package bcap

import (
	"net"
	"testing"
	"time"
)

func TestDecoderDecodeARP(t *testing.T) {
	decoder := NewDecoder()
	base := time.Unix(1700005000, 0)

	packet := mustBuildARPPacket(t, base, arpPacketSpec{
		srcMAC:    "02:00:00:00:00:01",
		dstMAC:    "ff:ff:ff:ff:ff:ff",
		senderMAC: "02:00:00:00:00:01",
		targetMAC: "00:00:00:00:00:00",
		senderIP:  "10.0.0.1",
		targetIP:  "10.0.0.2",
		operation: 1,
	})

	decoded, err := decoder.Decode(packet)
	if err != nil {
		t.Fatalf("decode arp: %v", err)
	}
	if decoded.Network.Family != NetworkFamilyARP {
		t.Fatalf("network family = %q, want %q", decoded.Network.Family, NetworkFamilyARP)
	}
	if decoded.Transport.Kind != ProtocolARP {
		t.Fatalf("protocol = %q, want %q", decoded.Transport.Kind, ProtocolARP)
	}
	if decoded.Network.ARP == nil {
		t.Fatal("expected arp facts")
	}
	if decoded.Network.ARP.SenderIP != "10.0.0.1" {
		t.Fatalf("sender ip = %q, want %q", decoded.Network.ARP.SenderIP, "10.0.0.1")
	}
	if decoded.Network.ARP.TargetIP != "10.0.0.2" {
		t.Fatalf("target ip = %q, want %q", decoded.Network.ARP.TargetIP, "10.0.0.2")
	}
}

func TestDecoderDecodeIPv4WithoutTransportReturnsUnknown(t *testing.T) {
	decoder := NewDecoder()
	base := time.Unix(1700005001, 0)

	packet := mustBuildIPv4OnlyPacket(t, base, "10.0.0.1", "10.0.0.2")
	decoded, err := decoder.Decode(packet)
	if err != nil {
		t.Fatalf("decode ipv4-only: %v", err)
	}
	if decoded.Network.Family != NetworkFamilyIPv4 {
		t.Fatalf("network family = %q, want %q", decoded.Network.Family, NetworkFamilyIPv4)
	}
	if decoded.Transport.Kind != ProtocolUnknown {
		t.Fatalf("transport kind = %q, want %q", decoded.Transport.Kind, ProtocolUnknown)
	}
}

func TestAnalyzerObservePacketTCP(t *testing.T) {
	analyzer := NewAnalyzer()
	defer analyzer.Stop()
	base := time.Unix(1700005002, 0)

	obs, err := analyzer.ObservePacket(mustBuildTCPPacket(t, base, tcpPacketSpec{
		srcIP:   "10.0.0.1",
		dstIP:   "10.0.0.2",
		srcPort: 12345,
		dstPort: 80,
		seq:     100,
		syn:     true,
		window:  4096,
	}))
	if err != nil {
		t.Fatalf("observe tcp packet: %v", err)
	}
	if obs.Flow.Forward.Protocol != ProtocolTCP {
		t.Fatalf("flow protocol = %q, want %q", obs.Flow.Forward.Protocol, ProtocolTCP)
	}
	if obs.Hints.TCP == nil {
		t.Fatal("expected tcp hint")
	}
	if obs.Hints.TCP.Event != TCPEventSYN {
		t.Fatalf("tcp event = %q, want %q", obs.Hints.TCP.Event, TCPEventSYN)
	}
	if obs.Hints.Summary.Code != string(TagTCPHandshakeSYN) {
		t.Fatalf("summary = %q, want %q", obs.Hints.Summary.Code, TagTCPHandshakeSYN)
	}
}

func TestAnalyzerObservePacketARP(t *testing.T) {
	analyzer := NewAnalyzer()
	defer analyzer.Stop()
	base := time.Unix(1700005003, 0)

	obs, err := analyzer.ObservePacket(mustBuildARPPacket(t, base, arpPacketSpec{
		srcMAC:    "02:00:00:00:00:01",
		dstMAC:    "ff:ff:ff:ff:ff:ff",
		senderMAC: "02:00:00:00:00:01",
		targetMAC: "00:00:00:00:00:00",
		senderIP:  "10.0.0.1",
		targetIP:  "10.0.0.2",
		operation: 1,
	}))
	if err != nil {
		t.Fatalf("observe arp packet: %v", err)
	}
	if obs.Flow.Forward.Protocol != ProtocolARP {
		t.Fatalf("flow protocol = %q, want %q", obs.Flow.Forward.Protocol, ProtocolARP)
	}
	if obs.Hints.ARP == nil {
		t.Fatal("expected arp hint")
	}
	if !obs.Hints.ARP.Request {
		t.Fatal("expected arp request hint")
	}
	if obs.Hints.Summary.Code != string(TagARPRequest) {
		t.Fatalf("summary = %q, want %q", obs.Hints.Summary.Code, TagARPRequest)
	}
}

func TestTrackerObserveDecodedTCPWithoutRawPacket(t *testing.T) {
	decoder := NewDecoder()
	tracker := NewTracker()
	defer tracker.Stop()
	base := time.Unix(1700005004, 0)

	decoded, err := decoder.Decode(mustBuildTCPPacket(t, base, tcpPacketSpec{
		srcIP:   "10.0.0.1",
		dstIP:   "10.0.0.2",
		srcPort: 12345,
		dstPort: 80,
		seq:     100,
		syn:     true,
		window:  4096,
	}))
	if err != nil {
		t.Fatalf("decode tcp: %v", err)
	}
	decoded.Raw.Packet = nil

	obs, err := tracker.Observe(decoded)
	if err != nil {
		t.Fatalf("observe decoded tcp: %v", err)
	}
	if obs.Hints.TCP == nil {
		t.Fatal("expected tcp hint")
	}
	if obs.Hints.TCP.Event != TCPEventSYN {
		t.Fatalf("tcp event = %q, want %q", obs.Hints.TCP.Event, TCPEventSYN)
	}
}

func TestAnalyzerObservePacketWithOptionsSrcMACOverride(t *testing.T) {
	analyzer := NewAnalyzer()
	defer analyzer.Stop()

	override := net.HardwareAddr{0x02, 0xaa, 0xbb, 0xcc, 0xdd, 0xee}
	base := time.Unix(1700005005, 0)

	obs, err := analyzer.ObservePacketWithOptions(mustBuildTCPPacket(t, base, tcpPacketSpec{
		srcIP:   "10.0.0.1",
		dstIP:   "10.0.0.2",
		srcPort: 12345,
		dstPort: 80,
		seq:     100,
		syn:     true,
		window:  4096,
	}), DecodeOptions{
		SrcMACOverride: override,
	})
	if err != nil {
		t.Fatalf("observe tcp packet with options: %v", err)
	}
	if got := obs.Packet.Link.SrcMAC.String(); got != override.String() {
		t.Fatalf("src mac = %q, want %q", got, override.String())
	}
	if obs.Packet.Meta.RelativeTime != 0 {
		t.Fatalf("relative time = %v, want 0", obs.Packet.Meta.RelativeTime)
	}
}

func TestAnalyzerObservePacketTCPKeepaliveResponse(t *testing.T) {
	analyzer := NewAnalyzer()
	defer analyzer.Stop()
	base := time.Unix(1700005006, 0)

	_, err := analyzer.ObservePacket(mustBuildTCPPacket(t, base, tcpPacketSpec{
		srcIP:   "122.210.105.240",
		dstIP:   "122.210.110.99",
		srcPort: 3306,
		dstPort: 60818,
		seq:     172126745,
		ack:     2951532891,
		ackFlag: true,
		window:  258,
	}))
	if err != nil {
		t.Fatalf("observe baseline packet: %v", err)
	}

	probe, err := analyzer.ObservePacket(mustBuildTCPPacket(t, base.Add(75*time.Second), tcpPacketSpec{
		srcIP:   "122.210.105.240",
		dstIP:   "122.210.110.99",
		srcPort: 3306,
		dstPort: 60818,
		seq:     172126745,
		ack:     2951532891,
		ackFlag: true,
		window:  258,
	}))
	if err != nil {
		t.Fatalf("observe keepalive probe: %v", err)
	}
	if probe.Hints.TCP == nil || probe.Hints.TCP.Event != TCPEventKeepalive {
		t.Fatalf("probe event = %#v, want %q", probe.Hints.TCP, TCPEventKeepalive)
	}

	resp, err := analyzer.ObservePacket(mustBuildTCPPacket(t, base.Add(75*time.Second+50*time.Millisecond), tcpPacketSpec{
		srcIP:   "122.210.110.99",
		dstIP:   "122.210.105.240",
		srcPort: 60818,
		dstPort: 3306,
		seq:     2951532891,
		ack:     172126746,
		ackFlag: true,
		window:  1024,
	}))
	if err != nil {
		t.Fatalf("observe keepalive response: %v", err)
	}
	if resp.Hints.TCP == nil {
		t.Fatal("expected tcp hint")
	}
	if resp.Hints.TCP.LegacyState != StateTcpKeepalive {
		t.Fatalf("legacy state = %d, want %d", resp.Hints.TCP.LegacyState, StateTcpKeepalive)
	}
	if resp.Hints.TCP.Event != TCPEventKeepaliveResp {
		t.Fatalf("tcp event = %q, want %q", resp.Hints.TCP.Event, TCPEventKeepaliveResp)
	}
	if !resp.Hints.TCP.KeepaliveResponse {
		t.Fatal("expected keepalive response flag")
	}
	if resp.Hints.Summary.Code != string(TagTCPKeepaliveResp) {
		t.Fatalf("summary = %q, want %q", resp.Hints.Summary.Code, TagTCPKeepaliveResp)
	}
	if !containsTag(resp.Hints.Tags, TagTCPKeepaliveResp) {
		t.Fatalf("tags = %v, want %q", resp.Hints.Tags, TagTCPKeepaliveResp)
	}
	if !containsTag(resp.Hints.Tags, TagTCPKeepalive) {
		t.Fatalf("tags = %v, want %q", resp.Hints.Tags, TagTCPKeepalive)
	}
}

func TestTrackerCleanupExpiredFlows(t *testing.T) {
	cfg := DefaultConfig()
	cfg.ConnectionTimeout = time.Second
	cfg.CleanupInterval = 0

	decoder := NewDecoder()
	tracker := NewTrackerWithConfig(cfg)
	defer tracker.Stop()

	stale, err := decoder.Decode(mustBuildTCPPacket(t, time.Now().Add(-5*time.Second), tcpPacketSpec{
		srcIP:   "10.0.0.1",
		dstIP:   "10.0.0.2",
		srcPort: 12345,
		dstPort: 80,
		seq:     100,
		syn:     true,
		window:  4096,
	}))
	if err != nil {
		t.Fatalf("decode stale packet: %v", err)
	}
	if _, err := tracker.Observe(stale); err != nil {
		t.Fatalf("observe stale packet: %v", err)
	}

	fresh, err := decoder.Decode(mustBuildTCPPacket(t, time.Now(), tcpPacketSpec{
		srcIP:   "10.0.0.3",
		dstIP:   "10.0.0.4",
		srcPort: 23456,
		dstPort: 443,
		seq:     200,
		syn:     true,
		window:  4096,
	}))
	if err != nil {
		t.Fatalf("decode fresh packet: %v", err)
	}
	if _, err := tracker.Observe(fresh); err != nil {
		t.Fatalf("observe fresh packet: %v", err)
	}

	if got := tracker.ActiveFlowCount(); got != 2 {
		t.Fatalf("active flow count = %d, want 2", got)
	}
	if removed := tracker.CleanupExpiredFlows(); removed != 1 {
		t.Fatalf("removed stale flows = %d, want 1", removed)
	}
	if got := tracker.ActiveFlowCount(); got != 1 {
		t.Fatalf("active flow count after cleanup = %d, want 1", got)
	}
}

func containsTag(tags []Tag, want Tag) bool {
	for _, tag := range tags {
		if tag == want {
			return true
		}
	}
	return false
}