feat: Add option for inputing template

Now a template file is required to run the cli command. That gives the
user an option to provide its own template file.

An default will be provided later.

1 files changed, 44 insertions, 0 deletions

diff --git a/template.go b/template.go
new file mode 100644
index 0000000..503af64
--- /dev/null
+++ b/template.go
@@ -0,0 +1,44 @@
+package main
+
+import (
+	html "html/template"
+	"io"
+	"os"
+	text "text/template"
+)
+
+type Templater interface {
+	Execute(wr io.Writer, data any) error
+}
+
+var (
+	templateFunc = map[string]any{
+		"DerefI": func(i *int) int { return *i },
+		"DerefS": func(i *string) string { return *i },
+	}
+)
+
+func GetTemplate(templateType, filePath string) (Templater, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	tmpl, err := io.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+
+	switch templateType {
+	case "text":
+		return text.New("text").
+			Funcs(templateFunc).
+			Parse(string(tmpl))
+	case "html":
+		return html.New("html").
+			Funcs(templateFunc).
+			Parse(string(tmpl))
+	default:
+		panic("Invalid template-type")
+	}
+}