Restructure webhook module (#22256)

Previously, there was an `import services/webhooks` inside
`modules/notification/webhook`.
This import was removed (after fighting against many import cycles).
Additionally, `modules/notification/webhook` was moved to
`modules/webhook`,
and a few structs/constants were extracted from `models/webhooks` to
`modules/webhook`.

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/webhook/general.go

@@ -9,9 +9,11 @@ import (
 	"net/url"
 	"strings"
 
+	webhook_model "code.gitea.io/gitea/models/webhook"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/util"
+	webhook_module "code.gitea.io/gitea/modules/webhook"
 )
 
 type linkFormatter = func(string, string) string
@@ -223,3 +225,36 @@ func getIssueCommentPayloadInfo(p *api.IssueCommentPayload, linkFormatter linkFo
 
 	return text, issueTitle, color
 }
+
+// ToHook convert models.Webhook to api.Hook
+// This function is not part of the convert package to prevent an import cycle
+func ToHook(repoLink string, w *webhook_model.Webhook) (*api.Hook, error) {
+	config := map[string]string{
+		"url":          w.URL,
+		"content_type": w.ContentType.Name(),
+	}
+	if w.Type == webhook_module.SLACK {
+		s := GetSlackHook(w)
+		config["channel"] = s.Channel
+		config["username"] = s.Username
+		config["icon_url"] = s.IconURL
+		config["color"] = s.Color
+	}
+
+	authorizationHeader, err := w.HeaderAuthorization()
+	if err != nil {
+		return nil, err
+	}
+
+	return &api.Hook{
+		ID:                  w.ID,
+		Type:                w.Type,
+		URL:                 fmt.Sprintf("%s/settings/hooks/%d", repoLink, w.ID),
+		Active:              w.IsActive,
+		Config:              config,
+		Events:              w.EventsArray(),
+		AuthorizationHeader: authorizationHeader,
+		Updated:             w.UpdatedUnix.AsTime(),
+		Created:             w.CreatedUnix.AsTime(),
+	}, nil
+}