[template] Add doesFollow and doesFollowLongerThan functions

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

functions_twitch.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/pkg/errors"
 
+	"github.com/Luzifer/twitch-bot/v3/pkg/twitch"
 	"github.com/Luzifer/twitch-bot/v3/plugins"
 )
 
@@ -19,12 +20,58 @@ func init() {
 		return displayName, err
 	}))
 
+	tplFuncs.Register("doesFollow", plugins.GenericTemplateFunctionGetter(func(from, to string) (bool, error) {
+		_, err := twitchClient.GetFollowDate(from, to)
+		switch {
+		case err == nil:
+			return true, nil
+
+		case errors.Is(err, twitch.ErrUserDoesNotFollow):
+			return false, nil
+
+		default:
+			return false, errors.Wrap(err, "getting follow date")
+		}
+	}))
+
 	tplFuncs.Register("followAge", plugins.GenericTemplateFunctionGetter(func(from, to string) (time.Duration, error) {
 		since, err := twitchClient.GetFollowDate(from, to)
 		return time.Since(since), errors.Wrap(err, "getting follow date")
 	}))
 	tplFuncs.Register("followDate", plugins.GenericTemplateFunctionGetter(func(from, to string) (time.Time, error) { return twitchClient.GetFollowDate(from, to) }))
 
+	tplFuncs.Register("doesFollowLongerThan", plugins.GenericTemplateFunctionGetter(func(from, to string, t any) (bool, error) {
+		var (
+			age time.Duration
+			err error
+		)
+
+		switch v := t.(type) {
+		case int64:
+			age = time.Duration(v) * time.Second
+
+		case string:
+			if age, err = time.ParseDuration(v); err != nil {
+				return false, errors.Wrap(err, "parsing duration")
+			}
+
+		default:
+			return false, errors.Errorf("unexpected input for duration %t", t)
+		}
+
+		fd, err := twitchClient.GetFollowDate(from, to)
+		switch {
+		case err == nil:
+			return time.Since(fd) > age, nil
+
+		case errors.Is(err, twitch.ErrUserDoesNotFollow):
+			return false, nil
+
+		default:
+			return false, errors.Wrap(err, "getting follow date")
+		}
+	}))
+
 	tplFuncs.Register("recentGame", plugins.GenericTemplateFunctionGetter(func(username string, v ...string) (string, error) {
 		game, _, err := twitchClient.GetRecentStreamInfo(strings.TrimLeft(username, "#"))
 		if len(v) > 0 && (err != nil || game == "") {

pkg/twitch/users.go

@@ -19,6 +19,8 @@ type (
 	}
 )
 
+var ErrUserDoesNotFollow = errors.New("no follow-relation found")
+
 func (c *Client) GetAuthorizedUser() (userID string, userName string, err error) {
 	var payload struct {
 		Data []User `json:"data"`
@@ -104,8 +106,15 @@ func (c *Client) GetFollowDate(from, to string) (time.Time, error) {
 		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)
+	switch len(payload.Data) {
+	case 0:
+		return time.Time{}, ErrUserDoesNotFollow
+
+	case 1:
+		// Handled below, no error
+
+	default:
+		return time.Time{}, errors.Errorf("unexpected number of records returned: %d", len(payload.Data))
 	}
 
 	// Follow date will not change that often, cache for a long time

wiki/Templating.md

@@ -108,6 +108,32 @@ Example:
 < Luziferus - foobar
 ```
 
+#### `doesFollow`
+
+Returns whether `from` follows `to`
+
+Syntax: `doesFollow <from> <to>`
+
+Example:
+
+```
+# {{ doesFollow "tezrian" "luziferus" }}
+< true
+```
+
+#### `doesFollowLongerThan`
+
+Returns whether `from` follows `to` for more than `duration`
+
+Syntax: `doesFollowLongerThan <from> <to> <duration>`
+
+Example:
+
+```
+# {{ doesFollowLongerThan "tezrian" "luziferus" "168h" }}
+< true
+```
+
 #### `fixUsername`
 
 Ensures the username no longer contains the `@` or `#` prefix