package vpn

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// Real output of `wg show all dump`, from the two machines here: gate, where devices dial in,
// and hamtv, which dials out through Mullvad. Keys are the real public ones, which are public.
const gateDump = "wg0\tPRIVATEKEYWOULDBEHERE=\t4VwqgzHyelmVmNY+EANRWQggSSxvYYguJQMvUty9Sns=\t51820\toff\n" +
	"wg0\tNeWxo9wfqgipBQLuP676WFcMlW5RDrOcanc9y8sT7kU=\t3KWsu0mdVb2l5B/j0qHE03yE9LXi3FJ1WAjWMuxaLAw=\t10.0.0.33:63573\t172.21.46.3/32\t1790565744\t134192164\t415977404\toff\n" +
	"wg0\twUnRD990c6aglU0TCREtmfuUTPzqSmHrd3qTORpRJBg=\t4Pd5u2t6U9EdHlFlneg+hMr0G2v+IvoE/EqGfFdDPI8=\t(none)\t172.21.46.2/32\t0\t0\t0\toff\n"

const hamtvDump = "wg0\tPRIVATEKEYWOULDBEHERE=\tF/rgcHi+ZiaWPoSQ9iPcldIUbbMotE1hwSB/74Y9Qi4=\t39281\toff\n" +
	"wg0\tzqsfGglzJPY657WMRxf/S4omG7+ZkSDIpDq+ggbc9yo=\t(none)\t23.234.72.2:51820\t0.0.0.0/0,::/0\t1790571246\t18206675520\t2687837240\t25\n"

func TestParseServerDump(t *testing.T) {
	ts := parseDump(gateDump)
	if len(ts) != 1 {
		t.Fatalf("got %d tunnels, want 1", len(ts))
	}
	w := ts[0]
	if w.Name != "wg0" || w.ListenPort != 51820 {
		t.Errorf("interface = %s:%d, want wg0:51820", w.Name, w.ListenPort)
	}
	if w.PublicKey != "4VwqgzHyelmVmNY+EANRWQggSSxvYYguJQMvUty9Sns=" {
		t.Errorf("public key = %q; the third column is the public one", w.PublicKey)
	}
	// The private key is column two of the interface line and must not appear anywhere.
	if w.PublicKey == "PRIVATEKEYWOULDBEHERE=" || w.FwMark == "PRIVATEKEYWOULDBEHERE=" {
		t.Error("the private key was kept")
	}
	if len(w.Peers) != 2 {
		t.Fatalf("got %d peers, want 2", len(w.Peers))
	}
	p := w.Peers[0]
	if p.PublicKey != "NeWxo9wfqgipBQLuP676WFcMlW5RDrOcanc9y8sT7kU=" || p.Endpoint != "10.0.0.33:63573" {
		t.Errorf("first peer = %+v", p)
	}
	if !p.PSK {
		t.Error("first peer has a pre-shared key and should say so")
	}
	if got := p.AllowedIPs; len(got) != 1 || got[0] != "172.21.46.3/32" {
		t.Errorf("allowed ips = %v", got)
	}
	if p.Rx != 134192164 || p.Tx != 415977404 {
		t.Errorf("counters = %d/%d", p.Rx, p.Tx)
	}
	if p.Handshake == nil || p.Handshake.Unix() != 1790565744 {
		t.Errorf("handshake = %v", p.Handshake)
	}
	// The second peer has never connected: no endpoint, no handshake, nothing moved.
	if q := w.Peers[1]; q.Endpoint != "" || q.Handshake != nil || q.Rx != 0 {
		t.Errorf("second peer = %+v, want one that has never been heard from", q)
	}
	if kind, exit := classify(w); kind != "server" || exit != "" {
		t.Errorf("classify = %q/%q, want server", kind, exit)
	}
}

func TestParseClientDump(t *testing.T) {
	ts := parseDump(hamtvDump)
	if len(ts) != 1 || len(ts[0].Peers) != 1 {
		t.Fatalf("got %d tunnels", len(ts))
	}
	w := ts[0]
	p := w.Peers[0]
	if len(p.AllowedIPs) != 2 || p.AllowedIPs[0] != "0.0.0.0/0" {
		t.Errorf("allowed ips = %v, want everything", p.AllowedIPs)
	}
	if p.Keepalive != 25 {
		t.Errorf("keepalive = %d, want 25", p.Keepalive)
	}
	if p.PSK {
		t.Error("this peer has no pre-shared key")
	}
	// It routes everything and has an endpoint, so this machine goes out through it.
	kind, exit := classify(w)
	if kind != "client" || exit != "23.234.72.2:51820" {
		t.Errorf("classify = %q/%q, want client through the endpoint", kind, exit)
	}
}

// A tunnel that is up but has no peers at all is neither, and must not be guessed at.
func TestClassifyUndecided(t *testing.T) {
	if kind, _ := classify(Tunnel{Name: "wg0", ListenPort: 51820}); kind != "" {
		t.Errorf("classify with no peers = %q, want no opinion", kind)
	}
}

// Peers are named by the comment above them in a wg-quick file. The public key's own base64
// padding is an '=' too, which is the thing to get wrong.
func TestConfNames(t *testing.T) {
	dir := t.TempDir()
	conf := `[Interface]
Address = 172.21.46.1/24
PrivateKey = SECRETSECRETSECRETSECRETSECRETSECRETSECRET=
ListenPort = 51820

# phone
[Peer]
PublicKey = NeWxo9wfqgipBQLuP676WFcMlW5RDrOcanc9y8sT7kU=
AllowedIPs = 172.21.46.3/32

# the laptop
[Peer]
PublicKey = wUnRD990c6aglU0TCREtmfuUTPzqSmHrd3qTORpRJBg=
AllowedIPs = 172.21.46.2/32
`
	if err := os.WriteFile(filepath.Join(dir, "wg0.conf"), []byte(conf), 0o600); err != nil {
		t.Fatal(err)
	}
	old := confDir
	confDir = dir
	defer func() { confDir = old }()

	names := confNames()
	if got := names["NeWxo9wfqgipBQLuP676WFcMlW5RDrOcanc9y8sT7kU="]; got != "phone" {
		t.Errorf("first peer named %q, want phone", got)
	}
	if got := names["wUnRD990c6aglU0TCREtmfuUTPzqSmHrd3qTORpRJBg="]; got != "the laptop" {
		t.Errorf("second peer named %q, want the laptop", got)
	}
	for k := range names {
		if k == "SECRETSECRETSECRETSECRETSECRETSECRETSECRET=" {
			t.Error("the private key was read as if it were a peer")
		}
	}
	if len(names) != 2 {
		t.Errorf("%d names, want 2: %v", len(names), names)
	}
}

func TestOnlineIsRecentHandshake(t *testing.T) {
	for _, tc := range []struct {
		name string
		hs   time.Time
		want bool
	}{
		{"just now", time.Now().Add(-30 * time.Second), true},
		{"a while back", time.Now().Add(-10 * time.Minute), false},
		{"never", time.Time{}, false},
	} {
		got := !tc.hs.IsZero() && time.Since(tc.hs) < onlineWithin
		if got != tc.want {
			t.Errorf("%s: online = %v, want %v", tc.name, got, tc.want)
		}
	}
}

// A peer that has never handshaken must carry no time at all, not the zero one. omitempty
// does nothing for a time.Time, so this is the difference between the page saying "never
// connected" and saying the device was last seen in the year one.
func TestNeverConnectedHasNoTimestamp(t *testing.T) {
	w := parseDump(gateDump)[0]
	b, err := json.Marshal(w.Peers[1])
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(string(b), "handshake") {
		t.Errorf("json = %s, want no handshake field at all", b)
	}
	if strings.Contains(string(b), "0001-01-01") {
		t.Errorf("json = %s, want no year-one timestamp", b)
	}
	// and the one that has connected still carries its time
	if b, _ := json.Marshal(w.Peers[0]); !strings.Contains(string(b), "handshake") {
		t.Errorf("json = %s, want the handshake of a peer that has one", b)
	}
}