package topology

import (
	"fmt"
	"network-topology-discovery/pkg/models"
	"strings"
)

// Builder 拓扑构建器
type Builder struct {
	devices []models.Device
}

// NewBuilder 创建拓扑构建器
func NewBuilder() *Builder {
	return &Builder{}
}

// AddDevice 添加设备
func (b *Builder) AddDevice(device models.Device) {
	b.devices = append(b.devices, device)
}

// AddDevices 批量添加设备
func (b *Builder) AddDevices(devices []models.Device) {
	b.devices = append(b.devices, devices...)
}

// Build 构建拓扑图
func (b *Builder) Build() models.TopologyGraph {
	graph := models.TopologyGraph{
		Nodes: make([]models.TopologyNode, 0),
		Edges: make([]models.TopologyEdge, 0),
	}

	// 构建节点
	nodeMap := make(map[string]models.TopologyNode)
	for _, device := range b.devices {
		// 优先使用主机名,如果没有则使用IP作为显示名
		hostname := device.Hostname
		if hostname == "" {
			hostname = device.IP
		}

		node := models.TopologyNode{
			ID:       device.IP,
			IP:       device.IP,
			Hostname: hostname,
			Type:     string(device.Type),
			Icon:     getDeviceIcon(device.Type),
		}
		nodeMap[device.IP] = node
		graph.Nodes = append(graph.Nodes, node)
	}

	fmt.Printf("\n========== TOPOLOGY BUILD ===========\n")
	fmt.Printf("Total devices: %d\n", len(b.devices))
	fmt.Printf("Total nodes created: %d\n", len(graph.Nodes))
	for _, node := range graph.Nodes {
		fmt.Printf("  Node: %s (%s) - Type: %s\n", node.ID, node.Hostname, node.Type)
	}

	// 构建边(基于邻居信息)
	edgeMap := make(map[string]bool) // 用于去重

	// 打印所有设备的MAC地址，用于调试
	fmt.Println("\n========== MAC Address Database ==========")
	for _, d := range b.devices {
		if len(d.MACAddresses) > 0 {
			fmt.Printf("Device %s (%s): %d MAC addresses\n", d.Hostname, d.IP, len(d.MACAddresses))
			for i, mac := range d.MACAddresses {
				if i < 5 { // 只打印前5个
					fmt.Printf("  MAC[%d]: %s\n", i, mac)
				}
			}
			if len(d.MACAddresses) > 5 {
				fmt.Printf("  ... and %d more\n", len(d.MACAddresses)-5)
			}
		}
	}
	fmt.Println("==========================================\n")

	for _, device := range b.devices {
		fmt.Printf("Building edges for device %s: %d neighbors, %d MAC addresses\n",
			device.IP, len(device.Neighbors), len(device.MACAddresses))

		for _, neighbor := range device.Neighbors {
			fmt.Printf("  Processing neighbor on %s: RemoteMAC=%s, RemoteDevice=%s, RemoteIP=%s\n",
				neighbor.LocalInterface, neighbor.RemoteMAC, neighbor.RemoteDevice, neighbor.RemoteIP)

			// 尝试匹配邻居设备 - 多重策略
			targetIP := neighbor.RemoteIP
			matchMethod := "IP"

			// 策略1: 如果已有IP，直接使用
			if targetIP != "" {
				fmt.Printf("    ✓ Using direct IP: %s\n", targetIP)
			} else if neighbor.RemoteDevice != "" {
				// 策略2: 尝试通过主机名匹配
				fmt.Printf("    Trying hostname match: %s\n", neighbor.RemoteDevice)
				for _, d := range b.devices {
					if d.Hostname == neighbor.RemoteDevice {
						targetIP = d.IP
						matchMethod = "hostname"
						fmt.Printf("    ✓ Matched by hostname: %s -> %s\n", d.Hostname, d.IP)
						break
					}
				}
			}

			// 策略3: 通过MAC地址匹配
			if targetIP == "" && neighbor.RemoteMAC != "" {
				fmt.Printf("    Trying MAC match: %s\n", neighbor.RemoteMAC)
				for _, d := range b.devices {
					for _, mac := range d.MACAddresses {
						// 标准化MAC地址进行比较（去除分隔符，转小写）
						normalizedNeighborMAC := normalizeMAC(neighbor.RemoteMAC)
						normalizedDeviceMAC := normalizeMAC(mac)

						if normalizedNeighborMAC == normalizedDeviceMAC {
							targetIP = d.IP
							matchMethod = "MAC"
							fmt.Printf("    ✓ Matched by MAC: %s (device) == %s (neighbor) -> %s\n",
								mac, neighbor.RemoteMAC, d.IP)
							break
						}
					}
					if targetIP != "" {
						break
					}
				}
			}

			// 策略4: 通过本地接口IP网段匹配（新增）
			if targetIP == "" {
				// 查找本地接口的IP地址
				localInterfaceIP := ""
				for _, iface := range device.Interfaces {
					if iface.Name == neighbor.LocalInterface && iface.IP != "" {
						localInterfaceIP = iface.IP
						break
					}
				}

				if localInterfaceIP != "" {
					fmt.Printf("    Trying subnet match: local interface %s has IP %s\n",
						neighbor.LocalInterface, localInterfaceIP)

					// 计算本地接口的网段
					localSubnet := getSubnet(localInterfaceIP)

					// 查找其他设备中是否有接口在同一网段
					for _, d := range b.devices {
						if d.IP == device.IP {
							continue // 跳过自己
						}

						// 检查设备的管理IP是否在同一网段
						if getSubnet(d.IP) == localSubnet {
							targetIP = d.IP
							matchMethod = "subnet(management IP)"
							fmt.Printf("    ✓ Matched by subnet: %s in %s\n", d.IP, localSubnet)
							break
						}

						// 检查设备的所有接口是否在同一网段
						for _, iface := range d.Interfaces {
							if iface.IP != "" && getSubnet(iface.IP) == localSubnet {
								targetIP = d.IP
								matchMethod = fmt.Sprintf("subnet(interface %s)", iface.Name)
								fmt.Printf("    ✓ Matched by subnet: %s (%s) in %s\n",
									d.IP, iface.Name, localSubnet)
								break
							}
						}
						if targetIP != "" {
							break
						}
					}
				} else {
					// 策略4b: 本地接口没有IP，尝试使用设备管理IP进行子网匹配（新增）
					// 注意：只有当该网段只有2台设备时才使用此策略（点对点连接）
					fmt.Printf("    Trying subnet match with management IP: %s\n", device.IP)
					localSubnet := getSubnet(device.IP)

					// 统计在该网段的设备数量
					var devicesInSubnet []string
					for _, d := range b.devices {
						if d.IP != device.IP && getSubnet(d.IP) == localSubnet {
							devicesInSubnet = append(devicesInSubnet, d.IP)
						}
					}

					// 只有当网段中恰好有1台其他设备时才匹配（点对点）
					if len(devicesInSubnet) == 1 {
						targetIP = devicesInSubnet[0]
						matchMethod = "subnet(management IP both sides)"
						fmt.Printf("    ✓ Matched by management subnet: %s in %s (only device in subnet)\n", targetIP, localSubnet)
					} else if len(devicesInSubnet) > 1 {
						fmt.Printf("    ✗ Skipping subnet match: %d devices in subnet %s (ambiguous)\n", len(devicesInSubnet)+1, localSubnet)
					}
				}
			}

			// 策略5: 通过接口描述匹配（新增）
			if targetIP == "" {
				// 查找本地接口的描述，看是否包含其他设备的IP或主机名
				for _, iface := range device.Interfaces {
					if iface.Name == neighbor.LocalInterface && iface.Description != "" {
						desc := strings.ToLower(iface.Description)
						fmt.Printf("    Trying description match: %s\n", iface.Description)

						for _, d := range b.devices {
							if d.IP == device.IP {
								continue
							}

							// 检查描述中是否包含目标设备的IP或主机名
							if strings.Contains(desc, strings.ToLower(d.IP)) ||
								(d.Hostname != "" && strings.Contains(desc, strings.ToLower(d.Hostname))) {
								targetIP = d.IP
								matchMethod = "description"
								fmt.Printf("    ✓ Matched by description: %s\n", iface.Description)
								break
							}
						}
					}
					if targetIP != "" {
						break
					}
				}
			}

			if targetIP == "" {
				fmt.Printf("    ✗ Could not match neighbor on %s (MAC: %s)\n", neighbor.LocalInterface, neighbor.RemoteMAC)
				continue
			}

			fmt.Printf("  ✓ Creating edge: %s (%s) -> %s via %s, matched by %s\n",
				device.IP, neighbor.LocalInterface, targetIP, neighbor.RemoteInterface, matchMethod)

			// 创建唯一的边ID
			edgeID := fmt.Sprintf("%s-%s-%s", device.IP, neighbor.LocalInterface, targetIP)
			reverseEdgeID := fmt.Sprintf("%s-%s-%s", targetIP, neighbor.RemoteInterface, device.IP)

			// 避免重复边
			if edgeMap[edgeID] || edgeMap[reverseEdgeID] {
				continue
			}

			edge := models.TopologyEdge{
				ID:              edgeID,
				Source:          device.IP,
				Target:          targetIP,
				SourceInterface: neighbor.LocalInterface,
				TargetInterface: neighbor.RemoteInterface,
				Protocol:        neighbor.Protocol,
			}

			graph.Edges = append(graph.Edges, edge)
			edgeMap[edgeID] = true
		}
	}

	fmt.Printf("\nTotal edges created: %d\n", len(graph.Edges))
	for _, edge := range graph.Edges {
		fmt.Printf("  Edge: %s (%s) -> %s (%s) [%s]\n",
			edge.Source, edge.SourceInterface,
			edge.Target, edge.TargetInterface,
			edge.Protocol)
	}
	fmt.Println("========================================\n")

	return graph
}

// normalizeMAC 标准化MAC地址（去除分隔符，转小写）
func normalizeMAC(mac string) string {
	// 去除所有分隔符（-、:、.）
	result := ""
	for _, c := range mac {
		if c != '-' && c != ':' && c != '.' {
			result += string(c)
		}
	}
	// 转小写
	return strings.ToLower(result)
}

// getSubnet 获取IP地址的C类网段（简化版，适用于/24网络）
func getSubnet(ip string) string {
	parts := strings.Split(ip, ".")
	if len(parts) == 4 {
		// 返回前3段作为网段，例如: 172.16.8.0/24 -> "172.16.8"
		return fmt.Sprintf("%s.%s.%s", parts[0], parts[1], parts[2])
	}
	return ip
}

// getDeviceIcon 获取设备图标
func getDeviceIcon(deviceType models.DeviceType) string {
	switch deviceType {
	case models.DeviceTypeCisco:
		return "router"
	case models.DeviceTypeHuawei:
		return "router"
	case models.DeviceTypeH3C:
		return "switch"
	case models.DeviceTypeASA:
		return "firewall"
	case models.DeviceTypeLinux:
		return "server"
	case models.DeviceTypeWindows:
		return "server"
	default:
		return "device"
	}
}

// GetDevices 获取所有设备
func (b *Builder) GetDevices() []models.Device {
	return b.devices
}

// Clear 清空拓扑
func (b *Builder) Clear() {
	b.devices = make([]models.Device, 0)
}