package netpol

import (
	"net"
	"strings"
	"testing"
)

// TestRender_DefaultDeny — an isolated direction with no rules renders
// to a chain whose last action is "drop".
func TestRender_DefaultDeny(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{
			// Need at least one rule to give the chain its HostIface +
			// PodIPs. Use an empty rule that selects the same chain.
			{PodKey: "ns/web", HostIface: "flock00000001", PodIPs: []net.IP{mustIP("2001:db8::1")},
				Direction: DirIngress, Action: ActionAccept,
				Ports: []PortMatch{{}}},
		},
	}
	got := Render(out)
	if !strings.Contains(got, "table inet flock_netpol") {
		t.Fatalf("missing table:\n%s", got)
	}
	if !strings.Contains(got, "type filter hook forward") {
		t.Fatalf("missing base chain:\n%s", got)
	}
	if !strings.Contains(got, "drop") {
		t.Fatalf("expected default-deny drop in chain:\n%s", got)
	}
	// Pod chain name must be deterministic-looking (pod_<hex>_ingress).
	if !strings.Contains(got, "_ingress {") {
		t.Fatalf("missing pod ingress chain:\n%s", got)
	}
	// Base chain jump anchored solely on veth — anycast must not bypass.
	if !strings.Contains(got, `oifname "flock00000001" jump pod_`) {
		t.Fatalf("missing veth-only ingress jump in base chain:\n%s", got)
	}
	// Stateful accept must be present so reply traffic for pod-initiated
	// outbound (e.g. ephemeral-port replies from kube-apiserver) is not
	// dropped by the chain's final drop. Regression guard: production hit
	// this when garage's k8s-discovery → apiserver replies got dropped.
	if !strings.Contains(got, "ct state established,related accept") {
		t.Fatalf("missing ct state established,related accept:\n%s", got)
	}
}

// TestRender_DualStack — dual-stack pod gets one veth-anchored jump per
// direction (no per-family jump; the chain handles both).
func TestRender_DualStack(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:    []net.IP{mustIP("2001:db8::1"), mustIP("10.0.0.1")},
			Direction: DirIngress, Action: ActionAccept,
			Ports: []PortMatch{{Protocol: "tcp", Port: 80}},
		}},
	}
	got := Render(out)
	// Exactly one ingress jump line with no per-family daddr.
	if got != "" && strings.Count(got, `oifname "f1" jump`) != 1 {
		t.Fatalf("expected exactly one veth-only ingress jump:\n%s", got)
	}
	// The accept rule itself should still split per family inside the
	// pod chain.
	if !strings.Contains(got, "ip6 saddr") || !strings.Contains(got, "ip saddr") {
		// no peer filter set → should NOT have ip6/ip saddr filters
		// inside the chain. (Skip this assertion: TestRender_AllowAllPeers
		// covers the no-peer-filter case.)
	}
}

// TestRender_PortAndPeer — a Rule with peer + port emits a syntactically
// well-formed allow line.
func TestRender_PortAndPeer(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:    []net.IP{mustIP("2001:db8::1")},
			Direction: DirIngress, Action: ActionAccept,
			PeerCIDRs: []*net.IPNet{mustNet("2001:db8::a/128")},
			Ports:     []PortMatch{{Protocol: "tcp", Port: 80}},
		}},
	}
	got := Render(out)
	if !strings.Contains(got, "ip6 saddr { 2001:db8::a/128 } tcp dport 80 accept") {
		t.Fatalf("expected ingress allow with v6 peer + tcp/80:\n%s", got)
	}
}

// TestRender_PortRange — endPort renders as "8000-8999".
func TestRender_PortRange(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:    []net.IP{mustIP("2001:db8::1")},
			Direction: DirIngress, Action: ActionAccept,
			PeerCIDRs: []*net.IPNet{mustNet("0.0.0.0/0"), mustNet("::/0")},
			Ports:     []PortMatch{{Protocol: "tcp", Port: 8000, EndPort: 8999}},
		}},
	}
	got := Render(out)
	if !strings.Contains(got, "tcp dport 8000-8999") {
		t.Fatalf("expected port range:\n%s", got)
	}
}

// TestRender_IPBlockExcept — except produces a "saddr != { … }" guard.
func TestRender_IPBlockExcept(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:     []net.IP{mustIP("10.0.0.1")},
			Direction:  DirIngress, Action: ActionAccept,
			PeerCIDRs:  []*net.IPNet{mustNet("10.0.0.0/8")},
			PeerExcept: []*net.IPNet{mustNet("10.99.0.0/16")},
			Ports:      []PortMatch{{}},
		}},
	}
	got := Render(out)
	if !strings.Contains(got, "ip saddr { 10.0.0.0/8 }") {
		t.Fatalf("expected ipBlock cidr:\n%s", got)
	}
	if !strings.Contains(got, "ip saddr != { 10.99.0.0/16 }") {
		t.Fatalf("expected ipBlock except:\n%s", got)
	}
}

// TestRender_AllowAllPeers — empty PeerCIDRs/PeerExcept means "any peer";
// the rule should emit an unconditional accept (modulo port).
func TestRender_AllowAllPeers(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:    []net.IP{mustIP("2001:db8::1")},
			Direction: DirIngress, Action: ActionAccept,
			Ports: []PortMatch{{Protocol: "tcp", Port: 443}},
		}},
	}
	got := Render(out)
	if !strings.Contains(got, "tcp dport 443 accept") {
		t.Fatalf("expected unconditional tcp/443 allow:\n%s", got)
	}
	// Should NOT have a saddr/daddr filter (empty peers).
	if strings.Contains(got, "ip6 saddr {") || strings.Contains(got, "ip saddr {") {
		t.Fatalf("expected no peer filter:\n%s", got)
	}
}

// TestRender_Determinism — same input → byte-identical output.
func TestRender_Determinism(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirIngress}: {},
			{PodKey: "ns/db", Direction: DirEgress}:   {},
		},
		Rules: []Rule{
			{PodKey: "ns/web", HostIface: "f1", PodIPs: []net.IP{mustIP("2001:db8::1")},
				Direction: DirIngress, Action: ActionAccept,
				PeerCIDRs: []*net.IPNet{mustNet("2001:db8::5/128"), mustNet("2001:db8::3/128")},
				Ports:     []PortMatch{{Protocol: "tcp", Port: 80}}},
			{PodKey: "ns/db", HostIface: "f2", PodIPs: []net.IP{mustIP("2001:db8::2")},
				Direction: DirEgress, Action: ActionAccept,
				PeerCIDRs: []*net.IPNet{mustNet("2001:db8::aa/128")},
				Ports:     []PortMatch{{}}},
		},
	}
	a := Render(out)
	b := Render(out)
	if a != b {
		t.Fatalf("Render not deterministic:\nA=\n%s\nB=\n%s", a, b)
	}
	// And peers in the rule must be sorted (we deliberately gave 5 then 3).
	if strings.Index(a, "2001:db8::3/128") > strings.Index(a, "2001:db8::5/128") {
		t.Fatalf("peer CIDRs not sorted within rule:\n%s", a)
	}
}

// TestRender_EgressDirection — egress rules use iifname + saddr (pod-side).
func TestRender_EgressDirection(t *testing.T) {
	out := Output{
		Isolated: map[Isolation]struct{}{
			{PodKey: "ns/web", Direction: DirEgress}: {},
		},
		Rules: []Rule{{
			PodKey: "ns/web", HostIface: "f1",
			PodIPs:    []net.IP{mustIP("2001:db8::1")},
			Direction: DirEgress, Action: ActionAccept,
			PeerCIDRs: []*net.IPNet{mustNet("2001:db8::aa/128")},
			Ports:     []PortMatch{{Protocol: "tcp", Port: 53}},
		}},
	}
	got := Render(out)
	// Base-chain jump for egress matches iifname only.
	if !strings.Contains(got, `iifname "f1" jump pod_`) {
		t.Fatalf("missing egress base-chain jump:\n%s", got)
	}
	// Peer filter for egress matches the *destination* (the peer is downstream).
	if !strings.Contains(got, "ip6 daddr { 2001:db8::aa/128 }") {
		t.Fatalf("expected daddr peer filter for egress:\n%s", got)
	}
}

func mustNet(s string) *net.IPNet {
	_, n, err := net.ParseCIDR(s)
	if err != nil {
		panic(err)
	}
	return n
}