plugin/product: improve product hooks API (#20556)

* plugin/product: improve product hooks API

* elaborate HookService.RegisterHooks method documentation

* remove unnecessary re-assigns

plugin/product.go

@@ -4,144 +4,38 @@
 package plugin
 
 import (
-	"errors"
-	"io"
 	"net/http"
-
-	"github.com/mattermost/mattermost-server/v6/model"
 )
 
-// ProductHooks is a subset of Hooks
-type ProductHooks interface {
-	OnConfigurationChange() error
-	MessageWillBePosted(ctx *Context, post *model.Post) (*model.Post, string)
-	MessageWillBeUpdated(ctx *Context, newPost, oldPost *model.Post) (*model.Post, string)
-	OnPluginClusterEvent(ctx *Context, ev model.PluginClusterEvent)
-	OnWebSocketDisconnect(webConnID, userID string)
-	OnWebSocketConnect(webConnID, userID string)
-	WebSocketMessageHasBeenPosted(webConnID, userID string, req *model.WebSocketRequest)
-}
-
 type registeredProduct struct {
-	productID   string
-	implemented map[int]struct{}
-	adapter     Hooks
+	productID string
+	adapter   Hooks
 }
 
 func (rp *registeredProduct) Implements(hookId int) bool {
-	_, ok := rp.implemented[hookId]
+	adapter, ok := rp.adapter.(*hooksAdapter)
+	if !ok {
+		return false
+	}
+
+	_, ok = adapter.implemented[hookId]
 	return ok
 }
 
-type hooksAdapter struct {
-	productHooks ProductHooks
-}
-
-func newRegisteredProduct(pluginID string, productHooks ProductHooks) *registeredProduct {
-	return &registeredProduct{
-		productID: pluginID,
-		implemented: map[int]struct{}{
-			OnConfigurationChangeID:         {},
-			MessageWillBePostedID:           {},
-			MessageWillBeUpdatedID:          {},
-			OnPluginClusterEventID:          {},
-			OnWebSocketConnectID:            {},
-			OnWebSocketDisconnectID:         {},
-			WebSocketMessageHasBeenPostedID: {},
-		},
-		adapter: &hooksAdapter{
-			productHooks: productHooks,
-		},
-	}
-}
-
-func (a *hooksAdapter) OnActivate() error {
-	return errors.New("not implemented")
-}
-
+// Implemented method is overridden intentionally to prevent calling it from outside.
 func (a *hooksAdapter) Implemented() ([]string, error) {
-	return nil, errors.New("not implemented")
+	return nil, nil
 }
 
+// OnActivate is overridden intentionally as product should not call it.
+func (a *hooksAdapter) OnActivate() error {
+	return nil
+}
+
+// OnDeactivate is overridden intentionally as product should not call it.
 func (a *hooksAdapter) OnDeactivate() error {
-	return errors.New("not implemented")
-}
-
-func (a *hooksAdapter) OnConfigurationChange() error {
-	return a.productHooks.OnConfigurationChange()
+	return nil
 }
 
+// ServeHTTP is overridden intentionally as product should not call it.
 func (a *hooksAdapter) ServeHTTP(c *Context, w http.ResponseWriter, r *http.Request) {}
-
-func (a *hooksAdapter) ExecuteCommand(c *Context, args *model.CommandArgs) (*model.CommandResponse, *model.AppError) {
-	return nil, model.NewAppError("ExecuteCommand", "api.command.execute_command.start.app_error", nil, "not implemented", http.StatusNotImplemented)
-}
-
-func (a *hooksAdapter) UserHasBeenCreated(c *Context, user *model.User) {}
-
-func (a *hooksAdapter) UserWillLogIn(c *Context, user *model.User) string {
-	return ""
-}
-
-func (a *hooksAdapter) UserHasLoggedIn(c *Context, user *model.User) {}
-
-func (a *hooksAdapter) MessageWillBePosted(c *Context, post *model.Post) (*model.Post, string) {
-	return a.productHooks.MessageWillBePosted(c, post)
-}
-
-func (a *hooksAdapter) MessageWillBeUpdated(c *Context, newPost, oldPost *model.Post) (*model.Post, string) {
-	return a.productHooks.MessageWillBeUpdated(c, newPost, oldPost)
-}
-
-func (a *hooksAdapter) MessageHasBeenPosted(c *Context, post *model.Post) {}
-
-func (a *hooksAdapter) MessageHasBeenUpdated(c *Context, newPost, oldPost *model.Post) {}
-
-func (a *hooksAdapter) ChannelHasBeenCreated(c *Context, channel *model.Channel) {}
-
-func (a *hooksAdapter) UserHasJoinedChannel(c *Context, channelMember *model.ChannelMember, actor *model.User) {
-}
-
-func (a *hooksAdapter) UserHasLeftChannel(c *Context, channelMember *model.ChannelMember, actor *model.User) {
-}
-
-func (a *hooksAdapter) UserHasJoinedTeam(c *Context, teamMember *model.TeamMember, actor *model.User) {
-}
-
-func (a *hooksAdapter) UserHasLeftTeam(c *Context, teamMember *model.TeamMember, actor *model.User) {}
-
-func (a *hooksAdapter) FileWillBeUploaded(c *Context, info *model.FileInfo, file io.Reader, output io.Writer) (*model.FileInfo, string) {
-	return nil, ""
-}
-
-func (a *hooksAdapter) ReactionHasBeenAdded(c *Context, reaction *model.Reaction) {}
-
-func (a *hooksAdapter) ReactionHasBeenRemoved(c *Context, reaction *model.Reaction) {}
-
-func (a *hooksAdapter) OnPluginClusterEvent(c *Context, ev model.PluginClusterEvent) {
-	a.productHooks.OnPluginClusterEvent(c, ev)
-}
-
-func (a *hooksAdapter) OnWebSocketConnect(webConnID, userID string) {
-	a.productHooks.OnWebSocketConnect(webConnID, userID)
-}
-
-func (a *hooksAdapter) OnWebSocketDisconnect(webConnID, userID string) {
-	a.productHooks.OnWebSocketDisconnect(webConnID, userID)
-}
-
-func (a *hooksAdapter) WebSocketMessageHasBeenPosted(webConnID, userID string, req *model.WebSocketRequest) {
-	a.productHooks.WebSocketMessageHasBeenPosted(webConnID, userID, req)
-}
-
-func (a *hooksAdapter) RunDataRetention(nowTime, batchSize int64) (int64, error) {
-	return -1, errors.New("not implemented")
-}
-
-func (a *hooksAdapter) OnInstall(c *Context, event model.OnInstallEvent) error {
-	return errors.New("not implemented")
-}
-
-func (a *hooksAdapter) OnSendDailyTelemetry() {}
-
-func (a *hooksAdapter) OnCloudLimitsUpdated(limits *model.ProductLimits) {}