package test

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"

	"v.io/v23"
	"v.io/v23/context"
	"v.io/v23/naming"
	"v.io/v23/options"
	"v.io/v23/rpc"
	"v.io/v23/security"
	"v.io/v23/verror"

	"v.io/x/ref/lib/flags/consts"
	_ "v.io/x/ref/profiles"
	inaming "v.io/x/ref/profiles/internal/naming"
	mounttable "v.io/x/ref/services/mounttable/lib"
	"v.io/x/ref/test"
	"v.io/x/ref/test/expect"
	"v.io/x/ref/test/modules"
	"v.io/x/ref/test/testutil"
)

//go:generate v23 test generate .

func rootMT(stdin io.Reader, stdout, stderr io.Writer, env map[string]string, args ...string) error {
	ctx, shutdown := v23.Init()
	defer shutdown()

	lspec := v23.GetListenSpec(ctx)
	server, err := v23.NewServer(ctx, options.ServesMountTable(true))
	if err != nil {
		return fmt.Errorf("root failed: %v", err)
	}
	mt, err := mounttable.NewMountTableDispatcher("")
	if err != nil {
		return fmt.Errorf("mounttable.NewMountTableDispatcher failed: %s", err)
	}
	eps, err := server.Listen(lspec)
	if err != nil {
		return fmt.Errorf("server.Listen failed: %s", err)
	}
	if err := server.ServeDispatcher("", mt); err != nil {
		return fmt.Errorf("root failed: %s", err)
	}
	fmt.Fprintf(stdout, "PID=%d\n", os.Getpid())
	for _, ep := range eps {
		fmt.Fprintf(stdout, "MT_NAME=%s\n", ep.Name())
	}
	modules.WaitForEOF(stdin)
	return nil
}

type treeDispatcher struct{ id string }

func (d treeDispatcher) Lookup(suffix string) (interface{}, security.Authorizer, error) {
	return &echoServerObject{d.id, suffix}, nil, nil
}

type echoServerObject struct {
	id, suffix string
}

func (es *echoServerObject) Echo(call rpc.ServerCall, m string) (string, error) {
	if len(es.suffix) > 0 {
		return fmt.Sprintf("%s.%s: %s\n", es.id, es.suffix, m), nil
	}
	return fmt.Sprintf("%s: %s\n", es.id, m), nil
}

func (es *echoServerObject) Sleep(call rpc.ServerCall, d string) error {
	duration, err := time.ParseDuration(d)
	if err != nil {
		return err
	}
	time.Sleep(duration)
	return nil
}

func echoServer(stdin io.Reader, stdout, stderr io.Writer, env map[string]string, args ...string) error {
	ctx, shutdown := v23.Init()
	defer shutdown()

	id, mp := args[0], args[1]
	disp := &treeDispatcher{id: id}
	server, err := v23.NewServer(ctx)
	if err != nil {
		return err
	}
	defer server.Stop()
	eps, err := server.Listen(v23.GetListenSpec(ctx))
	if err != nil {
		return err
	}
	if err := server.ServeDispatcher(mp, disp); err != nil {
		return err
	}
	fmt.Fprintf(stdout, "PID=%d\n", os.Getpid())
	for _, ep := range eps {
		fmt.Fprintf(stdout, "NAME=%s\n", ep.Name())
	}
	modules.WaitForEOF(stdin)
	return nil
}

func echoClient(stdin io.Reader, stdout, stderr io.Writer, env map[string]string, args ...string) error {
	ctx, shutdown := v23.Init()
	defer shutdown()

	name := args[0]
	args = args[1:]
	client := v23.GetClient(ctx)
	for _, a := range args {
		h, err := client.StartCall(ctx, name, "Echo", []interface{}{a})
		if err != nil {
			return err
		}
		var r string
		if err := h.Finish(&r); err != nil {
			return err
		}
		fmt.Fprintf(stdout, r)
	}
	return nil
}

func newCtx() (*context.T, v23.Shutdown) {
	ctx, shutdown := test.InitForTest()
	v23.GetNamespace(ctx).CacheCtl(naming.DisableCache(true))
	return ctx, shutdown
}

func runMountTable(t *testing.T, ctx *context.T) (*modules.Shell, func()) {
	sh, err := modules.NewShell(ctx, nil, testing.Verbose(), t)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	root, err := sh.Start("rootMT", nil)
	if err != nil {
		t.Fatalf("unexpected error for root mt: %s", err)
	}
	sh.Forget(root)

	root.ExpectVar("PID")
	rootName := root.ExpectVar("MT_NAME")

	deferFn := func() {
		sh.Cleanup(os.Stderr, os.Stderr)
		root.Shutdown(os.Stderr, os.Stderr)
	}

	if t.Failed() {
		deferFn()
		t.Fatalf("%s", root.Error())
	}
	sh.SetVar(consts.NamespaceRootPrefix, rootName)
	if err = v23.GetNamespace(ctx).SetRoots(rootName); err != nil {
		t.Fatalf("unexpected error setting namespace roots: %s", err)
	}

	return sh, deferFn
}

func runClient(t *testing.T, sh *modules.Shell) error {
	clt, err := sh.Start("echoClient", nil, "echoServer", "a message")
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	s := expect.NewSession(t, clt.Stdout(), 30*time.Second)
	s.Expect("echoServer: a message")
	if s.Failed() {
		return s.Error()
	}
	return nil
}

func numServers(t *testing.T, ctx *context.T, name string) int {
	me, err := v23.GetNamespace(ctx).Resolve(ctx, name)
	if err != nil {
		return 0
	}
	return len(me.Servers)
}

// TODO(cnicolaou): figure out how to test and see what the internals
// of tryCall are doing - e.g. using stats counters.
func TestMultipleEndpoints(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()

	sh, fn := runMountTable(t, ctx)
	defer fn()
	srv, err := sh.Start("echoServer", nil, "echoServer", "echoServer")
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	s := expect.NewSession(t, srv.Stdout(), time.Minute)
	s.ExpectVar("PID")
	s.ExpectVar("NAME")

	// Verify that there are 1 entries for echoServer in the mount table.
	if got, want := numServers(t, ctx, "echoServer"), 1; got != want {
		t.Fatalf("got: %d, want: %d", got, want)
	}

	runClient(t, sh)

	// Create a fake set of 100 entries in the mount table
	for i := 0; i < 100; i++ {
		// 203.0.113.0 is TEST-NET-3 from RFC5737
		ep := naming.FormatEndpoint("tcp", fmt.Sprintf("203.0.113.%d:443", i))
		n := naming.JoinAddressName(ep, "")
		if err := v23.GetNamespace(ctx).Mount(ctx, "echoServer", n, time.Hour); err != nil {
			t.Fatalf("unexpected error: %s", err)
		}
	}

	// Verify that there are 101 entries for echoServer in the mount table.
	if got, want := numServers(t, ctx, "echoServer"), 101; got != want {
		t.Fatalf("got: %q, want: %q", got, want)
	}

	// TODO(cnicolaou): ok, so it works, but I'm not sure how
	// long it should take or if the parallel connection code
	// really works. Use counters to inspect it for example.
	if err := runClient(t, sh); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}

	srv.CloseStdin()
	srv.Shutdown(nil, nil)

	// Verify that there are 100 entries for echoServer in the mount table.
	if got, want := numServers(t, ctx, "echoServer"), 100; got != want {
		t.Fatalf("got: %d, want: %d", got, want)
	}
}

func TestTimeoutCall(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	ctx, _ = context.WithTimeout(ctx, 100*time.Millisecond)
	name := naming.JoinAddressName(naming.FormatEndpoint("tcp", "203.0.113.10:443"), "")
	client := v23.GetClient(ctx)
	_, err := client.StartCall(ctx, name, "echo", []interface{}{"args don't matter"})
	if !verror.Is(err, verror.ErrTimeout.ID) {
		t.Fatalf("wrong error: %s", err)
	}
}

func childPing(stdin io.Reader, stdout, stderr io.Writer, env map[string]string, args ...string) error {
	ctx, shutdown := test.InitForTest()
	defer shutdown()
	v23.GetNamespace(ctx).CacheCtl(naming.DisableCache(true))

	name := args[0]
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Ping", nil)
	if err != nil {
		fmt.Errorf("unexpected error: %s", err)
	}
	got := ""
	if err := call.Finish(&got); err != nil {
		fmt.Errorf("unexpected error: %s", err)
	}
	fmt.Fprintf(stdout, "RESULT=%s\n", got)
	return nil
}

func initServer(t *testing.T, ctx *context.T) (string, func()) {
	server, err := v23.NewServer(ctx)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	done := make(chan struct{})
	deferFn := func() { close(done); server.Stop() }

	eps, err := server.Listen(v23.GetListenSpec(ctx))
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	server.Serve("", &simple{done}, nil)
	return eps[0].Name(), deferFn
}

func testForVerror(t *testing.T, err error, verr verror.IDAction) {
	_, file, line, _ := runtime.Caller(1)
	loc := fmt.Sprintf("%s:%d", filepath.Base(file), line)
	if !verror.Is(err, verr.ID) {
		if _, ok := err.(verror.E); !ok {
			t.Fatalf("%s: err %v not a verror", loc, err)
		}
		stack := ""
		if err != nil {
			stack = verror.Stack(err).String()
		}
		t.Fatalf("%s: expecting one of: %v, got: %v: stack: %s", loc, verr, err, stack)
	}
}

func TestTimeoutResponse(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()
	ctx, _ = context.WithTimeout(ctx, time.Millisecond)
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", nil)
	if err != nil {
		testForVerror(t, err, verror.ErrTimeout)
		return
	}
	err = call.Finish()
	testForVerror(t, err, verror.ErrTimeout)
}

func TestArgsAndResponses(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()

	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", []interface{}{"too many args"})
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	err = call.Finish()
	testForVerror(t, err, verror.ErrBadProtocol)

	call, err = v23.GetClient(ctx).StartCall(ctx, name, "Ping", nil)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	pong := ""
	dummy := ""
	err = call.Finish(&pong, &dummy)
	testForVerror(t, err, verror.ErrBadProtocol)
}

func TestAccessDenied(t *testing.T) {
	ctx, shutdown := test.InitForTest()
	defer shutdown()

	name, fn := initServer(t, ctx)
	defer fn()

	ctx1, err := v23.SetPrincipal(ctx, testutil.NewPrincipal("test-blessing"))
	// Client must recognize the server, otherwise it won't even send the request.
	v23.GetPrincipal(ctx1).AddToRoots(v23.GetPrincipal(ctx).BlessingStore().Default())
	if err != nil {
		t.Fatal(err)
	}
	call, err := v23.GetClient(ctx1).StartCall(ctx1, name, "Sleep", nil)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	err = call.Finish()
	testForVerror(t, err, verror.ErrNoAccess)
}

func TestCanceledBeforeFinish(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()

	ctx, cancel := context.WithCancel(ctx)
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", nil)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	// Cancel before we call finish.
	cancel()
	err = call.Finish()
	// TOO(cnicolaou): this should be Canceled only.
	testForVerror(t, err, verror.ErrCanceled)
}

func TestCanceledDuringFinish(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()

	ctx, cancel := context.WithCancel(ctx)
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", nil)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	// Cancel whilst the RPC is running.
	go func() {
		time.Sleep(100 * time.Millisecond)
		cancel()
	}()
	err = call.Finish()
	testForVerror(t, err, verror.ErrCanceled)
}

func TestRendezvous(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	sh, fn := runMountTable(t, ctx)
	defer fn()

	name := "echoServer"

	// We start the client before we start the server, StartCall will reresolve
	// the name until it finds an entry or timesout after an exponential
	// backoff of some minutes.
	startServer := func() {
		time.Sleep(10 * time.Millisecond)
		srv, _ := sh.Start("echoServer", nil, "message", name)
		s := expect.NewSession(t, srv.Stdout(), time.Minute)
		s.ExpectVar("PID")
		s.ExpectVar("NAME")
	}
	go startServer()

	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Echo", []interface{}{"hello"})
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}

	response := ""
	if err := call.Finish(&response); err != nil {
		testForVerror(t, err, verror.ErrCanceled)
		return
	}
	if got, want := response, "message: hello\n"; got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

func TestCallback(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	sh, fn := runMountTable(t, ctx)
	defer fn()

	name, fn := initServer(t, ctx)
	defer fn()

	srv, err := sh.Start("childPing", nil, name)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	s := expect.NewSession(t, srv.Stdout(), time.Minute)
	if got, want := s.ExpectVar("RESULT"), "pong"; got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

func TestStreamTimeout(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()

	want := 10
	ctx, _ = context.WithTimeout(ctx, 300*time.Millisecond)
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Source", []interface{}{want})
	if err != nil {
		if !verror.Is(err, verror.ErrTimeout.ID) {
			t.Fatalf("verror should be a timeout not %s: stack %s",
				err, verror.Stack(err))
		}
		return
	}

	for {
		got := 0
		err := call.Recv(&got)
		if err == nil {
			if got != want {
				t.Fatalf("got %d, want %d", got, want)
			}
			want++
			continue
		}
		// TOO(cnicolaou): this should be Timeout only.
		testForVerror(t, err, verror.ErrTimeout)
		break
	}
	err = call.Finish()
	testForVerror(t, err, verror.ErrTimeout)
}

func TestStreamAbort(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	name, fn := initServer(t, ctx)
	defer fn()

	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sink", nil)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}

	want := 10
	for i := 0; i <= want; i++ {
		if err := call.Send(i); err != nil {
			t.Fatalf("unexpected error: %s", err)
		}
	}
	call.CloseSend()
	err = call.Send(100)
	testForVerror(t, err, verror.ErrAborted)

	result := 0
	err = call.Finish(&result)
	if err != nil {
		t.Errorf("unexpected error: %#v", err)
	}
	if got := result; got != want {
		t.Errorf("got %d, want %d", got, want)
	}
}

func TestNoServersAvailable(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	_, fn := runMountTable(t, ctx)
	defer fn()
	name := "noservers"
	ctx, _ = context.WithTimeout(ctx, 1000*time.Millisecond)
	call, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", nil)
	if err != nil {
		testForVerror(t, err, verror.ErrNoServers)
		return
	}
	err = call.Finish()
	testForVerror(t, err, verror.ErrNoServers)
}

func TestNoMountTable(t *testing.T) {
	ctx, shutdown := newCtx()
	defer shutdown()
	v23.GetNamespace(ctx).SetRoots()
	name := "a_mount_table_entry"

	// If there is no mount table, then we'll get a NoServers error message.
	ctx, _ = context.WithTimeout(ctx, 300*time.Millisecond)
	_, err := v23.GetClient(ctx).StartCall(ctx, name, "Sleep", nil)
	testForVerror(t, err, verror.ErrNoServers)
}

// TestReconnect verifies that the client transparently re-establishes the
// connection to the server if the server dies and comes back (on the same
// endpoint).
func TestReconnect(t *testing.T) {
	t.Skip()
	ctx, shutdown := test.InitForTest()
	defer shutdown()

	sh, err := modules.NewShell(ctx, v23.GetPrincipal(ctx), testing.Verbose(), t)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	defer sh.Cleanup(os.Stderr, os.Stderr)
	server, err := sh.Start("echoServer", nil, "--veyron.tcp.address=127.0.0.1:0", "mymessage", "")
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	server.ReadLine()
	serverName := server.ExpectVar("NAME")
	serverEP, _ := naming.SplitAddressName(serverName)
	ep, _ := inaming.NewEndpoint(serverEP)

	makeCall := func(ctx *context.T, opts ...rpc.CallOpt) (string, error) {
		ctx, _ = context.WithDeadline(ctx, time.Now().Add(10*time.Second))
		call, err := v23.GetClient(ctx).StartCall(ctx, serverName, "Echo", []interface{}{"bratman"}, opts...)
		if err != nil {
			return "", fmt.Errorf("START: %s", err)
		}
		var result string
		if err := call.Finish(&result); err != nil {
			return "", err
		}
		return result, nil
	}

	expected := "mymessage: bratman\n"
	if result, err := makeCall(ctx); err != nil || result != expected {
		t.Errorf("Got (%q, %v) want (%q, nil)", result, err, expected)
	}
	// Kill the server, verify client can't talk to it anymore.
	if err := server.Shutdown(os.Stderr, os.Stderr); err != nil {
		t.Fatalf("unexpected error: %s", err)
	}

	if _, err := makeCall(ctx, options.NoRetry{}); err == nil || (!strings.HasPrefix(err.Error(), "START") && !strings.Contains(err.Error(), "EOF")) {
		t.Fatalf(`Got (%v) want ("START: <err>" or "EOF") as server is down`, err)
	}

	// Resurrect the server with the same address, verify client
	// re-establishes the connection. This is racy if another
	// process grabs the port.
	server, err = sh.Start("echoServer", nil, "--veyron.tcp.address="+ep.Address, "mymessage again", "")
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	defer server.Shutdown(os.Stderr, os.Stderr)
	expected = "mymessage again: bratman\n"
	if result, err := makeCall(ctx); err != nil || result != expected {
		t.Errorf("Got (%q, %v) want (%q, nil)", result, err, expected)
	}

}

// TODO(cnicolaou:) tests for:
// -- Test for bad discharges error and correct invalidation, client.go:870..880