/*
 * MikroTik Address List 插件 - 性能优化版
 *
 * 主要优化：
 * 1. 完全移除验证功能
 * 2. 启动时从MikroTik加载现有IP到内存
 * 3. 内存中判断IP是否存在，避免重复写入
 * 4. 支持/24网段掩码
 */

package mikrotik_addresslist

import (
	"context"
	"fmt"
	"net/netip"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/IrineSistiana/mosdns/v5/pkg/query_context"
	"github.com/miekg/dns"
	"go.uber.org/zap"

	routeros "github.com/go-routeros/routeros/v3"
)

type optimizedMikrotikAddressListPlugin struct {
	args *Args
	conn *routeros.Client
	log  *zap.Logger

	// 并发控制
	workerPool  chan struct{}
	wg          sync.WaitGroup
	mu          sync.RWMutex
	isConnected bool

	// 内存IP缓存 - 核心优化
	ipCache  map[string]map[string]bool // map[listName]map[cidrAddr]exists
	cacheMu  sync.RWMutex               // 保护IP缓存访问
	cacheTTL time.Duration

	// 网段缓存，用于/24掩码优化
	subnetCache map[string]map[string]time.Time // map[listName]map[subnet]addTime
	subnetMu    sync.RWMutex
}

func newOptimizedMikrotikAddressListPlugin(args *Args) (*optimizedMikrotikAddressListPlugin, error) {
	// 设置默认值
	if args.Mask4 == 0 {
		args.Mask4 = 24 // 默认使用/24网段掩码
	}
	if args.Mask6 == 0 {
		args.Mask6 = 64 // IPv6使用/64
	}
	if args.Port == 0 {
		args.Port = 9728
	}
	if args.Timeout == 0 {
		args.Timeout = 3 // 优化：减少超时时间
	}
	if !args.AddAllIPs {
		args.AddAllIPs = true
	}

	// 构建连接地址
	addr := fmt.Sprintf("%s:%d", args.Host, args.Port)

	// 创建 MikroTik 连接
	conn, err := routeros.Dial(addr, args.Username, args.Password)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to MikroTik: %w", err)
	}

	// 测试连接
	if err := testMikrotikConnection(conn); err != nil {
		conn.Close()
		return nil, fmt.Errorf("failed to test MikroTik connection: %w", err)
	}

	// 设置工作池大小
	workerCount := 20 // 增加工作线程数

	// 设置缓存 TTL
	cacheTTL := time.Hour * 2 // 2小时缓存
	if args.CacheTTL > 0 {
		cacheTTL = time.Duration(args.CacheTTL) * time.Second
	}

	plugin := &optimizedMikrotikAddressListPlugin{
		args:        args,
		conn:        conn,
		log:         zap.L().Named("mikrotik_optimized"),
		workerPool:  make(chan struct{}, workerCount),
		ipCache:     make(map[string]map[string]bool),
		subnetCache: make(map[string]map[string]time.Time),
		cacheTTL:    cacheTTL,
		isConnected: true,
	}

	// 🚀 核心优化：启动时加载现有IP到内存
	if err := plugin.loadExistingIPs(); err != nil {
		plugin.log.Warn("failed to load existing IPs, continuing anyway", zap.Error(err))
	}

	plugin.log.Info("optimized MikroTik plugin initialized",
		zap.String("host", args.Host),
		zap.Int("port", args.Port),
		zap.String("address_list4", args.AddressList4),
		zap.String("address_list6", args.AddressList6),
		zap.Int("worker_count", workerCount),
		zap.Duration("cache_ttl", cacheTTL),
		zap.Int("mask4", args.Mask4),
		zap.Int("mask6", args.Mask6))

	return plugin, nil
}

// 🚀 核心功能：启动时从MikroTik加载现有IP
func (p *optimizedMikrotikAddressListPlugin) loadExistingIPs() error {
	p.log.Info("loading existing IPs from MikroTik...")

	// 加载IPv4地址列表
	if p.args.AddressList4 != "" {
		if err := p.loadAddressListIPs(p.args.AddressList4); err != nil {
			p.log.Error("failed to load IPv4 addresses",
				zap.String("list", p.args.AddressList4),
				zap.Error(err))
		}
	}

	// 加载IPv6地址列表
	if p.args.AddressList6 != "" {
		if err := p.loadAddressListIPs(p.args.AddressList6); err != nil {
			p.log.Error("failed to load IPv6 addresses",
				zap.String("list", p.args.AddressList6),
				zap.Error(err))
		}
	}

	// 打印加载统计
	p.cacheMu.RLock()
	totalIPs := 0
	for listName, ips := range p.ipCache {
		count := len(ips)
		totalIPs += count
		p.log.Info("loaded address list",
			zap.String("list", listName),
			zap.Int("ip_count", count))
	}
	p.cacheMu.RUnlock()

	p.log.Info("finished loading existing IPs", zap.Int("total_ips", totalIPs))
	return nil
}

// 从指定的address list加载所有IP
func (p *optimizedMikrotikAddressListPlugin) loadAddressListIPs(listName string) error {
	// 查询指定列表的所有地址
	resp, err := p.conn.Run("/ip/firewall/address-list/print", "=list="+listName)
	if err != nil {
		return fmt.Errorf("failed to query address list %s: %w", listName, err)
	}

	p.cacheMu.Lock()
	defer p.cacheMu.Unlock()

	// 初始化缓存
	if p.ipCache[listName] == nil {
		p.ipCache[listName] = make(map[string]bool)
	}

	// 解析响应并添加到缓存
	for _, re := range resp.Re {
		if address, ok := re.Map["address"]; ok {
			p.ipCache[listName][address] = true

			// 如果是网段地址，也缓存网段信息
			if strings.Contains(address, "/") {
				p.subnetMu.Lock()
				if p.subnetCache[listName] == nil {
					p.subnetCache[listName] = make(map[string]time.Time)
				}
				p.subnetCache[listName][address] = time.Now()
				p.subnetMu.Unlock()
			}
		}
	}

	return nil
}

// 🚀 优化的IP存在性检查（纯内存操作）
func (p *optimizedMikrotikAddressListPlugin) isIPInMemoryCache(listName, cidrAddr string) bool {
	p.cacheMu.RLock()
	defer p.cacheMu.RUnlock()

	if listCache, exists := p.ipCache[listName]; exists {
		return listCache[cidrAddr]
	}
	return false
}

// 🚀 优化的网段存在性检查
func (p *optimizedMikrotikAddressListPlugin) isSubnetInCache(listName, subnet string) bool {
	p.subnetMu.RLock()
	defer p.subnetMu.RUnlock()

	if subnetMap, exists := p.subnetCache[listName]; exists {
		if addTime, exists := subnetMap[subnet]; exists {
			// 检查是否过期
			return time.Since(addTime) < p.cacheTTL
		}
	}
	return false
}

// 添加IP到内存缓存
func (p *optimizedMikrotikAddressListPlugin) addToMemoryCache(listName, cidrAddr string) {
	p.cacheMu.Lock()
	defer p.cacheMu.Unlock()

	if p.ipCache[listName] == nil {
		p.ipCache[listName] = make(map[string]bool)
	}
	p.ipCache[listName][cidrAddr] = true

	// 如果是网段，也更新网段缓存
	if strings.Contains(cidrAddr, "/") {
		p.subnetMu.Lock()
		if p.subnetCache[listName] == nil {
			p.subnetCache[listName] = make(map[string]time.Time)
		}
		p.subnetCache[listName][cidrAddr] = time.Now()
		p.subnetMu.Unlock()
	}
}

// 主执行函数
func (p *optimizedMikrotikAddressListPlugin) Exec(_ context.Context, qCtx *query_context.Context) error {
	if p.conn == nil {
		p.log.Error("MikroTik connection is nil")
		return nil
	}

	r := qCtx.R()
	if r != nil {
		var domain string
		if len(qCtx.Q().Question) > 0 {
			domain = strings.TrimSuffix(qCtx.Q().Question[0].Name, ".")
		}

		p.log.Debug("processing DNS response",
			zap.String("qname", domain),
			zap.Int("answer_count", len(r.Answer)))

		// 异步处理，不阻塞DNS响应
		go func(response *dns.Msg, domainName string) {
			if err := p.addToAddressList(response, domainName); err != nil {
				p.log.Error("failed to add addresses to MikroTik", zap.Error(err))
			}
		}(r, domain)
	}
	return nil
}

// 🚀 优化的地址添加逻辑
func (p *optimizedMikrotikAddressListPlugin) addToAddressList(r *dns.Msg, domain string) error {
	var ipv4Addresses []netip.Addr
	var ipv6Addresses []netip.Addr

	// 收集所有IP地址
	for i := range r.Answer {
		switch rr := r.Answer[i].(type) {
		case *dns.A:
			if len(p.args.AddressList4) == 0 {
				continue
			}
			addr, ok := netip.AddrFromSlice(rr.A.To4())
			if !ok {
				continue
			}
			ipv4Addresses = append(ipv4Addresses, addr)

		case *dns.AAAA:
			if len(p.args.AddressList6) == 0 {
				continue
			}
			addr, ok := netip.AddrFromSlice(rr.AAAA.To16())
			if !ok {
				continue
			}
			ipv6Addresses = append(ipv6Addresses, addr)
		}
	}

	// 应用IP数量限制
	if p.args.MaxIPs > 0 {
		if len(ipv4Addresses) > p.args.MaxIPs {
			ipv4Addresses = ipv4Addresses[:p.args.MaxIPs]
		}
		if len(ipv6Addresses) > p.args.MaxIPs {
			ipv6Addresses = ipv6Addresses[:p.args.MaxIPs]
		}
	}

	// 异步处理IPv4地址
	if len(ipv4Addresses) > 0 && len(p.args.AddressList4) > 0 {
		go p.processIPAddresses(ipv4Addresses, p.args.AddressList4, p.args.Mask4, domain, "IPv4")
	}

	// 异步处理IPv6地址
	if len(ipv6Addresses) > 0 && len(p.args.AddressList6) > 0 {
		go p.processIPAddresses(ipv6Addresses, p.args.AddressList6, p.args.Mask6, domain, "IPv6")
	}

	return nil
}

// 🚀 优化的IP处理逻辑
func (p *optimizedMikrotikAddressListPlugin) processIPAddresses(addresses []netip.Addr, listName string, mask int, domain, ipType string) {
	var needToAdd []string
	skippedCount := 0

	// 🚀 关键优化：先在内存中过滤已存在的IP
	for _, addr := range addresses {
		cidrAddr := p.buildCIDRAddress(addr, mask)

		// 纯内存检查，极快速度
		if p.isIPInMemoryCache(listName, cidrAddr) {
			skippedCount++
			p.log.Debug("IP already exists in memory cache, skipping",
				zap.String("ip", addr.String()),
				zap.String("cidr", cidrAddr),
				zap.String("list", listName))
			continue
		}

		// 对于/24网段，检查网段是否已存在
		if mask == 24 && p.isSubnetInCache(listName, cidrAddr) {
			skippedCount++
			p.log.Debug("subnet already cached, skipping",
				zap.String("cidr", cidrAddr),
				zap.String("list", listName))
			continue
		}

		needToAdd = append(needToAdd, cidrAddr)
	}

	p.log.Info("IP processing summary",
		zap.String("type", ipType),
		zap.String("domain", domain),
		zap.Int("total_ips", len(addresses)),
		zap.Int("need_to_add", len(needToAdd)),
		zap.Int("skipped_cached", skippedCount))

	// 只处理需要添加的IP
	if len(needToAdd) > 0 {
		p.batchAddOptimized(needToAdd, listName, domain)
	}
}

// 构建CIDR地址
func (p *optimizedMikrotikAddressListPlugin) buildCIDRAddress(addr netip.Addr, mask int) string {
	if addr.Is4() {
		networkAddr := netip.PrefixFrom(addr, mask).Addr()
		return networkAddr.String() + "/" + strconv.Itoa(mask)
	} else {
		networkAddr := netip.PrefixFrom(addr, mask).Addr()
		return networkAddr.String() + "/" + strconv.Itoa(mask)
	}
}

// 🚀 优化的批量添加
func (p *optimizedMikrotikAddressListPlugin) batchAddOptimized(addresses []string, listName, domain string) {
	for _, cidrAddr := range addresses {
		// 获取工作池槽位
		select {
		case p.workerPool <- struct{}{}:
			go func(addr string) {
				defer func() { <-p.workerPool }()

				if err := p.addSingleAddress(addr, listName, domain); err != nil {
					p.log.Error("failed to add address",
						zap.String("cidr", addr),
						zap.String("list", listName),
						zap.Error(err))
				} else {
					// 🚀 成功后立即更新内存缓存
					p.addToMemoryCache(listName, addr)
					p.log.Debug("successfully added and cached address",
						zap.String("cidr", addr),
						zap.String("list", listName))
				}
			}(cidrAddr)
		default:
			// 工作池满，直接执行
			if err := p.addSingleAddress(cidrAddr, listName, domain); err != nil {
				p.log.Error("failed to add address (direct)",
					zap.String("cidr", cidrAddr),
					zap.Error(err))
			} else {
				p.addToMemoryCache(listName, cidrAddr)
			}
		}
	}
}

// 添加单个地址到MikroTik
func (p *optimizedMikrotikAddressListPlugin) addSingleAddress(cidrAddr, listName, domain string) error {
	// 构造参数
	params := []string{
		"=list=" + listName,
		"=address=" + cidrAddr,
	}

	// 添加注释
	comment := domain
	if comment == "" && p.args.Comment != "" {
		comment = p.args.Comment
	}
	if comment != "" {
		params = append(params, "=comment="+comment)
	}

	// 添加超时时间
	if p.args.TimeoutAddr > 0 {
		params = append(params, "=timeout="+strconv.Itoa(p.args.TimeoutAddr))
	}

	p.log.Debug("adding address to MikroTik",
		zap.String("cidr", cidrAddr),
		zap.String("list", listName),
		zap.String("domain", domain))

	// 发送到MikroTik
	args := append([]string{"/ip/firewall/address-list/add"}, params...)
	_, err := p.conn.Run(args...)

	if err != nil {
		if strings.Contains(err.Error(), "already have such entry") {
			// 如果MikroTik说已存在，更新内存缓存
			p.addToMemoryCache(listName, cidrAddr)
			p.log.Debug("address already exists in MikroTik, updated cache",
				zap.String("cidr", cidrAddr))
			return nil
		}
		return fmt.Errorf("failed to add address %s: %v", cidrAddr, err)
	}

	return nil
}

// 获取缓存统计
func (p *optimizedMikrotikAddressListPlugin) getCacheStats() map[string]int {
	p.cacheMu.RLock()
	defer p.cacheMu.RUnlock()

	stats := make(map[string]int)
	for listName, ips := range p.ipCache {
		stats[listName] = len(ips)
	}
	return stats
}

// 关闭插件
func (p *optimizedMikrotikAddressListPlugin) Close() error {
	p.wg.Wait()

	// 打印最终统计
	stats := p.getCacheStats()
	p.log.Info("optimized plugin closing", zap.Any("final_cache_stats", stats))

	p.mu.Lock()
	defer p.mu.Unlock()

	if p.conn != nil {
		return p.conn.Close()
	}
	return nil
}