package namespace_test

import (
	"reflect"
	"runtime"
	"runtime/debug"
	"sort"
	"sync"
	"testing"
	"time"

	_ "veyron/lib/testutil"
	"veyron/runtimes/google/naming/namespace"
	service "veyron/services/mounttable/lib"

	"veyron2"
	"veyron2/ipc"
	"veyron2/naming"
	"veyron2/rt"
	"veyron2/services/mounttable"
	"veyron2/vlog"
)

func boom(t *testing.T, f string, v ...interface{}) {
	t.Logf(f, v...)
	t.Fatal(string(debug.Stack()))
}

func compare(t *testing.T, caller, name string, got, want []string) {
	if len(got) != len(want) {
		boom(t, "%s: %q returned wrong # servers: got %v, want %v, servers: got %v, want %v", caller, name, len(got), len(want), got, want)
	}
	sort.Strings(got)
	sort.Strings(want)
	if !reflect.DeepEqual(got, want) {
		boom(t, "%s: %q: got %v, want %v", caller, name, got, want)
	}
}

func doGlob(t *testing.T, r veyron2.Runtime, ns naming.Namespace, pattern string, limit int) []string {
	var replies []string
	rc, err := ns.Glob(r.NewContext(), pattern)
	if err != nil {
		boom(t, "Glob(%s): %s", pattern, err)
	}
	for s := range rc {
		replies = append(replies, s.Name)
		if limit > 0 && len(replies) > limit {
			boom(t, "Glob returns too many results, perhaps not limiting recursion")
		}
	}
	return replies
}

type testServer struct{}

func (*testServer) KnockKnock(call ipc.ServerCall) string {
	return "Who's there?"
}

func knockKnock(t *testing.T, runtime veyron2.Runtime, name string) {
	client := runtime.Client()
	ctx := runtime.NewContext()
	call, err := client.StartCall(ctx, name, "KnockKnock", nil)
	if err != nil {
		boom(t, "StartCall failed: %s", err)
	}
	var result string
	if err := call.Finish(&result); err != nil {
		boom(t, "Finish returned an error: %s", err)
	}
	if result != "Who's there?" {
		boom(t, "Wrong result: %v", result)
	}
}

func testResolveToMountTable(t *testing.T, r veyron2.Runtime, ns naming.Namespace, name string, want ...string) {
	servers, err := ns.ResolveToMountTable(r.NewContext(), name)
	if err != nil {
		boom(t, "Failed to ResolveToMountTable %q: %s", name, err)
	}
	compare(t, "ResolveToMoutTable", name, servers, want)
}

func testResolve(t *testing.T, r veyron2.Runtime, ns naming.Namespace, name string, want ...string) {
	servers, err := ns.Resolve(r.NewContext(), name)
	if err != nil {
		boom(t, "Failed to Resolve %q: %s", name, err)
	}
	compare(t, "Resolve", name, servers, want)
}

func testUnresolve(t *testing.T, r veyron2.Runtime, ns naming.Namespace, name string, want ...string) {
	servers, err := ns.Unresolve(r.NewContext(), name)
	if err != nil {
		boom(t, "Failed to Resolve %q: %s", name, err)
	}
	compare(t, "Unresolve", name, servers, want)
}

type serverEntry struct {
	mountPoint string
	server     ipc.Server
	endpoint   naming.Endpoint
	name       string
}

func runServer(t *testing.T, sr veyron2.Runtime, disp ipc.Dispatcher, mountPoint string) *serverEntry {
	return run(t, sr, disp, mountPoint, false)
}

func runMT(t *testing.T, sr veyron2.Runtime, mountPoint string) *serverEntry {
	mt, err := service.NewMountTable("")
	if err != nil {
		boom(t, "NewMountTable returned error: %v", err)
	}
	return run(t, sr, mt, mountPoint, true)
}

func run(t *testing.T, sr veyron2.Runtime, disp ipc.Dispatcher, mountPoint string, mt bool) *serverEntry {
	s, err := sr.NewServer(veyron2.ServesMountTableOpt(mt))
	if err != nil {
		boom(t, "r.NewServer: %s", err)
	}
	// Add a mount table server.
	// Start serving on a loopback address.
	ep, err := s.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		boom(t, "Failed to Listen: %s", err)
	}
	if err := s.Serve(mountPoint, disp); err != nil {
		boom(t, "Failed to serve mount table at %s: %s", mountPoint, err)
	}
	name := naming.JoinAddressName(ep.String(), "")
	if !mt {
		name = name + "//"
	}
	return &serverEntry{mountPoint: mountPoint, server: s, endpoint: ep, name: name}
}

const (
	mt1MP = "mt1"
	mt2MP = "mt2"
	mt3MP = "mt3"
	mt4MP = "mt4"
	mt5MP = "mt5"
	j1MP  = "joke1"
	j2MP  = "joke2"
	j3MP  = "joke3"

	ttl = 100 * time.Second
)

// runMountTables creates a root mountable with some mount tables mounted
// in it: mt{1,2,3,4,5}
func runMountTables(t *testing.T, r veyron2.Runtime) (*serverEntry, map[string]*serverEntry) {
	root := runMT(t, r, "")
	r.Namespace().SetRoots(root.name)
	t.Logf("mountTable %q -> %s", root.mountPoint, root.endpoint)

	mps := make(map[string]*serverEntry)
	for _, mp := range []string{mt1MP, mt2MP, mt3MP, mt4MP, mt5MP} {
		m := runMT(t, r, mp)
		t.Logf("mountTable %q -> %s", mp, m.endpoint)
		mps[mp] = m
	}
	return root, mps
}

// createNamespace creates a hiearachy of mounttables and servers
// as follows:
// /mt1, /mt2, /mt3, /mt4, /mt5, /joke1, /joke2, /joke3.
// That is, mt1 is a mount table mounted in the root mount table,
// joke1 is a server mounted in the root mount table.
func createNamespace(t *testing.T, r veyron2.Runtime) (*serverEntry, map[string]*serverEntry, map[string]*serverEntry, func()) {
	root, mts := runMountTables(t, r)
	jokes := make(map[string]*serverEntry)
	// Let's run some non-mount table services.
	for _, j := range []string{j1MP, j2MP, j3MP} {
		disp := ipc.LeafDispatcher(&testServer{}, nil)
		jokes[j] = runServer(t, r, disp, j)
	}
	return root, mts, jokes, func() {
		for _, s := range jokes {
			s.server.Stop()
		}
		for _, s := range mts {
			s.server.Stop()
		}
		root.server.Stop()
	}
}

// runNestedMountTables creates some nested mount tables in the hierarchy
// created by createNamespace as follows:
// /mt4/foo, /mt4/foo/bar and /mt4/baz where foo, bar and baz are mount tables.
func runNestedMountTables(t *testing.T, r veyron2.Runtime, mts map[string]*serverEntry) {
	ns, ctx := r.Namespace(), r.NewContext()
	// Set up some nested mounts and verify resolution.
	for _, m := range []string{"mt4/foo", "mt4/foo/bar"} {
		mts[m] = runMT(t, r, m)
	}

	// Use a global name for a mount, rather than a relative one.
	// We directly mount baz into the mt4/foo mount table.
	globalMP := naming.JoinAddressName(mts["mt4/foo"].name, "baz")
	mts["baz"] = runMT(t, r, "baz")
	if err := ns.Mount(ctx, globalMP, mts["baz"].name, ttl); err != nil {
		boom(t, "Failed to Mount %s: %s", globalMP, err)
	}
}

// TestNamespaceCommon tests common use of the Namespace library
// against a root mount table and some mount tables mounted on it.
func TestNamespaceCommon(t *testing.T) {
	// We need the default runtime for the server-side mounttable code
	// which references rt.R() to create new endpoints
	rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, jokes, stopper := createNamespace(t, r)
	defer stopper()
	ns := r.Namespace()

	// All of the initial mounts are served by the root mounttable
	// and hence ResolveToMountTable should return the root mountable
	// as the address portion of the terminal name for those mounttables.
	testResolveToMountTable(t, r, ns, "", root.name)
	for _, m := range []string{mt2MP, mt3MP, mt5MP} {
		rootMT := naming.MakeTerminal(naming.Join(root.name, m))
		// All of these mount tables are hosted by the root mount table
		testResolveToMountTable(t, r, ns, m, rootMT)
		testResolveToMountTable(t, r, ns, "//"+m, rootMT)

		// The server registered for each mount point is a mount table
		testResolve(t, r, ns, m, mts[m].name)

		// ResolveToMountTable will walk through to the sub MountTables
		mtbar := naming.Join(m, "bar")
		subMT := naming.MakeTerminal(naming.Join(mts[m].name, "bar"))
		testResolveToMountTable(t, r, ns, mtbar, subMT)

		// ResolveToMountTable will not walk through if the name is terminal
		testResolveToMountTable(t, r, ns, "//"+mtbar, naming.Join(rootMT, "bar"))
	}

	for _, j := range []string{j1MP, j2MP, j3MP} {
		testResolve(t, r, ns, j, jokes[j].name)
	}
}

// TestNamespaceDetails tests more detailed use of the Namespace library,
// including the intricacies of // meaning and placement.
func TestNamespaceDetails(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, _, stopper := createNamespace(t, sr)
	defer stopper()

	ns := r.Namespace()
	ns.SetRoots(root.name)

	// Mount using a relative name starting with //.
	// This means don't walk out of the namespace's root mount table
	// even if there is already something mounted at mt2. Thus, the example
	// below will fail.
	mt3Server := mts[mt3MP].name
	mt2a := "//mt2/a"
	if err := ns.Mount(r.NewContext(), mt2a, mt3Server, ttl); err != naming.ErrNoSuchName {
		boom(t, "Successfully mounted %s - expected an err %v, not %v", mt2a, naming.ErrNoSuchName, err)
	}

	// Mount using the relative name not starting with //.
	// This means walk through mt2 if it already exists and mount within
	// the lower level mount table, if the name doesn't exist we'll create
	// a new name for it.
	mt2a = "mt2/a"
	if err := ns.Mount(r.NewContext(), mt2a, mt3Server, ttl); err != nil {
		boom(t, "Failed to Mount %s: %s", mt2a, err)
	}

	mt2mt := naming.MakeTerminal(naming.Join(mts[mt2MP].name, "a"))
	// The mt2/a is served by the mt2 mount table
	testResolveToMountTable(t, r, ns, mt2a, mt2mt)
	// The server for mt2a is mt3server from the second mount above.
	testResolve(t, r, ns, mt2a, mt3Server)

	// Using a terminal or non-terminal name makes no difference if the
	// mount is directed to the root name server (since that's the root
	// for the namespace for this process) and the name exists within
	// that mount table. In both cases, the server will be added to the
	// set of mount table servers for that name.
	for _, mp := range []struct{ name, server string }{
		{"mt2", mts[mt4MP].name},
		{"//mt2", mts[mt5MP].name},
	} {
		if err := ns.Mount(r.NewContext(), mp.name, mp.server, ttl); err != nil {
			boom(t, "Failed to Mount %s: %s", mp.name, err)
		}
	}

	// We now have 3 mount tables prepared to serve mt2/a
	testResolveToMountTable(t, r, ns, "mt2/a",
		mts[mt2MP].name+"//a",
		mts[mt4MP].name+"//a",
		mts[mt5MP].name+"//a")
	testResolve(t, r, ns, "mt2", mts[mt2MP].name, mts[mt4MP].name, mts[mt5MP].name)
}

// TestNestedMounts tests some more deeply nested mounts
func TestNestedMounts(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, _, stopper := createNamespace(t, sr)
	runNestedMountTables(t, sr, mts)
	defer stopper()

	ns := r.Namespace()
	ns.SetRoots(root.name)

	// Set up some nested mounts and verify resolution.
	for _, m := range []string{"mt4/foo", "mt4/foo/bar"} {
		testResolve(t, r, ns, m, mts[m].name)
	}

	testResolveToMountTable(t, r, ns, "mt4/foo",
		mts[mt4MP].name+"//foo")
	testResolveToMountTable(t, r, ns, "mt4/foo/bar",
		mts["mt4/foo"].name+"//bar")
	testResolveToMountTable(t, r, ns, "mt4/foo/baz", mts["mt4/foo"].name+"//baz")
}

// TestServers tests invoking RPCs on simple servers
func TestServers(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, jokes, stopper := createNamespace(t, sr)
	defer stopper()
	ns := r.Namespace()
	ns.SetRoots(root.name)

	// Let's run some non-mount table servic
	for _, j := range []string{j1MP, j2MP, j3MP} {
		testResolve(t, r, ns, j, jokes[j].name)
		knockKnock(t, r, j)
		globalName := naming.JoinAddressName(mts["mt4"].name, j)
		disp := ipc.LeafDispatcher(&testServer{}, nil)
		gj := "g_" + j
		jokes[gj] = runServer(t, r, disp, globalName)
		testResolve(t, r, ns, "mt4/"+j, jokes[gj].name)
		knockKnock(t, r, "mt4/"+j)
		testResolveToMountTable(t, r, ns, "mt4/"+j, naming.MakeTerminal(globalName))
		testResolveToMountTable(t, r, ns, "mt4/"+j+"/garbage", naming.MakeTerminal(globalName+"/garbage"))
	}
}

// TestGlob tests some glob patterns.
func TestGlob(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, _, stopper := createNamespace(t, sr)
	runNestedMountTables(t, sr, mts)
	defer stopper()
	ns := r.Namespace()
	ns.SetRoots(root.name)

	tln := []string{"baz", "mt1", "mt2", "mt3", "mt4", "mt5", "joke1", "joke2", "joke3"}
	barbaz := []string{"mt4/foo/bar", "mt4/foo/baz"}
	foo := append([]string{"mt4/foo"}, barbaz...)
	// Try various globs.
	globTests := []struct {
		pattern  string
		expected []string
	}{
		{"*", tln},
		// TODO(cnicolaou): the glob that doesn't match a name should fail.
		//
		{"x", []string{"x"}},
		{"m*", []string{"mt1", "mt2", "mt3", "mt4", "mt5"}},
		{"mt[2,3]", []string{"mt2", "mt3"}},
		{"*z", []string{"baz"}},
		{"...", append(append(tln, foo...), "")},
		{"*/...", append(tln, foo...)},
		{"*/foo/*", barbaz},
		{"*/*/*z", []string{"mt4/foo/baz"}},
		{"*/f??/*z", []string{"mt4/foo/baz"}},
	}
	for _, test := range globTests {
		out := doGlob(t, r, ns, test.pattern, 0)
		compare(t, "Glob", test.pattern, test.expected, out)
		// Do the same with a full rooted name.
		out = doGlob(t, r, ns, naming.JoinAddressName(root.name, test.pattern), 0)
		var expectedWithRoot []string
		for _, s := range test.expected {
			expectedWithRoot = append(expectedWithRoot, naming.JoinAddressName(root.name, s))
		}
		compare(t, "Glob", test.pattern, expectedWithRoot, out)
	}
}

type GlobbableServer struct {
	callCount int
	mu        sync.Mutex
}

func (g *GlobbableServer) Glob(ipc.ServerContext, string, mounttable.GlobbableServiceGlobStream) error {
	g.mu.Lock()
	defer g.mu.Unlock()
	g.callCount++
	return nil
}

func (g *GlobbableServer) GetAndResetCount() int {
	g.mu.Lock()
	defer g.mu.Unlock()
	cnt := g.callCount
	g.callCount = 0

	return cnt
}

// TestGlobEarlyStop tests that Glob doesn't query terminal servers with finished patterns.
func TestGlobEarlyStop(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	root, mts, _, stopper := createNamespace(t, sr)
	runNestedMountTables(t, sr, mts)
	defer stopper()

	globServer := &GlobbableServer{}
	name := naming.JoinAddressName(mts["mt4/foo/bar"].name, "glob")
	runningGlobServer := runServer(t, r, ipc.LeafDispatcher(mounttable.NewServerGlobbable(globServer), nil), name)
	defer runningGlobServer.server.Stop()

	ns := r.Namespace()
	ns.SetRoots(root.name)

	tests := []struct {
		pattern       string
		expectedCalls int
	}{
		{"mt4/foo/bar/glob", 0},
		{"mt4/foo/bar/glob/...", 1},
		{"mt4/foo/bar/*", 0},
	}
	for _, test := range tests {
		out := doGlob(t, r, ns, test.pattern, 0)
		compare(t, "Glob", test.pattern, []string{"mt4/foo/bar/glob"}, out)
		if calls := globServer.GetAndResetCount(); calls != test.expectedCalls {
			boom(t, "Wrong number of Glob calls to terminal server got: %d want: %d.", calls, test.expectedCalls)
		}
	}
}

func TestCycles(t *testing.T) {
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	defer r.Cleanup()

	root, _, _, stopper := createNamespace(t, sr)
	defer stopper()
	ns := r.Namespace()
	ns.SetRoots(root.name)

	c1 := runMT(t, r, "c1")
	c2 := runMT(t, r, "c2")
	c3 := runMT(t, r, "c3")
	defer c1.server.Stop()
	defer c2.server.Stop()
	defer c3.server.Stop()

	m := "c1/c2"
	if err := ns.Mount(r.NewContext(), m, c1.name, ttl); err != nil {
		boom(t, "Failed to Mount %s: %s", "c1/c2", err)
	}

	m = "c1/c2/c3"
	if err := ns.Mount(r.NewContext(), m, c3.name, ttl); err != nil {
		boom(t, "Failed to Mount %s: %s", m, err)
	}

	m = "c1/c3/c4"
	if err := ns.Mount(r.NewContext(), m, c1.name, ttl); err != nil {
		boom(t, "Failed to Mount %s: %s", m, err)
	}

	testResolve(t, r, ns, "c1", c1.name)
	testResolve(t, r, ns, "c1/c2", c1.name)
	testResolve(t, r, ns, "c1/c3", c3.name)
	testResolve(t, r, ns, "c1/c3/c4", c1.name)
	testResolve(t, r, ns, "c1/c3/c4/c3/c4", c1.name)
	cycle := "c3/c4"
	for i := 0; i < 40; i++ {
		cycle += "/c3/c4"
	}
	if _, err := ns.Resolve(r.NewContext(), "c1/"+cycle); err.Error() != "Resolution depth exceeded" {
		boom(t, "Failed to detect cycle")
	}

	// Perform the glob with a response length limit.
	doGlob(t, r, ns, "c1/...", 1000)
}

func TestUnresolve(t *testing.T) {
	// TODO(cnicolaou): move unresolve tests into this test, right now,
	// that's annoying because the stub compiler has some blocking bugs and the
	// Unresolve functionality is partially implemented in the stubs.
	t.Skip()
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	defer r.Cleanup()
	root, mts, jokes, stopper := createNamespace(t, sr)
	runNestedMountTables(t, sr, mts)
	defer stopper()
	ns := r.Namespace()
	ns.SetRoots(root.name)

	vlog.Infof("Glob: %v", doGlob(t, r, ns, "*", 0))
	testResolve(t, r, ns, "joke1", jokes["joke1"].name)
	testUnresolve(t, r, ns, "joke1", "")
}

// TestGoroutineLeaks tests for leaking goroutines - we have many:-(
func TestGoroutineLeaks(t *testing.T) {
	t.Skip()
	sr := rt.Init()
	r, _ := rt.New() // We use a different runtime for the client side.
	defer r.Cleanup()
	_, _, _, stopper := createNamespace(t, sr)
	defer func() {
		vlog.Infof("%d goroutines:", runtime.NumGoroutine())
	}()
	defer stopper()
	defer func() {
		vlog.Infof("%d goroutines:", runtime.NumGoroutine())
	}()
	//panic("this will show up lots of goroutine+channel leaks!!!!")
}

func TestBadRoots(t *testing.T) {
	r, _ := rt.New()
	defer r.Cleanup()
	if _, err := namespace.New(r); err != nil {
		t.Errorf("namespace.New should not have failed with no roots")
	}
	if _, err := namespace.New(r, "not a rooted name"); err == nil {
		t.Errorf("namespace.New should have failed with an unrooted name")
	}
}