document.addEventListener('DOMContentLoaded', function(){
    const list = [];
    const form = document.querySelector(".shopping-form");
    const itemInput = document.querySelector(".shopping-form-input");
    
    const quantityInput = document.querySelector('.shopping-form-quantity-input');
    const incrementButton = document.querySelector('.shopping-form-increment-button');
    const decrementButton = document.querySelector('.shopping-form-decrement-button');
    const items = document.querySelector(".shopping-items");

    incrementButton.addEventListener("click", incrementQuantity)
    decrementButton.addEventListener("click", decrementQuantity)
    form.addEventListener("submit", addItemToList);

    function decrementQuantity(){
        const currentValue = Number(quantityInput.value);
        const newValue = currentValue - 1;
        if(newValue > 0){
        quantityInput.value = newValue;
        }
    }

    function incrementQuantity() {
        const currentValue = Number(quantityInput.value);
        const newValue = currentValue + 1;

        quantityInput.value = newValue;
    }

    function addItemToList(event){
        event.preventDefault();

        const itemName = event.target["item-name"].value;
        const itemQuantity = event.target["item-quantity"].value;
        if(itemName != ""){
            const item = {
                name: itemName,
                quantity: itemQuantity,
            };
            list.push(item);

            renderListItems();
            resetInputs();
        }
    }

    function renderListItems(){
        let itemStructure = "";
        list.forEach(function (item){
            itemStructure += `
            <li class="shopping-item">
                <span>${item.name}</span>
                <span>${item.quantity}</span>
            </li>`        
        });
        items.innerHTML = itemStructure;
    };
    function resetInputs(){
        itemInput.value = "";
        quantityInput.value = 1;
    }
})