//go:build linux || freebsd

package archive

import (
	"archive/tar"
	"archive/zip"
	"bytes"
	"compress/gzip"
	"io"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// --- DetectArchiveFormat ---

func TestDetectArchiveFormat(t *testing.T) {
	tests := []struct {
		filename string
		expected string
	}{
		// Standard formats
		{"file.tar", "tar"},
		{"file.tar.gz", "tar.gz"},
		{"file.tgz", "tar.gz"},
		{"file.tar.bz2", "tar.bz2"},
		{"file.tbz2", "tar.bz2"},
		{"file.zip", "zip"},
		// Non-archive files
		{"file.txt", ""},
		{"file", ""},
		{"", ""},
		// Case insensitivity
		{"FILE.TAR", "tar"},
		{"ARCHIVE.TAR.GZ", "tar.gz"},
		{"ARCHIVE.TGZ", "tar.gz"},
		{"ARCHIVE.TAR.BZ2", "tar.bz2"},
		{"ARCHIVE.TBZ2", "tar.bz2"},
		{"ARCHIVE.ZIP", "zip"},
		// Mixed case
		{"File.Tar", "tar"},
		{"File.Tar.Gz", "tar.gz"},
		// Paths with directories
		{"path/to/file.tar", "tar"},
		{"/absolute/path/file.tar.gz", "tar.gz"},
		{"./relative/file.zip", "zip"},
		// Edge cases: dotfiles, partial extensions
		{".tar", "tar"},
		{"file.tar.txt", ""},
		{"file.tgz.txt", ""},
		{"file.gzip", ""},
	}

	for _, tt := range tests {
		got := DetectArchiveFormat(tt.filename)
		if got != tt.expected {
			t.Errorf("DetectArchiveFormat(%q) = %q; want %q", tt.filename, got, tt.expected)
		}
	}
}

// --- IsArchiveFormat ---

func TestIsArchiveFormat(t *testing.T) {
	tests := []struct {
		filename string
		expected bool
	}{
		{"file.tar", true},
		{"file.tar.gz", true},
		{"file.tgz", true},
		{"file.tar.bz2", true},
		{"file.tbz2", true},
		{"file.zip", true},
		{"file.txt", false},
		{"file", false},
		{"", false},
		{".tar", true},
		{"file.tar.txt", false},
	}

	for _, tt := range tests {
		got := IsArchiveFormat(tt.filename)
		if got != tt.expected {
			t.Errorf("IsArchiveFormat(%q) = %v; want %v", tt.filename, got, tt.expected)
		}
	}
}

// --- GetArchiveAndCompression ---

func TestGetArchiveAndCompression(t *testing.T) {
	tests := []struct {
		filename        string
		wantArchive     string
		wantCompression string
	}{
		{"file.tar", "tar", ""},
		{"file.tar.gz", "tar", "gzip"},
		{"file.tgz", "tar", "gzip"},
		{"file.tar.bz2", "tar", "bzip2"},
		{"file.tbz2", "tar", "bzip2"},
		{"file.zip", "zip", ""},
		{"file.gz", "", "gzip"},
		{"file.bz2", "", "bzip2"},
		{"file.txt", "", ""},
		{"file", "", ""},
		{"", "", ""},
		// Case insensitivity
		{"FILE.TAR.GZ", "tar", "gzip"},
		{"File.Tar.Bz2", "tar", "bzip2"},
		// Paths
		{"dir/file.tar.bz2", "tar", "bzip2"},
	}

	for _, tt := range tests {
		archive, compression := GetArchiveAndCompression(tt.filename)
		if archive != tt.wantArchive || compression != tt.wantCompression {
			t.Errorf("GetArchiveAndCompression(%q) = (%q, %q); want (%q, %q)",
				tt.filename, archive, compression, tt.wantArchive, tt.wantCompression)
		}
	}
}

// --- BaseExtractor ---

func TestBaseExtractorName(t *testing.T) {
	e := NewBaseExtractor("test-format", []string{".ext1", ".ext2"})
	if got := e.Name(); got != "test-format" {
		t.Errorf("Name() = %q; want %q", got, "test-format")
	}
}

func TestBaseExtractorExtensions(t *testing.T) {
	exts := []string{".ext1", ".ext2"}
	e := NewBaseExtractor("test", exts)
	got := e.Extensions()
	if len(got) != len(exts) {
		t.Fatalf("Extensions() length = %d; want %d", len(got), len(exts))
	}
	for i, ext := range exts {
		if got[i] != ext {
			t.Errorf("Extensions()[%d] = %q; want %q", i, got[i], ext)
		}
	}
}

func TestBaseExtractorExtensionsConsistency(t *testing.T) {
	originalExts := []string{".ext1", ".ext2"}
	e := NewBaseExtractor("test", originalExts)
	got := e.Extensions()
	if len(got) != len(originalExts) {
		t.Fatalf("Extensions() length = %d; want %d", len(got), len(originalExts))
	}
	for i := range originalExts {
		if got[i] != originalExts[i] {
			t.Errorf("Extensions()[%d] = %q; want %q", i, got[i], originalExts[i])
		}
	}
}

func TestBaseExtractorCanHandle(t *testing.T) {
	e := NewBaseExtractor("test", []string{".tar.gz", ".tgz"})

	tests := []struct {
		filename string
		expected bool
	}{
		{"file.tar.gz", true},
		{"file.tgz", true},
		{"file.tar", false},
		{"file.zip", false},
		{"file.TAR.GZ", true}, // case insensitive
		{"file.TGZ", true},
		{"archive.Tar.Gz", true},
		{"", false},
		{"file", false},
		// Paths
		{"path/to/file.tar.gz", true},
		{"/absolute/path/file.tgz", true},
	}

	for _, tt := range tests {
		got := e.CanHandle(tt.filename)
		if got != tt.expected {
			t.Errorf("CanHandle(%q) = %v; want %v", tt.filename, got, tt.expected)
		}
	}
}

func TestBaseExtractorCanHandlePartialSuffix(t *testing.T) {
	// Ensure that ".tar" doesn't match ".tar.gz"
	e := NewBaseExtractor("tar", []string{".tar"})
	if e.CanHandle("file.tar.gz") {
		t.Error("CanHandle('file.tar.gz') should be false for extractor with '.tar' extension")
	}
	if !e.CanHandle("file.tar") {
		t.Error("CanHandle('file.tar') should be true for extractor with '.tar' extension")
	}
}

// --- Registry: Get ---

func TestRegistryGetSuccess(t *testing.T) {
	formats := []string{"tar", "tar.gz", "tar.bz2", "zip"}
	for _, format := range formats {
		e, err := Get(format)
		if err != nil {
			t.Errorf("Get(%q) returned error: %v", format, err)
		}
		if e == nil {
			t.Errorf("Get(%q) returned nil extractor", format)
		}
	}
}

func TestRegistryGetUnknown(t *testing.T) {
	_, err := Get("unknown_format")
	if err == nil {
		t.Error("Get('unknown_format') should return an error")
	}
}

func TestRegistryGetEmptyFormat(t *testing.T) {
	_, err := Get("")
	if err == nil {
		t.Error("Get('') should return an error")
	}
}

func TestRegistryGetCaseInsensitive(t *testing.T) {
	// Registry should handle case-insensitive lookups
	variants := []string{"TAR", "Tar", "tAr"}
	for _, v := range variants {
		e, err := Get(v)
		if err != nil {
			t.Errorf("Get(%q) returned error (should be case-insensitive): %v", v, err)
		}
		if e == nil || e.Name() != "tar" {
			t.Errorf("Get(%q) returned extractor with name %q; want 'tar'", v, e.Name())
		}
	}
}

// --- Registry: GetByFilename ---

func TestRegistryGetByFilename(t *testing.T) {
	tests := []struct {
		filename string
		wantName string
	}{
		{"file.tar", "tar"},
		{"file.tar.gz", "tar.gz"},
		{"file.tgz", "tar.gz"},
		{"file.tar.bz2", "tar.bz2"},
		{"file.tbz2", "tar.bz2"},
		{"file.zip", "zip"},
	}

	for _, tt := range tests {
		e, err := GetByFilename(tt.filename)
		if err != nil {
			t.Errorf("GetByFilename(%q) returned error: %v", tt.filename, err)
			continue
		}
		if e.Name() != tt.wantName {
			t.Errorf("GetByFilename(%q).Name() = %q; want %q", tt.filename, e.Name(), tt.wantName)
		}
	}
}

func TestRegistryGetByFilenameUnknown(t *testing.T) {
	_, err := GetByFilename("file.txt")
	if err == nil {
		t.Error("GetByFilename('file.txt') should return an error")
	}
}

func TestRegistryGetByFilenameEmpty(t *testing.T) {
	_, err := GetByFilename("")
	if err == nil {
		t.Error("GetByFilename('') should return an error")
	}
}

// --- Registry: Supports ---

func TestRegistrySupports(t *testing.T) {
	if !Supports("tar") {
		t.Error("Supports('tar') should be true")
	}
	if !Supports("zip") {
		t.Error("Supports('zip') should be true")
	}
	if Supports("rar") {
		t.Error("Supports('rar') should be false")
	}
	if Supports("7z") {
		t.Error("Supports('7z') should be false")
	}
	if Supports("unknown") {
		t.Error("Supports('unknown') should be false")
	}
}

func TestRegistrySupportsCaseInsensitive(t *testing.T) {
	if !Supports("TAR") {
		t.Error("Supports('TAR') should be true (case-insensitive)")
	}
	if !Supports("Zip") {
		t.Error("Supports('Zip') should be true (case-insensitive)")
	}
}

func TestRegistrySupportsEmpty(t *testing.T) {
	if Supports("") {
		t.Error("Supports('') should be false")
	}
}

// --- Registry: ListSupported ---

func TestRegistryListSupported(t *testing.T) {
	formats := ListSupported()

	// Should contain at least our 4 standard formats
	formatSet := make(map[string]bool)
	for _, f := range formats {
		formatSet[f] = true
	}

	expected := []string{"tar", "tar.gz", "tar.bz2", "zip"}
	for _, exp := range expected {
		if !formatSet[exp] {
			t.Errorf("ListSupported() missing format: %s", exp)
		}
	}
}

func TestRegistryListSupportedNoDuplicates(t *testing.T) {
	formats := ListSupported()
	seen := make(map[string]bool)
	for _, f := range formats {
		if seen[f] {
			t.Errorf("ListSupported() contains duplicate: %s", f)
		}
		seen[f] = true
	}
}

// --- Registration ---

// testExtractor is a simple extractor used for registration tests
type testExtractor struct {
	*BaseExtractor
}

func (e *testExtractor) Extract(_ io.Reader, _ string) error {
	return nil
}

func TestRegisterDuplicate(t *testing.T) {
	// All standard extractors are already registered via init()
	names := []string{"tar", "tar.gz", "tar.bz2", "zip"}
	for _, name := range names {
		e := &testExtractor{NewBaseExtractor(name, []string{".test"})}
		err := Register(e)
		if err == nil {
			t.Errorf("Register(%q) should return error for duplicate registration", name)
		}
	}
}

func TestRegisterSuccess(t *testing.T) {
	// Use a unique name that won't conflict
	e := &testExtractor{NewBaseExtractor("test_uniquereg", []string{".unique"})}
	err := Register(e)
	if err != nil {
		t.Fatalf("Register() returned error: %v", err)
	}

	// Verify it was registered
	if !Supports("test_uniquereg") {
		t.Error("Supports('test_uniquereg') should be true after registration")
	}

	// Verify it can be retrieved
	got, err := Get("test_uniquereg")
	if err != nil {
		t.Errorf("Get('test_uniquereg') returned error: %v", err)
	}
	if got == nil {
		t.Error("Get('test_uniquereg') returned nil")
	}
}

func TestRegisterEmptyName(t *testing.T) {
	e := &testExtractor{NewBaseExtractor("", []string{".ext"})}
	err := Register(e)
	if err == nil {
		t.Error("Register() with empty name should return error")
	}
}

func TestRegisterNilExtractor(t *testing.T) {
	defer func() {
		if r := recover(); r == nil {
			t.Log("Register(nil) did not panic (acceptable behavior)")
		}
	}()
	_ = Register(nil)
}

// --- Extraction: Invalid Data ---

func TestExtractInvalidFormat(t *testing.T) {
	destDir := t.TempDir()
	err := Extract("nonexistent", strings.NewReader("data"), destDir)
	if err == nil {
		t.Error("Extract with unknown format should return error")
	}
}

func TestExtractInvalidTar(t *testing.T) {
	destDir := t.TempDir()
	err := Extract("tar", strings.NewReader("this is not a tar file"), destDir)
	if err == nil {
		t.Error("Extract with invalid tar data should return error")
	}
}

func TestExtractInvalidTarGz(t *testing.T) {
	destDir := t.TempDir()
	err := Extract("tar.gz", strings.NewReader("this is not a gzip file"), destDir)
	if err == nil {
		t.Error("Extract with invalid tar.gz data should return error")
	}
}

func TestExtractInvalidZip(t *testing.T) {
	destDir := t.TempDir()
	err := Extract("zip", strings.NewReader("this is not a zip file"), destDir)
	if err == nil {
		t.Error("Extract with invalid zip data should return error")
	}
}

// --- Extraction: Valid Tar ---

func TestExtractTar(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "testdir/", mode: 0755, typ: tar.TypeDir},
		{name: "testdir/hello.txt", mode: 0644, content: []byte("hello world")},
	})

	err := Extract("tar", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract tar returned error: %v", err)
	}

	// Verify directory exists
	dirInfo, err := os.Stat(filepath.Join(destDir, "testdir"))
	if err != nil {
		t.Fatalf("Failed to stat extracted directory: %v", err)
	}
	if !dirInfo.IsDir() {
		t.Error("Extracted path is not a directory")
	}

	// Verify file exists and has correct content
	data, err = os.ReadFile(filepath.Join(destDir, "testdir", "hello.txt"))
	if err != nil {
		t.Fatalf("Failed to read extracted file: %v", err)
	}
	if string(data) != "hello world" {
		t.Errorf("Extracted file content = %q; want %q", string(data), "hello world")
	}
}

func TestExtractTarMultipleFiles(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "file1.txt", mode: 0644, content: []byte("content1")},
		{name: "file2.txt", mode: 0644, content: []byte("content2")},
		{name: "subdir/nested.txt", mode: 0644, content: []byte("nested content")},
	})

	err := Extract("tar", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract tar returned error: %v", err)
	}

	// Verify all files
	checkFileContent(t, destDir, "file1.txt", "content1")
	checkFileContent(t, destDir, "file2.txt", "content2")
	checkFileContent(t, destDir, "subdir/nested.txt", "nested content")
}

func TestExtractTarEmptyArchive(t *testing.T) {
	destDir := t.TempDir()
	var buf bytes.Buffer
	tw := tar.NewWriter(&buf)
	if err := tw.Close(); err != nil {
		t.Fatal(err)
	}

	err := Extract("tar", &buf, destDir)
	if err != nil {
		t.Fatalf("Extract tar (empty) returned error: %v", err)
	}

	// Directory should exist and be empty
	entries, err := os.ReadDir(destDir)
	if err != nil {
		t.Fatalf("Failed to read destDir: %v", err)
	}
	if len(entries) != 0 {
		t.Errorf("Expected empty directory, got %d entries", len(entries))
	}
}

func TestExtractTarSymlink(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "target.txt", mode: 0644, content: []byte("symlink target")},
		{name: "link.txt", mode: 0777, typ: tar.TypeSymlink, linkname: "target.txt"},
	})

	err := Extract("tar", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract tar with symlink returned error: %v", err)
	}

	// Read through symlink
	content, err := os.ReadFile(filepath.Join(destDir, "link.txt"))
	if err != nil {
		t.Fatalf("Failed to read symlink target: %v", err)
	}
	if string(content) != "symlink target" {
		t.Errorf("Symlink content = %q; want %q", string(content), "symlink target")
	}
}

// --- Extraction: Valid Tar.gz ---

func TestExtractTarGz(t *testing.T) {
	destDir := t.TempDir()

	// Create tar data
	tarData := createTar(t, []tarEntry{
		{name: "compressed.txt", mode: 0644, content: []byte("compressed data")},
	})

	// Compress with gzip
	gzipData := compressGzip(t, tarData)

	// Extract
	err := Extract("tar.gz", bytes.NewReader(gzipData), destDir)
	if err != nil {
		t.Fatalf("Extract tar.gz returned error: %v", err)
	}

	// Verify
	checkFileContent(t, destDir, "compressed.txt", "compressed data")
}

func TestExtractTarGzEmptyGzip(t *testing.T) {
	destDir := t.TempDir()

	// Create tar data and gzip it, but the tar is empty
	tarData := createTar(t, []tarEntry{})
	gzipData := compressGzip(t, tarData)

	err := Extract("tar.gz", bytes.NewReader(gzipData), destDir)
	if err != nil {
		t.Fatalf("Extract tar.gz (empty) returned error: %v", err)
	}
}

// --- Extraction: Valid Zip ---

func TestExtractZip(t *testing.T) {
	destDir := t.TempDir()
	data := createZip(t, []zipEntry{
		{name: "hello.txt", content: []byte("zip data")},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract zip returned error: %v", err)
	}

	checkFileContent(t, destDir, "hello.txt", "zip data")
}

func TestExtractZipMultipleFiles(t *testing.T) {
	destDir := t.TempDir()
	data := createZip(t, []zipEntry{
		{name: "f1.txt", content: []byte("file1")},
		{name: "sub/f2.txt", content: []byte("file2")},
		{name: "f3.txt", content: []byte("file3")},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract zip returned error: %v", err)
	}

	checkFileContent(t, destDir, "f1.txt", "file1")
	checkFileContent(t, destDir, "sub/f2.txt", "file2")
	checkFileContent(t, destDir, "f3.txt", "file3")
}

func TestExtractZipDirectory(t *testing.T) {
	destDir := t.TempDir()
	data := createZip(t, []zipEntry{
		{name: "adir/", content: nil, isDir: true},
		{name: "adir/afile.txt", content: []byte("nested")},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("Extract zip with directory returned error: %v", err)
	}

	dirInfo, err := os.Stat(filepath.Join(destDir, "adir"))
	if err != nil {
		t.Fatalf("Failed to stat directory: %v", err)
	}
	if !dirInfo.IsDir() {
		t.Error("Expected a directory")
	}

	checkFileContent(t, destDir, "adir/afile.txt", "nested")
}

func TestExtractZipEmpty(t *testing.T) {
	destDir := t.TempDir()
	var buf bytes.Buffer
	zw := zip.NewWriter(&buf)
	if err := zw.Close(); err != nil {
		t.Fatal(err)
	}

	err := Extract("zip", &buf, destDir)
	if err != nil {
		t.Fatalf("Extract zip (empty) returned error: %v", err)
	}

	entries, err := os.ReadDir(destDir)
	if err != nil {
		t.Fatalf("Failed to read destDir: %v", err)
	}
	if len(entries) != 0 {
		t.Errorf("Expected empty directory, got %d entries", len(entries))
	}
}

// --- AutoExtract ---

func TestAutoExtractTar(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "autotest.txt", mode: 0644, content: []byte("auto extract test")},
	})

	err := AutoExtract("test.tar", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("AutoExtract returned error: %v", err)
	}

	checkFileContent(t, destDir, "autotest.txt", "auto extract test")
}

func TestAutoExtractTarGz(t *testing.T) {
	destDir := t.TempDir()
	tarData := createTar(t, []tarEntry{
		{name: "autogz.txt", mode: 0644, content: []byte("auto gz test")},
	})
	gzipData := compressGzip(t, tarData)

	err := AutoExtract("test.tar.gz", bytes.NewReader(gzipData), destDir)
	if err != nil {
		t.Fatalf("AutoExtract tar.gz returned error: %v", err)
	}

	checkFileContent(t, destDir, "autogz.txt", "auto gz test")
}

func TestAutoExtractZip(t *testing.T) {
	destDir := t.TempDir()
	data := createZip(t, []zipEntry{
		{name: "autozip.txt", content: []byte("auto zip test")},
	})

	err := AutoExtract("test.zip", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("AutoExtract zip returned error: %v", err)
	}

	checkFileContent(t, destDir, "autozip.txt", "auto zip test")
}

func TestAutoExtractUnknownFormat(t *testing.T) {
	destDir := t.TempDir()
	err := AutoExtract("test.unknown", strings.NewReader("data"), destDir)
	if err == nil {
		t.Error("AutoExtract with unknown format should return error")
	}
}

// --- ExtractByFilename ---

func TestExtractByFilenameTar(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "byfilename.txt", mode: 0644, content: []byte("extract by filename")},
	})

	err := ExtractByFilename("archive.tar", bytes.NewReader(data), destDir)
	if err != nil {
		t.Fatalf("ExtractByFilename returned error: %v", err)
	}

	checkFileContent(t, destDir, "byfilename.txt", "extract by filename")
}

func TestExtractByFilenameTarGz(t *testing.T) {
	destDir := t.TempDir()
	tarData := createTar(t, []tarEntry{
		{name: "byfilename_gz.txt", mode: 0644, content: []byte("extract by filename gz")},
	})
	gzipData := compressGzip(t, tarData)

	err := ExtractByFilename("archive.tar.gz", bytes.NewReader(gzipData), destDir)
	if err != nil {
		t.Fatalf("ExtractByFilename returned error: %v", err)
	}

	checkFileContent(t, destDir, "byfilename_gz.txt", "extract by filename gz")
}

func TestExtractByFilenameUnknown(t *testing.T) {
	destDir := t.TempDir()
	err := ExtractByFilename("unknown.xyz", strings.NewReader("data"), destDir)
	if err == nil {
		t.Error("ExtractByFilename with unknown format should return error")
	}
}

// --- Extract helper (Extract / ExtractByFilename with matching/mismatched formats) ---

func TestExtractMismatchedFormat(t *testing.T) {
	destDir := t.TempDir()
	// Create tar data, but try to extract it as zip - should fail
	data := createTar(t, []tarEntry{
		{name: "test.txt", mode: 0644, content: []byte("test")},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err == nil {
		t.Error("Extract with format 'zip' on tar data should return error")
	}
}

// --- ExtractFile (requires real file on disk) ---

func TestExtractFile(t *testing.T) {
	destDir := t.TempDir()

	// Create a real tar file on disk
	tarData := createTar(t, []tarEntry{
		{name: "extractfile.txt", mode: 0644, content: []byte("extract file test")},
	})
	srcPath := filepath.Join(t.TempDir(), "test.tar")
	if err := os.WriteFile(srcPath, tarData, 0644); err != nil {
		t.Fatal(err)
	}

	err := ExtractFile(srcPath, destDir, nil)
	if err != nil {
		t.Fatalf("ExtractFile returned error: %v", err)
	}

	checkFileContent(t, destDir, "extractfile.txt", "extract file test")
}

func TestExtractFileWithConfig(t *testing.T) {
	destDir := t.TempDir()

	tarData := createTar(t, []tarEntry{
		{name: "withconfig.txt", mode: 0644, content: []byte("with config")},
	})
	srcPath := filepath.Join(t.TempDir(), "test.tar")
	if err := os.WriteFile(srcPath, tarData, 0644); err != nil {
		t.Fatal(err)
	}

	cfg := DefaultExtractConfig()
	cfg.DestDir = destDir
	err := ExtractFile(srcPath, destDir, cfg)
	if err != nil {
		t.Fatalf("ExtractFile with config returned error: %v", err)
	}

	checkFileContent(t, destDir, "withconfig.txt", "with config")
}

func TestExtractFileNonExistent(t *testing.T) {
	err := ExtractFile("/nonexistent/path/file.tar", t.TempDir(), nil)
	if err == nil {
		t.Error("ExtractFile with nonexistent path should return error")
	}
}

func TestExtractFileUnknownFormat(t *testing.T) {
	destDir := t.TempDir()
	srcPath := filepath.Join(t.TempDir(), "file.unknown")
	if err := os.WriteFile(srcPath, []byte("data"), 0644); err != nil {
		t.Fatal(err)
	}

	err := ExtractFile(srcPath, destDir, nil)
	if err == nil {
		t.Error("ExtractFile with unknown format should return error")
	}
}

// --- ShouldExtractFile ---

func TestShouldExtractFile(t *testing.T) {
	tests := []struct {
		filename string
		expected bool
	}{
		{"file.tar", true},
		{"file.tar.gz", true},
		{"file.zip", true},
		{"file.txt", false},
		{"file", false},
	}
	for _, tt := range tests {
		got := ShouldExtractFile(tt.filename)
		if got != tt.expected {
			t.Errorf("ShouldExtractFile(%q) = %v; want %v", tt.filename, got, tt.expected)
		}
	}
}

// --- ListSupportedFormats / SupportsFormat helpers ---

func TestListSupportedFormats(t *testing.T) {
	formats := ListSupportedFormats()
	formatSet := make(map[string]bool)
	for _, f := range formats {
		formatSet[f] = true
	}

	for _, expected := range []string{"tar", "tar.gz", "tar.bz2", "zip"} {
		if !formatSet[expected] {
			t.Errorf("ListSupportedFormats() missing: %s", expected)
		}
	}
}

func TestSupportsFormat(t *testing.T) {
	if !SupportsFormat("tar") {
		t.Error("SupportsFormat('tar') should be true")
	}
	if SupportsFormat("rar") {
		t.Error("SupportsFormat('rar') should be false")
	}
}

// --- DefaultExtractConfig ---

func TestDefaultExtractConfig(t *testing.T) {
	cfg := DefaultExtractConfig()
	if cfg == nil {
		t.Fatal("DefaultExtractConfig() returned nil")
	}
	if cfg.DestDir != "." {
		t.Errorf("Default DestDir = %q; want '.'", cfg.DestDir)
	}
	if cfg.StripComponents != 0 {
		t.Errorf("Default StripComponents = %d; want 0", cfg.StripComponents)
	}
	if cfg.IncludePatterns == nil {
		t.Error("Default IncludePatterns is nil")
	}
	if cfg.ExcludePatterns == nil {
		t.Error("Default ExcludePatterns is nil")
	}
	if !cfg.PreservePermissions {
		t.Error("Default PreservePermissions should be true")
	}
	if !cfg.Overwrite {
		t.Error("Default Overwrite should be true")
	}
	if cfg.Verbose {
		t.Error("Default Verbose should be false")
	}
}

func TestExtractWithNilConfig(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "nilconfig.txt", mode: 0644, content: []byte("nil config test")},
	})

	// Create a real file for ExtractFile
	srcPath := filepath.Join(t.TempDir(), "test.tar")
	if err := os.WriteFile(srcPath, data, 0644); err != nil {
		t.Fatal(err)
	}

	// Passing nil config should use defaults (no panic)
	err := ExtractFile(srcPath, destDir, nil)
	if err != nil {
		t.Fatalf("ExtractFile with nil config returned error: %v", err)
	}

	checkFileContent(t, destDir, "nilconfig.txt", "nil config test")
}

// --- Tar-slip protection ---

func TestExtractTarSlipProtection(t *testing.T) {
	destDir := t.TempDir()
	data := createTar(t, []tarEntry{
		{name: "../../../etc/passwd", mode: 0644, content: []byte("evil")},
	})

	err := Extract("tar", bytes.NewReader(data), destDir)
	if err == nil {
		t.Error("Extract tar with path traversal should return error")
	}
}

// TestExtractTarHardlinkProtection is a regression guard for the BACKLOG
// entry "Tar hardlink path traversal via prefix collision". The
// concern was that a naive strings.HasPrefix(linkTarget, destDir+"/")
// would let a sibling directory such as /tmp/output_extra/secret through
// when destDir is /tmp/out (because "/tmp/output_extra/secret" does not
// start with "/tmp/out/" but the substring "out" does appear). Verify
// the existing protection handles the realistic attack vectors.
func TestExtractTarHardlinkProtection(t *testing.T) {
	cases := []struct {
		name     string
		linkname string
		wantErr  bool
	}{
		{"absolute path", "/etc/passwd", true},
		{"parent escape via ..", "../etc/passwd", true},
		{"nested parent escape", "subdir/../../etc/passwd", true},
		{"legitimate relative link", "target.txt", false},
		{"legitimate subdir link", "subdir/other.txt", false},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			destDir := t.TempDir()
			// Create a target file inside destDir so legitimate links
			// can resolve. For malicious cases the rejection happens
			// before the link is created.
			targetPath := filepath.Join(destDir, "target.txt")
			if err := os.WriteFile(targetPath, []byte("target"), 0644); err != nil {
				t.Fatal(err)
			}
			subdir := filepath.Join(destDir, "subdir")
			if err := os.MkdirAll(subdir, 0755); err != nil {
				t.Fatal(err)
			}
			otherPath := filepath.Join(subdir, "other.txt")
			if err := os.WriteFile(otherPath, []byte("other"), 0644); err != nil {
				t.Fatal(err)
			}

			data := createTar(t, []tarEntry{
				{name: "link.txt", mode: 0644, typ: tar.TypeLink, linkname: tc.linkname},
			})

			err := Extract("tar", bytes.NewReader(data), destDir)
			if tc.wantErr && err == nil {
				t.Errorf("linkname=%q: expected error, got nil", tc.linkname)
			}
			if !tc.wantErr && err != nil {
				t.Errorf("linkname=%q: unexpected error: %v", tc.linkname, err)
			}
		})
	}
}

func TestExtractZipSlipProtection(t *testing.T) {
	destDir := t.TempDir()
	data := createZip(t, []zipEntry{
		{name: "../../../etc/passwd", content: []byte("evil")},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err == nil {
		t.Error("Extract zip with path traversal should return error")
	}
}

// TestZipBufferLimitExceeded verifies that archives larger than
// MaxZipBufferSize are rejected at the buffering stage, before they ever
// reach the zip parser.
func TestZipBufferLimitExceeded(t *testing.T) {
	orig := MaxZipBufferSize
	MaxZipBufferSize = 50
	t.Cleanup(func() { MaxZipBufferSize = orig })

	destDir := t.TempDir()

	// Build a 200-byte archive (a tiny valid zip with a tiny payload).
	data := createZip(t, []zipEntry{
		{name: "small.txt", content: bytes.Repeat([]byte("y"), 200)},
	})

	err := Extract("zip", bytes.NewReader(data), destDir)
	if err == nil {
		t.Fatal("Extract should reject archive larger than MaxZipBufferSize")
	}
	if !strings.Contains(err.Error(), "exceeds maximum size") {
		t.Errorf("error %q should mention size limit", err)
	}
}

// Note: the UncompressedSize64 check in extractFile is the primary defence
// against zip-bomb archives that declare a huge uncompressed size in
// their central directory. We do not have a unit test for it because
// archive/zip.Writer always sets UncompressedSize64 to the true payload
// size, so producing a "lying" zip requires hand-crafting the binary
// header — fragile across Go stdlib versions and not worth the maintenance
// burden. The io.LimitReader safety net below the check is similarly
// untested; it covers archives whose central directory is unset (size 0)
// or forged, which is a vanishingly rare case in practice.

// --- Helpers ---

type tarEntry struct {
	name     string
	mode     int64
	typ      byte
	content  []byte
	linkname string
}

func createTar(t *testing.T, entries []tarEntry) []byte {
	t.Helper()
	var buf bytes.Buffer
	tw := tar.NewWriter(&buf)

	for _, e := range entries {
		typ := e.typ
		if typ == 0 {
			if e.content == nil && strings.HasSuffix(e.name, "/") {
				typ = tar.TypeDir
			} else {
				typ = tar.TypeReg
			}
		}
		hdr := &tar.Header{
			Name:     e.name,
			Mode:     e.mode,
			Size:     int64(len(e.content)),
			Typeflag: typ,
			Linkname: e.linkname,
		}
		if err := tw.WriteHeader(hdr); err != nil {
			t.Fatal(err)
		}
		if len(e.content) > 0 {
			if _, err := tw.Write(e.content); err != nil {
				t.Fatal(err)
			}
		}
	}

	if err := tw.Close(); err != nil {
		t.Fatal(err)
	}
	return buf.Bytes()
}

type zipEntry struct {
	name    string
	content []byte
	isDir   bool
}

func createZip(t *testing.T, entries []zipEntry) []byte {
	t.Helper()
	var buf bytes.Buffer
	zw := zip.NewWriter(&buf)

	for _, e := range entries {
		var header *zip.FileHeader
		if e.isDir || strings.HasSuffix(e.name, "/") {
			header = &zip.FileHeader{
				Name:   e.name,
				Method: zip.Store,
			}
			header.SetMode(0755 | os.ModeDir)
		} else {
			header = &zip.FileHeader{
				Name:   e.name,
				Method: zip.Deflate,
			}
			header.SetMode(0644)
		}

		fw, err := zw.CreateHeader(header)
		if err != nil {
			t.Fatal(err)
		}
		if len(e.content) > 0 {
			if _, err := fw.Write(e.content); err != nil {
				t.Fatal(err)
			}
		}
	}

	if err := zw.Close(); err != nil {
		t.Fatal(err)
	}
	return buf.Bytes()
}

func compressGzip(t *testing.T, data []byte) []byte {
	t.Helper()
	var buf bytes.Buffer
	gw := gzip.NewWriter(&buf)
	if _, err := gw.Write(data); err != nil {
		t.Fatal(err)
	}
	if err := gw.Close(); err != nil {
		t.Fatal(err)
	}
	return buf.Bytes()
}

func checkFileContent(t *testing.T, destDir, relPath, wantContent string) {
	t.Helper()
	data, err := os.ReadFile(filepath.Join(destDir, relPath))
	if err != nil {
		t.Fatalf("Failed to read %s: %v", relPath, err)
	}
	if string(data) != wantContent {
		t.Errorf("Content of %s = %q; want %q", relPath, string(data), wantContent)
	}
}