package template
import (
"bytes"
"context"
"log/slog"
"text/template"
"github.com/manacore/mana-notify/internal/db"
)
type Engine struct {
db *db.DB
}
func NewEngine(database *db.DB) *Engine {
return &Engine{db: database}
}
type Rendered struct {
Subject string
Body string
}
// RenderBySlug looks up a template by slug and renders it with the given data.
func (e *Engine) RenderBySlug(ctx context.Context, slug string, data map[string]any, locale string) (*Rendered, error) {
if locale == "" {
locale = "de-DE"
}
var subject, bodyTemplate *string
err := e.db.Pool.QueryRow(ctx,
`SELECT subject, body_template FROM notify.templates WHERE slug = $1 AND locale = $2 AND is_active = true`,
slug, locale,
).Scan(&subject, &bodyTemplate)
if err != nil {
// Try default locale fallback
err = e.db.Pool.QueryRow(ctx,
`SELECT subject, body_template FROM notify.templates WHERE slug = $1 AND is_active = true ORDER BY locale LIMIT 1`,
slug,
).Scan(&subject, &bodyTemplate)
if err != nil {
return nil, err
}
}
rendered := &Rendered{}
if subject != nil {
s, err := renderTemplate(*subject, data)
if err != nil {
return nil, err
}
rendered.Subject = s
}
if bodyTemplate != nil {
b, err := renderTemplate(*bodyTemplate, data)
if err != nil {
return nil, err
}
rendered.Body = b
}
return rendered, nil
}
// RenderDirect renders a template string with data.
func RenderDirect(tmplStr string, data map[string]any) (string, error) {
return renderTemplate(tmplStr, data)
}
func renderTemplate(tmplStr string, data map[string]any) (string, error) {
tmpl, err := template.New("").Parse(tmplStr)
if err != nil {
return "", err
}
var buf bytes.Buffer
if err := tmpl.Execute(&buf, data); err != nil {
return "", err
}
return buf.String(), nil
}
// SeedDefaults inserts default system templates if they don't exist.
func (e *Engine) SeedDefaults(ctx context.Context) {
defaults := []struct {
slug string
channel string
subject string
body string
vars string
}{
{
slug: "auth-password-reset",
channel: "email",
subject: "Passwort zurücksetzen - ManaCore",
body: `Passwort zurücksetzen
Hallo {{.userName}},
Klicke auf den folgenden Link, um dein Passwort zurückzusetzen:
Passwort zurücksetzen
Falls du diese Anfrage nicht gestellt hast, kannst du diese E-Mail ignorieren.
`,
vars: `{"resetUrl": "URL zum Zurücksetzen", "userName": "Name des Benutzers"}`,
},
{
slug: "auth-verification",
channel: "email",
subject: "E-Mail bestätigen - ManaCore",
body: `E-Mail bestätigen
Hallo {{.userName}},
Bitte bestätige deine E-Mail-Adresse:
E-Mail bestätigen
`,
vars: `{"verificationUrl": "Bestätigungs-URL", "userName": "Name des Benutzers"}`,
},
{
slug: "auth-welcome",
channel: "email",
subject: "Willkommen bei ManaCore!",
body: `Willkommen!
Hallo {{.userName}},
Willkommen bei ManaCore! Du kannst dich jetzt anmelden:
Anmelden
`,
vars: `{"userName": "Name des Benutzers", "loginUrl": "Login-URL"}`,
},
{
slug: "calendar-reminder",
channel: "email",
subject: "Erinnerung: {{.eventTitle}}",
body: `{{.eventTitle}}
Wann: {{.eventTime}}
{{if .eventLocation}}Wo: {{.eventLocation}}
{{end}}Termin anzeigen
`,
vars: `{"eventTitle": "Titel", "eventTime": "Zeit", "eventLocation": "Ort (optional)", "eventUrl": "Link"}`,
},
}
for _, d := range defaults {
_, err := e.db.Pool.Exec(ctx,
`INSERT INTO notify.templates (slug, channel, subject, body_template, locale, is_system, variables)
VALUES ($1, $2, $3, $4, 'de-DE', true, $5)
ON CONFLICT (slug, locale) DO NOTHING`,
d.slug, d.channel, d.subject, d.body, d.vars,
)
if err != nil {
slog.Warn("seed template failed", "slug", d.slug, "error", err)
}
}
slog.Info("default templates seeded")
}