package statistic

import (
	"errors"
	"net"
	"time"

	"github.com/Dreamacro/clash/common/snifer/tls"
	"github.com/Dreamacro/clash/component/resolver"
	C "github.com/Dreamacro/clash/constant"
	"github.com/Dreamacro/clash/log"

	"github.com/gofrs/uuid"
	"go.uber.org/atomic"
)

type tracker interface {
	ID() string
	Close() error
}

type trackerInfo struct {
	UUID          uuid.UUID     `json:"id"`
	Metadata      *C.Metadata   `json:"metadata"`
	UploadTotal   *atomic.Int64 `json:"upload"`
	DownloadTotal *atomic.Int64 `json:"download"`
	Start         time.Time     `json:"start"`
	Chain         C.Chain       `json:"chains"`
	Rule          string        `json:"rule"`
	RulePayload   string        `json:"rulePayload"`
}

type tcpTracker struct {
	C.Conn `json:"-"`
	*trackerInfo
	manager *Manager
}

func (tt *tcpTracker) ID() string {
	return tt.UUID.String()
}

func (tt *tcpTracker) Read(b []byte) (int, error) {
	n, err := tt.Conn.Read(b)
	download := int64(n)
	tt.manager.PushDownloaded(download)
	tt.DownloadTotal.Add(download)
	return n, err
}

func (tt *tcpTracker) Write(b []byte) (int, error) {
	n, err := tt.Conn.Write(b)
	upload := int64(n)
	tt.manager.PushUploaded(upload)
	if tt.UploadTotal.Load() < 128 && tt.Metadata.Host == "" && (tt.Metadata.DstPort == "443" || tt.Metadata.DstPort == "8443") {
		header, err := tls.SniffTLS(b)
		if err != nil {
			// log.Errorln("Expect no error but actually %s %s:%s:%s", err.Error(), tt.Metadata.Host, tt.Metadata.DstIP.String(), tt.Metadata.DstPort)
		} else {
			resolver.InsertHostByIP(tt.Metadata.DstIP, header.Domain())
			log.Warnln("use sni update host: %s ip: %s", header.Domain(), tt.Metadata.DstIP.String())
			tt.manager.Leave(tt)
			tt.Conn.Close()
			return n, errors.New("sni update, break current link to avoid leaks")
		}
	}
	tt.UploadTotal.Add(upload)

	return n, err
}

func (tt *tcpTracker) Close() error {
	tt.manager.Leave(tt)
	return tt.Conn.Close()
}

func NewTCPTracker(conn C.Conn, manager *Manager, metadata *C.Metadata, rule C.Rule) *tcpTracker {
	uuid, _ := uuid.NewV4()

	t := &tcpTracker{
		Conn:    conn,
		manager: manager,
		trackerInfo: &trackerInfo{
			UUID:          uuid,
			Start:         time.Now(),
			Metadata:      metadata,
			Chain:         conn.Chains(),
			Rule:          "",
			UploadTotal:   atomic.NewInt64(0),
			DownloadTotal: atomic.NewInt64(0),
		},
	}

	if rule != nil {
		t.trackerInfo.Rule = rule.RuleType().String()
		t.trackerInfo.RulePayload = rule.Payload()
	}

	manager.Join(t)
	return t
}

type udpTracker struct {
	C.PacketConn `json:"-"`
	*trackerInfo
	manager *Manager
}

func (ut *udpTracker) ID() string {
	return ut.UUID.String()
}

func (ut *udpTracker) ReadFrom(b []byte) (int, net.Addr, error) {
	n, addr, err := ut.PacketConn.ReadFrom(b)
	download := int64(n)
	ut.manager.PushDownloaded(download)
	ut.DownloadTotal.Add(download)
	return n, addr, err
}

func (ut *udpTracker) WriteTo(b []byte, addr net.Addr) (int, error) {
	n, err := ut.PacketConn.WriteTo(b, addr)
	upload := int64(n)
	ut.manager.PushUploaded(upload)
	ut.UploadTotal.Add(upload)
	return n, err
}

func (ut *udpTracker) Close() error {
	ut.manager.Leave(ut)
	return ut.PacketConn.Close()
}

func NewUDPTracker(conn C.PacketConn, manager *Manager, metadata *C.Metadata, rule C.Rule) *udpTracker {
	uuid, _ := uuid.NewV4()

	ut := &udpTracker{
		PacketConn: conn,
		manager:    manager,
		trackerInfo: &trackerInfo{
			UUID:          uuid,
			Start:         time.Now(),
			Metadata:      metadata,
			Chain:         conn.Chains(),
			Rule:          "",
			UploadTotal:   atomic.NewInt64(0),
			DownloadTotal: atomic.NewInt64(0),
		},
	}

	if rule != nil {
		ut.trackerInfo.Rule = rule.RuleType().String()
		ut.trackerInfo.RulePayload = rule.Payload()
	}

	manager.Join(ut)
	return ut
}