package netaddr

import (
	"errors"
	"net"
	"path/filepath"
	"testing"
)

// A scheme-less address must stay unix. Every deploy in the tree writes a bare
// path, so this is the test that says the transport change costs them nothing.
func TestParseSchemelessIsUnix(t *testing.T) {
	a, err := Parse("/run/maven/stt.sock")
	if err != nil {
		t.Fatalf("parse: %v", err)
	}
	if !a.IsUnix() {
		t.Fatalf("want unix, got %q", a.Network)
	}
	if a.Address != "/run/maven/stt.sock" {
		t.Fatalf("address = %q", a.Address)
	}
	if a.Token != "" {
		t.Fatalf("unix seam carries a token: %q", a.Token)
	}
}

func TestParse(t *testing.T) {
	cases := []struct {
		in            string
		net, addr, tk string
		wantErr       bool
	}{
		{in: "", net: "unix", addr: ""},
		{in: "unix:///run/maven/core.sock", net: "unix", addr: "/run/maven/core.sock"},
		{in: "tcp://workstation:9310", net: "tcp", addr: "workstation:9310"},
		{in: "tcp://workstation:9310?token=hunter2", net: "tcp", addr: "workstation:9310", tk: "hunter2"},
		{in: "tcp://", wantErr: true},
		{in: "udp://workstation:9310", wantErr: true},
	}
	for _, c := range cases {
		a, err := Parse(c.in)
		if c.wantErr {
			if err == nil {
				t.Errorf("Parse(%q) = %v, want error", c.in, a)
			}
			continue
		}
		if err != nil {
			t.Errorf("Parse(%q): %v", c.in, err)
			continue
		}
		if a.Network != c.net || a.Address != c.addr || a.Token != c.tk {
			t.Errorf("Parse(%q) = %+v, want %s/%s/%s", c.in, a, c.net, c.addr, c.tk)
		}
	}
}

// The token must never reach a log line.
func TestStringHidesToken(t *testing.T) {
	a := MustParse("tcp://workstation:9310?token=hunter2")
	if got := a.String(); got != "tcp://workstation:9310" {
		t.Fatalf("String() = %q", got)
	}
}

// A unix seam must round-trip with no handshake in front of the payload: the
// first bytes the listener sees are the caller's, exactly as before.
func TestUnixRoundTripHasNoHandshake(t *testing.T) {
	a := MustParse(filepath.Join(t.TempDir(), "s.sock"))
	ln, err := Listen(a)
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	defer ln.Close()
	go echoOnce(ln)

	c, err := Dial(a)
	if err != nil {
		t.Fatalf("dial: %v", err)
	}
	defer c.Close()
	if got := roundTrip(t, c, "hello"); got != "hello" {
		t.Fatalf("got %q", got)
	}
}

func TestTCPRoundTripWithToken(t *testing.T) {
	ln, addr := listenLoopback(t, "s3cret")
	defer ln.Close()
	go echoOnce(ln)

	c, err := Dial(addr)
	if err != nil {
		t.Fatalf("dial: %v", err)
	}
	defer c.Close()
	if got := roundTrip(t, c, "hello"); got != "hello" {
		t.Fatalf("got %q", got)
	}
}

func TestTCPWrongTokenIsRejected(t *testing.T) {
	ln, addr := listenLoopback(t, "s3cret")
	defer ln.Close()
	// Accept keeps waiting past the bad peer, so nothing here should ever
	// reach the echo. A conn that does means the token was not checked.
	go echoOnce(ln)

	bad := addr
	bad.Token = "wrong"
	if _, err := Dial(bad); !errors.Is(err, ErrUnauthorized) {
		t.Fatalf("dial with wrong token: err = %v, want ErrUnauthorized", err)
	}
}

// A stranger that speaks the protocol instead of the greeting is dropped, and
// the listener stays up for the peer that follows it.
func TestTCPUngreetedPeerDoesNotKillTheListener(t *testing.T) {
	ln, addr := listenLoopback(t, "s3cret")
	defer ln.Close()
	go echoOnce(ln)

	raw, err := net.Dial("tcp", addr.Address)
	if err != nil {
		t.Fatalf("raw dial: %v", err)
	}
	if _, err := raw.Write([]byte("GET / HTTP/1.1\n")); err != nil {
		t.Fatalf("raw write: %v", err)
	}
	raw.Close()

	c, err := Dial(addr)
	if err != nil {
		t.Fatalf("dial after stranger: %v", err)
	}
	defer c.Close()
	if got := roundTrip(t, c, "still here"); got != "still here" {
		t.Fatalf("got %q", got)
	}
}

// A tcp seam with no token is a misconfiguration, and it must fail at bind
// rather than serve the owner's turns to anyone who connects.
func TestTCPListenRequiresToken(t *testing.T) {
	if _, err := Listen(MustParse("tcp://127.0.0.1:0")); err == nil {
		t.Fatal("listen on a tokenless tcp seam succeeded")
	}
}

func listenLoopback(t *testing.T, token string) (*Listener, Addr) {
	t.Helper()
	ln, err := Listen(Addr{Network: "tcp", Address: "127.0.0.1:0", Token: token})
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	return ln, Addr{Network: "tcp", Address: ln.Addr().String(), Token: token}
}

func echoOnce(ln *Listener) {
	c, err := ln.Accept()
	if err != nil {
		return
	}
	defer c.Close()
	buf := make([]byte, 256)
	n, err := c.Read(buf)
	if err != nil {
		return
	}
	_, _ = c.Write(buf[:n])
}

func roundTrip(t *testing.T, c net.Conn, msg string) string {
	t.Helper()
	if _, err := c.Write([]byte(msg)); err != nil {
		t.Fatalf("write: %v", err)
	}
	buf := make([]byte, 256)
	n, err := c.Read(buf)
	if err != nil {
		t.Fatalf("read: %v", err)
	}
	return string(buf[:n])
}