package dnsmasq

import (
	"fmt"
	"strings"
	"testing"

	"github.com/wild-cloud/wild-central/internal/config"
)

func instanceWith(domain, internalDomain, lbIP string) config.InstanceConfig {
	var inst config.InstanceConfig
	inst.Cluster.Name = "test"
	inst.Cloud.Domain = domain
	inst.Cloud.InternalDomain = internalDomain
	inst.Cluster.LoadBalancerIp = lbIP
	return inst
}

// Test: instanceLoadBalancerIP prefers cluster.loadBalancerIp
func TestInstanceLoadBalancerIP_ClusterField(t *testing.T) {
	inst := instanceWith("cloud.example.com", "internal.example.com", "10.0.0.5")
	if got := instanceLoadBalancerIP(inst); got != "10.0.0.5" {
		t.Errorf("got %q, want %q", got, "10.0.0.5")
	}
}

// Test: instanceLoadBalancerIP falls back to apps.metallb.loadBalancerIp
func TestInstanceLoadBalancerIP_MetalLBFallback(t *testing.T) {
	var inst config.InstanceConfig
	inst.Apps = map[string]any{
		"metallb": map[string]any{
			"loadBalancerIp": "10.0.0.9",
		},
	}
	if got := instanceLoadBalancerIP(inst); got != "10.0.0.9" {
		t.Errorf("got %q, want %q", got, "10.0.0.9")
	}
}

// Test: instanceLoadBalancerIP returns empty string when nothing is set
func TestInstanceLoadBalancerIP_Empty(t *testing.T) {
	var inst config.InstanceConfig
	if got := instanceLoadBalancerIP(inst); got != "" {
		t.Errorf("got %q, want empty string", got)
	}
}

// Test: cluster.loadBalancerIp takes precedence over metallb
func TestInstanceLoadBalancerIP_ClusterTakesPrecedence(t *testing.T) {
	inst := instanceWith("cloud.example.com", "internal.example.com", "10.0.0.5")
	inst.Apps = map[string]any{
		"metallb": map[string]any{
			"loadBalancerIp": "10.0.0.9",
		},
	}
	if got := instanceLoadBalancerIP(inst); got != "10.0.0.5" {
		t.Errorf("got %q, want cluster IP %q", got, "10.0.0.5")
	}
}

// Test: GenerateInstanceConfig with load balancer IP produces active DNS entries
func TestGenerateInstanceConfig_WithLBIP(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("cloud.example.com", "internal.example.com", "192.168.1.10")

	out := g.GenerateInstanceConfig(inst)

	if !strings.Contains(out, "local=/internal.example.com/") {
		t.Errorf("expected local=/ directive for internal domain, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/internal.example.com/192.168.1.10") {
		t.Errorf("expected address entry for internal domain, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/cloud.example.com/192.168.1.10") {
		t.Errorf("expected address entry for external domain, got:\n%s", out)
	}
	if strings.Contains(out, "WARNING") {
		t.Errorf("unexpected WARNING in output:\n%s", out)
	}
}

// Test: GenerateInstanceConfig without load balancer IP produces commented entries
func TestGenerateInstanceConfig_NoLBIP(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("cloud.example.com", "internal.example.com", "")

	out := g.GenerateInstanceConfig(inst)

	if !strings.Contains(out, "WARNING") {
		t.Errorf("expected WARNING in output when no LB IP, got:\n%s", out)
	}
	if !strings.Contains(out, "# local=/internal.example.com/") {
		t.Errorf("expected commented local=/ directive, got:\n%s", out)
	}
	if !strings.Contains(out, "# address=/internal.example.com/<load-balancer-ip>") {
		t.Errorf("expected commented address entry for internal domain, got:\n%s", out)
	}
	if !strings.Contains(out, "# address=/cloud.example.com/<load-balancer-ip>") {
		t.Errorf("expected commented address entry for external domain, got:\n%s", out)
	}
	if strings.Contains(out, "\nlocal=/") {
		t.Errorf("unexpected active local=/ directive when no LB IP, got:\n%s", out)
	}
}

// Test: GenerateInstanceConfig includes instance name in header comment
func TestGenerateInstanceConfig_IncludesInstanceName(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("cloud.example.com", "internal.example.com", "192.168.1.10")
	inst.Cluster.Name = "my-instance"

	out := g.GenerateInstanceConfig(inst)

	if !strings.Contains(out, "my-instance") {
		t.Errorf("expected instance name in config header, got:\n%s", out)
	}
}

// Test: Generate (monolithic) with instances produces expected DNS entries
func TestGenerate_WithInstances(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("cloud.example.com", "internal.example.com", "192.168.1.10")

	out := g.Generate(nil, []config.InstanceConfig{inst})

	if !strings.Contains(out, "local=/internal.example.com/") {
		t.Errorf("expected local=/ for internal domain, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/internal.example.com/192.168.1.10") {
		t.Errorf("expected address entry for internal domain, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/cloud.example.com/192.168.1.10") {
		t.Errorf("expected address entry for external domain, got:\n%s", out)
	}
	if !strings.Contains(out, "server=1.1.1.1") {
		t.Errorf("expected upstream DNS server, got:\n%s", out)
	}
}

// Test: Generate with no instances still produces valid config skeleton
func TestGenerate_NoInstances(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")

	out := g.Generate(nil, []config.InstanceConfig{})

	if !strings.Contains(out, "bind-interfaces") {
		t.Errorf("expected bind-interfaces in config, got:\n%s", out)
	}
	if !strings.Contains(out, "server=1.1.1.1") {
		t.Errorf("expected upstream DNS server, got:\n%s", out)
	}
	if !strings.Contains(out, "server=8.8.8.8") {
		t.Errorf("expected upstream DNS server 8.8.8.8, got:\n%s", out)
	}
}

// Test: Generate with instance missing LB IP produces commented entries
func TestGenerate_InstanceWithoutLBIP(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("cloud.example.com", "internal.example.com", "")
	inst.Cluster.Name = "no-lb-instance"

	out := g.Generate(nil, []config.InstanceConfig{inst})

	if !strings.Contains(out, "# No load balancer IP configured for instance no-lb-instance") {
		t.Errorf("expected comment about missing LB IP, got:\n%s", out)
	}
}

// Test: GenerateMainConfig produces conf-dir directive
func TestGenerateMainConfig(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")

	out := g.GenerateMainConfig(nil)

	if !strings.Contains(out, "conf-dir=") {
		t.Errorf("expected conf-dir directive in main config, got:\n%s", out)
	}
	if !strings.Contains(out, instanceConfigDir) {
		t.Errorf("expected instance config dir %q in conf-dir, got:\n%s", instanceConfigDir, out)
	}
	if !strings.Contains(out, "bind-interfaces") {
		t.Errorf("expected bind-interfaces in main config, got:\n%s", out)
	}
	if !strings.Contains(out, "server=1.1.1.1") {
		t.Errorf("expected upstream DNS server in main config, got:\n%s", out)
	}
}

// Test: GenerateMainConfig with DHCP disabled does not include dhcp-range
func TestGenerateMainConfig_DHCPDisabled(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = false

	out := g.GenerateMainConfig(cfg)

	if strings.Contains(out, "dhcp-range") {
		t.Errorf("expected no dhcp-range when DHCP disabled, got:\n%s", out)
	}
}

// Test: GenerateMainConfig with DHCP enabled includes dhcp-range
func TestGenerateMainConfig_DHCPEnabled(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = true
	cfg.Cloud.Dnsmasq.DHCP.RangeStart = "192.168.8.100"
	cfg.Cloud.Dnsmasq.DHCP.RangeEnd = "192.168.8.200"
	cfg.Cloud.Dnsmasq.DHCP.LeaseTime = "12h"
	cfg.Cloud.Router.IP = "192.168.8.1"

	out := g.GenerateMainConfig(cfg)

	if !strings.Contains(out, "dhcp-range=192.168.8.100,192.168.8.200,12h") {
		t.Errorf("expected dhcp-range directive, got:\n%s", out)
	}
	if !strings.Contains(out, "dhcp-option=3,192.168.8.1") {
		t.Errorf("expected gateway dhcp-option=3, got:\n%s", out)
	}
}

// Test: DHCP gateway falls back to router IP when not set
func TestGenerateMainConfig_DHCPGatewayFallback(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = true
	cfg.Cloud.Dnsmasq.DHCP.RangeStart = "192.168.8.100"
	cfg.Cloud.Dnsmasq.DHCP.RangeEnd = "192.168.8.200"
	cfg.Cloud.Router.IP = "192.168.8.1"
	// Gateway not set — should fall back to router IP

	out := g.GenerateMainConfig(cfg)

	if !strings.Contains(out, "dhcp-option=3,192.168.8.1") {
		t.Errorf("expected router IP as fallback gateway, got:\n%s", out)
	}
}

// Test: DHCP explicit gateway takes precedence over router IP
func TestGenerateMainConfig_DHCPExplicitGateway(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = true
	cfg.Cloud.Dnsmasq.DHCP.RangeStart = "192.168.8.100"
	cfg.Cloud.Dnsmasq.DHCP.RangeEnd = "192.168.8.200"
	cfg.Cloud.Dnsmasq.DHCP.Gateway = "192.168.8.254"
	cfg.Cloud.Router.IP = "192.168.8.1"

	out := g.GenerateMainConfig(cfg)

	if !strings.Contains(out, "dhcp-option=3,192.168.8.254") {
		t.Errorf("expected explicit gateway in dhcp-option=3, got:\n%s", out)
	}
	if strings.Contains(out, "dhcp-option=3,192.168.8.1") {
		t.Errorf("router IP should not appear as gateway when explicit gateway set, got:\n%s", out)
	}
}

// Test: DHCP static leases appear in output
func TestGenerateMainConfig_DHCPStaticLeases(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = true
	cfg.Cloud.Dnsmasq.DHCP.RangeStart = "192.168.8.100"
	cfg.Cloud.Dnsmasq.DHCP.RangeEnd = "192.168.8.200"
	cfg.Cloud.Dnsmasq.DHCP.StaticLeases = []config.DHCPStaticLease{
		{MAC: "aa:bb:cc:dd:ee:01", IP: "192.168.8.10", Hostname: "node1"},
		{MAC: "aa:bb:cc:dd:ee:02", IP: "192.168.8.11"},
	}

	out := g.GenerateMainConfig(cfg)

	if !strings.Contains(out, "dhcp-host=aa:bb:cc:dd:ee:01,192.168.8.10,node1") {
		t.Errorf("expected static lease with hostname, got:\n%s", out)
	}
	if !strings.Contains(out, "dhcp-host=aa:bb:cc:dd:ee:02,192.168.8.11") {
		t.Errorf("expected static lease without hostname, got:\n%s", out)
	}
}

// Test: DHCP lease time defaults to 24h when not specified
func TestGenerateMainConfig_DHCPLeaseTimeDefault(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.DHCP.Enabled = true
	cfg.Cloud.Dnsmasq.DHCP.RangeStart = "192.168.8.100"
	cfg.Cloud.Dnsmasq.DHCP.RangeEnd = "192.168.8.200"
	// LeaseTime not set

	out := g.GenerateMainConfig(cfg)

	if !strings.Contains(out, "dhcp-range=192.168.8.100,192.168.8.200,24h") {
		t.Errorf("expected default lease time of 24h, got:\n%s", out)
	}
}

// Test: NewConfigGenerator uses provided path
func TestNewConfigGenerator_CustomPath(t *testing.T) {
	g := NewConfigGenerator("/custom/path/dnsmasq.conf")
	if g.GetConfigPath() != "/custom/path/dnsmasq.conf" {
		t.Errorf("got %q, want /custom/path/dnsmasq.conf", g.GetConfigPath())
	}
}

// Test: NewConfigGenerator uses default path when empty
func TestNewConfigGenerator_DefaultPath(t *testing.T) {
	g := NewConfigGenerator("")
	if g.GetConfigPath() != "/etc/dnsmasq.d/wild-cloud.conf" {
		t.Errorf("got %q, want /etc/dnsmasq.d/wild-cloud.conf", g.GetConfigPath())
	}
}

// Test: Service registration — domain set but no internal domain
func TestGenerate_ServiceWithoutInternalDomain(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	// Service registration: only domain + backend IP, no internal domain
	inst := instanceWith("my-api.payne.io", "", "192.168.8.151")
	out := g.Generate(globalCfg, []config.InstanceConfig{inst})

	// Should have address entry for the domain
	if !strings.Contains(out, "address=/my-api.payne.io/192.168.8.151") {
		t.Errorf("expected address entry for service domain, got:\n%s", out)
	}
	// Must NOT have empty local=// entry
	if strings.Contains(out, "local=//") {
		t.Errorf("unexpected empty local=// in output:\n%s", out)
	}
	// Must NOT have empty address=// entry
	if strings.Contains(out, "address=//") {
		t.Errorf("unexpected empty address=// in output:\n%s", out)
	}
}

// Test: GenerateInstanceConfig — service without internal domain
func TestGenerateInstanceConfig_ServiceWithoutInternalDomain(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	inst := instanceWith("central.payne.io", "", "192.168.8.151")

	out := g.GenerateInstanceConfig(inst)

	if !strings.Contains(out, "address=/central.payne.io/192.168.8.151") {
		t.Errorf("expected address entry, got:\n%s", out)
	}
	if strings.Contains(out, "local=//") {
		t.Errorf("unexpected empty local=// in output:\n%s", out)
	}
	if strings.Contains(out, "address=//") {
		t.Errorf("unexpected empty address=// in output:\n%s", out)
	}
}

// Test: reach:internal → local=/ directive present (prevents upstream DNS forwarding)
func TestGenerate_ReachInternal_HasLocal(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	// Simulate reconciliation for an internal-reach service:
	// InternalDomain is set (reach:internal), Domain is empty (reach:public)
	inst := instanceWith("", "my-api.payne.io", "192.168.8.151")

	out := g.Generate(globalCfg, []config.InstanceConfig{inst})

	if !strings.Contains(out, "local=/my-api.payne.io/") {
		t.Errorf("reach:internal must produce local=/ directive, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/my-api.payne.io/192.168.8.151") {
		t.Errorf("reach:internal must produce address entry, got:\n%s", out)
	}
}

// Test: reach:public → no local=/ directive (allows upstream DNS forwarding)
func TestGenerate_ReachPublic_NoLocal(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	// Simulate reconciliation for a public-reach service:
	// Domain is set (reach:public), InternalDomain is empty
	inst := instanceWith("cloud.payne.io", "", "192.168.8.240")

	out := g.Generate(globalCfg, []config.InstanceConfig{inst})

	if !strings.Contains(out, "address=/cloud.payne.io/192.168.8.240") {
		t.Errorf("reach:public must produce address entry, got:\n%s", out)
	}
	if strings.Contains(out, "local=/cloud.payne.io/") {
		t.Errorf("reach:public must NOT produce local=/ directive, got:\n%s", out)
	}
}

// Test: InternalDomain field → local=/ entry for LAN-only resolution
func TestGenerate_InternalDomainOnly_HasLocal(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	// Instance with only an internal domain (no external domain)
	inst := instanceWith("", "internal.cloud.payne.io", "192.168.8.240")

	out := g.Generate(globalCfg, []config.InstanceConfig{inst})

	if !strings.Contains(out, "local=/internal.cloud.payne.io/") {
		t.Errorf("InternalDomain must produce local=/ entry, got:\n%s", out)
	}
	if !strings.Contains(out, "address=/internal.cloud.payne.io/192.168.8.240") {
		t.Errorf("InternalDomain must produce address entry, got:\n%s", out)
	}
	// No external domain → no address for empty domain
	if strings.Contains(out, "address=//") {
		t.Errorf("no external domain must not produce empty address=// entry, got:\n%s", out)
	}
}

// Test: Mix of instances with and without internal domains
func TestGenerate_MixedServicesAndInstances(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	instances := []config.InstanceConfig{
		instanceWith("cloud.payne.io", "internal.cloud.payne.io", "192.168.8.240"),  // k8s instance
		instanceWith("central.payne.io", "", "192.168.8.151"),                        // service (no internal domain)
		instanceWith("wild-cloud.payne.io", "", "192.168.8.151"),                     // service (no internal domain)
	}

	out := g.Generate(globalCfg, instances)

	// k8s instance should have both local= and address= for internal domain
	if !strings.Contains(out, "local=/internal.cloud.payne.io/") {
		t.Errorf("expected local=/ for k8s internal domain, got:\n%s", out)
	}
	// Services should have address= entries
	if !strings.Contains(out, "address=/central.payne.io/192.168.8.151") {
		t.Errorf("expected address for central, got:\n%s", out)
	}
	// No broken empty entries
	if strings.Contains(out, "local=//") {
		t.Errorf("unexpected empty local=// in output:\n%s", out)
	}
}

// Test: empty instances list produces base config with no address= entries
func TestGenerate_EmptyInstances(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	out := g.Generate(globalCfg, []config.InstanceConfig{})

	// Should have base config skeleton
	if !strings.Contains(out, "bind-interfaces") {
		t.Errorf("expected bind-interfaces in config, got:\n%s", out)
	}
	if !strings.Contains(out, "server=1.1.1.1") {
		t.Errorf("expected upstream DNS server, got:\n%s", out)
	}
	// Should not have any address= entries
	if strings.Contains(out, "address=/") {
		t.Errorf("expected no address= entries with empty instances, got:\n%s", out)
	}
	// Should not have any local=/ entries
	if strings.Contains(out, "local=/") {
		t.Errorf("expected no local=/ entries with empty instances, got:\n%s", out)
	}
}

// Test: multiple instances each get their own entries
func TestGenerate_MultipleInstances(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	globalCfg := &config.GlobalConfig{}

	instances := []config.InstanceConfig{
		instanceWith("cloud1.example.com", "internal1.example.com", "10.0.0.1"),
		instanceWith("cloud2.example.com", "internal2.example.com", "10.0.0.2"),
		instanceWith("cloud3.example.com", "internal3.example.com", "10.0.0.3"),
	}

	out := g.Generate(globalCfg, instances)

	for i, inst := range instances {
		ip := []string{"10.0.0.1", "10.0.0.2", "10.0.0.3"}[i]
		if !strings.Contains(out, fmt.Sprintf("address=/%s/%s", inst.Cloud.Domain, ip)) {
			t.Errorf("expected address entry for %s, got:\n%s", inst.Cloud.Domain, out)
		}
		if !strings.Contains(out, fmt.Sprintf("address=/%s/%s", inst.Cloud.InternalDomain, ip)) {
			t.Errorf("expected address entry for %s, got:\n%s", inst.Cloud.InternalDomain, out)
		}
		if !strings.Contains(out, fmt.Sprintf("local=/%s/", inst.Cloud.InternalDomain)) {
			t.Errorf("expected local=/ entry for %s, got:\n%s", inst.Cloud.InternalDomain, out)
		}
	}
}

// Test: nil config doesn't panic, uses auto-detect for IP
func TestGenerate_NilConfig(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")

	// Should not panic with nil config
	out := g.Generate(nil, []config.InstanceConfig{})

	if !strings.Contains(out, "bind-interfaces") {
		t.Errorf("expected valid config with nil cfg, got:\n%s", out)
	}
	if !strings.Contains(out, "server=1.1.1.1") {
		t.Errorf("expected upstream DNS server with nil cfg, got:\n%s", out)
	}
}

// Test: when cfg.Cloud.Dnsmasq.IP is set, uses that instead of auto-detect
func TestGenerate_ConfiguredDnsmasqIP(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}
	cfg.Cloud.Dnsmasq.IP = "192.168.8.100"

	out := g.Generate(cfg, []config.InstanceConfig{})

	if !strings.Contains(out, "listen-address=192.168.8.100") {
		t.Errorf("expected configured dnsmasq IP in listen-address, got:\n%s", out)
	}
}

// Test: verify no address=// or local=// entries appear in any test output
func TestGenerate_NoLeakedEmptyEntries(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	cfg := &config.GlobalConfig{}

	cases := []struct {
		name      string
		instances []config.InstanceConfig
	}{
		{"empty", nil},
		{"domain_only", []config.InstanceConfig{instanceWith("example.com", "", "10.0.0.1")}},
		{"internal_only", []config.InstanceConfig{instanceWith("", "internal.example.com", "10.0.0.1")}},
		{"both", []config.InstanceConfig{instanceWith("example.com", "internal.example.com", "10.0.0.1")}},
		{"no_lb_ip", []config.InstanceConfig{instanceWith("example.com", "internal.example.com", "")}},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			out := g.Generate(cfg, tc.instances)
			if strings.Contains(out, "address=//") {
				t.Errorf("leaked empty address=// in output:\n%s", out)
			}
			if strings.Contains(out, "local=//") {
				t.Errorf("leaked empty local=// in output:\n%s", out)
			}
		})
	}
}

// Test: GenerateInstanceConfig with all fields empty doesn't produce broken entries
func TestGenerateInstanceConfig_EmptyFields(t *testing.T) {
	g := NewConfigGenerator("/tmp/test-dnsmasq.conf")
	var inst config.InstanceConfig
	// All fields empty: no domain, no internal domain, no LB IP

	out := g.GenerateInstanceConfig(inst)

	if strings.Contains(out, "address=//") {
		t.Errorf("empty fields produced broken address=// entry:\n%s", out)
	}
	if strings.Contains(out, "local=//") {
		t.Errorf("empty fields produced broken local=// entry:\n%s", out)
	}
	// Should still contain the header comment
	if !strings.Contains(out, "DNS configuration for instance") {
		t.Errorf("expected header comment in output, got:\n%s", out)
	}
}