Refactor: Implement uber-go/fx dependency injection

- Replace global variable pattern with proper dependency injection
- Add uber-go/fx for automatic dependency resolution
- Refactor all services and handlers to use constructor injection
- Eliminate fragile initialization order dependencies
- Improve testability and modularity
- Add structured logging with zap

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/web/handlers/apiEndpoint.go

@@ -7,23 +7,25 @@ import (
 )
 
 type ApiEndpointHandler struct {
-	PostService services.PostService
+	postService    *services.PostService
+	imgKitHelper   *services.ImgKitHelper
 }
 
-var ApiEndpointHandlerInstance *ApiEndpointHandler
-
-func InitApiEndpointHandler() {
-	ApiEndpointHandlerInstance = &ApiEndpointHandler{
-		PostService: *services.PostServiceInstance,
+func NewApiEndpointHandler(
+	postService *services.PostService,
+	imgKitHelper *services.ImgKitHelper,
+) *ApiEndpointHandler {
+	return &ApiEndpointHandler{
+		postService:  postService,
+		imgKitHelper: imgKitHelper,
 	}
-
 }
 
-func (ps *ApiEndpointHandler) GetRandomPost(c *gin.Context) {
-	post := ps.PostService.GetRandomPost()
+func (aeh *ApiEndpointHandler) GetRandomPost(c *gin.Context) {
+	post := aeh.postService.GetRandomPost()
 	for i := range post.Attachments {
-		post.Attachments[i].RemoteUrl = services.GetRemoteUrl(post.Attachments[i].RemoteUrl)
-		post.Attachments[i].PreviewUrl = services.GetPreviewUrl(post.Attachments[i].RemoteUrl)
+		post.Attachments[i].RemoteUrl = aeh.imgKitHelper.GetRemoteUrl(post.Attachments[i].RemoteUrl)
+		post.Attachments[i].PreviewUrl = aeh.imgKitHelper.GetPreviewUrl(post.Attachments[i].RemoteUrl)
 	}
 	c.JSON(200, post)
-}
+}