// Copyright (C) 2014 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 ignore

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

	"github.com/syncthing/syncthing/lib/build"
	"github.com/syncthing/syncthing/lib/fs"
	"github.com/syncthing/syncthing/lib/ignore/ignoreresult"
	"github.com/syncthing/syncthing/lib/osutil"
	"github.com/syncthing/syncthing/lib/rand"
)

const escapePrefixEqual = escapePrefix + "="

var testFiles = map[string]string{
	".stignore": `#include excludes
bfile
dir1/cfile
**/efile
/ffile
lost+found
`,
	"excludes":         "dir2/dfile\n#include further-excludes\n",
	"further-excludes": "dir3\n",
}

func newTestFS() fs.Filesystem {
	testFS := fs.NewFilesystem(fs.FilesystemTypeFake, rand.String(32)+"?content=true&nostfolder=true")

	// Add some data expected by the tests, previously existing on disk.
	testFS.Mkdir("dir3", 0o777)
	for name, content := range testFiles {
		fs.WriteFile(testFS, name, []byte(content), 0o666)
	}

	return testFS
}

func TestIgnore(t *testing.T) {
	testFs := newTestFS()

	pats := New(testFs, WithCache(true))
	err := pats.Load(".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []struct {
		f string
		r bool
	}{
		{"afile", false},
		{"bfile", true},
		{"cfile", false},
		{"dfile", false},
		{"efile", true},
		{"ffile", true},

		{"dir1", false},
		{filepath.Join("dir1", "cfile"), true},
		{filepath.Join("dir1", "dfile"), false},
		{filepath.Join("dir1", "efile"), true},
		{filepath.Join("dir1", "ffile"), false},

		{"dir2", false},
		{filepath.Join("dir2", "cfile"), false},
		{filepath.Join("dir2", "dfile"), true},
		{filepath.Join("dir2", "efile"), true},
		{filepath.Join("dir2", "ffile"), false},

		{filepath.Join("dir3"), true},
		{filepath.Join("dir3", "afile"), true},

		{"lost+found", true},
	}

	for i, tc := range tests {
		if r := pats.Match(tc.f); r.IsIgnored() != tc.r {
			t.Errorf("Incorrect ignoreFile() #%d (%s); E: %v, A: %v", i, tc.f, tc.r, r)
		}
	}
}

func TestExcludes(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	!iex2
	!ign1/ex
	ign1
	i*2
	!ign2
	`
	pats := New(testFs, WithCache(true))
	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []struct {
		f string
		r bool
	}{
		{"ign1", true},
		{"ign2", true},
		{"ibla2", true},
		{"iex2", false},
		{filepath.Join("ign1", "ign"), true},
		{filepath.Join("ign1", "ex"), false},
		{filepath.Join("ign1", "iex2"), false},
		{filepath.Join("iex2", "ign"), false},
		{filepath.Join("foo", "bar", "ign1"), true},
		{filepath.Join("foo", "bar", "ign2"), true},
		{filepath.Join("foo", "bar", "iex2"), false},
	}

	for _, tc := range tests {
		if r := pats.Match(tc.f); r.IsIgnored() != tc.r {
			t.Errorf("Incorrect match for %s: %v != %v", tc.f, r, tc.r)
		}
	}
}

func TestFlagOrder(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	## Ok cases
	(?i)(?d)!ign1
	(?d)(?i)!ign2
	(?i)!(?d)ign3
	(?d)!(?i)ign4
	!(?i)(?d)ign5
	!(?d)(?i)ign6
	## Bad cases
	!!(?i)(?d)ign7
	(?i)(?i)(?d)ign8
	(?i)(?d)(?d)!ign9
	(?d)(?d)!ign10
	`
	pats := New(testFs, WithCache(true))
	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	for i := 1; i < 7; i++ {
		pat := fmt.Sprintf("ign%d", i)
		if r := pats.Match(pat); r.IsIgnored() || r.IsDeletable() {
			t.Errorf("incorrect %s", pat)
		}
	}
	for i := 7; i < 10; i++ {
		pat := fmt.Sprintf("ign%d", i)
		if r := pats.Match(pat); r.IsDeletable() {
			t.Errorf("incorrect %s", pat)
		}
	}

	if r := pats.Match("(?d)!ign10"); !r.IsIgnored() {
		t.Errorf("incorrect")
	}
}

func TestDeletables(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	(?d)ign1
	(?d)(?i)ign2
	(?i)(?d)ign3
	!(?d)ign4
	!ign5
	!(?i)(?d)ign6
	ign7
	(?i)ign8
	`
	pats := New(testFs, WithCache(true))
	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []struct {
		f string
		i bool
		d bool
	}{
		{"ign1", true, true},
		{"ign2", true, true},
		{"ign3", true, true},
		{"ign4", false, false},
		{"ign5", false, false},
		{"ign6", false, false},
		{"ign7", true, false},
		{"ign8", true, false},
	}

	for _, tc := range tests {
		if r := pats.Match(tc.f); r.IsIgnored() != tc.i || r.IsDeletable() != tc.d {
			t.Errorf("Incorrect match for %s: %v != Result{%t, %t}", tc.f, r, tc.i, tc.d)
		}
	}
}

func TestBadPatterns(t *testing.T) {
	testFs := newTestFS()

	t.Skip("to fix: bad pattern not happening")
	badPatterns := []string{
		"[",
		"/[",
		"**/[",
		"#include nonexistent",
		"#include .stignore",
	}

	for _, pat := range badPatterns {
		err := New(testFs, WithCache(true)).Parse(bytes.NewBufferString(pat), ".stignore")
		if err == nil {
			t.Errorf("No error for pattern %q", pat)
		}
		if !IsParseError(err) {
			t.Error("Should have been a parse error:", err)
		}
		if strings.HasPrefix(pat, "#include") {
			if fs.IsNotExist(err) {
				t.Error("Includes should not toss a regular isNotExist error")
			}
		}
	}
}

func TestCaseSensitivity(t *testing.T) {
	testFs := newTestFS()

	ign := New(testFs, WithCache(true))
	err := ign.Parse(bytes.NewBufferString("test"), ".stignore")
	if err != nil {
		t.Error(err)
	}

	match := []string{"test"}
	dontMatch := []string{"foo"}

	if build.IsDarwin || build.IsWindows {
		match = append(match, "TEST", "Test", "tESt")
	} else {
		dontMatch = append(dontMatch, "TEST", "Test", "tESt")
	}

	for _, tc := range match {
		if !ign.Match(tc).IsIgnored() {
			t.Errorf("Incorrect match for %q: should be matched", tc)
		}
	}

	for _, tc := range dontMatch {
		if ign.Match(tc).IsIgnored() {
			t.Errorf("Incorrect match for %q: should not be matched", tc)
		}
	}
}

func TestCaching(t *testing.T) {
	fs := fs.NewFilesystem(fs.FilesystemTypeFake, rand.String(32)+"?content=true")

	fd1, err := osutil.TempFile(fs, "", "")
	if err != nil {
		t.Fatal(err)
	}

	fd2, err := osutil.TempFile(fs, "", "")
	if err != nil {
		t.Fatal(err)
	}

	defer fd1.Close()
	defer fd2.Close()
	defer fs.Remove(fd1.Name())
	defer fs.Remove(fd2.Name())

	_, err = fd1.Write([]byte("/x/\n#include " + filepath.Base(fd2.Name()) + "\n"))
	if err != nil {
		t.Fatal(err)
	}

	fd2.Write([]byte("/y/\n"))

	pats := New(fs, WithCache(true))
	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}

	if pats.matches.len() != 0 {
		t.Fatal("Expected empty cache")
	}

	// Cache some outcomes

	for _, letter := range []string{"a", "b", "x", "y"} {
		pats.Match(letter)
	}

	if pats.matches.len() != 4 {
		t.Fatal("Expected 4 cached results")
	}

	// Reload file, expect old outcomes to be preserved

	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}
	if pats.matches.len() != 4 {
		t.Fatal("Expected 4 cached results")
	}

	// Modify the include file, expect empty cache. Ensure the timestamp on
	// the file changes.

	fd2.Write([]byte("/z/\n"))
	fd2.Sync()
	fakeTime := time.Now().Add(5 * time.Second)
	fs.Chtimes(fd2.Name(), fakeTime, fakeTime)

	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}

	if pats.matches.len() != 0 {
		t.Fatal("Expected 0 cached results")
	}

	// Cache some outcomes again

	for _, letter := range []string{"b", "x", "y"} {
		pats.Match(letter)
	}

	// Verify that outcomes preserved on next load

	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}
	if pats.matches.len() != 3 {
		t.Fatal("Expected 3 cached results")
	}

	// Modify the root file, expect cache to be invalidated

	fd1.Write([]byte("/a/\n"))
	fd1.Sync()
	fakeTime = time.Now().Add(5 * time.Second)
	fs.Chtimes(fd1.Name(), fakeTime, fakeTime)

	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}
	if pats.matches.len() != 0 {
		t.Fatal("Expected cache invalidation")
	}

	// Cache some outcomes again

	for _, letter := range []string{"b", "x", "y"} {
		pats.Match(letter)
	}

	// Verify that outcomes provided on next load

	err = pats.Load(fd1.Name())
	if err != nil {
		t.Fatal(err)
	}
	if pats.matches.len() != 3 {
		t.Fatal("Expected 3 cached results")
	}
}

func TestCommentsAndBlankLines(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	// foo
	//bar

	//!baz
	//#dex

	//                        ips


	`
	pats := New(testFs, WithCache(true))
	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Error(err)
	}
	if len(pats.patterns) > 0 {
		t.Errorf("Expected no patterns")
	}
}

var result ignoreresult.R

func BenchmarkMatch(b *testing.B) {
	testFs := newTestFS()

	stignore := `
.frog
.frog*
.frogfox
.whale
.whale/*
.dolphin
.dolphin/*
~ferret~.*
.ferret.*
flamingo.*
flamingo
*.crow
*.crow
	`
	pats := New(testFs)
	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		b.Error(err)
	}

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		result = pats.Match("filename")
	}
}

func BenchmarkMatchCached(b *testing.B) {
	stignore := `
.frog
.frog*
.frogfox
.whale
.whale/*
.dolphin
.dolphin/*
~ferret~.*
.ferret.*
flamingo.*
flamingo
*.crow
*.crow
	`
	// Caches per file, hence write the patterns to a file.

	fs := fs.NewFilesystem(fs.FilesystemTypeFake, rand.String(32)+"?content=true")

	fd, err := osutil.TempFile(fs, "", "")
	if err != nil {
		b.Fatal(err)
	}

	_, err = fd.Write([]byte(stignore))
	defer fd.Close()
	defer fs.Remove(fd.Name())
	if err != nil {
		b.Fatal(err)
	}

	// Load the patterns
	pats := New(fs, WithCache(true))
	err = pats.Load(fd.Name())
	if err != nil {
		b.Fatal(err)
	}
	// Cache the outcome for "filename"
	pats.Match("filename")

	// This load should now load the cached outcomes as the set of patterns
	// has not changed.
	err = pats.Load(fd.Name())
	if err != nil {
		b.Fatal(err)
	}
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		result = pats.Match("filename")
	}
}

func TestCacheReload(t *testing.T) {
	fs := fs.NewFilesystem(fs.FilesystemTypeFake, rand.String(32)+"?content=true")

	fd, err := osutil.TempFile(fs, "", "")
	if err != nil {
		t.Fatal(err)
	}

	defer fd.Close()
	defer fs.Remove(fd.Name())

	// Ignore file matches f1 and f2

	_, err = fd.Write([]byte("f1\nf2\n"))
	if err != nil {
		t.Fatal(err)
	}

	pats := New(fs, WithCache(true))
	err = pats.Load(fd.Name())
	if err != nil {
		t.Fatal(err)
	}

	// Verify that both are ignored

	if !pats.Match("f1").IsIgnored() {
		t.Error("Unexpected non-match for f1")
	}
	if !pats.Match("f2").IsIgnored() {
		t.Error("Unexpected non-match for f2")
	}
	if pats.Match("f3").IsIgnored() {
		t.Error("Unexpected match for f3")
	}

	// Rewrite file to match f1 and f3

	err = fd.Truncate(0)
	if err != nil {
		t.Fatal(err)
	}
	_, err = fd.Seek(0, io.SeekStart)
	if err != nil {
		t.Fatal(err)
	}
	_, err = fd.Write([]byte("f1\nf3\n"))
	if err != nil {
		t.Fatal(err)
	}
	fd.Sync()
	fakeTime := time.Now().Add(5 * time.Second)
	fs.Chtimes(fd.Name(), fakeTime, fakeTime)

	err = pats.Load(fd.Name())
	if err != nil {
		t.Fatal(err)
	}

	// Verify that the new patterns are in effect

	if !pats.Match("f1").IsIgnored() {
		t.Error("Unexpected non-match for f1")
	}
	if pats.Match("f2").IsIgnored() {
		t.Error("Unexpected match for f2")
	}
	if !pats.Match("f3").IsIgnored() {
		t.Error("Unexpected non-match for f3")
	}
}

func TestHash(t *testing.T) {
	testFs := newTestFS()

	p1 := New(testFs, WithCache(true))
	err := p1.Load(".stignore")
	if err != nil {
		t.Fatal(err)
	}

	// Same list of patterns as .stignore, after expansion
	stignore := `
	dir2/dfile
	dir3
	bfile
	dir1/cfile
	**/efile
	/ffile
	lost+found
	`
	p2 := New(testFs, WithCache(true))
	err = p2.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	// Not same list of patterns
	stignore = `
	dir2/dfile
	dir3
	bfile
	dir1/cfile
	/ffile
	lost+found
	`
	p3 := New(testFs, WithCache(true))
	err = p3.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	if p1.Hash() == "" {
		t.Error("p1 hash blank")
	}
	if p2.Hash() == "" {
		t.Error("p2 hash blank")
	}
	if p3.Hash() == "" {
		t.Error("p3 hash blank")
	}
	if p1.Hash() != p2.Hash() {
		t.Error("p1-p2 hashes differ")
	}
	if p1.Hash() == p3.Hash() {
		t.Error("p1-p3 hashes same")
	}
}

func TestHashOfEmpty(t *testing.T) {
	testFs := newTestFS()

	p1 := New(testFs, WithCache(true))

	err := p1.Load(".stignore")
	if err != nil {
		t.Fatal(err)
	}

	firstHash := p1.Hash()

	// Reloading with a non-existent file should empty the patterns and
	// recalculate the hash.
	// e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 is
	// the sah256 of nothing.

	p1.Load("file/does/not/exist")
	secondHash := p1.Hash()

	if firstHash == secondHash {
		t.Error("hash did not change")
	}
	if secondHash != "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855" {
		t.Error("second hash is not hash of empty string")
	}
	if len(p1.patterns) != 0 {
		t.Error("there are more than zero patterns")
	}
}

func TestWindowsPatterns(t *testing.T) {
	testFs := newTestFS()

	// We should accept patterns as both a/b and a\b and match that against
	// both kinds of slash as well.
	if !build.IsWindows {
		t.Skip("Windows specific test")
		return
	}

	stignore := `
	a/b
	c\d
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []string{`a\b`, `c\d`}
	for _, pat := range tests {
		if !pats.Match(pat).IsIgnored() {
			t.Errorf("Should match %s", pat)
		}
	}
}

func TestAutomaticCaseInsensitivity(t *testing.T) {
	testFs := newTestFS()

	// We should do case insensitive matching by default on some platforms.
	if !build.IsWindows && !build.IsDarwin {
		t.Skip("Windows/Mac specific test")
		return
	}

	stignore := `
	A/B
	c/d
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []string{`a/B`, `C/d`}
	for _, pat := range tests {
		if !pats.Match(pat).IsIgnored() {
			t.Errorf("Should match %s", pat)
		}
	}
}

func TestCommas(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	foo,bar.txt
	{baz,quux}.txt
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	tests := []struct {
		name  string
		match bool
	}{
		{"foo.txt", false},
		{"bar.txt", false},
		{"foo,bar.txt", true},
		{"baz.txt", true},
		{"quux.txt", true},
		{"baz,quux.txt", false},
	}

	for _, tc := range tests {
		if pats.Match(tc.name).IsIgnored() != tc.match {
			t.Errorf("Match of %s was %v, should be %v", tc.name, !tc.match, tc.match)
		}
	}
}

func TestIssue3164(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	(?d)(?i)*.part
	(?d)(?i)/foo
	(?d)(?i)**/bar
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	expanded := pats.Patterns()
	t.Log(expanded)
	expected := []string{
		"(?d)(?i)*.part",
		"(?d)(?i)**/*.part",
		"(?d)(?i)*.part/**",
		"(?d)(?i)**/*.part/**",
		"(?d)(?i)/foo",
		"(?d)(?i)/foo/**",
		"(?d)(?i)**/bar",
		"(?d)(?i)bar",
		"(?d)(?i)**/bar/**",
		"(?d)(?i)bar/**",
	}

	if len(expanded) != len(expected) {
		t.Errorf("Unmatched count: %d != %d", len(expanded), len(expected))
	}

	for i := range expanded {
		if expanded[i] != expected[i] {
			t.Errorf("Pattern %d does not match: %s != %s", i, expanded[i], expected[i])
		}
	}
}

func TestIssue3174(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	*ä*
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	// The pattern above is normalized when parsing, and in order for this
	// string to match the pattern, it needs to use the same normalization. And
	// Go always uses NFC regardless of OS, while we use NFD on macos.
	if !pats.Match(nativeUnicodeNorm("åäö")).IsIgnored() {
		t.Error("Should match")
	}
}

func TestIssue3639(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	foo/
	`
	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	if !pats.Match("foo/bar").IsIgnored() {
		t.Error("Should match 'foo/bar'")
	}

	if pats.Match("foo").IsIgnored() {
		t.Error("Should not match 'foo'")
	}
}

func TestIssue3674(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	a*b
	a**c
	`

	testcases := []struct {
		file    string
		matches bool
	}{
		{"ab", true},
		{"asdfb", true},
		{"ac", true},
		{"asdfc", true},
		{"as/db", false},
		{"as/dc", true},
	}

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	for _, tc := range testcases {
		res := pats.Match(tc.file).IsIgnored()
		if res != tc.matches {
			t.Errorf("Matches(%q) == %v, expected %v", tc.file, res, tc.matches)
		}
	}
}

func TestGobwasGlobIssue18(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	a?b
	bb?
	`

	testcases := []struct {
		file    string
		matches bool
	}{
		{"ab", false},
		{"acb", true},
		{"asdb", false},
		{"bb", false},
		{"bba", true},
		{"bbaa", false},
	}

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	for _, tc := range testcases {
		res := pats.Match(tc.file).IsIgnored()
		if res != tc.matches {
			t.Errorf("Matches(%q) == %v, expected %v", tc.file, res, tc.matches)
		}
	}
}

func TestRoot(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	!/a
	/*
	`

	testcases := []struct {
		file    string
		matches bool
	}{
		{".", false},
		{"a", false},
		{"b", true},
	}

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	for _, tc := range testcases {
		res := pats.Match(tc.file).IsIgnored()
		if res != tc.matches {
			t.Errorf("Matches(%q) == %v, expected %v", tc.file, res, tc.matches)
		}
	}
}

func TestLines(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	#include excludes

	!/a
	/*
	!/a
	`

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	expectedLines := []string{
		"",
		"#include excludes",
		"",
		"!/a",
		"/*",
		"!/a",
		"",
	}

	lines := pats.Lines()
	if len(lines) != len(expectedLines) {
		t.Fatalf("len(Lines()) == %d, expected %d", len(lines), len(expectedLines))
	}
	for i := range lines {
		if lines[i] != expectedLines[i] {
			t.Fatalf("Lines()[%d] == %s, expected %s", i, lines[i], expectedLines[i])
		}
	}
}

func TestDuplicateLines(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	!/a
	/*
	!/a
	`
	stignoreFiltered := `
	!/a
	/*
	`

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}
	patsLen := len(pats.patterns)

	err = pats.Parse(bytes.NewBufferString(stignoreFiltered), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	if patsLen != len(pats.patterns) {
		t.Fatalf("Parsed patterns differ when manually removing duplicate lines")
	}
}

func TestIssue4680(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	#snapshot
	`

	testcases := []struct {
		file    string
		matches bool
	}{
		{"#snapshot", true},
		{"#snapshot/foo", true},
	}

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	for _, tc := range testcases {
		res := pats.Match(tc.file).IsIgnored()
		if res != tc.matches {
			t.Errorf("Matches(%q) == %v, expected %v", tc.file, res, tc.matches)
		}
	}
}

func TestIssue4689(t *testing.T) {
	testFs := newTestFS()

	stignore := `// orig`

	pats := New(testFs, WithCache(true))

	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	if lines := pats.Lines(); len(lines) != 1 || lines[0] != "// orig" {
		t.Fatalf("wrong lines parsing original comment:\n%q", lines)
	}

	stignore = `// new`

	err = pats.Parse(bytes.NewBufferString(stignore), ".stignore")
	if err != nil {
		t.Fatal(err)
	}

	if lines := pats.Lines(); len(lines) != 1 || lines[0] != "// new" {
		t.Fatalf("wrong lines parsing changed comment:\n%v", lines)
	}
}

func TestIssue4901(t *testing.T) {
	testFs := newTestFS()

	stignore := `
	#include unicorn-lazor-death
	puppy
	`

	pats := New(testFs, WithCache(true))

	fd, err := pats.fs.Create(".stignore")
	if err != nil {
		t.Fatalf(err.Error())
	}
	if _, err := fd.Write([]byte(stignore)); err != nil {
		t.Fatal(err)
	}

	// Cache does not suddenly make the load succeed.
	for i := 0; i < 2; i++ {
		err := pats.Load(".stignore")
		if err == nil {
			t.Fatal("expected an error")
		}
		if err == fs.ErrNotExist {
			t.Fatalf("unexpected error type: %T", err)
		}
		if !IsParseError(err) {
			t.Fatal("failure to load included file should be a parse error")
		}
	}

	fd, err = pats.fs.Create("unicorn-lazor-death")
	if err != nil {
		t.Fatalf(err.Error())
	}
	if _, err := fd.Write([]byte(" ")); err != nil {
		t.Fatal(err)
	}

	err = pats.Load(".stignore")
	if err != nil {
		t.Fatalf("unexpected error: %s", err.Error())
	}
}

// TestIssue5009 checks that ignored dirs are only skipped if there are no include patterns.
// https://github.com/syncthing/syncthing/issues/5009 (rc-only bug)
func TestIssue5009(t *testing.T) {
	testFs := newTestFS()

	pats := New(testFs, WithCache(true))

	stignore := `
	ign1
	i*2
	`
	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}
	if m := pats.Match("ign2"); !m.CanSkipDir() {
		t.Error("CanSkipDir should be true without excludes")
	}

	stignore = `
	!iex2
	!ign1/ex
	ign1
	i*2
	!ign2
	`

	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}

	if m := pats.Match("ign2"); m.CanSkipDir() {
		t.Error("CanSkipDir should not be true with excludes")
	}
}

func TestSpecialChars(t *testing.T) {
	testFs := newTestFS()

	pats := New(testFs, WithCache(true))

	stignore := `(?i)/#recycle
(?i)/#nosync
(?i)/$Recycle.bin
(?i)/$RECYCLE.BIN
(?i)/System Volume Information`
	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}

	cases := []string{
		"#nosync",
		"$RECYCLE.BIN",
		filepath.FromSlash("$RECYCLE.BIN/S-1-5-18/desktop.ini"),
	}

	for _, c := range cases {
		if !pats.Match(c).IsIgnored() {
			t.Errorf("%q should be ignored", c)
		}
	}
}

func TestIntlWildcards(t *testing.T) {
	testFs := newTestFS()

	pats := New(testFs, WithCache(true))

	stignore := `1000春
200?春
300[0-9]春
400[0-9]?`
	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}

	cases := []string{
		"1000春",
		"2002春",
		"3003春",
		"4004春",
	}

	for _, c := range cases {
		if !pats.Match(c).IsIgnored() {
			t.Errorf("%q should be ignored", c)
		}
	}
}

func TestPartialIncludeLine(t *testing.T) {
	testFs := newTestFS()

	// Loading a partial #include line (no file mentioned) should error but not crash.

	pats := New(testFs, WithCache(true))

	cases := []string{
		"#include",
		"#include\n",
		"#include ",
		"#include \n",
		"#include   \n\n\n",
	}

	for _, tc := range cases {
		err := pats.Parse(bytes.NewBufferString(tc), ".stignore")
		if err == nil {
			t.Fatal("should error out")
		}
		if !IsParseError(err) {
			t.Fatal("failure to load included file should be a parse error")
		}
	}
}

func TestSkipIgnoredDirs(t *testing.T) {
	testFs := newTestFS()

	tcs := []struct {
		pattern  string
		expected bool
	}{
		{`!/test`, true},
		{`!/t[eih]t`, true},
		{`!/t*t`, true},
		{`!/t?t`, true},
		{`!/**`, true},
		{`!/parent/test`, false},
		{`!/parent/t[eih]t`, false},
		{`!/parent/t*t`, false},
		{`!/parent/t?t`, false},
		{`!/**.mp3`, false},
		{`!/pa*nt/test`, false},
		{`!/pa[sdf]nt/t[eih]t`, false},
		{`!/lowest/pa[sdf]nt/test`, false},
		{`!/lo*st/parent/test`, false},
		{`/pa*nt/test`, true},
		{`test`, true},
		{`*`, true},
	}

	for _, tc := range tcs {
		pats, err := parseLine(tc.pattern)
		if err != nil {
			t.Error(err)
		}
		for _, pat := range pats {
			if got := pat.allowsSkippingIgnoredDirs(); got != tc.expected {
				t.Errorf(`Pattern "%v": got %v, expected %v`, pat, got, tc.expected)
			}
		}
	}

	pats := New(testFs, WithCache(true))

	stignore := `
	/foo/ign*
	!/f*
	!/bar
	*
	`
	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}
	if m := pats.Match("whatever"); !m.CanSkipDir() {
		t.Error("CanSkipDir should be true")
	}

	stignore = `
	!/foo/ign*
	*
	`
	if err := pats.Parse(bytes.NewBufferString(stignore), ".stignore"); err != nil {
		t.Fatal(err)
	}
	if m := pats.Match("whatever"); m.CanSkipDir() {
		t.Error("CanSkipDir should be false")
	}
}

func TestEmptyPatterns(t *testing.T) {
	testFs := newTestFS()

	// These patterns are all invalid and should be rejected as such (without panicking...)
	tcs := []string{
		"!",
		"(?d)",
		"(?i)",
	}

	for _, tc := range tcs {
		m := New(testFs)
		err := m.Parse(strings.NewReader(tc), ".stignore")
		if err == nil {
			t.Error("Should reject invalid pattern", tc)
		}
		if !IsParseError(err) {
			t.Fatal("bad pattern should be a parse error")
		}
	}
}

func TestWindowsLineEndings(t *testing.T) {
	testFs := newTestFS()

	if !build.IsWindows {
		t.Skip("Windows specific")
	}
	lines := "foo\nbar\nbaz\n"

	m := New(testFs)
	if err := m.Parse(strings.NewReader(lines), ".stignore"); err != nil {
		t.Fatal(err)
	}
	if err := WriteIgnores(testFs, ".stignore", m.Lines()); err != nil {
		t.Fatal(err)
	}

	fd, err := testFs.Open(".stignore")
	if err != nil {
		t.Fatal(err)
	}
	bs, err := io.ReadAll(fd)
	fd.Close()
	if err != nil {
		t.Fatal(err)
	}

	unixLineEndings := bytes.Count(bs, []byte("\n"))
	windowsLineEndings := bytes.Count(bs, []byte("\r\n"))
	if unixLineEndings == 0 || windowsLineEndings != unixLineEndings {
		t.Error("expected there to be a non-zero number of Windows line endings")
	}
}

type escapeTest struct {
	pattern string
	match   string
	want    bool
}

// pathSepIsBackslash could also be set to build.IsWindows, but this will work
// on any platform where the os.PathSeparator is a backslash (which is
// currently only Windows).
const pathSepIsBackslash = os.PathSeparator == '\\'

var backslashTests = []escapeTest{
	{`a`, `a`, true},

	{`a*`, `a`, true},
	{`a*b`, `ab`, true},
	{`*a`, `a`, true},
	{`*a*`, `a`, true},

	{`a?`, `ab`, true},
	{`a?b`, `acb`, true},
	{`?a`, `ba`, true},
	{`?a?`, `bac`, true},

	{`a[bc]`, `ab`, true},
	{`a[bc]d`, `abd`, true},
	{`[ab]c`, `ac`, true},
	{`[ab]c[de]`, `acd`, true},

	{`a{b,c}`, `ab`, true},
	{`a{b,c}d`, `abd`, true},
	{`{a,b}c`, `ac`, true},
	{`{a,b}c{d,e}`, `acd`, true},

	{`a/**`, `a/b/c`, true},
	{`a**c`, `a/b/c`, true},
	{`**/c`, `a/b/c`, true},
	{`a**b**c`, `a/b/c`, true},
	{`**/c/**`, `a/b/c/d/e`, true},

	{`a]b`, `a]b`, true},
	{`a}b`, `a}b`, true},

	{`a\*`, `a*`, !pathSepIsBackslash},
	{`a\*b`, `a*b`, !pathSepIsBackslash},
	{`\*a`, `*a`, true}, // backslash is first character
	{`\*a\*`, `*a*`, !pathSepIsBackslash},

	{`a\?`, `a?`, !pathSepIsBackslash},
	{`a\?b`, `a?b`, !pathSepIsBackslash},
	{`\?a`, `?a`, true}, // backslash is first character
	{`\?a\?`, `?a?`, !pathSepIsBackslash},

	{`a\[bc\]`, `a[bc]`, !pathSepIsBackslash},
	{`a\[bc\]d`, `a[bc]d`, !pathSepIsBackslash},
	{`\[ab\]c`, `[ab]c`, !pathSepIsBackslash},
	{`\[ab\]c\[de\]`, `[ab]c[de]`, !pathSepIsBackslash},

	{`a\{b,c\}`, `a{b,c}`, !pathSepIsBackslash},
	{`a\{b,c\}d`, `a{b,c}d`, !pathSepIsBackslash},
	{`\{a,b\}c`, `{a,b}c`, !pathSepIsBackslash},
	{`\{a,b\}c\{d,e\}`, `{a,b}c{d,e}`, !pathSepIsBackslash},

	{`a/\*\*`, `a/**`, !pathSepIsBackslash},
	{`a\*\*c`, `a**c`, !pathSepIsBackslash},
	{`\*\*/c`, `**/c`, !pathSepIsBackslash},
	{`a\*\*b\*\*c`, `a**b**c`, !pathSepIsBackslash},
	{`\*\*/c/\*\*`, `**/c/**`, !pathSepIsBackslash},

	{`\a`, `a`, true}, // backslash is first character

	{`\a\b`, `ab`, !pathSepIsBackslash},
	{`\a\b`, `a/b`, pathSepIsBackslash},

	{`a\r\n`, `arn`, !pathSepIsBackslash},
	{`a\r\n`, `a/r/n`, pathSepIsBackslash},

	{`\a\r\n`, `arn`, !pathSepIsBackslash},
	{`\a\r\n`, `a/r/n`, pathSepIsBackslash},
	{`\a\r\n`, `/a/r/n`, false}, // leading backslash is stripped off
}

// TestEscapeBackslash tests backslash (\) as the escape character.
func TestEscapeBackslash(t *testing.T) {
	testEscape(t, backslashTests, true)
}

// pipeTests contains the same wants as backslashTests, but
// !pathSepIsBackslash is changed to true and
// pathSepIsBackslash is changed to false.
var pipeTests = []escapeTest{
	{`a|*`, `a*`, true},
	{`a|*b`, `a*b`, true},
	{`|*a`, `*a`, true}, // backslash is first character
	{`|*a|*`, `*a*`, true},

	{`a|?`, `a?`, true},
	{`a|?b`, `a?b`, true},
	{`|?a`, `?a`, true}, // backslash is first character
	{`|?a|?`, `?a?`, true},

	{`a|[bc|]`, `a[bc]`, true},
	{`a|[bc|]d`, `a[bc]d`, true},
	{`|[ab|]c`, `[ab]c`, true},
	{`|[ab|]c|[de|]`, `[ab]c[de]`, true},

	{`a|{b,c|}`, `a{b,c}`, true},
	{`a|{b,c|}d`, `a{b,c}d`, true},
	{`|{a,b|}c`, `{a,b}c`, true},
	{`|{a,b|}c|{d,e|}`, `{a,b}c{d,e}`, true},

	{`a/|*|*`, `a/**`, true},
	{`a|*|*c`, `a**c`, true},
	{`|*|*/c`, `**/c`, true},
	{`a|*|*b|*|*c`, `a**b**c`, true},
	{`|*|*/c/|*|*`, `**/c/**`, true},

	{`a]b`, `a]b`, true},
	{`a}b`, `a}b`, true},

	{`|a`, `a`, true}, // backslash is first character

	{`|a|b`, `ab`, true},
	{`|a|b`, `a/b`, false},

	{`a|r|n`, `arn`, true},
	{`a|r|n`, `a/r/n`, false},

	{`|a|r|n`, `arn`, true},
	{`|a|r|n`, `a/r/n`, false},
	{`|a|r|n`, `/a/r/n`, false}, // leading backslash is stripped off
}

// TestEscapePipe tests when pipe (|) is the defaultEscapeChar character
// (as it is on Windows).
func TestEscapePipe(t *testing.T) {
	if defaultEscapeChar != '|' {
		t.Skip("Skipping: defaultEscapeChar is not a '|'")
	}

	testEscape(t, pipeTests, true)
}

// overrideBackslashTests has the same wants as the pipeTests tests.
// The only difference in the tests is the pipe symbol in the pattern has been
// changed to a backslash. This could be done programmatically, if desired.
var overrideBackslashTests = []escapeTest{
	{`a\*`, `a*`, true},
	{`a\*b`, `a*b`, true},
	{`\*a`, `*a`, true}, // backslash is first character
	{`\*a\*`, `*a*`, true},

	{`a\?`, `a?`, true},
	{`a\?b`, `a?b`, true},
	{`\?a`, `?a`, true}, // backslash is first character
	{`\?a\?`, `?a?`, true},

	{`a\[bc\]`, `a[bc]`, true},
	{`a\[bc\]d`, `a[bc]d`, true},
	{`\[ab\]c`, `[ab]c`, true},
	{`\[ab\]c\[de\]`, `[ab]c[de]`, true},

	{`a\{b,c\}`, `a{b,c}`, true},
	{`a\{b,c\}d`, `a{b,c}d`, true},
	{`\{a,b\}c`, `{a,b}c`, true},
	{`\{a,b\}c\{d,e\}`, `{a,b}c{d,e}`, true},

	{`a/\*\*`, `a/**`, true},
	{`a\*\*c`, `a**c`, true},
	{`\*\*/c`, `**/c`, true},
	{`a\*\*b\*\*c`, `a**b**c`, true},
	{`\*\*/c/\*\*`, `**/c/**`, true},

	{`a]b`, `a]b`, true},
	{`a}b`, `a}b`, true},

	{`\a`, `a`, true}, // backslash is first character

	{`\a\b`, `ab`, true},
	{`\a\b`, `a/b`, false},

	{`a\r\n`, `arn`, true},
	{`a\r\n`, `a/r/n`, false},

	{`\a\r\n`, `arn`, true},
	{`\a\r\n`, `a/r/n`, false},
	{`\a\r\n`, `/a/r/n`, false}, // leading backslash is stripped off
}

// TestEscapeOverrideBackslash tests when #escape=\ is in the .stignore file.
func TestEscapeOverrideBackslash(t *testing.T) {
	tests := make([]escapeTest, 0, len(overrideBackslashTests))

	for _, test := range overrideBackslashTests {
		tests = append(tests, escapeTest{
			escapePrefixEqual + "\\\n" + test.pattern,
			test.match,
			test.want,
		})
	}

	testEscape(t, tests, true)
}

// TestEscapeOverridePipe tests when #escape=| (or another character) is in the
// .stignore file.
func TestEscapeOverridePipe(t *testing.T) {
	escapeChars := []string{
		"|",
		">",
		"\u241B", // ␛
	}

	tests := make([]escapeTest, 0, len(pipeTests))

	for _, test := range pipeTests {
		for _, escapeChar := range escapeChars {
			tests = append(tests, escapeTest{
				escapePrefixEqual + escapeChar + "\n" + strings.ReplaceAll(test.pattern, "|", escapeChar),
				test.match,
				test.want,
			})
		}
	}

	testEscape(t, tests, true)
}

var escapePrefixes = []string{
	"",
	"\n",
	"// comment\n",
	"\n// comment\n",
	"#include escape-excludes\n",
	"// comment\n#include escape-excludes\n",
	"#include escape-excludes\n//comment\n",
	"// comment\n#include escape-excludes\n//comment\n",
}

// TestEscapeBeforePattern tests when #escape= is found before a pattern in the
// .stignore file.
func TestEscapeBeforePattern(t *testing.T) {
	tests := make([]escapeTest, 0, len(overrideBackslashTests)*len(escapePrefixes))

	for _, test := range overrideBackslashTests {
		for _, prefix := range escapePrefixes {
			tests = append(tests, escapeTest{
				// Use backslash, as it should not be ignored,
				// so test against the overrideBackslashTests.
				prefix + escapePrefixEqual + "\\\n" + test.pattern,
				test.match,
				test.want,
			})
		}
	}

	testEscape(t, tests, true)
}

// TestEscapeEmpty tests when #escape= (no char) is in the .stignore file.
func TestEscapeEmpty(t *testing.T) {
	suffixes := []string{"", " ", "\t", "=", "= ", "=\t", "x"}

	tests := make([]escapeTest, 0, len(backslashTests)*len(suffixes))

	for _, test := range backslashTests {
		for _, suffix := range suffixes {
			tests = append(tests, escapeTest{
				escapePrefix + suffix + "\n" + test.pattern,
				test.match,
				false,
			})
		}
	}

	testEscape(t, tests, false)
}

// TestEscapeInvalid tests when #escape=x has extra characters after it
func TestEscapeInvalid(t *testing.T) {
	suffixes := []string{"\\\\", "||", "\u241B\u241B", "xx"} // ␛

	tests := make([]escapeTest, 0, len(backslashTests)*len(suffixes))

	for _, test := range backslashTests {
		for _, suffix := range suffixes {
			tests = append(tests, escapeTest{
				escapePrefixEqual + suffix + "\n" + test.pattern,
				test.match,
				false,
			})
		}
	}

	testEscape(t, tests, false)
}

// TestEscapeAfterPattern tests when #escape= is found after a pattern in the
// .stignore file.
func TestEscapeAfterPattern(t *testing.T) {
	suffixes := []string{
		"pattern\n",
		"pattern/\n",
		"pattern/**\n",
	}

	tests := make([]escapeTest, 0, len(backslashTests)*len(escapePrefixes)*len(suffixes))

	for _, test := range backslashTests {
		for _, prefix := range escapePrefixes {
			for _, suffix := range suffixes {
				tests = append(tests, escapeTest{
					// Use a different character, as it should be ignored,
					// so test against the backslashTests.
					prefix + suffix + escapePrefixEqual + "\u241B\n" + test.pattern,
					test.match,
					false,
				})
			}
		}
	}

	testEscape(t, tests, false)
}

// TestEscapeDoubled tests when #escape= is found more than once.
func TestEscapeDoubled(t *testing.T) {
	suffixes := []string{
		"#escape\n",
		"#escape=\n",
		"#escape=\\\n",
		"#escape=|\n",
	}

	tests := make([]escapeTest, 0, len(backslashTests)*len(suffixes))

	for _, test := range backslashTests {
		for _, suffix := range suffixes {
			tests = append(tests, escapeTest{
				escapePrefixEqual + "\\\n" + suffix + test.pattern,
				test.match,
				false,
			})
		}
	}

	testEscape(t, tests, false)
}

var testEscapeFiles = map[string]string{
	"escape-excludes": "dir4\n",
}

func testEscape(t *testing.T, tests []escapeTest, noErrors bool) {
	t.Helper()

	for i, test := range tests {
		testFS := fs.NewFilesystem(fs.FilesystemTypeFake, rand.String(32)+"?content=true&nostfolder=true")

		for name, content := range testEscapeFiles {
			fs.WriteFile(testFS, name, []byte(content), 0o666)
		}
		pats := New(testFS, WithCache(true))

		err := pats.Parse(bytes.NewBufferString(test.pattern), ".stignore")
		if noErrors {
			if err != nil {
				t.Fatalf("%q: err=%v (test %d)", test.pattern, err, i+1)
			}
		} else {
			if err == nil {
				t.Fatalf("%q: got nil, want error (test %d)", test.pattern, i+1)
			}
			continue
		}

		got := pats.Match(test.match).IsIgnored()
		if got != test.want {
			t.Errorf("%-20q: %-20q: got %v, want %v (test %d)", test.pattern, test.match, got, test.want, i+1)
		}
	}
}