billing docs service

api/billing/documents/internal/service/documents/template.go

@@ -0,0 +1,60 @@
+package documents
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"text/template"
+	"time"
+
+	"github.com/shopspring/decimal"
+	"github.com/tech/sendico/billing/documents/renderer"
+	"github.com/tech/sendico/billing/documents/storage/model"
+)
+
+type templateRenderer struct {
+	tpl *template.Template
+}
+
+func newTemplateRenderer(path string) (*templateRenderer, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read template: %w", err)
+	}
+
+	funcs := template.FuncMap{
+		"money": formatMoney,
+		"date":  formatDate,
+	}
+
+	tpl, err := template.New("acceptance").Funcs(funcs).Option("missingkey=error").Parse(string(data))
+	if err != nil {
+		return nil, fmt.Errorf("parse template: %w", err)
+	}
+
+	return &templateRenderer{tpl: tpl}, nil
+}
+
+func (r *templateRenderer) Render(snapshot model.ActSnapshot) ([]renderer.Block, error) {
+	var buf bytes.Buffer
+	if err := r.tpl.Execute(&buf, snapshot); err != nil {
+		return nil, fmt.Errorf("execute template: %w", err)
+	}
+	return renderer.ParseBlocks(buf.String())
+}
+
+func formatMoney(amount decimal.Decimal, currency string) string {
+	currency = strings.TrimSpace(currency)
+	if currency == "" {
+		return amount.String()
+	}
+	return fmt.Sprintf("%s %s", amount.String(), currency)
+}
+
+func formatDate(t time.Time) string {
+	if t.IsZero() {
+		return ""
+	}
+	return t.Format("2006-01-02")
+}