package sneklog

import (
	"bytes"
	"encoding/json"
	"errors"
	"net/http"
	"os"
	"strings"
	"testing"
)

type stubLoggerWriter struct {
	printErr   error
	closeErr   error
	printCalls int
	closeCalls int
	messages   []any
}

func (w *stubLoggerWriter) Formatter() *Formatter {
	return &Formatter{}
}
func (w *stubLoggerWriter) Close() error {
	w.closeCalls++
	return w.closeErr
}

func (w *stubLoggerWriter) Write(p []byte) (int, error) {
	return len(p), nil
}

func (w *stubLoggerWriter) Print(_ LogLevel, _ string, _ []*MethodTraceback, messages ...any) error {
	w.printCalls++
	w.messages = append([]any(nil), messages...)
	return w.printErr
}

func TestLoggerCloseReturnsJoinedErrorsWithoutRelogging(t *testing.T) {
	firstErr := errors.New("first close failed")
	secondErr := errors.New("second close failed")
	first := &stubLoggerWriter{closeErr: firstErr}
	second := &stubLoggerWriter{closeErr: secondErr}

	logger := CreateLogger().AddWriters(first, second)
	err := logger.Close()
	if !errors.Is(err, firstErr) {
		t.Fatalf("Close() error should include first writer error, got %v", err)
	}
	if !errors.Is(err, secondErr) {
		t.Fatalf("Close() error should include second writer error, got %v", err)
	}
	if first.printCalls != 0 || second.printCalls != 0 {
		t.Fatalf("Close() should not log through writers again, got print calls first=%d second=%d", first.printCalls, second.printCalls)
	}
	if first.closeCalls != 1 || second.closeCalls != 1 {
		t.Fatalf("Close() should close each writer once, got close calls first=%d second=%d", first.closeCalls, second.closeCalls)
	}
	if err := logger.Close(); err != nil {
		t.Fatalf("second Close() should be a no-op, got %v", err)
	}
}

func TestLoggerPrintDoesNotRecurseOnWriterError(t *testing.T) {
	oldStderr := os.Stderr
	stderrFile, err := os.CreateTemp(t.TempDir(), "stderr")
	if err != nil {
		t.Fatalf("CreateTemp() error = %v", err)
	}
	os.Stderr = stderrFile
	t.Cleanup(func() {
		os.Stderr = oldStderr
		_ = stderrFile.Close()
	})

	bad := &stubLoggerWriter{printErr: errors.New("print failed")}
	good := &stubLoggerWriter{}

	logger := CreateLogger().AddWriters(bad, good)
	logger.Error("boom")

	if bad.printCalls != 1 {
		t.Fatalf("bad writer should be called once, got %d", bad.printCalls)
	}
	if good.printCalls != 1 {
		t.Fatalf("good writer should be called once, got %d", good.printCalls)
	}
}

func TestLoggerPreservesMessageTypesWithoutReplacers(t *testing.T) {
	writer := &stubLoggerWriter{}
	logger := CreateLogger().AddWriter(writer)

	logger.Error("status", 500)

	if len(writer.messages) != 2 {
		t.Fatalf("writer should receive two messages, got %d", len(writer.messages))
	}
	if _, ok := writer.messages[1].(int); !ok {
		t.Fatalf("writer should receive original int message type, got %T", writer.messages[1])
	}
}

func TestLoggerPrintfFormatsMessage(t *testing.T) {
	writer := &stubLoggerWriter{}
	logger := CreateLogger().
		SetLevel(DEBUG).
		AddWriter(writer)

	logger.Printf(INFO, "status=%d %s", 200, "ok")

	if writer.printCalls != 1 {
		t.Fatalf("Printf() should write once, got %d calls", writer.printCalls)
	}
	if len(writer.messages) != 1 {
		t.Fatalf("Printf() should produce one formatted message, got %d parts", len(writer.messages))
	}
	if got, ok := writer.messages[0].(string); !ok || got != "status=200 ok" {
		t.Fatalf("Printf() should format message, got %#v", writer.messages)
	}
}

func TestLoggerUsesSeverityOrderingWhenThresholdModeIsDisabled(t *testing.T) {
	writer := &stubLoggerWriter{}
	logger := CreateLogger().
		SetLevel(NewThresholdLogLevel(1, 0, "warn")).
		AddWriter(writer)

	logger.Print(NewThresholdLogLevel(0, 100, "info"))
	logger.Print(NewThresholdLogLevel(2, 0, "error"))

	if writer.printCalls != 1 {
		t.Fatalf("severity mode should allow only lower-or-equal severity levels, got %d writes", writer.printCalls)
	}
}

func TestLoggerUsesThresholdOrderingWhenThresholdModeIsEnabled(t *testing.T) {
	writer := &stubLoggerWriter{}
	logger := CreateLogger().
		SetLevel(NewThresholdLogLevel(4, 20, "custom")).
		SetThresholdMode(true).
		AddWriter(writer)

	logger.Print(NewThresholdLogLevel(4, 10, "debug"))
	logger.Print(NewThresholdLogLevel(0, 30, "info"))

	if writer.printCalls != 1 {
		t.Fatalf("threshold mode should allow only entries at or below the configured threshold, got %d writes", writer.printCalls)
	}
}

func TestDeprecatedLevelMethodKeepsLegacySeverityBehavior(t *testing.T) {
	writer := &stubLoggerWriter{}
	logger := CreateLogger().
		Level(FATAL).
		AddWriter(writer)

	logger.Print(INFO, "info")
	logger.Print(WARN, "warn")
	logger.Print(ERROR, "error")
	logger.Print(FATAL, "fatal")
	logger.Print(DEBUG, "debug")

	if writer.printCalls != 4 {
		t.Fatalf("Level(FATAL) should keep legacy behavior and allow INFO/WARN/ERROR/FATAL only, got %d writes", writer.printCalls)
	}
}

func TestSameLevelIgnoresThresholdDifferencesForCompatibility(t *testing.T) {
	legacy := NewLogLevel(1, "warn")
	threshold := NewThresholdLogLevel(1, 20, "warn")

	if !legacy.SameLevel(threshold) {
		t.Fatalf("SameLevel() should continue comparing only severity index")
	}
	if legacy.Equal(threshold) {
		t.Fatalf("Equal() should distinguish levels with different threshold configuration")
	}
}

func TestSameThresholdComparesOnlyThresholdValue(t *testing.T) {
	first := NewThresholdLogLevel(1, 20, "warn")
	second := NewThresholdLogLevel(9, 20, "custom")
	third := NewThresholdLogLevel(1, 30, "warn")

	if !first.SameThreshold(second) {
		t.Fatalf("SameThreshold() should ignore severity and compare threshold only")
	}
	if first.SameThreshold(third) {
		t.Fatalf("SameThreshold() should detect different threshold values")
	}
}

func TestLogLevelForMethodReturnsExpectedLevels(t *testing.T) {
	tests := []struct {
		name   string
		method string
		want   LogLevel
	}{
		{name: "get", method: http.MethodGet, want: HTTPGetLevel},
		{name: "head", method: http.MethodHead, want: HTTPHeadLevel},
		{name: "post", method: http.MethodPost, want: HTTPPostLevel},
		{name: "put", method: http.MethodPut, want: HTTPPutLevel},
		{name: "patch", method: http.MethodPatch, want: HTTPPatchLevel},
		{name: "delete", method: http.MethodDelete, want: HTTPDeleteLevel},
		{name: "options", method: http.MethodOptions, want: HTTPOptionsLevel},
		{name: "connect", method: http.MethodConnect, want: HTTPConnectLevel},
		{name: "trace", method: http.MethodTrace, want: HTTPTraceLevel},
		{name: "unknown", method: "PROPFIND", want: HTTPUnknownLevel},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := LogLevelForMethod(tt.method)
			if got.n != tt.want.n || got.t != tt.want.t || got.fg != tt.want.fg || got.bg != tt.want.bg {
				t.Fatalf("LogLevelForMethod(%q) = %#v, want %#v", tt.method, got, tt.want)
			}
		})
	}
}

func TestNewLevelConstructorsSetExpectedSeverity(t *testing.T) {
	tests := []struct {
		name   string
		got    LogLevel
		want   LogLevel
		wantTh uint8
	}{
		{name: "info", got: NewInfoLogLevel("custom"), want: INFO, wantTh: 10},
		{name: "warn", got: NewWarnLogLevel("custom"), want: WARN, wantTh: 20},
		{name: "error", got: NewErrorLogLevel("custom"), want: ERROR, wantTh: 30},
		{name: "fatal", got: NewFatalLogLevel("custom"), want: FATAL, wantTh: 40},
		{name: "debug", got: NewDebugLogLevel("custom"), want: DEBUG, wantTh: 0},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if tt.got.n != tt.want.n {
				t.Fatalf("%s severity = %d, want %d", tt.name, tt.got.n, tt.want.n)
			}
			if tt.got.th != tt.wantTh {
				t.Fatalf("%s threshold = %d, want %d", tt.name, tt.got.th, tt.wantTh)
			}
			if tt.got.GetName() != "custom" {
				t.Fatalf("%s constructor should preserve name, got %q", tt.name, tt.got.GetName())
			}
		})
	}
}

func TestNewLevelConstructorsWithColorsSetExpectedFields(t *testing.T) {
	info := NewInfoLogLevelWithColors("info-custom", FgBlue, BgYellow)
	if info.n != INFO.n || info.GetName() != "info-custom" || info.fg != FgBlue || info.bg != BgYellow {
		t.Fatalf("NewInfoLogLevelWithColors() = %#v", info)
	}

	warn := NewWarnLogLevelWithColors("warn-custom", FgMagenta, BgCyan)
	if warn.n != WARN.n || warn.GetName() != "warn-custom" || warn.fg != FgMagenta || warn.bg != BgCyan {
		t.Fatalf("NewWarnLogLevelWithColors() = %#v", warn)
	}

	errLevel := NewErrorLogLevelWithColors("error-custom", FgRed, BgWhite)
	if errLevel.n != ERROR.n || errLevel.GetName() != "error-custom" || errLevel.fg != FgRed || errLevel.bg != BgWhite {
		t.Fatalf("NewErrorLogLevelWithColors() = %#v", errLevel)
	}

	fatal := NewFatalLogLevelWithColors("fatal-custom", FgHiRed, BgBlack)
	if fatal.n != FATAL.n || fatal.GetName() != "fatal-custom" || fatal.fg != FgHiRed || fatal.bg != BgBlack {
		t.Fatalf("NewFatalLogLevelWithColors() = %#v", fatal)
	}

	debug := NewDebugLogLevelWithColors("debug-custom", FgGreen, BgDefault)
	if debug.n != DEBUG.n || debug.GetName() != "debug-custom" || debug.fg != FgGreen || debug.bg != BgDefault {
		t.Fatalf("NewDebugLogLevelWithColors() = %#v", debug)
	}
}

func TestCreateTextWriterCloseOnNonCloserIsNoOp(t *testing.T) {
	writer := CreateTextWriter(&bytes.Buffer{})
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
}

func TestCreateTextWriterDoesNotCloseExternalCloser(t *testing.T) {
	file, err := os.CreateTemp(t.TempDir(), "text-writer")
	if err != nil {
		t.Fatalf("CreateTemp() error = %v", err)
	}
	t.Cleanup(func() {
		_ = file.Close()
	})

	writer := CreateTextWriter(file)
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
	if _, err := file.WriteString("still open"); err != nil {
		t.Fatalf("CreateTextWriter() should not close external writers, got %v", err)
	}
}

func TestCreateJsonWriterCloseOnNonCloserIsNoOp(t *testing.T) {
	writer := CreateJsonWriter(&bytes.Buffer{}, false)
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
}

func TestCreateJsonWriterDoesNotCloseExternalCloser(t *testing.T) {
	file, err := os.CreateTemp(t.TempDir(), "json-writer")
	if err != nil {
		t.Fatalf("CreateTemp() error = %v", err)
	}
	t.Cleanup(func() {
		_ = file.Close()
	})

	writer := CreateJsonWriter(file, false)
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
	if _, err := file.WriteString("still open"); err != nil {
		t.Fatalf("CreateJsonWriter() should not close external writers, got %v", err)
	}
}

func TestJsonWriterPrintAllowsEmptyMessages(t *testing.T) {
	var buf bytes.Buffer
	writer := CreateJsonWriter(&buf, false)

	if err := writer.Print(INFO, "TEST", nil); err != nil {
		t.Fatalf("Print() error = %v", err)
	}

	var message LoggerJsonMessage
	if err := json.Unmarshal(buf.Bytes(), &message); err != nil {
		t.Fatalf("json.Unmarshal() error = %v", err)
	}
	if message.Message != "" {
		t.Fatalf("message should be empty, got %q", message.Message)
	}
}

func TestJsonWriterPrintPreservesTrailingNewlineSemantic(t *testing.T) {
	var buf bytes.Buffer
	writer := CreateJsonWriter(&buf, false)

	if err := writer.Print(INFO, "TEST", nil, "hello\n"); err != nil {
		t.Fatalf("Print() error = %v", err)
	}

	data := buf.Bytes()
	if !bytes.HasSuffix(data, []byte("\n")) {
		t.Fatalf("JSON output should end with newline, got %q", data)
	}

	var message LoggerJsonMessage
	if err := json.Unmarshal(bytes.TrimSuffix(data, []byte("\n")), &message); err != nil {
		t.Fatalf("json.Unmarshal() error = %v", err)
	}
	if message.Message != "hello" {
		t.Fatalf("message should not include trailing newline, got %q", message.Message)
	}
}

func TestTextWriterPrintlnDoesNotLeaveTrailingMessageSeparator(t *testing.T) {
	var buf bytes.Buffer
	formatter := NewFormatter().
		SetFormat("%m (%S)").
		SetColorOutput(false)
	writer := CreateTextWriter(&buf).SetFormatter(formatter)

	if err := writer.Print(DEBUG, "TEST", nil, "debug details", "\n"); err != nil {
		t.Fatalf("Print() error = %v", err)
	}

	got := strings.TrimSuffix(buf.String(), "\n")
	if got != "debug details (%S)" {
		t.Fatalf("println newline marker should not leave trailing message separator, got %q", got)
	}
}

func TestTextWriterPrintlnDoesNotLeaveTrailingMessageSeparatorAfterReplacement(t *testing.T) {
	var buf bytes.Buffer
	formatter := NewFormatter().
		SetFormat("%m (%S)").
		SetColorOutput(false)
	writer := CreateTextWriter(&buf).SetFormatter(formatter)
	logger := CreateLogger().
		SetLevel(DEBUG).
		AddWriter(writer).
		AddReplacer("details", "details")

	logger.Debugln("debug details")

	got := strings.TrimSuffix(buf.String(), "\n")
	if got != "debug details (%S)" {
		t.Fatalf("println newline marker should not leave trailing message separator after replacements, got %q", got)
	}
}

func TestJsonWriterPrintlnDoesNotLeaveTrailingMessageSeparator(t *testing.T) {
	var buf bytes.Buffer
	writer := CreateJsonWriter(&buf, false)

	if err := writer.Print(INFO, "TEST", nil, "hello", "\n"); err != nil {
		t.Fatalf("Print() error = %v", err)
	}

	var message LoggerJsonMessage
	if err := json.Unmarshal(bytes.TrimSuffix(buf.Bytes(), []byte("\n")), &message); err != nil {
		t.Fatalf("json.Unmarshal() error = %v", err)
	}
	if message.Message != "hello" {
		t.Fatalf("message should not include trailing separator from newline marker, got %q", message.Message)
	}
}

func TestLogLevelForegroundSettersOverridePreviousColorMode(t *testing.T) {
	level := NewLogLevel(0, "custom")
	formatter := NewFormatter()

	level.SetFgColor(FgRed)
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, FgRed.String()) {
		t.Fatalf("expected plain foreground color prefix %q, got %q", FgRed.String(), got)
	}

	level.SetForeground256Color(FgColor256(123))
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, FgColor256(123).String()) {
		t.Fatalf("expected 256-color foreground prefix %q, got %q", FgColor256(123).String(), got)
	}

	level.SetForegroundRGB(1, 2, 3)
	expectedRGB := NewFgColorRGB(1, 2, 3).String()
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, expectedRGB) {
		t.Fatalf("expected RGB foreground prefix %q, got %q", expectedRGB, got)
	}

	level.SetFgColor(FgBlue)
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, FgBlue.String()) {
		t.Fatalf("expected last plain foreground color to win with prefix %q, got %q", FgBlue.String(), got)
	}
}

func TestLogLevelBackgroundSettersOverridePreviousColorMode(t *testing.T) {
	level := NewLogLevel(0, "custom")
	formatter := NewFormatter()

	level.SetBgColor(BgRed)
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, BgRed.String()) {
		t.Fatalf("expected plain background color prefix %q, got %q", BgRed.String(), got)
	}

	level.SetBackground256Color(BgColor256(123))
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, BgColor256(123).String()) {
		t.Fatalf("expected 256-color background prefix %q, got %q", BgColor256(123).String(), got)
	}

	level.SetBackgroundRGB(1, 2, 3)
	expectedRGB := NewBgColorRGB(1, 2, 3).String()
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, expectedRGB) {
		t.Fatalf("expected RGB background prefix %q, got %q", expectedRGB, got)
	}

	level.SetBgColor(BgBlue)
	if got := formatter.ColorizeString("x", level); !strings.HasPrefix(got, BgBlue.String()) {
		t.Fatalf("expected last plain background color to win with prefix %q, got %q", BgBlue.String(), got)
	}
}

func TestLogLevelAttributesAffectColorizedOutput(t *testing.T) {
	level := NewLogLevel(0, "custom")
	level.AddAttribute(Italic).AddAttribute(Bold)

	got := NewFormatter().ColorizeString("x", level)
	if !strings.Contains(got, Italic.String()) {
		t.Fatalf("expected italic attribute in colorized output, got %q", got)
	}
	if !strings.Contains(got, Bold.String()) {
		t.Fatalf("expected bold attribute in colorized output, got %q", got)
	}
}

func TestLogLevelRemoveAttributeRemovesAllMatches(t *testing.T) {
	level := NewLogLevel(0, "custom")
	level.AddAttribute(Bold).AddAttribute(Italic).AddAttribute(Bold)

	level.RemoveAttribute(Bold)

	got := level.GetAttributes()
	if len(got) != 1 || got[0] != Italic {
		t.Fatalf("expected only italic attribute to remain, got %#v", got)
	}
}

func TestLogLevelSetAttributesCopiesInputSlice(t *testing.T) {
	level := NewLogLevel(0, "custom")
	attrs := []Attribute{Bold, Italic}

	level.SetAttributes(attrs)
	attrs[0] = Underline

	got := level.GetAttributes()
	if len(got) != 2 || got[0] != Bold || got[1] != Italic {
		t.Fatalf("expected SetAttributes to copy input slice, got %#v", got)
	}
}

func TestLogLevelGetAttributesReturnsCopy(t *testing.T) {
	level := NewLogLevel(0, "custom")
	level.SetAttributes([]Attribute{Bold, Italic})

	got := level.GetAttributes()
	got[0] = Underline

	again := level.GetAttributes()
	if len(again) != 2 || again[0] != Bold || again[1] != Italic {
		t.Fatalf("expected GetAttributes to return a copy, got %#v", again)
	}
}

func TestLogLevelDeprecatedForegroundAccessorsRemainCompatible(t *testing.T) {
	level := NewLogLevel(0, "custom")

	level.SetFgColor(FgBlue)
	if got := level.GetFgColor(); got != FgBlue {
		t.Fatalf("expected deprecated foreground accessors to round-trip %v, got %v", FgBlue, got)
	}

	level.SetForegroundColor(FgRed)
	if got := level.GetFgColor(); got != FgRed {
		t.Fatalf("expected deprecated getter to reflect new foreground setter, got %v", got)
	}
}

func TestLogLevelDeprecatedBackgroundAccessorsRemainCompatible(t *testing.T) {
	level := NewLogLevel(0, "custom")

	level.SetBgColor(BgBlue)
	if got := level.GetBgColor(); got != BgBlue {
		t.Fatalf("expected deprecated background accessors to round-trip %v, got %v", BgBlue, got)
	}

	level.SetBackgroundColor(BgRed)
	if got := level.GetBgColor(); got != BgRed {
		t.Fatalf("expected deprecated getter to reflect new background setter, got %v", got)
	}
}

func TestFormatterHandlesEmptyTracebackPlaceholders(t *testing.T) {
	formatter := NewFormatter().
		SetFormat("%m|%b|%B|%M|%f|%n|%s|%p")

	got := formatter.FormatMessage(INFO, "TEST", nil, "hello")
	if got != "hello|||||||" {
		t.Fatalf("empty traceback placeholders should be empty, got %q", got)
	}
}

func TestFormatterDoesNotInterpretPlaceholdersInsideMessages(t *testing.T) {
	formatter := NewFormatter().
		SetFormat("%L:%m")

	message := "literal %L %s %p"
	got := formatter.FormatMessage(INFO, "TEST", nil, message)
	if got != "INFO:literal %L %s %p" {
		t.Fatalf("message placeholder-looking text should stay literal, got %q", got)
	}
}

func TestNewFormatterDoesNotMutateDefaultFormatter(t *testing.T) {
	formatter := NewFormatter()
	formatter.SetFormat("custom")

	if DefaultTextFormatter.Format == "custom" {
		t.Fatal("NewFormatter() should return a copy, not mutate DefaultTextFormatter")
	}
}

func TestTextWriterColorOutputHonorsColorOnlyStdoutFalse(t *testing.T) {
	var buf bytes.Buffer
	formatter := NewFormatter().
		SetFormat("%m").
		SetColorOutput(true).
		SetColorOnlyStdout(false)
	writer := CreateTextWriter(&buf).SetFormatter(formatter)

	if err := writer.Print(INFO, "TEST", nil, "hello"); err != nil {
		t.Fatalf("Print() error = %v", err)
	}
	if !strings.Contains(buf.String(), "\x1b[") {
		t.Fatalf("ColorOnlyStdout(false) should allow color for external writers, got %q", buf.String())
	}
}

func TestTextWriterColorOutputCanBeDisabled(t *testing.T) {
	var buf bytes.Buffer
	formatter := NewFormatter().
		SetFormat("%m").
		SetColorOutput(false).
		SetColorOnlyStdout(false)
	writer := CreateTextWriter(&buf).SetFormatter(formatter)

	if err := writer.Print(INFO, "TEST", nil, "hello"); err != nil {
		t.Fatalf("Print() error = %v", err)
	}
	if strings.Contains(buf.String(), "\x1b[") {
		t.Fatalf("SetColorOutput(false) should disable color output, got %q", buf.String())
	}
}

func TestCreateTextStdoutWriterDoesNotCloseStdout(t *testing.T) {
	stdoutFile := swapStdout(t)

	writer := CreateTextStdoutWriter()
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
	if _, err := stdoutFile.WriteString("still open"); err != nil {
		t.Fatalf("stdout writer Close() should not close stdout, got %v", err)
	}
}

func TestCreateJsonStdoutWriterDoesNotCloseStdout(t *testing.T) {
	stdoutFile := swapStdout(t)

	writer := CreateJsonStdoutWriter(false)
	if err := writer.Close(); err != nil {
		t.Fatalf("Close() error = %v", err)
	}
	if _, err := stdoutFile.WriteString("still open"); err != nil {
		t.Fatalf("stdout writer Close() should not close stdout, got %v", err)
	}
}

func TestGetFullTracebackSkipsRuntimeAndSneklogFrames(t *testing.T) {
	tracebacks := captureTracebackForTest()
	if len(tracebacks) == 0 {
		t.Fatal("expected at least one traceback frame")
	}

	first := tracebacks[0]
	if first.Method != "captureTracebackForTest" {
		t.Fatalf("first frame should be the nearest user frame, got %s", first.Method)
	}
	for _, tb := range tracebacks {
		if strings.HasPrefix(tb.Signature, "runtime.") {
			t.Fatalf("runtime frame should be filtered out, got %s", tb.Signature)
		}
		if _, ok := internalTracebackMethods[tb.Method]; ok {
			t.Fatalf("internal sneklog frame should be filtered out, got %s", tb.Signature)
		}
	}
}

func TestGetTracebackReturnsNearestUserFrame(t *testing.T) {
	tb := captureSingleTracebackForTest()
	if tb == nil {
		t.Fatal("expected traceback frame")
	}
	if tb.Method != "captureSingleTracebackForTest" {
		t.Fatalf("expected nearest user frame, got %s", tb.Method)
	}
	if strings.HasPrefix(tb.Signature, "runtime.") {
		t.Fatalf("runtime frame should be filtered out, got %s", tb.Signature)
	}
	if _, ok := internalTracebackMethods[tb.Method]; ok {
		t.Fatalf("internal sneklog frame should be filtered out, got %s", tb.Signature)
	}
}

func swapStdout(t *testing.T) *os.File {
	t.Helper()

	oldStdout := os.Stdout
	stdoutFile, err := os.CreateTemp(t.TempDir(), "stdout")
	if err != nil {
		t.Fatalf("CreateTemp() error = %v", err)
	}
	os.Stdout = stdoutFile
	t.Cleanup(func() {
		os.Stdout = oldStdout
		_ = stdoutFile.Close()
	})
	return stdoutFile
}

func captureTracebackForTest() []*MethodTraceback {
	return getFullTraceback(0)
}

func captureSingleTracebackForTest() *MethodTraceback {
	return getTraceback()
}