window.onload = function () {
    // 获取所需的 DOM 元素
    const btn = document.querySelector(".s_ck_all"); 
    const buttons = document.querySelectorAll(".s_ck"); 
    const del = document.querySelector(".del-all"); 
    var totalPrice = document.getElementById("totalPrice"); 
    var totalCount = document.getElementById("totalCount"); 
    var carBody = document.getElementById("carBody"); 
    var tr = carBody.getElementsByTagName("tr"); 
    const clear = document.querySelector(".clear"); 

    // 第一步 设置全选
    btn.onclick = function () {
        for (let button of buttons) {
            button.checked = btn.checked;
        }
        getTotal();
    };

    // 第二步 设置选中删除
    del.onclick = function () {
        const selectedItems = Array.from(buttons).filter((button) => button.checked);  
        if (selectedItems.length === 0) {   
            alert("请选择要删除的商品"); 
        } else {
            selectedItems.forEach((button) => {    
                                   
                button.closest("tr").remove();
            });
            getTotal();
        }
    };

    // 数量加减、删除
    for (let item of tr) {
        item.addEventListener("click", (e) => {
            const target = e.target;
            if (target.classList.contains("add")) {
                increaseQuantity(target);     
            } else if (target.classList.contains("reduce")) {
                decreaseQuantity(target);      
            } else if (target.classList.contains("del")) {
                deleteItem(target);       
            }
            getTotal();
        });
    }

    // 增加数量
    function increaseQuantity(element) {   
        const input = element.previousElementSibling;     
        input.value = parseInt(input.value) + 1;    
    }

    // 减少数量
    function decreaseQuantity(element) {
        const input = element.nextElementSibling;
        const newValue = parseInt(input.value) - 1;
        input.value = newValue < 1 ? 1 : newValue;
    }

    // 删除商品
    function deleteItem(element) {
        element.closest("tr").remove();
    }

    // 合计、已选商品件数
    function getTotal() {
        let price = 0;    
        let count = 0;

        for (let item of tr) {           
            const checkbox = item.querySelector("input[type='checkbox']");    
            if (checkbox.checked) {      
                const priceCell = item.querySelector("td:nth-child(3)");     //获取单价
                const quantityInput = item.querySelector("input[type='text']");     
                const totalCell = item.querySelector("td:nth-child(5)"); 

                const unitPrice = parseFloat(priceCell.innerText);   
                const quantity = parseInt(quantityInput.value);
                const itemTotal = unitPrice * quantity;

                totalCell.innerText = itemTotal.toFixed(2);  //更新商品行的总计和统计变量
                price += itemTotal;  
                count += quantity;
            }
        }

        totalPrice.innerText = price.toFixed(2);   
        totalCount.innerText = count;    
    }

    // 清空购物车
    clear.onclick = function () {    
        carBody.innerHTML = "";    
        getTotal();  
    };
};