inventory-middleware/main.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/go-chi/chi"
)

//Go Best practices: https://github.com/golovers/effective-go
type Item struct {
	ID                int64       `json:"id"`
	Name              string      `json:"name"`
	ValueCents        int64       `json:"valueCents"`
	PurchaseCostCents int64       `json:"purchasedCostCents"`
	Aquired           time.Time   `json:"aquired"`
	Description       string      `json:"description"`
	Notes             string      `json:"notes"`
	SoldForCents      int64       `json:"soldForCents"`
	SoldTo            string      `json:"soldTo"`
	Quantity          int64       `json:"quantity"`
	Category          Category    `json:"category"`
	Subcategory       Subcategory `json:"subcategory"`
}

func main() {
	r := chi.NewRouter()

	r.Route("/categories", func(r chi.Router) {
		r.Get("/", getCategoriesHandler)
	})

	r.Route("/category", func(r chi.Router) {
		r.Get("/{id:[0-9]+}", getCategoryHandler)
		r.Post("/", insertCategoryHandler)
		r.Delete("/{id:[0-9]+}", deleteCategoryHandler)
	})

	r.Route("/subcategory", func(r chi.Router) {
		r.Post("/", insertSubcategoryHandler)
		r.Delete("/{id:[0-9]+}", deleteSubcategoryHandler)
	})

	err := http.ListenAndServe(":8088", r)

	if err != nil {
		panic(err)
	}

}

func deleteSubcategoryHandler(w http.ResponseWriter, r *http.Request) {
	value, _ := strconv.ParseInt(chi.URLParam(r, "id"), 0, 64)

	if !deleteSubcategory(value) {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(fmt.Sprintf("Failed to delete %d", value)))
		return
	}

	w.WriteHeader(http.StatusOK)
}

func getCategoryHandler(w http.ResponseWriter, r *http.Request) {
	value, _ := strconv.ParseInt(chi.URLParam(r, "id"), 0, 64)

	category, ok := getCategoryByID(value)

	if !ok {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to get category."))
		return
	}

	jsonBytes, err := json.Marshal(&category)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write(jsonBytes)
}

func deleteCategoryHandler(w http.ResponseWriter, r *http.Request) {
	id := strings.TrimPrefix(r.URL.Path, "/category/")

	value, err := strconv.ParseInt(id, 0, 64)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(err.Error()))
		return
	}

	if !deleteCategory(value) {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(fmt.Sprintf("Failed to delete %d", value)))
		return
	}

	w.WriteHeader(http.StatusOK)
}

func getCategoriesHandler(w http.ResponseWriter, r *http.Request) {
	categories, ok := getAllCategories()

	if !ok {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to fetch a list of categories."))
		return
	}

	jsonBytes, err := json.Marshal(categories)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to get a list of categories."))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write(jsonBytes)
}

func insertCategoryHandler(w http.ResponseWriter, r *http.Request) {
	ct := r.Header.Get("content-type")

	if ct != "application/json" {
		w.WriteHeader(http.StatusUnsupportedMediaType)
		w.Write([]byte(fmt.Sprintf("Unsupported media type '%s', expected application/json", ct)))
		return
	}

	bodyBytes, err := ioutil.ReadAll(r.Body)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to parse request body"))
		return
	}

	defer r.Body.Close()

	var category Category

	err = json.Unmarshal(bodyBytes, &category)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to unmarshal JSON"))
		return
	}

	id, ok := insertNewCategory(category.Name, category.Subcategories)

	if !ok {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to create the new category."))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write([]byte(fmt.Sprintf("New Record: %d", id)))
}

func insertSubcategoryHandler(w http.ResponseWriter, r *http.Request) {
	ct := r.Header.Get("content-type")

	if ct != "application/json" {
		w.WriteHeader(http.StatusUnsupportedMediaType)
		w.Write([]byte(fmt.Sprintf("Unsupported media type '%s', expected application/json", ct)))
		return
	}

	bodyBytes, err := ioutil.ReadAll(r.Body)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to parse request body"))
		return
	}

	defer r.Body.Close()

	var subcategory Subcategory

	err = json.Unmarshal(bodyBytes, &subcategory)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to unmarshal JSON"))
		return
	}

	id, ok := insertSubcategory(subcategory.Name, subcategory.CategoryId)

	if !ok {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to create the new subcategory."))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write([]byte(fmt.Sprintf("New Record: %d", id)))
}