HomesteadGateway/ws/websocket.go

package ws

import (
	"context"
	"encoding/json"
	"fmt"
	"homestead/homestead_gateway/util/config"
	"log/slog"
	"net"
	"net/http"
	"os/signal"
	"syscall"
	"time"

	"github.com/gorilla/websocket"
)

func NewWsGateway(cfg config.GatewayConfig, logger *slog.Logger, closefn func() error, modH ModHandler, botH BotHandler) *WebsocketGateway {
	return &WebsocketGateway{
		logger:  logger,
		closeFn: closefn,
		apiKey:  cfg.Websocket,
		upgrader: websocket.Upgrader{
			ReadBufferSize:  1024,
			WriteBufferSize: 1024,
			CheckOrigin: func(r *http.Request) bool {
				return true // local by default; change for production
			},
		},
		conns:         make(map[*websocket.Conn]connectionMetaData),
		bodySizeBytes: int64(cfg.BodySize) * 1024 * 1024,
		port:          cfg.HttpPort,
		modHandler:    modH,
		botHandler:    botH,
	}
}

func (wsg *WebsocketGateway) Start() error {
	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	return wsg.Serve(ctx, fmt.Sprintf(":%d", wsg.port))
}

func (wsg *WebsocketGateway) Serve(ctx context.Context, listenAddr string) error {
	mux := http.NewServeMux()
	mux.HandleFunc("/push", wsg.handlePush)
	mux.HandleFunc("/ready", wsg.handleReady)
	mux.HandleFunc("/health", wsg.handleHealth)
	mux.HandleFunc("/register", wsg.handleRegister)

	srv := &http.Server{
		Addr:        listenAddr,
		Handler:     loggingMiddleware(wsg.logger, mux),
		BaseContext: func(l net.Listener) context.Context { return ctx },
	}
	errCh := make(chan error, 1)

	go wsg.listen(srv, listenAddr, errCh)

	select {
	case <-ctx.Done():
		wsg.deafen(srv)
		return nil
	case err := <-errCh:
		return err
	}
}

//

func (wsg *WebsocketGateway) modReadLoop(c *websocket.Conn, meta connectionMetaData) {
	defer func() {
		wsg.unregisterConn(c)
		_ = c.Close()
		wsg.logger.Info("mod disconnected", "server_id", meta.id, "remote", c.RemoteAddr().String())
	}()

	pingTicker := time.NewTicker(30 * time.Second)
	defer pingTicker.Stop()

	// Send pings in a separate goroutine
	go func() {
		for range pingTicker.C {
			_ = c.SetWriteDeadline(time.Now().Add(5 * time.Second))
			if err := c.WriteMessage(websocket.PingMessage, nil); err != nil {
				wsg.logger.Debug("write ping failed", "server_id", meta.id, "err", err)
				return
			}
			wsg.logger.Debug("sent ping to mod", "server_id", meta.id)
		}
	}()

	for {
		typ, data, err := c.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure) {
				wsg.logger.Warn("unexpected mod close", "server_id", meta.id, "err", err)
			} else {
				wsg.logger.Debug("mod read error", "server_id", meta.id, "err", err)
			}
			return
		}

		if typ != websocket.TextMessage && typ != websocket.BinaryMessage {
			continue
		}

		var msg GatewayModMessageIn
		if err := json.Unmarshal(data, &msg); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": "invalid json: " + err.Error()})
			wsg.logger.Warn("invalid json from mod", "server_id", meta.id, "remote", c.RemoteAddr().String(), "err", err)
			continue
		}

		msg.ReceivedAt = time.Now().UTC()
		if err := msg.Validate(); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": err.Error()})
			wsg.logger.Warn("mod message validation failed", "server_id", meta.id, "remote", c.RemoteAddr().String(), "err", err)
			continue
		}

		// Handle the message (forward to bot, enrich, etc.)
		if err := wsg.modHandler.Handle(context.Background(), msg); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": "handler error: " + err.Error()})
			wsg.logger.Error("mod handler error", "server_id", meta.id, "err", err)
			continue
		}

		_ = writeJSONSafe(c, map[string]string{"status": "ok"})
	}
}

func (wsg *WebsocketGateway) botReadLoop(c *websocket.Conn, meta connectionMetaData) {
	defer func() {
		wsg.unregisterConn(c)
		_ = c.Close()
		wsg.logger.Info("bot disconnected", "bot_id", meta.id, "remote", c.RemoteAddr().String())
	}()

	pingTicker := time.NewTicker(30 * time.Second)
	defer pingTicker.Stop()

	// Send pings in a separate goroutine
	go func() {
		for range pingTicker.C {
			_ = c.SetWriteDeadline(time.Now().Add(5 * time.Second))
			if err := c.WriteMessage(websocket.PingMessage, nil); err != nil {
				wsg.logger.Debug("write ping failed", "bot_id", meta.id, "err", err)
				return
			}
			wsg.logger.Debug("sent ping to bot", "bot_id", meta.id)
		}
	}()

	for {
		typ, data, err := c.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure) {
				wsg.logger.Warn("unexpected bot close", "bot_id", meta.id, "err", err)
			} else {
				wsg.logger.Debug("bot read error", "bot_id", meta.id, "err", err)
			}
			return
		}

		if typ != websocket.TextMessage && typ != websocket.BinaryMessage {
			continue
		}

		var msg GatewayBotMessageIn
		if err := json.Unmarshal(data, &msg); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": "invalid json: " + err.Error()})
			wsg.logger.Warn("invalid json from bot", "bot_id", meta.id, "remote", c.RemoteAddr().String(), "err", err)
			continue
		}

		msg.ReceivedAt = time.Now().UTC()
		if err := msg.Validate(); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": err.Error()})
			wsg.logger.Warn("bot message validation failed", "bot_id", meta.id, "remote", c.RemoteAddr().String(), "err", err)
			continue
		}

		// Handle the message (forward to mod, enrich, etc.)
		if err := wsg.botHandler.Handle(context.Background(), msg); err != nil {
			_ = writeJSONSafe(c, map[string]string{"error": "handler error: " + err.Error()})
			wsg.logger.Error("bot handler error", "bot_id", meta.id, "err", err)
			continue
		}

		_ = writeJSONSafe(c, map[string]string{"status": "ok"})
	}
}