let selectedItems = new Set();

// 页面加载完成后初始化
document.addEventListener('DOMContentLoaded', function() {
    updateSelectAllState();
    updateTotalPrice();
});

// 全选/取消全选
document.getElementById('selectAll').addEventListener('change', function() {
    const checkboxes = document.querySelectorAll('.item-checkbox:not(:disabled)');
    checkboxes.forEach(checkbox => {
        checkbox.checked = this.checked;
        if (this.checked) {
            selectedItems.add(parseInt(checkbox.value));
        } else {
            selectedItems.delete(parseInt(checkbox.value));
        }
    });
    updateTotalPrice();
});

// 单个商品选择
document.querySelectorAll('.item-checkbox').forEach(checkbox => {
    checkbox.addEventListener('change', function() {
        const cartId = parseInt(this.value);
        if (this.checked) {
            selectedItems.add(cartId);
        } else {
            selectedItems.delete(cartId);
        }
        updateSelectAllState();
        updateTotalPrice();
    });
});

// 更新全选状态
function updateSelectAllState() {
    const selectAllCheckbox = document.getElementById('selectAll');
    const availableCheckboxes = document.querySelectorAll('.item-checkbox:not(:disabled)');
    const checkedCheckboxes = document.querySelectorAll('.item-checkbox:not(:disabled):checked');

    if (availableCheckboxes.length === 0) {
        selectAllCheckbox.disabled = true;
        selectAllCheckbox.checked = false;
    } else {
        selectAllCheckbox.disabled = false;
        selectAllCheckbox.checked = availableCheckboxes.length === checkedCheckboxes.length;
    }
}

// 更新总价
function updateTotalPrice() {
    let totalPrice = 0;
    let selectedCount = 0;

    selectedItems.forEach(cartId => {
        const cartItem = document.querySelector(`[data-cart-id="${cartId}"]`);
        if (cartItem) {
            const itemTotal = parseFloat(cartItem.querySelector('.item-total').textContent);
            const quantity = parseInt(cartItem.querySelector('.quantity-input').value);
            totalPrice += itemTotal;
            selectedCount += quantity;
        }
    });

    document.getElementById('selectedCount').textContent = selectedCount;
    document.getElementById('selectedTotal').textContent = totalPrice.toFixed(2);
    document.getElementById('finalTotal').textContent = totalPrice.toFixed(2);

    // 更新结算按钮状态
    const checkoutBtn = document.getElementById('checkoutBtn');
    checkoutBtn.disabled = selectedItems.size === 0;
}

// 修改数量
function changeQuantity(cartId, delta) {
    const input = document.querySelector(`[data-cart-id="${cartId}"]`);
    const currentValue = parseInt(input.value);
    const newValue = currentValue + delta;

    if (newValue >= 1 && newValue <= parseInt(input.max)) {
        updateQuantity(cartId, newValue);
    }
}

// 更新数量
function updateQuantity(cartId, quantity) {
    if (quantity < 1) return;

    fetch('/cart/update', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            cart_id: cartId,
            quantity: parseInt(quantity)
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // 更新页面显示
            const cartItem = document.querySelector(`[data-cart-id="${cartId}"]`);
            cartItem.querySelector('.quantity-input').value = quantity;
            cartItem.querySelector('.item-total').textContent = data.item_total.toFixed(2);

            // 更新总价
            updateTotalPrice();

            // 更新全局购物车数量
            updateCartBadge(data.cart_count);

            showSuccessMessage('数量更新成功');
        } else {
            alert(data.message);
            // 恢复原始值
            location.reload();
        }
    })
    .catch(error => {
        console.error('Error:', error);
        alert('更新失败');
        location.reload();
    });
}

// 删除商品
function removeItem(cartId) {
    if (!confirm('确定要删除这件商品吗？')) {
        return;
    }

    fetch('/cart/remove', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            cart_id: cartId
        })
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // 从页面中移除商品
            const cartItem = document.querySelector(`[data-cart-id="${cartId}"]`);
            cartItem.remove();

            // 从选中列表中移除
            selectedItems.delete(cartId);

            // 更新显示
            updateSelectAllState();
            updateTotalPrice();
            updateCartBadge(data.cart_count);

            showSuccessMessage('商品已删除');

            // 如果购物车为空，刷新页面
            if (data.cart_count === 0) {
                setTimeout(() => {
                    location.reload();
                }, 1000);
            }
        } else {
            alert(data.message);
        }
    })
    .catch(error => {
        console.error('Error:', error);
        alert('删除失败');
    });
}

// 清空购物车
function clearCart() {
    if (!confirm('确定要清空购物车吗？')) {
        return;
    }

    fetch('/cart/clear', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        }
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            showSuccessMessage('购物车已清空');
            setTimeout(() => {
                location.reload();
            }, 1000);
        } else {
            alert(data.message);
        }
    })
    .catch(error => {
        console.error('Error:', error);
        alert('清空失败');
    });
}

// 去结算
function checkout() {
    if (selectedItems.size === 0) {
        alert('请选择要购买的商品');
        return;
    }

    const params = new URLSearchParams();
    selectedItems.forEach(cartId => {
        params.append('items', cartId);
    });

    window.location.href = `/cart/checkout?${params.toString()}`;
}