MosswartOverlord/go-services/discord-go/ws.go

package main

import (
	"context"
	"encoding/json"
	"log/slog"
	"strings"
	"time"

	"github.com/coder/websocket"
)

// bot consumes the tracker's /ws/live firehose (subscribed to rare+chat) and
// routes events to a poster. It reconnects with exponential backoff, mirroring
// monitor_websocket().
type bot struct {
	wsURL       string
	monitorChar string
	out         poster
	log         *slog.Logger
}

func (b *bot) run(ctx context.Context) {
	backoff := time.Second
	const maxBackoff = 60 * time.Second
	for ctx.Err() == nil {
		err := b.connectAndConsume(ctx)
		if ctx.Err() != nil {
			return
		}
		if err != nil {
			b.log.Warn("ws disconnected; reconnecting", "err", err, "backoff", backoff.String())
		}
		select {
		case <-ctx.Done():
			return
		case <-time.After(backoff):
		}
		backoff *= 2
		if backoff > maxBackoff {
			backoff = maxBackoff
		}
	}
}

func (b *bot) connectAndConsume(ctx context.Context) error {
	b.log.Info("connecting to /ws/live", "url", b.wsURL)
	c, _, err := websocket.Dial(ctx, b.wsURL, nil)
	if err != nil {
		return err
	}
	defer c.CloseNow()
	c.SetReadLimit(8 << 20) // payloads (nearby_objects etc.) can be large; we only read rare/chat but the socket carries all

	// Subscribe to just rare + chat (server-side filtering), like the Python bot.
	sub, _ := json.Marshal(map[string]any{"type": "subscribe", "message_types": []string{"rare", "chat"}})
	if err := c.Write(ctx, websocket.MessageText, sub); err != nil {
		return err
	}
	b.log.Info("subscribed", "message_types", []string{"rare", "chat"})
	b.out.postStatus("🔗 (go) WebSocket connection established")

	// Keepalive pings, like ping_interval=20.
	pingCtx, cancel := context.WithCancel(ctx)
	defer cancel()
	go func() {
		t := time.NewTicker(20 * time.Second)
		defer t.Stop()
		for {
			select {
			case <-pingCtx.Done():
				return
			case <-t.C:
				pc, cc := context.WithTimeout(pingCtx, 10*time.Second)
				_ = c.Ping(pc)
				cc()
			}
		}
	}()

	for {
		_, data, err := c.Read(ctx)
		if err != nil {
			return err
		}
		b.handleMessage(data)
	}
}

func (b *bot) handleMessage(raw []byte) {
	var data map[string]any
	if err := json.Unmarshal(raw, &data); err != nil {
		return // ignore invalid JSON, like the Python bot
	}
	switch asString(data["type"]) {
	case "rare":
		b.handleRare(data)
	case "chat":
		b.handleChat(data)
	}
}

func (b *bot) handleRare(data map[string]any) {
	ev := rareEvent{
		Name:          asStringOr(data["name"], "Unknown Rare"),
		CharacterName: asStringOr(data["character_name"], "Unknown Character"),
		Timestamp:     asString(data["timestamp"]),
		EW:            asFloatPtr(data["ew"]),
		NS:            asFloatPtr(data["ns"]),
		Z:             asFloatPtr(data["z"]),
	}
	tier := classify(ev.Name)
	b.log.Info("rare", "name", ev.Name, "character", ev.CharacterName, "tier", tier)
	b.out.postRare(ev, tier)
}

func (b *bot) handleChat(data map[string]any) {
	charName := asString(data["character_name"])
	text := asString(data["text"])
	if charName != b.monitorChar {
		return
	}
	if strings.Contains(text, "m in whirlwind of vortexes") {
		b.out.postVortex(parseAllegianceSpeaker(text), text, asString(data["timestamp"]))
		return
	}
	b.out.postChat(charName, text, asString(data["timestamp"]))
}

// parseAllegianceSpeaker extracts <name> from "[Allegiance] <name> says, ...".
func parseAllegianceSpeaker(text string) string {
	const prefix = "[Allegiance] "
	if i := strings.Index(text, prefix); i >= 0 {
		rest := text[i+len(prefix):]
		if j := strings.Index(rest, " says,"); j >= 0 {
			return rest[:j]
		}
	}
	return "Unknown"
}

func asString(v any) string {
	s, _ := v.(string)
	return s
}

func asStringOr(v any, def string) string {
	if s, ok := v.(string); ok && s != "" {
		return s
	}
	return def
}

func asFloatPtr(v any) *float64 {
	if f, ok := v.(float64); ok {
		return &f
	}
	return nil
}