// Copyright (C) 2016 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.

package model

import (
	"bytes"
	"errors"
	"io/ioutil"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"

	"github.com/syncthing/syncthing/lib/config"
	"github.com/syncthing/syncthing/lib/db"
	"github.com/syncthing/syncthing/lib/events"
	"github.com/syncthing/syncthing/lib/fs"
	"github.com/syncthing/syncthing/lib/ignore"
	"github.com/syncthing/syncthing/lib/protocol"
)

func TestRequestSimple(t *testing.T) {
	// Verify that the model performs a request and creates a file based on
	// an incoming index update.

	m, fc, tmpDir := setupModelWithConnection()
	defer m.Stop()
	defer os.RemoveAll(tmpDir)

	// We listen for incoming index updates and trigger when we see one for
	// the expected test file.
	done := make(chan struct{})
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		for _, f := range fs {
			if f.Name == "testfile" {
				close(done)
				return
			}
		}
	}
	fc.mut.Unlock()

	// Send an update for the test file, wait for it to sync and be reported back.
	contents := []byte("test file contents\n")
	fc.addFile("testfile", 0644, protocol.FileInfoTypeFile, contents)
	fc.sendIndexUpdate()
	<-done

	// Verify the contents
	if err := equalContents(filepath.Join(tmpDir, "testfile"), contents); err != nil {
		t.Error("File did not sync correctly:", err)
	}
}

func TestSymlinkTraversalRead(t *testing.T) {
	// Verify that a symlink can not be traversed for reading.

	if runtime.GOOS == "windows" {
		t.Skip("no symlink support on CI")
		return
	}

	m, fc, tmpDir := setupModelWithConnection()
	defer m.Stop()
	defer os.RemoveAll(tmpDir)

	// We listen for incoming index updates and trigger when we see one for
	// the expected test file.
	done := make(chan struct{})
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		for _, f := range fs {
			if f.Name == "symlink" {
				close(done)
				return
			}
		}
	}
	fc.mut.Unlock()

	// Send an update for the symlink, wait for it to sync and be reported back.
	contents := []byte("..")
	fc.addFile("symlink", 0644, protocol.FileInfoTypeSymlink, contents)
	fc.sendIndexUpdate()
	<-done

	// Request a file by traversing the symlink
	buf := make([]byte, 10)
	err := m.Request(device1, "default", "symlink/requests_test.go", 0, nil, false, buf)
	if err == nil || !bytes.Equal(buf, make([]byte, 10)) {
		t.Error("Managed to traverse symlink")
	}
}

func TestSymlinkTraversalWrite(t *testing.T) {
	// Verify that a symlink can not be traversed for writing.

	if runtime.GOOS == "windows" {
		t.Skip("no symlink support on CI")
		return
	}

	m, fc, tmpDir := setupModelWithConnection()
	defer m.Stop()
	defer os.RemoveAll(tmpDir)

	// We listen for incoming index updates and trigger when we see one for
	// the expected names.
	done := make(chan struct{}, 1)
	badReq := make(chan string, 1)
	badIdx := make(chan string, 1)
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		for _, f := range fs {
			if f.Name == "symlink" {
				done <- struct{}{}
				return
			}
			if strings.HasPrefix(f.Name, "symlink") {
				badIdx <- f.Name
				return
			}
		}
	}
	fc.requestFn = func(folder, name string, offset int64, size int, hash []byte, fromTemporary bool) ([]byte, error) {
		if name != "symlink" && strings.HasPrefix(name, "symlink") {
			badReq <- name
		}
		return fc.fileData[name], nil
	}
	fc.mut.Unlock()

	// Send an update for the symlink, wait for it to sync and be reported back.
	contents := []byte("..")
	fc.addFile("symlink", 0644, protocol.FileInfoTypeSymlink, contents)
	fc.sendIndexUpdate()
	<-done

	// Send an update for things behind the symlink, wait for requests for
	// blocks for any of them to come back, or index entries. Hopefully none
	// of that should happen.
	contents = []byte("testdata testdata\n")
	fc.addFile("symlink/testfile", 0644, protocol.FileInfoTypeFile, contents)
	fc.addFile("symlink/testdir", 0644, protocol.FileInfoTypeDirectory, contents)
	fc.addFile("symlink/testsyml", 0644, protocol.FileInfoTypeSymlink, contents)
	fc.sendIndexUpdate()

	select {
	case name := <-badReq:
		t.Fatal("Should not have requested the data for", name)
	case name := <-badIdx:
		t.Fatal("Should not have sent the index entry for", name)
	case <-time.After(3 * time.Second):
		// Unfortunately not much else to trigger on here. The puller sleep
		// interval is 1s so if we didn't get any requests within two
		// iterations we should be fine.
	}
}

func TestRequestCreateTmpSymlink(t *testing.T) {
	// Test that an update for a temporary file is invalidated

	m, fc, tmpDir := setupModelWithConnection()
	defer m.Stop()
	defer os.RemoveAll(tmpDir)

	// We listen for incoming index updates and trigger when we see one for
	// the expected test file.
	goodIdx := make(chan struct{})
	name := fs.TempName("testlink")
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		for _, f := range fs {
			if f.Name == name {
				if f.Invalid {
					goodIdx <- struct{}{}
				} else {
					t.Fatal("Received index with non-invalid temporary file")
				}
				return
			}
		}
	}
	fc.mut.Unlock()

	// Send an update for the test file, wait for it to sync and be reported back.
	fc.addFile(name, 0644, protocol.FileInfoTypeSymlink, []byte(".."))
	fc.sendIndexUpdate()

	select {
	case <-goodIdx:
	case <-time.After(3 * time.Second):
		t.Fatal("Timed out without index entry being sent")
	}
}

func TestRequestVersioningSymlinkAttack(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("no symlink support on Windows")
	}

	// Sets up a folder with trashcan versioning and tries to use a
	// deleted symlink to escape

	tmpDir := createTmpDir()
	defer os.RemoveAll(tmpDir)

	cfg := defaultCfgWrapper.RawCopy()
	cfg.Folders[0] = config.NewFolderConfiguration(protocol.LocalDeviceID, "default", "default", fs.FilesystemTypeBasic, tmpDir)
	cfg.Folders[0].Devices = []config.FolderDeviceConfiguration{
		{DeviceID: device1},
		{DeviceID: device2},
	}
	cfg.Folders[0].Versioning = config.VersioningConfiguration{
		Type: "trashcan",
	}
	w, path := createTmpWrapper(cfg)
	defer os.Remove(path)

	db := db.OpenMemory()
	m := NewModel(w, device1, "syncthing", "dev", db, nil)
	m.AddFolder(cfg.Folders[0])
	m.ServeBackground()
	m.StartFolder("default")
	defer m.Stop()

	defer os.RemoveAll(tmpDir)

	fc := addFakeConn(m, device2)
	fc.folder = "default"

	// Create a temporary directory that we will use as target to see if
	// we can escape to it
	tmpdir, err := ioutil.TempDir("", "syncthing-test")
	if err != nil {
		t.Fatal(err)
	}

	// We listen for incoming index updates and trigger when we see one for
	// the expected test file.
	idx := make(chan int)
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		idx <- len(fs)
	}
	fc.mut.Unlock()

	// Send an update for the test file, wait for it to sync and be reported back.
	fc.addFile("foo", 0644, protocol.FileInfoTypeSymlink, []byte(tmpdir))
	fc.sendIndexUpdate()

	for updates := 0; updates < 1; updates += <-idx {
	}

	// Delete the symlink, hoping for it to get versioned
	fc.deleteFile("foo")
	fc.sendIndexUpdate()
	for updates := 0; updates < 1; updates += <-idx {
	}

	// Recreate foo and a file in it with some data
	fc.addFile("foo", 0755, protocol.FileInfoTypeDirectory, nil)
	fc.addFile("foo/test", 0644, protocol.FileInfoTypeFile, []byte("testtesttest"))
	fc.sendIndexUpdate()
	for updates := 0; updates < 1; updates += <-idx {
	}

	// Remove the test file and see if it escaped
	fc.deleteFile("foo/test")
	fc.sendIndexUpdate()
	for updates := 0; updates < 1; updates += <-idx {
	}

	path = filepath.Join(tmpdir, "test")
	if _, err := os.Lstat(path); !os.IsNotExist(err) {
		t.Fatal("File escaped to", path)
	}
}

func TestPullInvalidIgnoredSO(t *testing.T) {
	pullInvalidIgnored(t, config.FolderTypeSendOnly)

}

func TestPullInvalidIgnoredSR(t *testing.T) {
	pullInvalidIgnored(t, config.FolderTypeSendReceive)
}

// This test checks that (un-)ignored/invalid/deleted files are treated as expected.
func pullInvalidIgnored(t *testing.T, ft config.FolderType) {
	t.Helper()

	tmpDir := createTmpDir()
	defer os.RemoveAll(tmpDir)

	cfg := defaultCfgWrapper.RawCopy()
	cfg.Devices = append(cfg.Devices, config.NewDeviceConfiguration(device2, "device2"))
	cfg.Folders[0] = config.NewFolderConfiguration(protocol.LocalDeviceID, "default", "default", fs.FilesystemTypeBasic, tmpDir)
	cfg.Folders[0].Devices = []config.FolderDeviceConfiguration{
		{DeviceID: device1},
		{DeviceID: device2},
	}
	cfg.Folders[0].Type = ft
	m, fc := setupModelWithConnectionManual(cfg)
	defer m.Stop()

	// Reach in and update the ignore matcher to one that always does
	// reloads when asked to, instead of checking file mtimes. This is
	// because we might be changing the files on disk often enough that the
	// mtimes will be unreliable to determine change status.
	m.fmut.Lock()
	m.folderIgnores["default"] = ignore.New(cfg.Folders[0].Filesystem(), ignore.WithChangeDetector(newAlwaysChanged()))
	m.fmut.Unlock()

	if err := m.SetIgnores("default", []string{"*ignored*"}); err != nil {
		panic(err)
	}

	contents := []byte("test file contents\n")
	otherContents := []byte("other test file contents\n")

	invIgn := "invalid:ignored"
	invDel := "invalid:deleted"
	ign := "ignoredNonExisting"
	ignExisting := "ignoredExisting"

	fc.addFile(invIgn, 0644, protocol.FileInfoTypeFile, contents)
	fc.addFile(invDel, 0644, protocol.FileInfoTypeFile, contents)
	fc.deleteFile(invDel)
	fc.addFile(ign, 0644, protocol.FileInfoTypeFile, contents)
	fc.addFile(ignExisting, 0644, protocol.FileInfoTypeFile, contents)
	if err := ioutil.WriteFile(filepath.Join(tmpDir, ignExisting), otherContents, 0644); err != nil {
		panic(err)
	}

	done := make(chan struct{})
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		expected := map[string]struct{}{invIgn: {}, ign: {}, ignExisting: {}}
		for _, f := range fs {
			if _, ok := expected[f.Name]; !ok {
				t.Fatalf("Unexpected file %v was added to index", f.Name)
			}
			if !f.Invalid {
				t.Errorf("File %v wasn't marked as invalid", f.Name)
			}
			delete(expected, f.Name)
		}
		for name := range expected {
			t.Errorf("File %v wasn't added to index", name)
		}
		done <- struct{}{}
	}
	fc.mut.Unlock()

	sub := events.Default.Subscribe(events.FolderErrors)
	defer events.Default.Unsubscribe(sub)

	fc.sendIndexUpdate()

	timeout := time.NewTimer(5 * time.Second)
	select {
	case ev := <-sub.C():
		t.Fatalf("Errors while pulling: %v", ev)
	case <-timeout.C:
		t.Fatalf("timed out before index was received")
	case <-done:
		return
	}

	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		expected := map[string]struct{}{ign: {}, ignExisting: {}}
		for _, f := range fs {
			if _, ok := expected[f.Name]; !ok {
				t.Fatalf("Unexpected file %v was updated in index", f.Name)
			}
			if f.Invalid {
				t.Errorf("File %v is still marked as invalid", f.Name)
			}
			// The unignored files should only have a local version,
			// to mark them as in conflict with any other existing versions.
			ev := protocol.Vector{}.Update(device1.Short())
			if v := f.Version; !v.Equal(ev) {
				t.Errorf("File %v has version %v, expected %v", f.Name, v, ev)
			}
			if f.Name == ign {
				if !f.Deleted {
					t.Errorf("File %v was not marked as deleted", f.Name)
				}
			} else if f.Deleted {
				t.Errorf("File %v is marked as deleted", f.Name)
			}
			delete(expected, f.Name)
		}
		for name := range expected {
			t.Errorf("File %v wasn't updated in index", name)
		}
		done <- struct{}{}
	}
	// Make sure pulling doesn't interfere, as index updates are racy and
	// thus we cannot distinguish between scan and pull results.
	fc.requestFn = func(folder, name string, offset int64, size int, hash []byte, fromTemporary bool) ([]byte, error) {
		return nil, nil
	}
	fc.mut.Unlock()

	if err := m.SetIgnores("default", []string{"*:ignored*"}); err != nil {
		panic(err)
	}

	timeout = time.NewTimer(5 * time.Second)
	select {
	case <-timeout.C:
		t.Fatalf("timed out before index was received")
	case <-done:
		return
	}
}

func TestIssue4841(t *testing.T) {
	m, fc, tmpDir := setupModelWithConnection()
	defer m.Stop()
	defer os.RemoveAll(tmpDir)

	received := make(chan protocol.FileInfo)
	fc.mut.Lock()
	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
		if len(fs) != 1 {
			t.Fatalf("Sent index with %d files, should be 1", len(fs))
		}
		if fs[0].Name != "foo" {
			t.Fatalf(`Sent index with file %v, should be "foo"`, fs[0].Name)
		}
		received <- fs[0]
		return
	}
	fc.mut.Unlock()

	// Setup file from remote that was ignored locally
	m.updateLocals(defaultFolderConfig.ID, []protocol.FileInfo{{
		Name:    "foo",
		Type:    protocol.FileInfoTypeFile,
		Invalid: true,
		Version: protocol.Vector{}.Update(device2.Short()),
	}})
	<-received

	// Scan without ignore patterns with "foo" not existing locally
	if err := m.ScanFolder("default"); err != nil {
		t.Fatal("Failed scanning:", err)
	}

	f := <-received
	if expected := (protocol.Vector{}.Update(device1.Short())); !f.Version.Equal(expected) {
		t.Errorf("Got Version == %v, expected %v", f.Version, expected)
	}
}

func setupModelWithConnection() (*Model, *fakeConnection, string) {
	tmpDir := createTmpDir()
	cfg := defaultCfgWrapper.RawCopy()
	cfg.Devices = append(cfg.Devices, config.NewDeviceConfiguration(device2, "device2"))
	cfg.Folders[0] = config.NewFolderConfiguration(protocol.LocalDeviceID, "default", "default", fs.FilesystemTypeBasic, tmpDir)
	cfg.Folders[0].Devices = []config.FolderDeviceConfiguration{
		{DeviceID: device1},
		{DeviceID: device2},
	}
	m, fc := setupModelWithConnectionManual(cfg)
	return m, fc, tmpDir
}

func setupModelWithConnectionManual(cfg config.Configuration) (*Model, *fakeConnection) {
	w, path := createTmpWrapper(cfg)
	defer os.Remove(path)

	db := db.OpenMemory()
	m := NewModel(w, device1, "syncthing", "dev", db, nil)
	m.AddFolder(cfg.Folders[0])
	m.ServeBackground()
	m.StartFolder("default")

	fc := addFakeConn(m, device2)
	fc.folder = "default"

	m.ScanFolder("default")

	return m, fc
}

func createTmpDir() string {
	tmpDir, err := ioutil.TempDir("testdata", "_request-")
	if err != nil {
		panic("Failed to create temporary testing dir")
	}
	return tmpDir
}

func equalContents(path string, contents []byte) error {
	if bs, err := ioutil.ReadFile(path); err != nil {
		return err
	} else if !bytes.Equal(bs, contents) {
		return errors.New("incorrect data")
	}
	return nil
}