//go:build e2e

package harness

import (
	"os"
	"path/filepath"
	"slices"
	"testing"
)

// stubResolvConf is the /etc/resolv.conf an Ubuntu cloud-image guest serves
// verbatim: a symlink to systemd-resolved's stub, advertising the loopback
// forwarder rather than the nameserver DHCP leased.
const stubResolvConf = `# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.

nameserver 127.0.0.53
options edns0 trust-ad
search .
`

func TestResolvConfNameservers(t *testing.T) {
	cases := []struct {
		name string
		conf string
		want []string
	}{
		{
			// The stub hides the leased nameserver behind 127.0.0.53, which is why
			// GuestResolvers has to follow it to the uplink file.
			name: "systemd-resolved stub yields only the loopback forwarder",
			conf: stubResolvConf,
			want: []string{"127.0.0.53"},
		},
		{
			name: "uplink view yields the leased VPC resolver",
			conf: "# This is /run/systemd/resolve/resolv.conf managed by man:systemd-resolved(8).\nnameserver 169.254.169.253\nsearch ap-southeast-2.compute.internal\n",
			want: []string{"169.254.169.253"},
		},
		{
			name: "image whose DHCP client writes resolv.conf directly",
			conf: "search compute.internal\nnameserver 169.254.169.253\n",
			want: []string{"169.254.169.253"},
		},
		{
			name: "multiple nameservers retain lease order",
			conf: "nameserver 10.0.0.2\nnameserver 169.254.169.253\n",
			want: []string{"10.0.0.2", "169.254.169.253"},
		},
		{
			// A commented-out nameserver is not in effect and must not be reported.
			name: "comments and malformed lines are ignored",
			conf: "#nameserver 169.254.169.253\n# nameserver 169.254.169.253\nnameserver\noptions edns0\n\n",
			want: nil,
		},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := resolvConfNameservers(tc.conf)
			if !slices.Equal(got, tc.want) {
				t.Fatalf("resolvConfNameservers = %v, want %v", got, tc.want)
			}
		})
	}
}

func TestNorthstarBaseDomain(t *testing.T) {
	cases := []struct {
		name string
		toml string
		want string
	}{
		{
			// The shape `spx admin init` writes: the domain rides the local node's
			// northstar sub-table alongside config_path.
			name: "resolves the local node's northstar default_domain",
			toml: `node = "dev1"
[nodes.dev1]
host = "192.168.1.20"
[nodes.dev1.northstar]
config_path = "/etc/spinifex/northstar/northstar.toml"
default_domain = "spx3.net"
internal_domain = "compute.internal"
`,
			want: "spx3.net",
		},
		{
			name: "prefers the local node over co-tenant stanzas",
			toml: `node = "n2"
[nodes.n1.northstar]
default_domain = "wrong.example"
[nodes.n2.northstar]
default_domain = "right.example"
`,
			want: "right.example",
		},
		{
			// The zone is cluster-wide, so any node carrying it answers when the
			// local stanza is absent or domainless.
			name: "falls back to a peer node when the local stanza has no domain",
			toml: `node = "n1"
[nodes.n1]
host = "10.0.0.1"
[nodes.n2.northstar]
default_domain = "peer.example"
`,
			want: "peer.example",
		},
		{
			name: "empty when northstar is not configured",
			toml: `node = "dev1"
[nodes.dev1]
host = "192.168.1.20"
`,
			want: "",
		},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			dir := t.TempDir()
			if err := os.WriteFile(filepath.Join(dir, "spinifex.toml"), []byte(tc.toml), 0o600); err != nil {
				t.Fatalf("write toml: %v", err)
			}
			if got := NorthstarBaseDomain(&Env{ConfigDir: dir}); got != tc.want {
				t.Fatalf("NorthstarBaseDomain = %q, want %q", got, tc.want)
			}
		})
	}
}

func TestNorthstarInternalDomain(t *testing.T) {
	dir := t.TempDir()
	config := `node = "dev1"
[nodes.dev1.northstar]
internal_domain = "compute.internal"
`
	if err := os.WriteFile(filepath.Join(dir, "spinifex.toml"), []byte(config), 0o600); err != nil {
		t.Fatalf("write toml: %v", err)
	}
	if got := NorthstarInternalDomain(&Env{ConfigDir: dir}); got != "compute.internal" {
		t.Fatalf("NorthstarInternalDomain = %q, want %q", got, "compute.internal")
	}
}

func TestRequireDNSEnabled(t *testing.T) {
	dir := t.TempDir()
	config := `[nodes.dev1.northstar]
default_domain = "spx3.net"
`
	if err := os.WriteFile(filepath.Join(dir, "spinifex.toml"), []byte(config), 0o600); err != nil {
		t.Fatalf("write toml: %v", err)
	}
	if got := RequireDNSEnabled(t, &Env{ConfigDir: dir}); got != "spx3.net" {
		t.Fatalf("RequireDNSEnabled = %q, want %q", got, "spx3.net")
	}
}

func TestNorthstarDomainsMissing(t *testing.T) {
	for _, tc := range []struct {
		name string
		env  *Env
	}{
		{name: "nil environment"},
		{name: "no config directory", env: &Env{}},
		{name: "missing config file", env: &Env{ConfigDir: t.TempDir()}},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if got := NorthstarBaseDomain(tc.env); got != "" {
				t.Fatalf("NorthstarBaseDomain = %q, want empty", got)
			}
			if got := NorthstarInternalDomain(tc.env); got != "" {
				t.Fatalf("NorthstarInternalDomain = %q, want empty", got)
			}
		})
	}
}