Add followDate function

Signed-off-by: Knut Ahlers <knut@ahlers.me>

msgformatter.go

@@ -19,6 +19,7 @@ func formatMessage(tplString string, m *irc.Message, r *rule, fields map[string]
 	// Generic functions
 	messageFunctions["toLower"] = strings.ToLower
 	messageFunctions["toUpper"] = strings.ToUpper
+	messageFunctions["followDate"] = twitch.GetFollowDate
 
 	// Message specific functions
 	messageFunctions["arg"] = func(arg int) (string, error) {
@@ -43,7 +44,7 @@ func formatMessage(tplString string, m *irc.Message, r *rule, fields map[string]
 		return store.GetCounterValue(name)
 	}
 
-	messageFunctions["fixUsername"] = func(username string) string { return strings.TrimLeft(username, "@") }
+	messageFunctions["fixUsername"] = func(username string) string { return strings.TrimLeft(username, "@#") }
 
 	messageFunctions["group"] = func(idx int) (string, error) {
 		fields := r.matchMessage.FindStringSubmatch(m.Trailing())

twitch.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 
 	"github.com/pkg/errors"
 )
@@ -36,6 +37,42 @@ func (t twitchClient) getAuthorizedUsername() (string, error) {
 	return payload.Data[0].Login, nil
 }
 
+func (t twitchClient) GetFollowDate(from, to string) (time.Time, error) {
+	fromID, err := t.getIDForUsername(from)
+	if err != nil {
+		return time.Time{}, errors.Wrap(err, "getting id for 'from' user")
+	}
+	toID, err := t.getIDForUsername(to)
+	if err != nil {
+		return time.Time{}, errors.Wrap(err, "getting id for 'to' user")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), twitchRequestTimeout)
+	defer cancel()
+
+	var payload struct {
+		Data []struct {
+			FollowedAt time.Time `json:"followed_at"`
+		} `json:"data"`
+	}
+
+	if err := t.request(
+		ctx,
+		http.MethodGet,
+		fmt.Sprintf("https://api.twitch.tv/helix/users/follows?to_id=%s&from_id=%s", toID, fromID),
+		nil,
+		&payload,
+	); err != nil {
+		return time.Time{}, errors.Wrap(err, "request follow info")
+	}
+
+	if l := len(payload.Data); l != 1 {
+		return time.Time{}, errors.Errorf("unexpected number of records returned: %d", l)
+	}
+
+	return payload.Data[0].FollowedAt, nil
+}
+
 func (t twitchClient) getIDForUsername(username string) (string, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), twitchRequestTimeout)
 	defer cancel()

wiki/Home.md

@@ -79,7 +79,8 @@ Additionally there are some functions available in the templates:
 - `arg <idx>` - Takes the message sent to the channel, splits by space and returns the Nth element
 - `channelCounter <counter name>` - Wraps the counter name into a channel specific counter name including the channel name
 - `counterValue <counter name>` - Returns the current value of the counter which identifier was supplied
-- `fixUsername <username>` - Ensures the username no longer contains the `@` prefix
+- `fixUsername <username>` - Ensures the username no longer contains the `@` or `#` prefix
+- `followDate <from> <to>` - Looks up when `from` followed `to`
 - `group <idx>` - Gets matching group specified by index from `match_message` regular expression
 - `recentGame <username> [fallback]` - Returns the last played game name of the specified user (see shoutout example) or the `fallback` if the game could not be fetched. If no fallback was supplied the message will fail and not be sent.
 - `tag <tagname>` - Takes the message sent to the channel, returns the value of the tag specified
@@ -160,6 +161,15 @@ The example was dumped using this action:
     match_message: '(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z0-9][a-z0-9-]{0,61}[a-z0-9]'
 ```
 
+### Post follow date for an user
+
+```
+  - actions:
+    - respond: 'You followed on {{ ( followDate .username ( fixUsername .channel ) ).Format "2006-01-02" }}'
+    match_channels: ['#mychannel']
+    match_message: '^!followage'
+```
+
 ### Send a notification on successful permit
 
 ```yaml