first commit

2021-09-03 09:52:42 +00:00
commit eef066b179
11 changed files with 477 additions and 0 deletions
--- a/entity/product.go
+++ b/entity/product.go
@ -0,0 +1,123 @@
+package entity
+
+import (
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"os"
+)
+
+//Product defines a structure for an item in product catalog
+type Product struct {
+	ID          string  `json:"id"`
+	Name        string  `json:"name"`
+	Description string  `json:"description"`
+	Price       float64 `json:"price"`
+	IsAvailable bool    `json:"isAvailable"`
+}
+
+// ErrNoProduct is used if no product found
+var ErrNoProduct = errors.New("no product found")
+
+// GetProducts returns the JSON file content if available else returns an error.
+func GetProducts() ([]byte, error) {
+	// Read JSON file
+	data, err := ioutil.ReadFile("./data/data.json")
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
+// GetProduct takes id as input and returns the corresponding product, else it returns ErrNoProduct error.
+func GetProduct(id string) (Product, error) {
+	// Read JSON file
+	data, err := ioutil.ReadFile("./data/data.json")
+	if err != nil {
+		return Product{}, err
+	}
+	// read products
+	var products []Product
+	err = json.Unmarshal(data, &products)
+	if err != nil {
+		return Product{}, err
+	}
+	// iterate through product array
+	for i := 0; i < len(products); i++ {
+		// if we find one product with the given ID
+		if products[i].ID == id {
+			// return product
+			return products[i], nil
+		}
+	}
+	return Product{}, ErrNoProduct
+}
+
+// DeleteProduct takes id as input and deletes the corresponding product, else it returns ErrNoProduct error.
+func DeleteProduct(id string) error {
+	// Read JSON file
+	data, err := ioutil.ReadFile("./data/data.json")
+	if err != nil {
+		return err
+	}
+	// read products
+	var products []Product
+	err = json.Unmarshal(data, &products)
+	if err != nil {
+		return err
+	}
+	// iterate through product array
+	for i := 0; i < len(products); i++ {
+		// if we find one product with the given ID
+		if products[i].ID == id {
+			products = removeElement(products, i)
+			// Write Updated JSON file
+			updatedData, err := json.Marshal(products)
+			if err != nil {
+				return err
+			}
+			err = ioutil.WriteFile("./data/data.json", updatedData, os.ModePerm)
+			if err != nil {
+				return err
+			}
+			return nil
+		}
+	}
+	return ErrNoProduct
+}
+
+// AddProduct adds an input product to the product list in JSON document.
+func AddProduct(product Product) error {
+	// Load existing products and append the data to product list
+	var products []Product
+	data, err := ioutil.ReadFile("./data/data.json")
+	if err != nil {
+		return err
+	}
+	// Load our JSON file to memory using array of products
+	err = json.Unmarshal(data, &products)
+	if err != nil {
+		return err
+	}
+	// Add new Product to our list
+	products = append(products, product)
+
+	// Write Updated JSON file
+	updatedData, err := json.Marshal(products)
+	if err != nil {
+		return err
+	}
+	err = ioutil.WriteFile("./data/data.json", updatedData, os.ModePerm)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// removeElement is used to remove element from product array at given index
+func removeElement(arr []Product, index int) []Product {
+	ret := make([]Product, 0)
+	ret = append(ret, arr[:index]...)
+	return append(ret, arr[index+1:]...)
+}