1 files changed, 215 insertions, 0 deletions
diff --git a/teleirc/matterbridge/bridge/matrix/helpers.go b/teleirc/matterbridge/bridge/matrix/helpers.go
new file mode 100644
index 0000000..5a91f74
--- /dev/null
+++ b/teleirc/matterbridge/bridge/matrix/helpers.go
@@ -0,0 +1,215 @@
+package bmatrix
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"html"
+	"strings"
+	"time"
+
+	matrix "github.com/matterbridge/gomatrix"
+)
+
+func newMatrixUsername(username string) *matrixUsername {
+	mUsername := new(matrixUsername)
+
+	// check if we have a </tag>. if we have, we don't escape HTML. #696
+	if htmlTag.MatchString(username) {
+		mUsername.formatted = username
+		// remove the HTML formatting for beautiful push messages #1188
+		mUsername.plain = htmlReplacementTag.ReplaceAllString(username, "")
+	} else {
+		mUsername.formatted = html.EscapeString(username)
+		mUsername.plain = username
+	}
+
+	return mUsername
+}
+
+// getRoomID retrieves a matching room ID from the channel name.
+func (b *Bmatrix) getRoomID(channel string) string {
+	b.RLock()
+	defer b.RUnlock()
+	for ID, name := range b.RoomMap {
+		if name == channel {
+			return ID
+		}
+	}
+
+	return ""
+}
+
+// interface2Struct marshals and immediately unmarshals an interface.
+// Useful for converting map[string]interface{} to a struct.
+func interface2Struct(in interface{}, out interface{}) error {
+	jsonObj, err := json.Marshal(in)
+	if err != nil {
+		return err //nolint:wrapcheck
+	}
+
+	return json.Unmarshal(jsonObj, out)
+}
+
+// getDisplayName retrieves the displayName for mxid, querying the homeserver if the mxid is not in the cache.
+func (b *Bmatrix) getDisplayName(mxid string) string {
+	if b.GetBool("UseUserName") {
+		return mxid[1:]
+	}
+
+	b.RLock()
+	if val, present := b.NicknameMap[mxid]; present {
+		b.RUnlock()
+
+		return val.displayName
+	}
+	b.RUnlock()
+
+	displayName, err := b.mc.GetDisplayName(mxid)
+	var httpError *matrix.HTTPError
+	if errors.As(err, &httpError) {
+		b.Log.Warnf("Couldn't retrieve the display name for %s", mxid)
+	}
+
+	if err != nil {
+		return b.cacheDisplayName(mxid, mxid[1:])
+	}
+
+	return b.cacheDisplayName(mxid, displayName.DisplayName)
+}
+
+// cacheDisplayName stores the mapping between a mxid and a display name, to be reused later without performing a query to the homserver.
+// Note that old entries are cleaned when this function is called.
+func (b *Bmatrix) cacheDisplayName(mxid string, displayName string) string {
+	now := time.Now()
+
+	// scan to delete old entries, to stop memory usage from becoming too high with old entries.
+	// In addition, we also detect if another user have the same username, and if so, we append their mxids to their usernames to differentiate them.
+	toDelete := []string{}
+	conflict := false
+
+	b.Lock()
+	for mxid, v := range b.NicknameMap {
+		// to prevent username reuse across matrix servers - or even on the same server, append
+		// the mxid to the username when there is a conflict
+		if v.displayName == displayName {
+			conflict = true
+			// TODO: it would be nice to be able to rename previous messages from this user.
+			// The current behavior is that only users with clashing usernames and *that have spoken since the bridge last started* will get their mxids shown, and I don't know if that's the expected behavior.
+			v.displayName = fmt.Sprintf("%s (%s)", displayName, mxid)
+			b.NicknameMap[mxid] = v
+		}
+
+		if now.Sub(v.lastUpdated) > 10*time.Minute {
+			toDelete = append(toDelete, mxid)
+		}
+	}
+
+	if conflict {
+		displayName = fmt.Sprintf("%s (%s)", displayName, mxid)
+	}
+
+	for _, v := range toDelete {
+		delete(b.NicknameMap, v)
+	}
+
+	b.NicknameMap[mxid] = NicknameCacheEntry{
+		displayName: displayName,
+		lastUpdated: now,
+	}
+	b.Unlock()
+
+	return displayName
+}
+
+// handleError converts errors into httpError.
+//nolint:exhaustivestruct
+func handleError(err error) *httpError {
+	var mErr matrix.HTTPError
+	if !errors.As(err, &mErr) {
+		return &httpError{
+			Err: "not a HTTPError",
+		}
+	}
+
+	var httpErr httpError
+
+	if err := json.Unmarshal(mErr.Contents, &httpErr); err != nil {
+		return &httpError{
+			Err: "unmarshal failed",
+		}
+	}
+
+	return &httpErr
+}
+
+func (b *Bmatrix) containsAttachment(content map[string]interface{}) bool {
+	// Skip empty messages
+	if content["msgtype"] == nil {
+		return false
+	}
+
+	// Only allow image,video or file msgtypes
+	if !(content["msgtype"].(string) == "m.image" ||
+		content["msgtype"].(string) == "m.video" ||
+		content["msgtype"].(string) == "m.file") {
+		return false
+	}
+
+	return true
+}
+
+// getAvatarURL returns the avatar URL of the specified sender.
+func (b *Bmatrix) getAvatarURL(sender string) string {
+	urlPath := b.mc.BuildURL("profile", sender, "avatar_url")
+
+	s := struct {
+		AvatarURL string `json:"avatar_url"`
+	}{}
+
+	err := b.mc.MakeRequest("GET", urlPath, nil, &s)
+	if err != nil {
+		b.Log.Errorf("getAvatarURL failed: %s", err)
+
+		return ""
+	}
+
+	url := strings.ReplaceAll(s.AvatarURL, "mxc://", b.GetString("Server")+"/_matrix/media/r0/thumbnail/")
+	if url != "" {
+		url += "?width=37&height=37&method=crop"
+	}
+
+	return url
+}
+
+// handleRatelimit handles the ratelimit errors and return if we're ratelimited and the amount of time to sleep
+func (b *Bmatrix) handleRatelimit(err error) (time.Duration, bool) {
+	httpErr := handleError(err)
+	if httpErr.Errcode != "M_LIMIT_EXCEEDED" {
+		return 0, false
+	}
+
+	b.Log.Debugf("ratelimited: %s", httpErr.Err)
+	b.Log.Infof("getting ratelimited by matrix, sleeping approx %d seconds before retrying", httpErr.RetryAfterMs/1000)
+
+	return time.Duration(httpErr.RetryAfterMs) * time.Millisecond, true
+}
+
+// retry function will check if we're ratelimited and retries again when backoff time expired
+// returns original error if not 429 ratelimit
+func (b *Bmatrix) retry(f func() error) error {
+	b.rateMutex.Lock()
+	defer b.rateMutex.Unlock()
+
+	for {
+		if err := f(); err != nil {
+			if backoff, ok := b.handleRatelimit(err); ok {
+				time.Sleep(backoff)
+			} else {
+				return err
+			}
+		} else {
+			return nil
+		}
+	}
+}