poc.go

package main

import (
	"github.com/labstack/echo/v4"
	"net/http"
)

type Response struct {
	Data    interface{} `json:"data,omitempty"`
	Status  string      `json:"status,omitempty"`
	Message string      `json:"message,omitempty"`
}

type Book struct {
	Name   string `json:"name"`
	Author string `json:"author"`
}

type IBookRepo interface {
	Get(id string) (Book, error)
}

type BookRepo struct{}

func (b BookRepo) Get(id string) (Book, error) {
	return Book{Name: "Great shit", Author: "Someone on earth"}, nil
}

type IBookUsecase interface {
	Get(id string) (Book, error)
}

type BookUsecase struct {
	Repo IBookRepo
}

func (b BookUsecase) Get(id string) (Book, error) {
	return b.Repo.Get(id)
}

type IBookHandler interface {
	Handler(c echo.Context) error
}

type BookHandler struct {
	Usecase IBookUsecase
}

func (b BookHandler) Handler(c echo.Context) error {
	bookID := c.Param("id")
	book, err := b.Usecase.Get(bookID)
	if err != nil {
		return c.JSON(http.StatusNotFound, &Response{Status: "error", Message: "Book not found"})
	}
	return c.JSON(http.StatusOK, &Response{Data: book, Status: "ok"})
}

type Server struct {
	E           *echo.Echo
	BookHandler IBookHandler
}

func (s Server) Init() {
	// Do route register and apply middleware here
	s.E.GET("/", func(c echo.Context) error {
		return c.JSON(http.StatusOK, &Response{Status: "ok", Message: "Hello World"})
	})
	s.E.GET("/books/:id", s.BookHandler.Handler)
}

func (s Server) Run() {
	s.E.Logger.Fatal(s.E.Start(":1234"))
}

func main() {
	h := BookHandler{Usecase: BookUsecase{Repo: BookRepo{}}}
	e := echo.New()
	s := Server{E: e, BookHandler: h}
	s.Init()
	s.Run()
}