//go:build !windows

package localapi

import (
	"bufio"
	"context"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/slackhq/nebula/commands"
	"github.com/slackhq/nebula/config"
	"github.com/slackhq/nebula/test"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.org/x/sys/unix"
)

type whoamiFlags struct {
	Name  string
	Shout bool
}

// infoRegistry holds one identity command, whoami, whose -name selects an outcome, and
// one command the info API must withhold.
func infoRegistry() *commands.Registry {
	reg := commands.New()
	reg.Register(&commands.Command{
		Name:             "whoami",
		ShortDescription: "reports who a name belongs to",
		Identity:         true,
		Flags: func() (*flag.FlagSet, any) {
			fl := flag.NewFlagSet("", flag.ContinueOnError)
			s := &whoamiFlags{}
			fl.StringVar(&s.Name, "name", "", "the name to look up")
			fl.BoolVar(&s.Shout, "shout", false, "answers in capitals")
			return fl, s
		},
		Run: func(fs any, a []string) (commands.Result, error) {
			if f := fs.(*whoamiFlags); f.Shout {
				return commands.Value(map[string]any{"name": strings.ToUpper(f.Name)}), nil
			}
			switch name := fs.(*whoamiFlags).Name; name {
			case "":
				return commands.Value(map[string]any{"name": "me", "groups": []string{}}), nil
			case "nobody":
				return commands.NotFound("No active tunnel for vpn addr: %s", name), nil
			case "bad":
				return commands.Failed("The provided vpn addr could not be parsed: %s", name), nil
			case "boom":
				panic("this command is broken")
			case "err":
				return commands.Result{}, errors.New("an internal detail")
			case "silent":
				return commands.Result{}, nil
			case "done":
				return commands.Nothing(), nil
			default:
				return commands.Value(map[string]any{"name": name}), nil
			}
		},
	})
	reg.Register(echoCommand())
	return reg
}

func serveInfo(t *testing.T, reg *commands.Registry, mode os.FileMode) (*InfoServer, string) {
	t.Helper()

	path := testSocket(t)
	s := NewInfoServer(test.NewLogger(), reg)
	require.NoError(t, s.Rebind(context.Background(), path, Access{Mode: mode}))
	t.Cleanup(s.Stop)
	return s, path
}

// httpDo sends one request over the socket at path and returns the status, body and
// headers. The host in the URL is a placeholder: the dialer ignores it.
func TestInfoServesIdentityCommands(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	status, body, hdr := test.HTTPDo(t, path, http.MethodGet, "/v1/whoami?name=alice")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"alice"}`, body)
	assert.Equal(t, "application/json", hdr.Get("Content-Type"))

	status, body = test.HTTPGet(t, path, "/v1/whoami")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"me","groups":[]}`, body, "a parameter left out is the command's default")
}

// TestInfoWithholdsTheRest checks the filter at the wire: a command that exists but is
// not an identity command is refused with the reason, and a name nothing is registered
// under is unknown, so a caller can tell a typo from a closed door.
func TestInfoWithholdsTheRest(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	status, body := test.HTTPGet(t, path, "/v1/echo?x=1")
	assert.Equal(t, http.StatusForbidden, status)
	assert.Contains(t, body, "echo is not available on this surface")
	assert.Contains(t, body, "identity lookups only")

	status, body = test.HTTPGet(t, path, "/v1/nope")
	assert.Equal(t, http.StatusNotFound, status)
	assert.Contains(t, body, `unknown command \"nope\"`)

	for _, target := range []string{"/", "/v2/whoami", "/v1/", "/v1/whoami/extra", "//v1/whoami", "/v1/x/../whoami", "/v1/../v1/whoami"} {
		status, body = test.HTTPGet(t, path, target)
		assert.Equal(t, http.StatusNotFound, status, target)
		assert.Contains(t, body, `"error"`, "%s: misses are JSON too", target)
	}
}

func TestInfoStatusCodes(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	for _, tc := range []struct {
		target string
		status int
		body   string
	}{
		{"/v1/whoami?name=nobody", http.StatusNotFound, `{"error":"No active tunnel for vpn addr: nobody"}`},
		{"/v1/whoami?name=bad", http.StatusBadRequest, `{"error":"The provided vpn addr could not be parsed: bad"}`},
		{"/v1/whoami?nope=1", http.StatusBadRequest, `{"error":"whoami has no parameter \"nope\""}`},
		{"/v1/whoami?name=a&name=b", http.StatusBadRequest, `{"error":"parameter \"name\" was given more than once"}`},
		{"/v1/whoami?pretty=maybe", http.StatusBadRequest, `{"error":"pretty: expected a boolean, got \"maybe\""}`},
		// A pair that does not decode is a malformed request, not a request without
		// the pair: the lenient parser would drop it and keep the rest.
		{"/v1/whoami?name=%zz", http.StatusBadRequest, `{"error":"malformed query string: invalid URL escape \"%zz\""}`},
		{"/v1/whoami?name=a;shout", http.StatusBadRequest, `{"error":"malformed query string: invalid semicolon separator in query"}`},
		// A boolean parameter with no value is set, as -shout is on a command line.
		{"/v1/whoami?name=alice&shout", http.StatusOK, `{"name":"ALICE"}`},
		{"/v1/whoami?name=alice&shout=false", http.StatusOK, `{"name":"alice"}`},
		// Run failed: the caller hears that it did and no more; the detail is for the log.
		{"/v1/whoami?name=err", http.StatusInternalServerError, `{"error":"command failed"}`},
		// A refusal with no reason, the zero Result, fails the same way rather than
		// passing as a success with nothing to say.
		{"/v1/whoami?name=silent", http.StatusInternalServerError, `{"error":"command failed"}`},
	} {
		status, body := test.HTTPGet(t, path, tc.target)
		assert.Equal(t, tc.status, status, tc.target)
		assert.JSONEq(t, tc.body, body, tc.target)
	}

	// A success with nothing to say is the one empty reply.
	status, body := test.HTTPGet(t, path, "/v1/whoami?name=done")
	assert.Equal(t, http.StatusNoContent, status)
	assert.Empty(t, body)

	status, body, hdr := test.HTTPDo(t, path, http.MethodPost, "/v1/whoami?name=alice")
	assert.Equal(t, http.StatusMethodNotAllowed, status)
	assert.Equal(t, http.MethodGet, hdr.Get("Allow"))
	assert.Contains(t, body, "read only")

	status, _, _ = test.HTTPDo(t, path, http.MethodDelete, "/v1")
	assert.Equal(t, http.StatusMethodNotAllowed, status)
}

// TestInfoPanicDoesNotKillTheDaemon: a broken command costs a request, not the overlay.
// This surface may be open to anyone on the host, so that holds against them too.
func TestInfoPanicDoesNotKillTheDaemon(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	status, body := test.HTTPGet(t, path, "/v1/whoami?name=boom")
	assert.Equal(t, http.StatusInternalServerError, status)
	assert.JSONEq(t, `{"error":"command failed"}`, body)

	status, body = test.HTTPGet(t, path, "/v1/whoami?name=alice")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"alice"}`, body)
}

func TestInfoDescribe(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	status, body := test.HTTPGet(t, path, "/v1")
	require.Equal(t, http.StatusOK, status)

	var schema []commands.CommandSchema
	require.NoError(t, json.Unmarshal([]byte(body), &schema))

	var names []commands.Name
	flags := map[commands.Name][]string{}
	for _, c := range schema {
		names = append(names, c.Name)
		for _, f := range c.Flags {
			flags[c.Name] = append(flags[c.Name], f.Name)
		}
	}
	assert.ElementsMatch(t, []commands.Name{"help", "whoami"}, names, "only what is served is described")
	assert.Equal(t, []string{"name", "shout", commands.FlagJSON, commands.FlagPretty}, flags["whoami"])
}

// TestInfoPresentationFlags: the query string takes -json and -pretty as a command line
// would. The answer is JSON either way; pretty indents it.
func TestInfoPresentationFlags(t *testing.T) {
	_, path := serveInfo(t, infoRegistry(), 0600)

	_, compact := test.HTTPGet(t, path, "/v1/whoami?name=alice&json=true")
	//nolint:testifylint // the exact bytes, newline included, are what is under test
	assert.Equal(t, "{\"name\":\"alice\"}\n", compact)

	_, pretty := test.HTTPGet(t, path, "/v1/whoami?name=alice&pretty")
	//nolint:testifylint // the layout is what is under test
	assert.Equal(t, "{\n    \"name\": \"alice\"\n}\n", pretty)

	_, off := test.HTTPGet(t, path, "/v1/whoami?name=alice&pretty=false")
	assert.Equal(t, compact, off)
}

// TestInfoSocketMode: the mode is the operator's, pinned regardless of the umask, and a
// changed mode on a reload is applied in place rather than by rebinding.
func TestInfoSocketMode(t *testing.T) {
	old := unix.Umask(0077)
	defer unix.Umask(old)

	s, path := serveInfo(t, infoRegistry(), 0660)

	fi, err := os.Stat(path)
	require.NoError(t, err)
	assert.Equal(t, os.FileMode(0660), fi.Mode().Perm())

	require.NoError(t, s.Rebind(context.Background(), path, Access{Mode: 0640}))
	fi, err = os.Stat(path)
	require.NoError(t, err)
	assert.Equal(t, os.FileMode(0640), fi.Mode().Perm())
	assert.Equal(t, path, s.Path())

	status, _ := test.HTTPGet(t, path, "/v1/whoami")
	assert.Equal(t, http.StatusOK, status, "the same listener is still serving")
}

// TestInfoModeChangeRefusesASwappedSocket: whoever can write the directory can replace
// the node with a link to a file of their choosing; the daemon must not set the
// operator's mode on that file. The node is seen to be gone, the link is refused by the
// stale check, the file is untouched, and the endpoint reports itself down, since
// nothing of ours is reachable at the path.
func TestInfoModeChangeRefusesASwappedSocket(t *testing.T) {
	s, path := serveInfo(t, infoRegistry(), 0600)

	target := filepath.Join(filepath.Dir(path), "target")
	require.NoError(t, os.WriteFile(target, nil, 0600))
	require.NoError(t, os.Remove(path))
	require.NoError(t, os.Symlink(target, path))

	err := s.Rebind(context.Background(), path, Access{Mode: 0666})
	require.ErrorContains(t, err, "is not a socket")
	fi, err := os.Stat(target)
	require.NoError(t, err)
	assert.Equal(t, os.FileMode(0600), fi.Mode().Perm(), "the file behind the link keeps its mode")
	assert.Empty(t, s.Path(), "nothing of ours answers at the path, so nothing is served")
}

func TestInfoRebindMovesAndStopRemoves(t *testing.T) {
	s, first := serveInfo(t, infoRegistry(), 0600)

	second := testSocket(t)
	require.NoError(t, s.Rebind(context.Background(), second, Access{Mode: 0600}))
	assert.Equal(t, second, s.Path())
	_, err := os.Stat(first)
	assert.True(t, os.IsNotExist(err), "the old socket is removed")

	status, body := test.HTTPGet(t, second, "/v1/whoami?name=alice")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"alice"}`, body)

	s.Stop()
	assert.Empty(t, s.Path())
	_, err = os.Stat(second)
	assert.True(t, os.IsNotExist(err), "Stop removes the socket")
}

func TestInfoRebindFailureKeepsTheOldSocket(t *testing.T) {
	s, first := serveInfo(t, infoRegistry(), 0600)

	err := s.Rebind(context.Background(), filepath.Join(privateBase(t), "missing", "n", "s.sock"), Access{Mode: 0600})
	require.Error(t, err)
	assert.Equal(t, first, s.Path())

	status, _ := test.HTTPGet(t, first, "/v1/whoami")
	assert.Equal(t, http.StatusOK, status)
}

func TestInfoContextCancellationStops(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	path := testSocket(t)
	s := NewInfoServer(test.NewLogger(), infoRegistry())
	require.NoError(t, s.Rebind(ctx, path, Access{Mode: 0600}))
	t.Cleanup(s.Stop)

	cancel()
	require.Eventually(t, func() bool { return s.Path() == "" }, time.Second, 10*time.Millisecond)
	_, err := os.Stat(path)
	assert.True(t, os.IsNotExist(err))

	// And a reload that lands during shutdown must not bring it back.
	err = s.Rebind(ctx, path, Access{Mode: 0600})
	require.Error(t, err)
	assert.ErrorContains(t, err, "shutting down")
}

func TestInfoConfig(t *testing.T) {
	load := func(t *testing.T, yaml string) (infoConfig, error) {
		t.Helper()
		c := config.NewC(test.NewLogger())
		require.NoError(t, c.LoadString(yaml))
		return infoConfigFrom(c)
	}

	cfg, err := load(t, "local_api: {}\n")
	require.NoError(t, err)
	assert.False(t, cfg.Enabled)

	cfg, err = load(t, "local_api:\n  info:\n    socket: /run/nebula/info.sock\n")
	require.NoError(t, err)
	assert.False(t, cfg.Enabled, "a socket alone does not enable it")

	_, err = load(t, "local_api:\n  info:\n    enabled: true\n")
	require.Error(t, err)
	require.ErrorContains(t, err, "needs a socket path")

	cfg, err = load(t, "local_api:\n  info:\n    enabled: true\n    socket: /run/nebula/info.sock\n")
	require.NoError(t, err)
	assert.Equal(t, infoConfig{Enabled: true, Path: "/run/nebula/info.sock", Access: Access{Mode: 0600}}, cfg)

	cfg, err = load(t, "local_api:\n  info:\n    enabled: true\n    socket: /run/nebula/info.sock\n    socket_mode: \"0660\"\n")
	require.NoError(t, err)
	assert.Equal(t, infoConfig{Enabled: true, Path: "/run/nebula/info.sock", Access: Access{Mode: 0660}}, cfg)

	_, err = load(t, "local_api:\n  info:\n    enabled: true\n    socket: run/info.sock\n")
	require.Error(t, err, "a relative socket path is refused rather than resolved against anything")
	require.ErrorContains(t, err, "must be an absolute path")
	require.ErrorContains(t, err, InfoSocketKey)

	_, err = load(t, "local_api:\n  info:\n    enabled: true\n    socket: /run/nebula/info.sock\n    socket_mode: 0660\n")
	require.Error(t, err, "a bare number is whichever integer the yaml parser made of it")
	require.ErrorContains(t, err, "quoted octal string")

	for _, bad := range []string{`"abc"`, `"1777"`, `"08"`} {
		_, err = load(t, "local_api:\n  info:\n    enabled: true\n    socket: /run/nebula/info.sock\n    socket_mode: "+bad+"\n")
		require.Error(t, err, bad)
		require.ErrorContains(t, err, "not an octal file mode", bad)
	}

	_, err = load(t, fmt.Sprintf("local_api:\n  info:\n    enabled: true\n    socket: /%s\n", strings.Repeat("x", sunPathMax)))
	require.Error(t, err)
	assert.ErrorContains(t, err, "too long")
}

// TestWireInfoFollowsConfig: off by default, up when enabled, down when disabled, and
// never on the control socket's path.
func TestWireInfoFollowsConfig(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	t.Cleanup(cancel)

	ctlPath := testSocket(t)
	infoPath := testSocket(t)
	sectionWithMode := func(enabled bool, socket, mode string) string {
		return fmt.Sprintf("local_api:\n  control:\n    socket: %s\n  info:\n    enabled: %t\n    socket: %s\n    socket_mode: \"%s\"\n", ctlPath, enabled, socket, mode)
	}
	section := func(enabled bool, socket string) string {
		return sectionWithMode(enabled, socket, "0600")
	}

	c := config.NewC(test.NewLogger())
	require.NoError(t, c.LoadString(section(false, infoPath)))

	var logs lockedBuffer
	eps := Wire(ctx, test.NewLoggerWithOutput(&logs), c, infoRegistry())
	t.Cleanup(eps.Stop)
	assert.Equal(t, ctlPath, eps.Control.Path())
	assert.Empty(t, eps.Info.Path(), "off until enabled")

	require.NoError(t, c.ReloadConfigString(section(true, infoPath)).Err)
	assert.Equal(t, infoPath, eps.Info.Path())
	status, body := test.HTTPGet(t, infoPath, "/v1/whoami?name=alice")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"alice"}`, body)

	// A reload that changes nothing leaves it where it is.
	require.NoError(t, c.ReloadConfigString(section(true, infoPath)).Err)
	assert.Equal(t, infoPath, eps.Info.Path())

	// A reload that changes only the mode applies it in place.
	require.NoError(t, c.ReloadConfigString(sectionWithMode(true, infoPath, "0660")).Err)
	assert.Equal(t, infoPath, eps.Info.Path())
	fi, err := os.Stat(infoPath)
	require.NoError(t, err)
	assert.Equal(t, os.FileMode(0660), fi.Mode().Perm())

	// A reload that moves the socket moves it, and removes the old one.
	moved := testSocket(t)
	require.NoError(t, c.ReloadConfigString(section(true, moved)).Err)
	assert.Equal(t, moved, eps.Info.Path())
	_, err = os.Stat(infoPath)
	assert.True(t, os.IsNotExist(err))
	status, body = test.HTTPGet(t, moved, "/v1/whoami?name=bob")
	assert.Equal(t, http.StatusOK, status)
	assert.JSONEq(t, `{"name":"bob"}`, body)
	require.NoError(t, c.ReloadConfigString(section(true, infoPath)).Err)
	require.Equal(t, infoPath, eps.Info.Path())

	// The control socket's path is refused, and the running endpoint is kept, which is
	// what the log says.
	require.NoError(t, c.ReloadConfigString(section(true, ctlPath)).Err)
	assert.Equal(t, infoPath, eps.Info.Path())
	assert.Equal(t, ctlPath, eps.Control.Path())
	assert.Contains(t, logs.String(), "keeping the current endpoint")
	assert.NotContains(t, logs.String(), "Local info API is not available")

	require.NoError(t, c.ReloadConfigString(section(false, infoPath)).Err)
	assert.Empty(t, eps.Info.Path())
	_, err = os.Stat(infoPath)
	assert.True(t, os.IsNotExist(err))

	// One Stop takes both down.
	require.NoError(t, c.ReloadConfigString(section(true, infoPath)).Err)
	eps.Stop()
	assert.Empty(t, eps.Info.Path())
	assert.Empty(t, eps.Control.Path())
}

// TestWireInfoKeepsRunningOnABadReload: a typo in the section must not cut off the
// programs relying on the endpoint; the operator is told and the endpoint stays.
func TestWireInfoKeepsRunningOnABadReload(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	t.Cleanup(cancel)

	infoPath := testSocket(t)
	good := fmt.Sprintf("local_api:\n  info:\n    enabled: true\n    socket: %s\n", infoPath)

	c := config.NewC(test.NewLogger())
	require.NoError(t, c.LoadString(good))

	srv := wireInfo(ctx, test.NewLogger(), c, infoRegistry())
	t.Cleanup(srv.Stop)
	require.Equal(t, infoPath, srv.Path())

	require.NoError(t, c.ReloadConfigString(good+"    socket_mode: 0660\n").Err)
	assert.Equal(t, infoPath, srv.Path())
	status, _ := test.HTTPGet(t, infoPath, "/v1/whoami")
	assert.Equal(t, http.StatusOK, status)
}

// rawInfoRequest opens the socket and writes req as it is, so a test can send what an
// HTTP client would not: a body that never arrives. It returns the connection.
func rawInfoRequest(t *testing.T, path, req string) net.Conn {
	t.Helper()
	conn, err := net.DialTimeout("unix", path, time.Second)
	require.NoError(t, err)
	t.Cleanup(func() { _ = conn.Close() })
	_, err = conn.Write([]byte(req))
	require.NoError(t, err)
	return conn
}

// TestInfoRefusesARequestBody: a request that announces a body is answered 400 at once,
// before the body arrives, and the connection is closed once the read deadline has ended
// the wait for it, so a client that never sends the body holds its slot for the deadline
// and no longer.
func TestInfoRefusesARequestBody(t *testing.T) {
	oldHeader, oldRead := infoReadHeaderTimeout, infoReadTimeout
	infoReadHeaderTimeout, infoReadTimeout = 200*time.Millisecond, 300*time.Millisecond
	t.Cleanup(func() { infoReadHeaderTimeout, infoReadTimeout = oldHeader, oldRead })
	_, path := serveInfo(t, infoRegistry(), 0600)

	start := time.Now()
	conn := rawInfoRequest(t, path, "GET /v1/whoami HTTP/1.1\r\nHost: nebula\r\nContent-Length: 10\r\n\r\n")
	require.NoError(t, conn.SetReadDeadline(time.Now().Add(2*time.Second)))
	res, err := http.ReadResponse(bufio.NewReader(conn), nil)
	require.NoError(t, err)
	body, _ := io.ReadAll(res.Body)
	res.Body.Close()
	assert.Equal(t, http.StatusBadRequest, res.StatusCode)
	assert.Contains(t, string(body), "takes no request body")
	assert.True(t, res.Close, "the connection is not kept for another request")
	assert.Less(t, time.Since(start), 200*time.Millisecond, "answered before the body, which never comes")

	_, err = conn.Read(make([]byte, 1))
	require.ErrorIs(t, err, io.EOF, "the server closed the connection")
	assert.Less(t, time.Since(start), time.Second, "and did so at the read deadline, not later")
}

// TestInfoDropsASlowClient: a client that sends its headers and then nothing loses its
// connection at the read timeout rather than holding a slot for as long as it likes.
func TestInfoDropsASlowClient(t *testing.T) {
	oldHeader, oldRead := infoReadHeaderTimeout, infoReadTimeout
	infoReadHeaderTimeout, infoReadTimeout = 200*time.Millisecond, 300*time.Millisecond
	t.Cleanup(func() { infoReadHeaderTimeout, infoReadTimeout = oldHeader, oldRead })
	_, path := serveInfo(t, infoRegistry(), 0600)

	// Half a request line, then silence: the header deadline ends it.
	conn := rawInfoRequest(t, path, "GET /v1/whoami HTTP/1.1\r\nHost: neb")
	require.NoError(t, conn.SetReadDeadline(time.Now().Add(2*time.Second)))
	start := time.Now()
	_, err := conn.Read(make([]byte, 1))
	require.Error(t, err, "the server closed the connection")
	assert.Less(t, time.Since(start), time.Second)

	// And the server still answers the next client.
	status, _ := test.HTTPGet(t, path, "/v1/whoami")
	assert.Equal(t, http.StatusOK, status)
}