Add solution for Challenge 13 by imankhodadi

challenge-13/submissions/imankhodadi/solution-template.go

@@ -0,0 +1,228 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type Product struct {
+	ID       int64
+	Name     string
+	Price    float64
+	Quantity int
+	Category string
+}
+
+type ProductStore struct {
+	db *sql.DB
+}
+
+func NewProductStore(db *sql.DB) *ProductStore {
+	return &ProductStore{db: db}
+}
+
+func InitDB(dbPath string) (*sql.DB, error) {
+	db, err := sql.Open("sqlite3", dbPath)
+	if err != nil {
+		return nil, err
+	}
+	if err = db.Ping(); err != nil {
+		db.Close()
+		return nil, err
+	}
+	_, err = db.Exec(
+		"CREATE TABLE IF NOT EXISTS products (id INTEGER PRIMARY KEY, name TEXT, price REAL, quantity INTEGER, category TEXT)")
+	if err != nil {
+		db.Close()
+		return nil, err
+	}
+	return db, nil
+}
+
+func (ps *ProductStore) CreateProduct(product *Product) error {
+	result, err := ps.db.Exec(
+		"INSERT INTO products (name, price, quantity, category) VALUES (?, ?, ?, ?)",
+		product.Name, product.Price, product.Quantity, product.Category)
+	if err != nil {
+		return err
+	}
+	id, err := result.LastInsertId()
+	if err != nil {
+		return err
+	}
+	product.ID = id
+	return nil
+}
+
+func (ps *ProductStore) GetProduct(id int64) (*Product, error) {
+	row := ps.db.QueryRow("SELECT id, name, price, quantity, category FROM products WHERE id = ?", id)
+	p := &Product{}
+
+	err := row.Scan(&p.ID, &p.Name, &p.Price, &p.Quantity, &p.Category)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, fmt.Errorf("product with ID %d not found", id)
+		}
+		return nil, err
+	}
+	return p, nil
+}
+
+func (ps *ProductStore) UpdateProduct(product *Product) error {
+	result, err := ps.db.Exec("UPDATE products SET name = ?, price = ?, quantity = ?, category = ? WHERE id = ?",
+		product.Name, product.Price, product.Quantity, product.Category, product.ID)
+	if err != nil {
+		return err
+	}
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return err
+	}
+	if rowsAffected == 0 {
+		return fmt.Errorf("product with ID %d not found", product.ID)
+	}
+	return nil
+}
+
+func (ps *ProductStore) DeleteProduct(id int64) error {
+	result, err := ps.db.Exec("DELETE FROM products WHERE id = ?", id)
+	if err != nil {
+		return err
+	}
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return err
+	}
+	if rowsAffected == 0 {
+		return fmt.Errorf("product with ID %d not found", id)
+	}
+	return nil
+}
+
+func (ps *ProductStore) ListProducts(category string) ([]*Product, error) {
+	var rows *sql.Rows
+	var err error
+	if len(category) > 0 {
+		rows, err = ps.db.Query("SELECT id, name, price, quantity, category FROM products WHERE category = ?", category)
+	} else {
+		rows, err = ps.db.Query("SELECT id, name, price, quantity, category FROM products")
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var products []*Product
+	for rows.Next() {
+		p := &Product{}
+
+		err := rows.Scan(&p.ID, &p.Name, &p.Price, &p.Quantity, &p.Category)
+		if err != nil {
+			return nil, err
+		}
+		products = append(products, p)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return products, nil
+}
+
+func (ps *ProductStore) BatchUpdateInventory(updates map[int64]int) error {
+	if ps.db == nil {
+		return fmt.Errorf("database is not initialized")
+	}
+	tx, err := ps.db.Begin()
+	if err != nil {
+		return err
+	}
+	committed := false
+	defer func() {
+		if !committed {
+			_ = tx.Rollback()
+		}
+	}()
+	stmt, err := tx.Prepare("UPDATE products SET quantity = ? WHERE id = ?")
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+	for id, quantity := range updates {
+		result, execErr := stmt.Exec(quantity, id)
+		if execErr != nil {
+			return execErr
+		}
+		rowsAffected, raErr := result.RowsAffected()
+		if raErr != nil {
+			return raErr
+		}
+		if rowsAffected == 0 {
+			return fmt.Errorf("product with ID %d not found", id)
+		}
+	}
+	err = tx.Commit()
+	if err == nil {
+		committed = true
+	}
+	return err
+}
+
+func (ps *ProductStore) ShowData() {
+	products, err := ps.ListProducts("")
+	if err != nil {
+		fmt.Println("Error reading the data", err)
+		return
+	}
+	fmt.Println("products:")
+	for _, prd := range products {
+		fmt.Println(prd)
+	}
+}
+func main() {
+	db, err := InitDB("database.db")
+	if err != nil {
+		fmt.Println("Failed to initialize database:", err)
+		return
+	}
+	defer db.Close()
+	ps := NewProductStore(db)
+
+	err = ps.CreateProduct(&Product{0, "Cacao", 10.5, 3, "junk"})
+	if err != nil {
+		fmt.Println("Failed to create product:", err)
+		return
+	}
+	err = ps.CreateProduct(&Product{0, "milk", 20.5, 2, "dairy"})
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	ps.ShowData()
+
+	if err := ps.BatchUpdateInventory(map[int64]int{1: 100, 2: 100}); err != nil {
+		fmt.Println("Failed to batch update:", err)
+		return
+	}
+	ps.ShowData()
+	prd, err := ps.GetProduct(1)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(prd)
+
+	if err := ps.UpdateProduct(&Product{2, "new milk", 30.0, 150, "new dairy"}); err != nil {
+		fmt.Println("Failed to update product:", err)
+		return
+	}
+	ps.ShowData()
+
+	if err := ps.DeleteProduct(1); err != nil {
+		fmt.Println("Failed to delete product:", err)
+		return
+	}
+	ps.ShowData()
+
+}