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}"].quantity-input`);
    if (!input) return;
    
    const currentValue = parseInt(input.value);
    const newValue = currentValue + delta;
    
    if (newValue >= 1) {
        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}"]`);
            const quantityInput = cartItem.querySelector('.quantity-input');
            quantityInput.value = quantity;
            cartItem.querySelector('.item-total').textContent = data.item_total.toFixed(2);

            // 简单的按钮状态更新
            const minusBtn = cartItem.querySelector('button[onclick*="-1"]');
            const plusBtn = cartItem.querySelector('button[onclick*="1"]');
            
            if (minusBtn) {
                minusBtn.disabled = quantity <= 1;
            }
            
            // 暂时不限制最大值，避免选择器错误
            if (plusBtn) {
                plusBtn.disabled = false;
            }

            // 更新总价
            updateTotalPrice();

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

            // 显示成功消息
            showSuccessMessage('数量更新成功');
        } else {
            alert(data.message || '更新失败');
            location.reload();
        }
    })
    .catch(error => {
        console.error('Error:', error);
        alert('网络错误，请重试');
        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()}`;
}

// 显示成功消息
function showSuccessMessage(message) {
    const alert = document.createElement('div');
    alert.className = 'alert alert-success alert-dismissible fade show position-fixed';
    alert.style.cssText = 'top: 20px; right: 20px; z-index: 1050; min-width: 300px;';
    alert.innerHTML = `
        ${message}
        <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
    `;
    
    document.body.appendChild(alert);
    
    setTimeout(() => {
        if (alert.parentNode) {
            alert.remove();
        }
    }, 3000);
}

// 更新购物车徽章
// 验证数量输入
function validateQuantityInput(input) {
    // 只允许数字
    input.value = input.value.replace(/[^0-9]/g, "");
    
    // 如果为空或0，显示1
    if (input.value === "" || parseInt(input.value) < 1) {
        input.value = "1";
    }
    
    // 检查最大值
    const maxStock = parseInt(input.getAttribute("max")) || 999;
    if (parseInt(input.value) > maxStock) {
        input.value = maxStock.toString();
    }
}

// 从输入框更新数量
function updateQuantityFromInput(cartId, input) {
    let quantity = parseInt(input.value);
    
    // 验证输入
    if (isNaN(quantity) || quantity < 1) {
        quantity = 1;
        input.value = "1";
    }
    
    const maxStock = parseInt(input.getAttribute("max")) || 999;
    if (quantity > maxStock) {
        quantity = maxStock;
        input.value = maxStock.toString();
    }
    
    // 更新数量
    updateQuantity(cartId, quantity);
}

// 处理键盘事件
function handleQuantityKeyPress(event, cartId, input) {
    // 回车键确认
    if (event.key === "Enter") {
        input.blur();
        return;
    }
    
    // 只允许数字键
    if (!/[0-9]/.test(event.key) && !["Backspace", "Delete", "Tab", "Escape", "Enter", "Home", "End", "ArrowLeft", "ArrowRight"].includes(event.key)) {
        event.preventDefault();
    }
}

function updateCartBadge(count) {
    const badge = document.querySelector('.cart-badge');
    if (badge) {
        badge.textContent = count;
        badge.style.display = count > 0 ? 'inline' : 'none';
    }
}