Extract template functions into registry

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

functions.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"strings"
+	"sync"
+	"text/template"
+
+	korvike "github.com/Luzifer/korvike/functions"
+	"github.com/go-irc/irc"
+)
+
+var tplFuncs = newTemplateFuncProvider()
+
+type (
+	templateFuncGetter   func(*irc.Message, *rule, map[string]interface{}) interface{}
+	templateFuncProvider struct {
+		funcs map[string]templateFuncGetter
+		lock  *sync.RWMutex
+	}
+)
+
+func newTemplateFuncProvider() *templateFuncProvider {
+	out := &templateFuncProvider{
+		funcs: map[string]templateFuncGetter{},
+		lock:  new(sync.RWMutex),
+	}
+
+	return out
+}
+
+func (t *templateFuncProvider) GetFuncMap(m *irc.Message, r *rule, fields map[string]interface{}) template.FuncMap {
+	t.lock.RLock()
+	defer t.lock.RUnlock()
+
+	out := make(template.FuncMap)
+
+	for n, fg := range t.funcs {
+		out[n] = fg(m, r, fields)
+	}
+
+	return out
+}
+
+func (t *templateFuncProvider) Register(name string, fg templateFuncGetter) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	t.funcs[name] = fg
+}
+
+func genericTemplateFunctionGetter(f interface{}) templateFuncGetter {
+	return func(*irc.Message, *rule, map[string]interface{}) interface{} { return f }
+}
+
+func init() {
+	// Register Korvike functions
+	for n, f := range korvike.GetFunctionMap() {
+		tplFuncs.Register(n, genericTemplateFunctionGetter(f))
+	}
+
+	tplFuncs.Register("toLower", genericTemplateFunctionGetter(strings.ToLower))
+	tplFuncs.Register("toUpper", genericTemplateFunctionGetter(strings.ToUpper))
+	tplFuncs.Register("followDate", genericTemplateFunctionGetter(twitch.GetFollowDate))
+}

functions_counter.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/go-irc/irc"
+	"github.com/pkg/errors"
+)
+
+func init() {
+	tplFuncs.Register("channelCounter", func(m *irc.Message, r *rule, fields map[string]interface{}) interface{} {
+		return func(name string) (string, error) {
+			channel, ok := fields["channel"].(string)
+			if !ok {
+				return "", errors.New("channel not available")
+			}
+
+			return strings.Join([]string{channel, name}, ":"), nil
+		}
+	})
+
+	tplFuncs.Register("counterValue", genericTemplateFunctionGetter(func(name string, _ ...string) int64 {
+		return store.GetCounterValue(name)
+	}))
+}

functions_irc.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"strings"
+
+	"github.com/go-irc/irc"
+	"github.com/pkg/errors"
+)
+
+func init() {
+	tplFuncs.Register("arg", func(m *irc.Message, r *rule, fields map[string]interface{}) interface{} {
+		return func(arg int) (string, error) {
+			msgParts := strings.Split(m.Trailing(), " ")
+			if len(msgParts) <= arg {
+				return "", errors.New("argument not found")
+			}
+
+			return msgParts[arg], nil
+		}
+	})
+
+	tplFuncs.Register("fixUsername", genericTemplateFunctionGetter(func(username string) string { return strings.TrimLeft(username, "@#") }))
+
+	tplFuncs.Register("group", func(m *irc.Message, r *rule, fields map[string]interface{}) interface{} {
+		return func(idx int) (string, error) {
+			fields := r.matchMessage.FindStringSubmatch(m.Trailing())
+			if len(fields) <= idx {
+				return "", errors.New("group not found")
+			}
+
+			return fields[idx], nil
+		}
+	})
+
+	tplFuncs.Register("tag", func(m *irc.Message, r *rule, fields map[string]interface{}) interface{} {
+		return func(tag string) string {
+			s, _ := m.GetTag(tag)
+			return s
+		}
+	})
+}

functions_twitch.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"strings"
+)
+
+func init() {
+	tplFuncs.Register("recentGame", genericTemplateFunctionGetter(func(username string, v ...string) (string, error) {
+		game, _, err := twitch.GetRecentStreamInfo(strings.TrimLeft(username, "#"))
+		if err != nil && len(v) > 0 {
+			return v[0], nil
+		}
+
+		return game, err
+	}))
+}

msgformatter.go

@@ -2,85 +2,14 @@ package main
 
 import (
 	"bytes"
-	"strings"
 	"text/template"
 	"time"
 
-	korvike "github.com/Luzifer/korvike/functions"
-
 	"github.com/go-irc/irc"
 	"github.com/pkg/errors"
 )
 
 func formatMessage(tplString string, m *irc.Message, r *rule, fields map[string]interface{}) (string, error) {
-	// Create anonymous functions in current context in order to access function variables
-	messageFunctions := make(template.FuncMap)
-	for n, f := range korvike.GetFunctionMap() {
-		messageFunctions[n] = f
-	}
-
-	// Generic functions
-	messageFunctions["toLower"] = strings.ToLower
-	messageFunctions["toUpper"] = strings.ToUpper
-	messageFunctions["followDate"] = twitch.GetFollowDate
-
-	// Message specific functions
-	messageFunctions["arg"] = func(arg int) (string, error) {
-		msgParts := strings.Split(m.Trailing(), " ")
-		if len(msgParts) <= arg {
-			return "", errors.New("argument not found")
-		}
-
-		return msgParts[arg], nil
-	}
-
-	messageFunctions["channelCounter"] = func(name string) (string, error) {
-		channel, ok := fields["channel"].(string)
-		if !ok {
-			return "", errors.New("channel not available")
-		}
-
-		return strings.Join([]string{channel, name}, ":"), nil
-	}
-
-	messageFunctions["counterValue"] = func(name string, _ ...string) int64 {
-		return store.GetCounterValue(name)
-	}
-
-	messageFunctions["fixUsername"] = func(username string) string { return strings.TrimLeft(username, "@#") }
-
-	messageFunctions["group"] = func(idx int) (string, error) {
-		fields := r.matchMessage.FindStringSubmatch(m.Trailing())
-		if len(fields) <= idx {
-			return "", errors.New("group not found")
-		}
-
-		return fields[idx], nil
-	}
-
-	messageFunctions["recentGame"] = func(username string, v ...string) (string, error) {
-		game, _, err := twitch.GetRecentStreamInfo(strings.TrimLeft(username, "#"))
-		if err != nil && len(v) > 0 {
-			return v[0], nil
-		}
-
-		return game, err
-	}
-
-	messageFunctions["tag"] = func(tag string) string {
-		s, _ := m.GetTag(tag)
-		return s
-	}
-
-	// Parse and execute template
-	tpl, err := template.
-		New(tplString).
-		Funcs(messageFunctions).
-		Parse(tplString)
-	if err != nil {
-		return "", errors.Wrap(err, "parse template")
-	}
-
 	if fields == nil {
 		fields = map[string]interface{}{}
 	}
@@ -93,6 +22,15 @@ func formatMessage(tplString string, m *irc.Message, r *rule, fields map[string]
 		fields["channel"] = m.Params[0]
 	}
 
+	// Parse and execute template
+	tpl, err := template.
+		New(tplString).
+		Funcs(tplFuncs.GetFuncMap(m, r, fields)).
+		Parse(tplString)
+	if err != nil {
+		return "", errors.Wrap(err, "parse template")
+	}
+
 	buf := new(bytes.Buffer)
 	err = tpl.Execute(buf, fields)