport.FoundryTransport
	IsAvailable bool

	// Logger *slog.Logger
	Status types.FoundryStatus
	wg     sync.WaitGroup
}

func NewFoundry() *FoundryApi {
	return &FoundryApi{}
}

func (foundry *FoundryApi) SetTransport(tr *transport.FoundryTransport) {
	foundry.transport = tr
}

func (foundry *FoundryApi) ListenAndServeWS() error {
	var err error

	foundry.transport.ReadChan = *types.InitWsChannels()
	defer foundry.transport.ReadChan.Close()

	foundry.background(foundry.transport.ListenWebSocket)

	err = foundry.ServeWebSocket()
	if err != nil {
		foundry.IsAvailable = false
	}
	return err
}

func (foundry *FoundryApi) ServeWebSocket() error {
	var err error
	wsChannels := &foundry.transport.ReadChan

	for {
		select {
		case message, ok := <-wsChannels.Msg():
			if !ok {
				foundry.transport.Logger.Debug("Read channel is closed", "type", types.WebSocketCode)
				foundry.transport.Http.SessionID = nil
				return ChannelIsClosed
			}
			foundry.transport.Logger.Debug("Data has been received\n", "msg", message.Code, "type", types.WebSocketCode) //, "msg", message.MsgJson)

			switch message.Code {
			case types.RespPingCode, types.RespSessionDataCode:
				err := foundry.transport.SendOnlyCodeRequest(message.Code)
				if err != nil {
					wsChannels.Err() <- &types.FoundryError{Direction: types.WriterCode, Err: err, Type: types.WebSocketCode}
					continue
				}
			case types.RespServerChangeCode:
				foundry.IsAvailable = true
				data, err := actions.SplitToTypeAndData([]byte(message.MsgJson))
				if err != nil {
					wsChannels.Err() <- &types.FoundryError{Direction: types.ReaderCode, Err: err, Type: types.WebSocketCode}
					continue
				}

				foundry.transport.Logger.Debug("RespServerChangeCode", "data", data)
				if data == nil {
					continue
				}

				err = data.Action(foundry.transport, &foundry.Status)
				if err != nil {
					wsChannels.Err() <- &types.FoundryError{Direction: types.ReaderCode, Err: err, Type: types.WebSocketCode}
					continue
				}
			case types.RespDataCode:
				foundry.transport.ExchangeChan.Msgs[message.Id] = make(chan []byte, 1)
				foundry.transport.ExchangeChan.Msgs[message.Id] <- []byte(message.MsgJson)
				go foundry.transport.CloseMsgChannel(message.Id, 5*time.Second)
			default:
			}
		case err = <-wsChannels.Err():
			var foundryErr *types.FoundryError
			if errors.As(err, &foundryErr) {
				if foundryErr.IsFatal {
					foundry.transport.CloseWebSocketConn()
					foundry.transport.Http.SessionID = nil
					return foundryErr
				}
				foundry.transport.Logger.Warn("Got error when listening or served", "err", err.Error(), "type", foundryErr.Type, "direction", foundryErr.Direction)
			}
		case <-wsChannels.Done():
			foundry.transport.CloseWebSocketConn()
			foundry.transport.Http.SessionID = nil
			return ListenIsDone
		case <-wsChannels.Reconnect():
			foundry.transport.CloseWebSocketConn()
			return ReconnectToWebSocket
		}
	}
}

func (foundry *FoundryApi) HandleWSRequest(msgType string) ([]byte, error) {
	msg := types.NewWsMessageByPage(msgType, foundry.transport.CurrWsId)

	return foundry.transport.HandleWebsocketRequest(msg)
}

func (foundry *FoundryApi) Shutdown() error {
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()

	foundry.transport.Logger.Info("Completing foundry background tasks")

	foundryClosed := make(chan struct{})
	go func() {
		types.CloseChannel(foundry.transport.ReadChan.Done())

		foundry.wg.Wait()
		foundry.transport.ExchangeChan.Close()
		foundry.transport.ReadChan.Close()

		types.CloseChannel(foundryClosed)
	}()

	select {
	case <-foundryClosed:
		foundry.transport.Logger.Info("Stopped foundry server")
	case <-ctx.Done():
		return CloseTimeoutExceed
	}

	return nil
}

func (foundry *FoundryApi) ConnectToWebSocket() (bool, error) {
	var err error
	if !foundry.transport.HasSessionId() {
		err = foundry.transport.InitSessionId()
		if err != nil {
			return false, err
		}

		err = foundry.transport.ConnectToFoundry()
		if err != nil {
			return false, err
		}
	}

	err = foundry.transport.InitWebSocketConnection()
	if err != nil {
		return false, err
	}

	status, err := foundry.transport.Http.GetStatus()
	if err != nil {
		return false, err
	}
	foundry.Status = *types.NewFoundryStatus(status)

	err = foundry.ListenAndServeWS()
	if err != nil && err != ListenIsDone {
		return true, err
	}

	return true, nil
}

func (foundry *FoundryApi) StartListenFoundry() {
	foundry.background(func() {
		timeInterval := 1 * time.Second

		for {
			ok, err := foundry.ConnectToWebSocket()
			if err != nil {
				if errors.Is(err, ReconnectToWebSocket) {
					if foundry.transport.ReconnectNum >= foundry.transport.ReconnectNumMax {
						return
					}
					time.Sleep(foundry.transport.ReconnectTimeout)
					foundry.transport.ReconnectNum++
					foundry.transport.Logger.Info("Reconnecting to WebSocket", "times", foundry.transport.ReconnectNum)
					continue
				}

				foundry.transport.Logger.Error("Error raised", "err", err.Error())

				if ok {
					timeInterval = 1 * time.Second
				}
				foundry.transport.Logger.Info("Trying to reconnect", "timer", timeInterval.String())

				time.Sleep(timeInterval)
				timeInterval = min(timeInterval*2, 15*time.Second)
				continue
			}
			return
		}
	})
}

func (foundry *FoundryApi) Test() ([]byte, error) {
	wsMsg := types.NewWsMessage("world", foundry.transport.CurrWsId)
	foundry.transport.CurrWsId++

	answer, err := foundry.transport.HandleWebsocketRequest(wsMsg)
	if err != nil {
		return nil, err
	}
	// foundry.transport.Logger.Info("World data", "answer", string(answer))
	return answer, nil
}

// TODO: remove
func (foundry *FoundryApi) GetHTTP() *requests.FoundryHttpRequest {
	return foundry.transport.Http
}