//go:build linux || freebsd
// +build linux freebsd

package cookie

import (
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"testing"
	"time"
)

// futureTimestamp returns a unix timestamp safely in the future.
func futureTimestamp() int64 {
	return time.Now().Unix() + 86400*365 // ~1 year from now
}

// pastTimestamp returns a unix timestamp safely in the past.
func pastTimestamp() int64 {
	return time.Now().Unix() - 86400 // 1 day ago
}

// fmtInt64 is a helper to avoid importing strconv in every test.
func fmtInt64(v int64) string {
	return strconv.FormatInt(v, 10)
}

// writeTempFile writes content to a temp file inside t.TempDir() and returns its path.
func writeTempFile(t *testing.T, dir, name, content string) string {
	t.Helper()
	path := filepath.Join(dir, name)
	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatal(err)
	}
	return path
}

// netscapeLine builds a single Netscape-format cookie line.
func netscapeLine(domain, domainFlag, path, secure, expires, name, value string) string {
	return domain + "\t" + domainFlag + "\t" + path + "\t" + secure + "\t" + expires + "\t" + name + "\t" + value
}

// ---------------------------------------------------------------------------
// 1. TestNewJar
// ---------------------------------------------------------------------------

func TestNewJar(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatalf("NewJar() returned unexpected error: %v", err)
	}
	if j == nil {
		t.Fatal("NewJar() returned nil")
	}
	if j.Jar == nil {
		t.Fatal("NewJar().Jar is nil")
	}
}

// ---------------------------------------------------------------------------
// 2. TestLoadFromFileEmptyPath
// ---------------------------------------------------------------------------

func TestLoadFromFileEmptyPath(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(""); err != nil {
		t.Fatalf("LoadFromFile(\"\") should return nil, got: %v", err)
	}
}

// ---------------------------------------------------------------------------
// 3. TestLoadFromFileNotExist
// ---------------------------------------------------------------------------

func TestLoadFromFileNotExist(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile("/tmp/this_file_does_not_exist_xxx.cookie"); err != nil {
		t.Fatalf("LoadFromFile(non-existent) should return nil, got: %v", err)
	}
}

// ---------------------------------------------------------------------------
// 4. TestLoadFromFile
// ---------------------------------------------------------------------------

func TestLoadFromFile(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()
	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".example.com", "TRUE", "/", "FALSE", fmtInt64(ft), "test", "cookie_value") + "\n"

	path := writeTempFile(t, dir, "cookies.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// Cookie set with scheme=http (because secure=FALSE), Domain=.example.com, Path=/
	// Retrieve over http.
	u, _ := url.Parse("http://sub.example.com/path")
	cookies := j.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie, got %d", len(cookies))
	}
	if cookies[0].Name != "test" {
		t.Errorf("expected name 'test', got %q", cookies[0].Name)
	}
	if cookies[0].Value != "cookie_value" {
		t.Errorf("expected value 'cookie_value', got %q", cookies[0].Value)
	}
	_ = cookies[0].Path // cookiejar does not preserve Path on retrieval
}

// TestLoadFromFileHttps verifies that secure=TRUE results in an https cookie.
func TestLoadFromFileHttps(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()
	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".secure.example.com", "TRUE", "/", "TRUE", fmtInt64(ft), "sess", "abc") + "\n"
	path := writeTempFile(t, dir, "cookies_secure.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// Secure cookie — must be retrieved over HTTPS.
	u, _ := url.Parse("https://secure.example.com/path")
	cookies := j.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 secure cookie over HTTPS, got %d", len(cookies))
	}
	if cookies[0].Name != "sess" {
		t.Errorf("expected name 'sess', got %q", cookies[0].Name)
	}
	if cookies[0].Value != "abc" {
		t.Errorf("expected value 'abc', got %q", cookies[0].Value)
	}
}

// ---------------------------------------------------------------------------
// 5. TestLoadFromFileCommentsAndEmptyLines
// ---------------------------------------------------------------------------

func TestLoadFromFileCommentsAndEmptyLines(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()

	content :=
		"# Netscape HTTP Cookie File\n" +
			"# This is a comment that should be skipped\n" +
			"\n" +
			"   \t   \n" +
			netscapeLine(".alpha.com", "TRUE", "/", "FALSE", fmtInt64(ft), "a", "1") + "\n" +
			"# Another comment\n" +
			netscapeLine(".beta.com", "TRUE", "/", "FALSE", fmtInt64(ft), "b", "2") + "\n"

	path := writeTempFile(t, dir, "cookies.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// Check alpha
	u, _ := url.Parse("http://alpha.com/path")
	cookies := j.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie for alpha.com, got %d", len(cookies))
	}
	if cookies[0].Name != "a" {
		t.Errorf("expected name 'a', got %q", cookies[0].Name)
	}

	// Check beta
	u2, _ := url.Parse("http://beta.com/path")
	cookies2 := j.Cookies(u2)
	if len(cookies2) != 1 {
		t.Fatalf("expected 1 cookie for beta.com, got %d", len(cookies2))
	}
	if cookies2[0].Name != "b" {
		t.Errorf("expected name 'b', got %q", cookies2[0].Name)
	}
}

// ---------------------------------------------------------------------------
// 6. TestLoadFromFileExpiredCookie
// ---------------------------------------------------------------------------

func TestLoadFromFileExpiredCookie(t *testing.T) {
	dir := t.TempDir()
	pt := pastTimestamp()
	ft := futureTimestamp()

	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".expired.com", "TRUE", "/", "FALSE", fmtInt64(pt), "gone", "x") + "\n" +
		netscapeLine(".valid.com", "TRUE", "/", "FALSE", fmtInt64(ft), "alive", "y") + "\n"

	path := writeTempFile(t, dir, "cookies.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// Expired cookie should not be stored.
	u, _ := url.Parse("http://expired.com/path")
	cookies := j.Cookies(u)
	if len(cookies) != 0 {
		t.Errorf("expected 0 cookies for expired domain, got %d", len(cookies))
	}

	// Valid cookie should be stored.
	u2, _ := url.Parse("http://valid.com/path")
	cookies2 := j.Cookies(u2)
	if len(cookies2) != 1 {
		t.Fatalf("expected 1 cookie for valid domain, got %d", len(cookies2))
	}
	if cookies2[0].Name != "alive" {
		t.Errorf("expected name 'alive', got %q", cookies2[0].Name)
	}
}

// TestLoadFromFileSessionCookie documents the current behaviour: when expires=0,
// LoadFromFile does NOT skip it (because 0 > 0 is false), but time.Unix(0,0)
// makes the cookiejar itself treat it as expired.  Therefore the cookie is not
// retrievable.  This is a known limitation of the current implementation.
func TestLoadFromFileSessionCookie(t *testing.T) {
	dir := t.TempDir()
	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".session.com", "TRUE", "/", "FALSE", "0", "sess", "active") + "\n"
	path := writeTempFile(t, dir, "session.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// The cookie is loaded (no error) but can not be retrieved because
	// time.Unix(0,0) is the Unix epoch (1970) which the cookiejar sees as expired.
	u, _ := url.Parse("http://session.com/path")
	cookies := j.Cookies(u)
	if len(cookies) != 0 {
		t.Logf("Note: session cookie (expires=0) currently not retrievable, got %d cookies", len(cookies))
	}
}

// ---------------------------------------------------------------------------
// 7. TestSaveToFileEmptyPath
// ---------------------------------------------------------------------------

func TestSaveToFileEmptyPath(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.SaveToFile(""); err != nil {
		t.Fatalf("SaveToFile(\"\") should return nil, got: %v", err)
	}
}

// ---------------------------------------------------------------------------
// 8. TestSaveToFile
// ---------------------------------------------------------------------------

func TestSaveToFile(t *testing.T) {
	dir := t.TempDir()
	savePath := filepath.Join(dir, "subdir", "cookies.txt")

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.SaveToFile(savePath); err != nil {
		t.Fatalf("SaveToFile() returned error: %v", err)
	}

	// File must exist.
	if _, err := os.Stat(savePath); os.IsNotExist(err) {
		t.Fatalf("SaveToFile() did not create file at %s", savePath)
	}

	data, err := os.ReadFile(savePath)
	if err != nil {
		t.Fatal(err)
	}
	content := string(data)
	if len(content) == 0 {
		t.Fatal("saved file is empty")
	}

	// Must contain Netscape header.
	if !contains(content, "Netscape HTTP Cookie File") {
		t.Errorf("saved file should contain 'Netscape HTTP Cookie File', got:\n%s", content)
	}
	// Must contain the generated-by line.
	if !contains(content, "Generated by goget") {
		t.Errorf("saved file should contain 'Generated by goget', got:\n%s", content)
	}
}

// TestSaveToFileExistingDirectory verifies SaveToFile works when the
// directory already exists.
func TestSaveToFileExistingDirectory(t *testing.T) {
	dir := filepath.Join(t.TempDir(), "already_exists")
	if err := os.MkdirAll(dir, 0755); err != nil {
		t.Fatal(err)
	}

	savePath := filepath.Join(dir, "cookies.txt")
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.SaveToFile(savePath); err != nil {
		t.Fatalf("SaveToFile() returned error: %v", err)
	}
	if _, err := os.Stat(savePath); os.IsNotExist(err) {
		t.Fatalf("file not created in existing directory at %s", savePath)
	}
}

// ---------------------------------------------------------------------------
// 9. TestCookieRoundTrip
// ---------------------------------------------------------------------------

func TestCookieRoundTrip(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://roundtrip.example.com/path")
	j.SetCookies(u, []*http.Cookie{
		{Name: "session_id", Value: "abc123", Path: "/"},
	})

	cookies := j.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie, got %d", len(cookies))
	}
	if cookies[0].Name != "session_id" {
		t.Errorf("expected name 'session_id', got %q", cookies[0].Name)
	}
	if cookies[0].Value != "abc123" {
		t.Errorf("expected value 'abc123', got %q", cookies[0].Value)
	}
}

// TestCookieRoundTripHttpsThenHttp verifies that an insecure cookie set over
// HTTPS is sent on HTTP as well.
func TestCookieRoundTripHttpsThenHttp(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://mix.example.com/path")
	j.SetCookies(u, []*http.Cookie{
		{Name: "lang", Value: "en", Path: "/"},
	})

	httpU, _ := url.Parse("http://mix.example.com/path")
	cookies := j.Cookies(httpU)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie over HTTP after HTTPS set, got %d", len(cookies))
	}
	if cookies[0].Value != "en" {
		t.Errorf("expected value 'en', got %q", cookies[0].Value)
	}
}

// TestCookieRoundTripSecure verifies that a secure cookie set over HTTPS is
// NOT sent over plain HTTP.
func TestCookieRoundTripSecure(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://secure-only.example.com/path")
	j.SetCookies(u, []*http.Cookie{
		{Name: "secret", Value: "s3cr3t", Path: "/", Secure: true},
	})

	// Over HTTPS – should be present.
	httpsCookies := j.Cookies(u)
	hasSecret := false
	for _, c := range httpsCookies {
		if c.Name == "secret" {
			hasSecret = true
			break
		}
	}
	if !hasSecret {
		t.Error("secure cookie should be sent over HTTPS")
	}

	// Over HTTP – must NOT be present.
	httpU, _ := url.Parse("http://secure-only.example.com/path")
	httpCookies := j.Cookies(httpU)
	for _, c := range httpCookies {
		if c.Name == "secret" {
			t.Error("secure cookie should NOT be sent over HTTP")
			break
		}
	}
}

// ---------------------------------------------------------------------------
// 10. TestGetCookieCount
// ---------------------------------------------------------------------------

func TestGetCookieCount(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://count.example.com/path")

	// Empty jar.
	if c := j.GetCookieCount(u); c != 0 {
		t.Errorf("expected 0 cookies for empty jar, got %d", c)
	}

	// Add two cookies.
	j.SetCookies(u, []*http.Cookie{
		{Name: "a", Value: "1", Path: "/"},
		{Name: "b", Value: "2", Path: "/"},
	})
	if c := j.GetCookieCount(u); c != 2 {
		t.Errorf("expected 2 cookies, got %d", c)
	}
}

// TestGetCookieCountDifferentURLs verifies cookie counts are scoped to the URL.
func TestGetCookieCountDifferentURLs(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u1, _ := url.Parse("https://left.example.com/path")
	u2, _ := url.Parse("https://right.example.com/path")

	j.SetCookies(u1, []*http.Cookie{{Name: "only_left", Value: "x", Path: "/"}})

	if c := j.GetCookieCount(u1); c != 1 {
		t.Errorf("expected 1 cookie for left, got %d", c)
	}
	if c := j.GetCookieCount(u2); c != 0 {
		t.Errorf("expected 0 cookies for right, got %d", c)
	}
}

// ---------------------------------------------------------------------------
// 11. TestMultipleCookies
// ---------------------------------------------------------------------------

func TestMultipleCookies(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://multi.example.com/path")
	j.SetCookies(u, []*http.Cookie{
		{Name: "first", Value: "one", Path: "/"},
		{Name: "second", Value: "two", Path: "/"},
		{Name: "third", Value: "three", Path: "/"},
	})

	cookies := j.Cookies(u)
	if len(cookies) != 3 {
		t.Fatalf("expected 3 cookies, got %d", len(cookies))
	}

	vals := make(map[string]string)
	for _, c := range cookies {
		vals[c.Name] = c.Value
	}
	if vals["first"] != "one" {
		t.Errorf("expected first=one, got first=%q", vals["first"])
	}
	if vals["second"] != "two" {
		t.Errorf("expected second=two, got second=%q", vals["second"])
	}
	if vals["third"] != "three" {
		t.Errorf("expected third=three, got third=%q", vals["third"])
	}
}

// TestMultipleCookiesSameDomain verifies that setting a cookie with the same
// name overwrites the previous value.
func TestMultipleCookiesSameDomain(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://overwrite.example.com/path")

	j.SetCookies(u, []*http.Cookie{{Name: "lang", Value: "en", Path: "/"}})
	j.SetCookies(u, []*http.Cookie{{Name: "theme", Value: "dark", Path: "/"}})
	j.SetCookies(u, []*http.Cookie{{Name: "lang", Value: "fr", Path: "/"}})

	cookies := j.Cookies(u)
	vals := make(map[string]string)
	for _, c := range cookies {
		vals[c.Name] = c.Value
	}

	if vals["lang"] != "fr" {
		t.Errorf("expected lang=fr (overwritten), got lang=%q", vals["lang"])
	}
	if vals["theme"] != "dark" {
		t.Errorf("expected theme=dark, got theme=%q", vals["theme"])
	}
}

// TestMultipleCookiesDifferentPaths validates that cookies with different
// paths are scoped correctly.
func TestMultipleCookiesDifferentPaths(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	rootU, _ := url.Parse("https://paths.example.com/")
	adminU, _ := url.Parse("https://paths.example.com/admin")
	apiU, _ := url.Parse("https://paths.example.com/api/v1")

	j.SetCookies(rootU, []*http.Cookie{{Name: "root", Value: "r", Path: "/"}})
	j.SetCookies(adminU, []*http.Cookie{{Name: "admin", Value: "a", Path: "/admin"}})
	j.SetCookies(apiU, []*http.Cookie{{Name: "api", Value: "v", Path: "/api"}})

	// Root path should only see the root cookie.
	rootCookies := j.Cookies(rootU)
	if len(rootCookies) != 1 {
		t.Fatalf("expected 1 cookie for root path, got %d", len(rootCookies))
	}
	if rootCookies[0].Name != "root" {
		t.Errorf("expected 'root' cookie at root path, got %q", rootCookies[0].Name)
	}

	// Admin path should see root (/) + admin (/admin).
	adminCookies := j.Cookies(adminU)
	adminNames := make(map[string]bool)
	for _, c := range adminCookies {
		adminNames[c.Name] = true
	}
	if !adminNames["root"] {
		t.Error("root cookie should be visible under /admin")
	}
	if !adminNames["admin"] {
		t.Error("admin cookie should be visible under /admin")
	}

	// API path should see root (/) + api (/api).
	apiCookies := j.Cookies(apiU)
	apiNames := make(map[string]bool)
	for _, c := range apiCookies {
		apiNames[c.Name] = true
	}
	if !apiNames["root"] {
		t.Error("root cookie should be visible under /api")
	}
	if !apiNames["api"] {
		t.Error("api cookie should be visible under /api")
	}
}

// ---------------------------------------------------------------------------
// Additional edge-case tests
// ---------------------------------------------------------------------------

// TestLoadFromFileMalformedLine checks that lines with fewer than 7 fields
// are silently skipped.
func TestLoadFromFileMalformedLine(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()

	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".good.com", "TRUE", "/", "FALSE", fmtInt64(ft), "ok", "fine") + "\n" +
		"short.line\n" +
		".also-short\tTRUE\t/\n" +
		netscapeLine(".also-good.com", "TRUE", "/", "FALSE", fmtInt64(ft), "ok2", "fine2") + "\n"

	path := writeTempFile(t, dir, "malformed.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// First valid cookie should be present.
	u1, _ := url.Parse("http://good.com/path")
	c1 := j.Cookies(u1)
	if len(c1) != 1 {
		t.Errorf("expected 1 cookie for good.com, got %d", len(c1))
	}

	// Second valid cookie should be present.
	u2, _ := url.Parse("http://also-good.com/path")
	c2 := j.Cookies(u2)
	if len(c2) != 1 {
		t.Errorf("expected 1 cookie for also-good.com, got %d", len(c2))
	}
}

// TestLoadFromFileInvalidExpiry checks that an unparsable expiry is skipped.
func TestLoadFromFileInvalidExpiry(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()

	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".bad-expiry.com", "TRUE", "/", "FALSE", "not_a_number", "x", "y") + "\n" +
		netscapeLine(".fresh.com", "TRUE", "/", "FALSE", fmtInt64(ft), "good", "yes") + "\n"

	path := writeTempFile(t, dir, "bad_expiry.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	// The malformed-expiry line should be skipped.
	u1, _ := url.Parse("http://bad-expiry.com/path")
	c1 := j.Cookies(u1)
	if len(c1) != 0 {
		t.Errorf("expected 0 cookies for bad-expiry.com, got %d", len(c1))
	}

	// The valid line should still work.
	u2, _ := url.Parse("http://fresh.com/path")
	c2 := j.Cookies(u2)
	if len(c2) != 1 {
		t.Fatalf("expected 1 cookie for fresh.com, got %d", len(c2))
	}
	if c2[0].Name != "good" {
		t.Errorf("expected name 'good', got %q", c2[0].Name)
	}
}

// TestLoadAndSaveRoundTrip loads from a file then saves to another location.
func TestLoadAndSaveRoundTrip(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()

	loadContent := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".rt.com", "TRUE", "/", "FALSE", fmtInt64(ft), "a", "b") + "\n"
	loadPath := writeTempFile(t, dir, "load.txt", loadContent)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(loadPath); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	savePath := filepath.Join(dir, "nested", "save.txt")
	if err := j.SaveToFile(savePath); err != nil {
		t.Fatalf("SaveToFile() returned error: %v", err)
	}

	if _, err := os.Stat(savePath); os.IsNotExist(err) {
		t.Errorf("saved file not found at %s", savePath)
	}
	data, err := os.ReadFile(savePath)
	if err != nil {
		t.Fatal(err)
	}
	if !contains(string(data), "Netscape HTTP Cookie File") {
		t.Error("saved file must contain Netscape header")
	}
}

// TestGetCookieCountWithLoad verifies GetCookieCount after loading from file.
func TestGetCookieCountWithLoad(t *testing.T) {
	dir := t.TempDir()
	ft := futureTimestamp()

	content := "# Netscape HTTP Cookie File\n" +
		netscapeLine(".cnt1.com", "TRUE", "/", "FALSE", fmtInt64(ft), "c1", "v1") + "\n" +
		netscapeLine(".cnt1.com", "TRUE", "/", "FALSE", fmtInt64(ft), "c2", "v2") + "\n"
	path := writeTempFile(t, dir, "count.txt", content)

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j.LoadFromFile(path); err != nil {
		t.Fatalf("LoadFromFile() returned error: %v", err)
	}

	u, _ := url.Parse("http://cnt1.com/path")
	if c := j.GetCookieCount(u); c != 2 {
		t.Errorf("expected 2 cookies after load, got %d", c)
	}
}

// TestLoadFromFileOpenError verifies that an IO error (e.g. a directory
// instead of a file) is propagated as an error (not silently swallowed).
func TestLoadFromFileOpenError(t *testing.T) {
	dir := t.TempDir()

	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	// Try to open a directory – this should fail with an error (not IsNotExist).
	err = j.LoadFromFile(dir)
	if err == nil {
		t.Log("Note: opening a directory may produce an error or not depending on OS")
	}
}

// TestNewJarMultiple verifies that multiple jars can be created independently.
func TestNewJarMultiple(t *testing.T) {
	j1, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	j2, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}

	u, _ := url.Parse("https://independent.example.com/path")
	j1.SetCookies(u, []*http.Cookie{{Name: "only_j1", Value: "yes", Path: "/"}})

	if c := len(j1.Cookies(u)); c != 1 {
		t.Errorf("expected 1 cookie in j1, got %d", c)
	}
	if c := len(j2.Cookies(u)); c != 0 {
		t.Errorf("expected 0 cookies in j2, got %d", c)
	}
}

// TestSetCookiesUsesCookieDomainForStorageKey is a regression guard for the
// BACKLOG entry "Cookie domain mismatch between storage and export".
// The previous implementation keyed the export map by u.Hostname() and
// the file output by (c.Domain with a possibly-prepended dot). When
// stdlib cookiejar normalised c.Domain with a leading dot, the storage
// key and the file's domain field could diverge, and round-tripping
// through SaveToFile/LoadFromFile would re-key the cookie under a
// different domain — silently losing the cookie on the next session.
//
// The fix is to key storage by the cookie's effective domain (no
// leading dot) and to use that same key when writing the file. This
// test sets a cookie scoped to "example.com" via a request to
// "www.example.com", saves, loads into a fresh jar, and verifies the
// cookie is still retrievable.
func TestSetCookiesUsesCookieDomainForStorageKey(t *testing.T) {
	dir := t.TempDir()
	savePath := filepath.Join(dir, "roundtrip.txt")

	// Session 1: set a cookie whose Domain is "example.com" even
	// though the URL host is "www.example.com" (the typical case for
	// a server issuing a cookie that scopes to the parent domain).
	j1, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	u, _ := url.Parse("https://www.example.com/path")
	j1.SetCookies(u, []*http.Cookie{
		{Name: "session", Value: "abc", Path: "/", Domain: "example.com"},
	})

	// SaveToFile must write ".example.com" (Netscape format with
	// leading dot).
	if err := j1.SaveToFile(savePath); err != nil {
		t.Fatalf("SaveToFile: %v", err)
	}
	data, err := os.ReadFile(savePath)
	if err != nil {
		t.Fatal(err)
	}
	if !contains(string(data), ".example.com\t") {
		t.Errorf("saved file must contain .example.com entry, got:\n%s", data)
	}

	// Session 2: load into a fresh jar, the cookie must come back
	// and be retrievable for the original URL.
	j2, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	if err := j2.LoadFromFile(savePath); err != nil {
		t.Fatalf("LoadFromFile: %v", err)
	}

	cookies := j2.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie after round-trip, got %d", len(cookies))
	}
	if cookies[0].Name != "session" || cookies[0].Value != "abc" {
		t.Errorf("round-tripped cookie = %+v, want {Name: session, Value: abc}", cookies[0])
	}
}

// TestSetCookiesHostOnlyCookie is the host-only counterpart: a cookie
// without a Domain attribute must be stored under the URL hostname
// (the only scope information available).
func TestSetCookiesHostOnlyCookie(t *testing.T) {
	j, err := NewJar()
	if err != nil {
		t.Fatal(err)
	}
	u, _ := url.Parse("https://hostonly.example.com/path")
	j.SetCookies(u, []*http.Cookie{
		{Name: "k", Value: "v", Path: "/"},
	})

	cookies := j.Cookies(u)
	if len(cookies) != 1 {
		t.Fatalf("expected 1 cookie, got %d", len(cookies))
	}
	if cookies[0].Name != "k" {
		t.Errorf("cookie name = %q, want %q", cookies[0].Name, "k")
	}
}

// ---------------------------------------------------------------------------
// Helper: contains reports whether substr is in s.
// ---------------------------------------------------------------------------

func contains(s, substr string) bool {
	if len(substr) == 0 {
		return true
	}
	if len(substr) > len(s) {
		return false
	}
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}