feat(webhook): add webhook client for RSVP and photo uploads

server/internal/webhook/webhook.go

@@ -0,0 +1,98 @@
+package webhook
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"wedding-server/internal/config"
+	"wedding-server/internal/store"
+)
+
+type Client struct {
+	cfg        config.WebhookConfig
+	httpClient *http.Client
+}
+
+func New(cfg config.WebhookConfig) *Client {
+	return &Client{
+		cfg:        cfg,
+		httpClient: &http.Client{Timeout: time.Duration(cfg.TimeoutSeconds) * time.Second},
+	}
+}
+
+func (c *Client) post(url, event string, data any) error {
+	if url == "" {
+		return nil
+	}
+
+	body, err := json.Marshal(map[string]any{
+		"event":  event,
+		"sentAt": time.Now().UTC(),
+		"data":   data,
+	})
+	if err != nil {
+		return err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, url, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	for k, v := range c.cfg.Headers {
+		req.Header.Set(k, v)
+	}
+	if c.cfg.Secret != "" {
+		req.Header.Set("X-Webhook-Signature", sign(c.cfg.Secret, body))
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	io.Copy(io.Discard, resp.Body)
+
+	if resp.StatusCode >= 300 {
+		return fmt.Errorf("webhook %s: unexpected status %d", url, resp.StatusCode)
+	}
+	return nil
+}
+
+func sign(secret string, body []byte) string {
+	mac := hmac.New(sha256.New, []byte(secret))
+	mac.Write(body)
+	return "sha256=" + hex.EncodeToString(mac.Sum(nil))
+}
+
+func (c *Client) SendRSVP(r store.RSVP) error {
+	guests := make([]map[string]any, len(r.Guests))
+	for i, g := range r.Guests {
+		guests[i] = map[string]any{"name": g.Name, "isChild": g.IsChild}
+	}
+	return c.post(c.cfg.RSVPURL, "rsvp.created", map[string]any{
+		"guests":  guests,
+		"message": r.Message,
+	})
+}
+
+func (c *Client) SendPhotoUpload(u store.PhotoUpload, files []store.PhotoFile) error {
+	urls := make([]string, len(files))
+	for i, f := range files {
+		urls[i] = f.URL
+	}
+	return c.post(c.cfg.PhotoURL, "photos.uploaded", map[string]any{
+		"name":      u.Name,
+		"message":   u.Message,
+		"email":     u.Email,
+		"phone":     u.Phone,
+		"photoUrls": urls,
+	})
+}