v0.1.0 (#17)

internal/email/templates.go

@@ -0,0 +1,52 @@
+package email
+
+import (
+	"bytes"
+	"embed"
+	"fmt"
+	"html/template"
+	text_template "text/template"
+)
+
+//go:embed templates/*.html templates/*.txt
+var templateFS embed.FS
+
+// templates holds the parsed HTML and plain-text template sets.
+type templates struct {
+	html *template.Template
+	text *text_template.Template
+}
+
+// mustLoadTemplates parses all embedded templates. Panics on error
+// because malformed templates are a build-time bug.
+func mustLoadTemplates() *templates {
+	html, err := template.ParseFS(templateFS, "templates/*.html")
+	if err != nil {
+		panic(fmt.Sprintf("email: failed to parse HTML templates: %v", err))
+	}
+
+	text, err := text_template.ParseFS(templateFS, "templates/*.txt")
+	if err != nil {
+		panic(fmt.Sprintf("email: failed to parse text templates: %v", err))
+	}
+
+	return &templates{html: html, text: text}
+}
+
+// renderHTML executes the HTML base template with the given data.
+func (t *templates) renderHTML(data EmailData) (string, error) {
+	var buf bytes.Buffer
+	if err := t.html.ExecuteTemplate(&buf, "base.html", data); err != nil {
+		return "", fmt.Errorf("execute html template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// renderText executes the plain-text base template with the given data.
+func (t *templates) renderText(data EmailData) (string, error) {
+	var buf bytes.Buffer
+	if err := t.text.ExecuteTemplate(&buf, "base.txt", data); err != nil {
+		return "", fmt.Errorf("execute text template: %w", err)
+	}
+	return buf.String(), nil
+}