Lots of small cleanups

resources/resources.go

@@ -12,6 +12,7 @@ import (
 	"net/http"
 	"os"
 	"path"
+	"reflect"
 	"strings"
 )
 
@@ -58,7 +59,7 @@ func init() {
 			l.Fatal("Unable to find templates")
 		}
 
-		Templates = loadTemplates(templateFS, *externalResources == "")
+		Templates = loadTemplates(templateFS, *externalResources != "")
 		StaticFiles, err = fs.Sub(Resources, "static")
 		if err != nil {
 			l.Fatal("Cannot find static files", zap.Error(err))
@@ -98,9 +99,19 @@ func extractResources(dst string) {
 	})
 }
 
+type AvailableTemplates int
+
+const (
+	ATHtml AvailableTemplates = 1 << iota
+	ATText
+	ATComboCount
+)
+
 type TemplateSource struct {
-	htmlCache *jet.Set
-	textCache *jet.Set
+	htmlCache             *jet.Set
+	textCache             *jet.Set
+	isDevMode             bool
+	availableContentTypes map[string]AvailableTemplates
 }
 
 func loadTemplates(src fs.FS, devMode bool) TemplateSource {
@@ -112,17 +123,63 @@ func loadTemplates(src fs.FS, devMode bool) TemplateSource {
 	}
 
 	loader := genFsLoader{fs: src}
-	return TemplateSource{
-		htmlCache: jet.NewSet(loader, devModeOpt),
-		textCache: jet.NewSet(loader, devModeOpt, jet.WithSafeWriter(nil)),
+	res := TemplateSource{
+		isDevMode:             devMode,
+		htmlCache:             jet.NewSet(loader, devModeOpt, jet.WithTemplateNameExtensions([]string{".html", ".html.jet"})),
+		textCache:             jet.NewSet(loader, devModeOpt, jet.WithTemplateNameExtensions([]string{".txt", ".txt.jet"}), jet.WithSafeWriter(nil)),
+		availableContentTypes: make(map[string]AvailableTemplates),
 	}
+
+	res.htmlCache.AddGlobal("TemplateMode", "html")
+	res.textCache.AddGlobal("TemplateMode", "text")
+
+	return res
 }
 
-func (ts TemplateSource) HtmlTemplate(name string) (*jet.Template, error) {
+// Add a global variable available to all templates
+func (ts *TemplateSource) AddGlobalVar(name string, value interface{}) {
+	ts.textCache.AddGlobal(name, value)
+	ts.htmlCache.AddGlobal(name, value)
+}
+
+// Add a global function available to HTML templates
+func (ts *TemplateSource) AddHtmlFunction(name string, value func(arguments jet.Arguments) reflect.Value) {
+	ts.htmlCache.AddGlobalFunc(name, value)
+}
+
+// Adds a global function available to text templates
+func (ts *TemplateSource) AddTextFunction(name string, value func(arguments jet.Arguments) reflect.Value) {
+	ts.htmlCache.AddGlobalFunc(name, value)
+}
+
+// Adds a global function available to all templates. Equivalent to calling AddHtmlFunction and AddTextFunction
+func (ts *TemplateSource) AddFunction(name string, value func(arguments jet.Arguments) reflect.Value) {
+	ts.AddHtmlFunction(name, value)
+	ts.AddTextFunction(name, value)
+}
+
+func (ts *TemplateSource) GetContentTypes(name string) AvailableTemplates {
+	if result, ok := ts.availableContentTypes[name]; ok {
+		return result
+	}
+	var result AvailableTemplates
+	if _, err := ts.HtmlTemplate(name); err == nil {
+		result = result | ATHtml
+	}
+	if _, err := ts.TextTemplate(name); err == nil {
+		result = result | ATText
+	}
+	if !ts.isDevMode {
+		ts.availableContentTypes[name] = result
+	}
+	return result
+}
+
+func (ts *TemplateSource) HtmlTemplate(name string) (*jet.Template, error) {
 	return ts.htmlCache.GetTemplate(name)
 }
 
-func (ts TemplateSource) TextTemplate(name string) (*jet.Template, error) {
+func (ts *TemplateSource) TextTemplate(name string) (*jet.Template, error) {
 	return ts.textCache.GetTemplate(name)
 }