package bird

import (
	"strings"
	"testing"
)

func TestRender_Host001(t *testing.T) {
	out, err := Render(NodeBGP{
		NodeName: "host001",
		RouterID: "172.25.25.101",
		LocalASN: 65101,
		Peers: []Peer{
			{Family: "v6", Address: "2602:817:3000:a25::1", ASN: 65000},
			{Family: "v4", Address: "172.25.25.1", ASN: 65000},
		},
		CIDR6: []string{"2602:817:3000:f001::/64"},
		CIDR4: []string{"172.25.210.0/24"},
	})
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{
		"router id 172.25.25.101",
		"local as 65101;",
		"neighbor 2602:817:3000:a25::1 as 65000;",
		"neighbor 172.25.25.1 as 65000;",
		"if net = 2602:817:3000:f001::/64 then accept;",
		"if net = 172.25.210.0/24 then accept;",
		"graceful restart;",
	} {
		if !strings.Contains(out, want) {
			t.Errorf("missing %q in output:\n%s", want, out)
		}
	}
}

func TestRender_AnycastInjection(t *testing.T) {
	out, err := Render(NodeBGP{
		RouterID: "10.0.0.1",
		LocalASN: 65101,
		Peers:    []Peer{{Family: "v6", Address: "2001:db8::1", ASN: 65000}},
		CIDR6:    []string{"2001:db8:f001::/64"},
		Anycast6: []string{"2001:db8:a::1"},
	})
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(out, "if net = 2001:db8:a::1/128 then accept;") {
		t.Fatalf("anycast /128 not advertised:\n%s", out)
	}
}

func TestRender_StableOutput(t *testing.T) {
	in := NodeBGP{
		RouterID: "10.0.0.1",
		LocalASN: 65101,
		Peers: []Peer{
			{Family: "v4", Address: "10.0.0.2", ASN: 65000},
			{Family: "v6", Address: "2001:db8::1", ASN: 65000},
		},
		CIDR6: []string{"2001:db8:f002::/64", "2001:db8:f001::/64"},
		CIDR4: []string{"10.1.1.0/24", "10.0.1.0/24"},
	}
	a, _ := Render(in)
	b, _ := Render(in)
	if a != b {
		t.Fatalf("render not deterministic")
	}
	// Sorted ordering of CIDR6.
	i1 := strings.Index(a, "2001:db8:f001::/64")
	i2 := strings.Index(a, "2001:db8:f002::/64")
	if !(i1 < i2) {
		t.Fatalf("CIDR6 not sorted")
	}
}

func TestRender_LocalSubnetImportFilter(t *testing.T) {
	out, err := Render(NodeBGP{
		RouterID:      "172.25.25.104",
		LocalASN:      65104,
		Peers:         []Peer{{Family: "v6", Address: "2602:817:3000:a25::1", ASN: 65000}, {Family: "v4", Address: "172.25.25.1", ASN: 65000}},
		CIDR6:         []string{"2602:817:3000:f004::/64"},
		CIDR4:         []string{"172.25.214.0/24"},
		LocalSubnetV6: "2602:817:3000:a25::/64",
		LocalSubnetV4: "172.25.25.0/24",
	})
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{
		"import where net != 2602:817:3000:a25::/64;",
		"import where net != 172.25.25.0/24;",
	} {
		if !strings.Contains(out, want) {
			t.Errorf("missing %q in output:\n%s", want, out)
		}
	}
	// Each BGP peer block should use the import filter, not import all.
	// Slice out just the `protocol bgp ...` stanzas to avoid catching the
	// kernel proto's legitimate `import all;`.
	for _, marker := range []string{"protocol bgp upstream6_", "protocol bgp upstream4_"} {
		idx := strings.Index(out, marker)
		if idx < 0 {
			continue
		}
		end := strings.Index(out[idx:], "\n}")
		if end < 0 {
			continue
		}
		stanza := out[idx : idx+end]
		if strings.Contains(stanza, "import all;") {
			t.Errorf("BGP stanza still has `import all;`:\n%s", stanza)
		}
	}
}

func TestRender_LocalSubnetEmpty_FallsBackToImportAll(t *testing.T) {
	out, err := Render(NodeBGP{
		RouterID: "10.0.0.1",
		LocalASN: 65101,
		Peers:    []Peer{{Family: "v6", Address: "2001:db8::1", ASN: 65000}},
		CIDR6:    []string{"2001:db8:f001::/64"},
	})
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(out, "import all;") {
		t.Errorf("expected `import all;` when LocalSubnetV6 unset:\n%s", out)
	}
}

func TestRender_LocalSubnetValidation(t *testing.T) {
	cases := []struct {
		name    string
		v6, v4  string
		wantErr string
	}{
		{name: "non-canonical v6", v6: "2602:817:3000:a25::1/64", wantErr: "non-zero host bits"},
		{name: "non-canonical v4", v4: "172.25.25.1/24", wantErr: "non-zero host bits"},
		{name: "v6 family mismatch", v6: "172.25.25.0/24", wantErr: "is IPv4"},
		{name: "v4 family mismatch", v4: "2602:817:3000:a25::/64", wantErr: "is IPv6"},
		{name: "garbage", v6: "not-a-cidr", wantErr: "not a valid CIDR"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			_, err := Render(NodeBGP{
				RouterID:      "10.0.0.1",
				LocalASN:      65101,
				Peers:         []Peer{{Family: "v6", Address: "2001:db8::1", ASN: 65000}},
				LocalSubnetV6: tc.v6,
				LocalSubnetV4: tc.v4,
			})
			if err == nil || !strings.Contains(err.Error(), tc.wantErr) {
				t.Fatalf("want error containing %q, got %v", tc.wantErr, err)
			}
		})
	}
}

func TestFamilyOf(t *testing.T) {
	if FamilyOf("2001:db8::1") != "v6" {
		t.Fatal("v6 detection broken")
	}
	if FamilyOf("10.0.0.1") != "v4" {
		t.Fatal("v4 detection broken")
	}
	if FamilyOf("not-an-ip") != "" {
		t.Fatal("garbage should return empty")
	}
}