refactor

2026-06-29 12:34:58 +02:00
parent d711348863
commit 46be260fcc
35 changed files with 1765 additions and 198 deletions
@@ -0,0 +1,508 @@
+package order
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"embed"
+	"encoding/json"
+	"fmt"
+	htmltmpl "html/template"
+	"io/fs"
+	"mime"
+	"mime/quotedprintable"
+	"net"
+	"net/mail"
+	"net/smtp"
+	"os"
+	"path/filepath"
+	"strings"
+	texttmpl "text/template"
+	"time"
+
+	"git.k6n.net/mats/go-cart-actor/pkg/flow"
+)
+
+// EmailMessage is the rendered mail payload a sender delivers.
+type EmailMessage struct {
+	From     mail.Address
+	To       []mail.Address
+	Subject  string
+	TextBody string
+	HTMLBody string
+}
+
+// EmailSender delivers an already-rendered mail and exposes its default sender.
+type EmailSender interface {
+	Send(ctx context.Context, msg EmailMessage) error
+	DefaultFrom() mail.Address
+}
+
+// SMTPEmailSenderConfig configures the SMTP mail transport.
+type SMTPEmailSenderConfig struct {
+	Host        string
+	Port        int
+	Username    string
+	Password    string
+	DefaultFrom mail.Address
+	Timeout     time.Duration
+}
+
+type smtpEmailSender struct {
+	host        string
+	addr        string
+	auth        smtp.Auth
+	defaultFrom mail.Address
+	timeout     time.Duration
+}
+
+// NewSMTPEmailSender returns an SMTP-backed sender. It supports plain SMTP with
+// opportunistic STARTTLS, which is the only configured transport for now.
+func NewSMTPEmailSender(cfg SMTPEmailSenderConfig) (EmailSender, error) {
+	if strings.TrimSpace(cfg.Host) == "" {
+		return nil, fmt.Errorf("smtp sender: missing host")
+	}
+	if cfg.Port <= 0 {
+		return nil, fmt.Errorf("smtp sender: invalid port %d", cfg.Port)
+	}
+	if cfg.Timeout <= 0 {
+		cfg.Timeout = 10 * time.Second
+	}
+	if strings.TrimSpace(cfg.DefaultFrom.Address) == "" {
+		return nil, fmt.Errorf("smtp sender: missing default from address")
+	}
+	s := &smtpEmailSender{
+		host:        cfg.Host,
+		addr:        net.JoinHostPort(cfg.Host, fmt.Sprintf("%d", cfg.Port)),
+		defaultFrom: cfg.DefaultFrom,
+		timeout:     cfg.Timeout,
+	}
+	if cfg.Username != "" {
+		s.auth = smtp.PlainAuth("", cfg.Username, cfg.Password, cfg.Host)
+	}
+	return s, nil
+}
+
+func (s *smtpEmailSender) DefaultFrom() mail.Address { return s.defaultFrom }
+
+func (s *smtpEmailSender) Send(ctx context.Context, msg EmailMessage) error {
+	if strings.TrimSpace(msg.From.Address) == "" {
+		return fmt.Errorf("smtp sender: missing from address")
+	}
+	if len(msg.To) == 0 {
+		return fmt.Errorf("smtp sender: missing recipients")
+	}
+	if strings.TrimSpace(msg.Subject) == "" {
+		return fmt.Errorf("smtp sender: missing subject")
+	}
+	body, err := buildSMTPMessage(msg)
+	if err != nil {
+		return err
+	}
+
+	conn, err := (&net.Dialer{Timeout: s.timeout}).DialContext(ctx, "tcp", s.addr)
+	if err != nil {
+		return fmt.Errorf("smtp sender: dial %s: %w", s.addr, err)
+	}
+	defer conn.Close()
+	_ = conn.SetDeadline(time.Now().Add(s.timeout))
+
+	client, err := smtp.NewClient(conn, s.host)
+	if err != nil {
+		return fmt.Errorf("smtp sender: create client: %w", err)
+	}
+	defer client.Close()
+
+	if ok, _ := client.Extension("STARTTLS"); ok {
+		if err := client.StartTLS(&tls.Config{ServerName: s.host, MinVersion: tls.VersionTLS12}); err != nil {
+			return fmt.Errorf("smtp sender: starttls: %w", err)
+		}
+	}
+	if s.auth != nil {
+		if ok, _ := client.Extension("AUTH"); !ok {
+			return fmt.Errorf("smtp sender: server does not support auth")
+		}
+		if err := client.Auth(s.auth); err != nil {
+			return fmt.Errorf("smtp sender: auth: %w", err)
+		}
+	}
+	if err := client.Mail(msg.From.Address); err != nil {
+		return fmt.Errorf("smtp sender: mail from %s: %w", msg.From.Address, err)
+	}
+	for _, rcpt := range msg.To {
+		if err := client.Rcpt(rcpt.Address); err != nil {
+			return fmt.Errorf("smtp sender: rcpt to %s: %w", rcpt.Address, err)
+		}
+	}
+	w, err := client.Data()
+	if err != nil {
+		return fmt.Errorf("smtp sender: data: %w", err)
+	}
+	if _, err := w.Write(body); err != nil {
+		_ = w.Close()
+		return fmt.Errorf("smtp sender: write body: %w", err)
+	}
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("smtp sender: close body: %w", err)
+	}
+	if err := client.Quit(); err != nil {
+		return fmt.Errorf("smtp sender: quit: %w", err)
+	}
+	return nil
+}
+
+func buildSMTPMessage(msg EmailMessage) ([]byte, error) {
+	if strings.TrimSpace(msg.TextBody) == "" && strings.TrimSpace(msg.HTMLBody) == "" {
+		return nil, fmt.Errorf("email: missing body")
+	}
+
+	var buf bytes.Buffer
+	writeHeader := func(name, value string) {
+		buf.WriteString(name)
+		buf.WriteString(": ")
+		buf.WriteString(value)
+		buf.WriteString("\r\n")
+	}
+	writeHeader("From", msg.From.String())
+	toList := make([]string, 0, len(msg.To))
+	for _, rcpt := range msg.To {
+		toList = append(toList, rcpt.String())
+	}
+	writeHeader("To", strings.Join(toList, ", "))
+	writeHeader("Subject", mime.QEncoding.Encode("utf-8", msg.Subject))
+	writeHeader("Date", time.Now().Format(time.RFC1123Z))
+	writeHeader("MIME-Version", "1.0")
+
+	switch {
+	case msg.TextBody != "" && msg.HTMLBody != "":
+		boundary := fmt.Sprintf("alt-%d", time.Now().UnixNano())
+		writeHeader("Content-Type", fmt.Sprintf(`multipart/alternative; boundary="%s"`, boundary))
+		buf.WriteString("\r\n")
+		writeMIMEPart(&buf, boundary, "text/plain; charset=utf-8", msg.TextBody)
+		writeMIMEPart(&buf, boundary, "text/html; charset=utf-8", msg.HTMLBody)
+		buf.WriteString("--")
+		buf.WriteString(boundary)
+		buf.WriteString("--\r\n")
+	case msg.HTMLBody != "":
+		writeHeader("Content-Type", `text/html; charset=utf-8`)
+		writeHeader("Content-Transfer-Encoding", "quoted-printable")
+		buf.WriteString("\r\n")
+		if err := writeQuotedPrintable(&buf, msg.HTMLBody); err != nil {
+			return nil, fmt.Errorf("email: encode html body: %w", err)
+		}
+	default:
+		writeHeader("Content-Type", `text/plain; charset=utf-8`)
+		writeHeader("Content-Transfer-Encoding", "quoted-printable")
+		buf.WriteString("\r\n")
+		if err := writeQuotedPrintable(&buf, msg.TextBody); err != nil {
+			return nil, fmt.Errorf("email: encode text body: %w", err)
+		}
+	}
+	return buf.Bytes(), nil
+}
+
+func writeMIMEPart(buf *bytes.Buffer, boundary, contentType, body string) {
+	buf.WriteString("--")
+	buf.WriteString(boundary)
+	buf.WriteString("\r\n")
+	buf.WriteString("Content-Type: ")
+	buf.WriteString(contentType)
+	buf.WriteString("\r\n")
+	buf.WriteString("Content-Transfer-Encoding: quoted-printable\r\n\r\n")
+	_ = writeQuotedPrintable(buf, body)
+	buf.WriteString("\r\n")
+}
+
+func writeQuotedPrintable(buf *bytes.Buffer, body string) error {
+	w := quotedprintable.NewWriter(buf)
+	if _, err := w.Write([]byte(strings.ReplaceAll(body, "\n", "\r\n"))); err != nil {
+		return err
+	}
+	return w.Close()
+}
+
+// EmailTemplate is a named mail template, typically selected by a flow hook.
+type EmailTemplate struct {
+	Subject string `json:"subject"`
+	Text    string `json:"text,omitempty"`
+	HTML    string `json:"html,omitempty"`
+}
+
+func (t EmailTemplate) validate(name string) error {
+	if strings.TrimSpace(t.Subject) == "" {
+		return fmt.Errorf("email template %q: missing subject", name)
+	}
+	if strings.TrimSpace(t.Text) == "" && strings.TrimSpace(t.HTML) == "" {
+		return fmt.Errorf("email template %q: missing text/html body", name)
+	}
+	return nil
+}
+
+// EmailTemplateStore resolves a template by name.
+type EmailTemplateStore interface {
+	Get(name string) (EmailTemplate, error)
+}
+
+type emailTemplateCatalog struct {
+	templates map[string]EmailTemplate
+}
+
+func newEmailTemplateCatalog(seed map[string]EmailTemplate) *emailTemplateCatalog {
+	out := &emailTemplateCatalog{templates: make(map[string]EmailTemplate, len(seed))}
+	for name, tmpl := range seed {
+		out.templates[name] = tmpl
+	}
+	return out
+}
+
+func (c *emailTemplateCatalog) Get(name string) (EmailTemplate, error) {
+	tmpl, ok := c.templates[name]
+	if !ok {
+		return EmailTemplate{}, fmt.Errorf("unknown template %q", name)
+	}
+	return tmpl, nil
+}
+
+//go:embed email_templates/*.json
+var embeddedEmailTemplateFS embed.FS
+
+// LoadEmailTemplates returns the embedded templates overlaid by any JSON files in
+// dir (same precedence model as flow definitions: on-disk wins).
+func LoadEmailTemplates(dir string) (EmailTemplateStore, error) {
+	templates := map[string]EmailTemplate{}
+
+	matches, err := fs.Glob(embeddedEmailTemplateFS, "email_templates/*.json")
+	if err != nil {
+		return nil, fmt.Errorf("list embedded email templates: %w", err)
+	}
+	for _, match := range matches {
+		data, err := embeddedEmailTemplateFS.ReadFile(match)
+		if err != nil {
+			return nil, fmt.Errorf("read embedded email template %s: %w", match, err)
+		}
+		name := strings.TrimSuffix(filepath.Base(match), ".json")
+		tmpl, err := parseEmailTemplate(name, data)
+		if err != nil {
+			return nil, err
+		}
+		templates[name] = tmpl
+	}
+
+	if dir != "" {
+		if _, err := os.Stat(dir); err == nil {
+			files, err := filepath.Glob(filepath.Join(dir, "*.json"))
+			if err != nil {
+				return nil, fmt.Errorf("list email templates in %s: %w", dir, err)
+			}
+			for _, file := range files {
+				data, err := os.ReadFile(file)
+				if err != nil {
+					return nil, fmt.Errorf("read email template %s: %w", file, err)
+				}
+				name := strings.TrimSuffix(filepath.Base(file), ".json")
+				tmpl, err := parseEmailTemplate(name, data)
+				if err != nil {
+					return nil, err
+				}
+				templates[name] = tmpl
+			}
+		} else if !os.IsNotExist(err) {
+			return nil, fmt.Errorf("stat email template dir %s: %w", dir, err)
+		}
+	}
+
+	return newEmailTemplateCatalog(templates), nil
+}
+
+func parseEmailTemplate(name string, data []byte) (EmailTemplate, error) {
+	var tmpl EmailTemplate
+	if err := json.Unmarshal(data, &tmpl); err != nil {
+		return EmailTemplate{}, fmt.Errorf("parse email template %q: %w", name, err)
+	}
+	if err := tmpl.validate(name); err != nil {
+		return EmailTemplate{}, err
+	}
+	return tmpl, nil
+}
+
+type emailHookParams struct {
+	Template string `json:"template"`
+	To       string `json:"to,omitempty"`
+	From     string `json:"from,omitempty"`
+	Subject  string `json:"subject,omitempty"`
+}
+
+type flowTemplateData struct {
+	Order           *OrderGrain
+	OrderID         string
+	Step            string
+	Phase           flow.Phase
+	Error           string
+	Vars            map[string]any
+	Fulfillment     *Fulfillment
+	ShippingAddress any
+	BillingAddress  any
+}
+
+// RegisterEmailHook registers the "send_email" flow hook. It reads the current
+// order for template data, renders the named template, and delivers it through
+// the configured sender. Hook params:
+//
+//	{
+//	  "template": "fulfillment-shipped",
+//	  "to": "{{ .Order.CustomerEmail }}",
+//	  "from": "Warehouse <warehouse@example.com>"
+//	}
+func RegisterEmailHook(reg *flow.Registry, app Applier, sender EmailSender, templates EmailTemplateStore) {
+	reg.HookWithMeta("send_email", func(ctx context.Context, st *flow.State, info flow.HookInfo, params json.RawMessage) error {
+		if sender == nil {
+			return fmt.Errorf("send_email: no sender configured")
+		}
+		if templates == nil {
+			return fmt.Errorf("send_email: no template store configured")
+		}
+		var p emailHookParams
+		if len(params) > 0 {
+			if err := json.Unmarshal(params, &p); err != nil {
+				return fmt.Errorf("send_email: bad params: %w", err)
+			}
+		}
+		if p.Template == "" {
+			return fmt.Errorf("send_email: missing template")
+		}
+		o, err := app.Get(ctx, st.ID)
+		if err != nil {
+			return err
+		}
+		tmpl, err := templates.Get(p.Template)
+		if err != nil {
+			return fmt.Errorf("send_email: %w", err)
+		}
+		data := buildFlowTemplateData(o, st, info)
+
+		subjectSource := tmpl.Subject
+		if p.Subject != "" {
+			subjectSource = p.Subject
+		}
+		subject, err := renderTextTemplate("email-subject", subjectSource, data)
+		if err != nil {
+			return fmt.Errorf("send_email: render subject: %w", err)
+		}
+		textBody, err := renderOptionalTextTemplate("email-text", tmpl.Text, data)
+		if err != nil {
+			return fmt.Errorf("send_email: render text body: %w", err)
+		}
+		htmlBody, err := renderOptionalHTMLTemplate("email-html", tmpl.HTML, data)
+		if err != nil {
+			return fmt.Errorf("send_email: render html body: %w", err)
+		}
+
+		toSource := p.To
+		if strings.TrimSpace(toSource) == "" {
+			toSource = o.CustomerEmail
+		}
+		toRendered, err := renderTextTemplate("email-to", toSource, data)
+		if err != nil {
+			return fmt.Errorf("send_email: render recipient: %w", err)
+		}
+		recipients, err := mail.ParseAddressList(toRendered)
+		if err != nil {
+			return fmt.Errorf("send_email: parse recipient %q: %w", toRendered, err)
+		}
+		to := make([]mail.Address, 0, len(recipients))
+		for _, rcpt := range recipients {
+			to = append(to, *rcpt)
+		}
+
+		from := sender.DefaultFrom()
+		if strings.TrimSpace(p.From) != "" {
+			fromRendered, err := renderTextTemplate("email-from", p.From, data)
+			if err != nil {
+				return fmt.Errorf("send_email: render sender: %w", err)
+			}
+			parsed, err := mail.ParseAddress(strings.TrimSpace(fromRendered))
+			if err != nil {
+				return fmt.Errorf("send_email: parse sender %q: %w", fromRendered, err)
+			}
+			from = *parsed
+		}
+
+		return sender.Send(ctx, EmailMessage{
+			From:     from,
+			To:       to,
+			Subject:  subject,
+			TextBody: textBody,
+			HTMLBody: htmlBody,
+		})
+	}, flow.CapabilityMeta{
+		Description:   "Render a named email template and send it through the configured sender.",
+		ExampleParams: json.RawMessage(`{"template":"fulfillment-shipped","to":"{{ .Order.CustomerEmail }}","from":"Store <no-reply@example.com>"}`),
+	})
+}
+
+func buildFlowTemplateData(o *OrderGrain, st *flow.State, info flow.HookInfo) flowTemplateData {
+	errStr := ""
+	if info.Err != nil {
+		errStr = info.Err.Error()
+	}
+	var lastFulfillment *Fulfillment
+	if n := len(o.Fulfillments); n > 0 {
+		lastFulfillment = &o.Fulfillments[n-1]
+	}
+	return flowTemplateData{
+		Order:           o,
+		OrderID:         OrderId(st.ID).String(),
+		Step:            info.Step,
+		Phase:           info.Phase,
+		Error:           errStr,
+		Vars:            st.Vars,
+		Fulfillment:     lastFulfillment,
+		ShippingAddress: decodeEmailTemplateJSON(o.ShippingAddress),
+		BillingAddress:  decodeEmailTemplateJSON(o.BillingAddress),
+	}
+}
+
+func decodeEmailTemplateJSON(raw json.RawMessage) any {
+	if len(raw) == 0 {
+		return nil
+	}
+	var v any
+	if err := json.Unmarshal(raw, &v); err != nil {
+		return string(raw)
+	}
+	return v
+}
+
+func renderTextTemplate(name, src string, data any) (string, error) {
+	tmpl, err := texttmpl.New(name).Option("missingkey=error").Parse(src)
+	if err != nil {
+		return "", err
+	}
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, data); err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(buf.String()), nil
+}
+
+func renderOptionalTextTemplate(name, src string, data any) (string, error) {
+	if strings.TrimSpace(src) == "" {
+		return "", nil
+	}
+	return renderTextTemplate(name, src, data)
+}
+
+func renderOptionalHTMLTemplate(name, src string, data any) (string, error) {
+	if strings.TrimSpace(src) == "" {
+		return "", nil
+	}
+	tmpl, err := htmltmpl.New(name).Option("missingkey=error").Parse(src)
+	if err != nil {
+		return "", err
+	}
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, data); err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(buf.String()), nil
+}