feat: add incrementing visitor counter

internal/handler/visitor.go

@@ -14,5 +14,8 @@ func HandleGetVisitorCounter(w http.ResponseWriter, r *http.Request) {
 }
 
 func HandlePatchVisitorCounter(w http.ResponseWriter, r *http.Request) {
-	w.Write([]byte("hello world"))
+	data := service.IncrementVisitorCounter()
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(data)
 }

internal/model/model.go

@@ -0,0 +1,5 @@
+package model
+
+type Success struct {
+	Success bool `json:"success"`
+}

internal/service/visitor.go

@@ -10,28 +10,56 @@ import (
 	"backend/internal/model"
 )
 
+const path = "./data/visitor.json"
+
 func GetVisitorCounter() model.VisitorCounter {
 	var data model.VisitorCounter
 
-	path := filepath.Join(".", "data", "visitor.json")
 	jsonFile, err := os.Open(path)
 	if err != nil {
-		slog.Warn("File not found or unable to open", slog.Any("error", err), slog.Any("file", path))
+		slog.Warn("File not found or unable to open", slog.Any("error", err), slog.Any("path", path))
 		return data
 	}
 	defer jsonFile.Close()
 
 	bytes, err := io.ReadAll(jsonFile)
 	if err != nil {
-		slog.Error("Error reading file", slog.Any("error", err), slog.Any("file", path))
+		slog.Error("Error reading file", slog.Any("error", err), slog.Any("path", path))
 		return data
 	}
 
 	err = json.Unmarshal(bytes, &data)
 	if err != nil {
-		slog.Error("Error unmarshalling JSON", slog.Any("error", err), slog.Any("file", path))
+		slog.Error("Error unmarshalling JSON", slog.Any("error", err), slog.Any("path", path))
 		return data
 	}
 
 	return data
 }
+
+func IncrementVisitorCounter() model.Success {
+	data := GetVisitorCounter()
+	data.Counter++
+
+	err := os.MkdirAll(filepath.Dir(path), 0755)
+	if err != nil {
+		slog.Error("Unable to create directory", slog.Any("error", err), slog.Any("path", filepath.Dir(path)))
+		return model.Success{}
+	}
+
+	jsonString, err := json.Marshal(data)
+	if err != nil {
+		slog.Error("Error marshalling JSON", slog.Any("error", err), slog.Any("path", path))
+		return model.Success{}
+	}
+
+	err = os.WriteFile(path, jsonString, 0644)
+	if err != nil {
+		slog.Error("Error writing to file", slog.Any("error", err), slog.Any("path", path))
+		return model.Success{}
+	}
+
+	return model.Success{
+		Success: true,
+	}
+}