package progressbar

import (
	"bytes"
	"context"
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"os"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/chengxilo/virtualterm"

	"github.com/stretchr/testify/assert"
)

func TestMain(m *testing.M) {
	termWidth = func(w io.Writer) (int, error) {
		return 0, os.ErrPermission
	}
	os.Exit(m.Run())
}

func BenchmarkRender(b *testing.B) {
	bar := NewOptions64(100000000,
		OptionSetWriter(os.Stderr),
		OptionShowIts(),
	)
	for i := 0; i < b.N; i++ {
		bar.Add(1)
	}
}

func ExampleProgressBar() {
	bar := New(100)
	bar.Add(10)
	// Output:
	// 10% |████                                    |  [0s:0s]
}

func ExampleProgressBar_Set() {
	bar := New(100)
	bar.Set(10)
	// Output:
	// 10% |████                                    |  [0s:0s]
}

func ExampleProgressBar_Set64() {
	bar := New(100)
	bar.Set64(10)
	// Output:
	// 10% |████                                    |  [0s:0s]
}

func ExampleProgressBar_basic() {
	bar := NewOptions(100, OptionSetWidth(10))
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	// Output:
	// 10% |█         |  [1s:9s]
}

func ExampleProgressBar_invisible() {
	bar := NewOptions(100, OptionSetWidth(10), OptionSetRenderBlankState(true), OptionSetVisibility(false))
	bar.Reset()
	fmt.Println("hello, world")
	time.Sleep(1 * time.Second)
	bar.Add(10)
	// Output:
	// hello, world
}

func ExampleOptionThrottle() {
	bar := NewOptions(100, OptionSetWidth(10), OptionThrottle(100*time.Millisecond))
	bar.Reset()
	bar.Add(5)
	time.Sleep(150 * time.Millisecond)
	bar.Add(5)
	bar.Add(10)
	// Output:
	// 10% |█         |  [0s:1s]
}

func ExampleOptionClearOnFinish() {
	bar := NewOptions(100, OptionSetWidth(10), OptionClearOnFinish())
	bar.Reset()
	bar.Finish()
	fmt.Println("Finished")
	// Output:
	// Finished
}

func TestSpinnerClearOnFinish(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(-1, OptionSetWidth(100), OptionShowCount(), OptionShowBytes(true), OptionShowIts(), OptionClearOnFinish(), OptionSetWriter(&buf))
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	time.Sleep(1 * time.Second)
	bar.Finish()
	result, _ := virtualterm.Process(buf.String())
	expect := "                                "
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func ExampleProgressBar_Finish() {
	bar := NewOptions(100, OptionSetWidth(10), OptionShowCount(), OptionShowBytes(true), OptionShowIts())
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Finish()
	// Output:
	// 100% |██████████| (100/100 B, 100 B/s, 100 it/s)
}

func TestSpinnerFinish(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(-1, OptionSetWidth(100), OptionShowCount(), OptionShowBytes(true), OptionShowIts(), OptionSetWriter(&buf))
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	time.Sleep(1 * time.Second)
	bar.Finish()
	result, err := virtualterm.Process(buf.String())
	if err != nil {
		t.Error(err)
	}
	// the "\r \r"
	expect := "|  (10 B,  5 B/s, 5 it/s) [2s]  "
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func Example_xOutOfY() {
	bar := NewOptions(100, OptionSetPredictTime(true))

	for i := 0; i < 100; i++ {
		bar.Add(1)
		time.Sleep(1 * time.Millisecond)
	}
}

func ExampleOptionShowIts_count() {
	bar := NewOptions(100, OptionSetWidth(10), OptionShowIts(), OptionShowCount())
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	// Output:
	// 10% |█         | (10/100, 10 it/s) [1s:9s]
}

func ExampleOptionShowIts() {
	bar := NewOptions(100, OptionSetWidth(10), OptionShowIts(), OptionSetPredictTime(false))
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	// Output:
	// 10% |█         | (10 it/s)
}

func ExampleOptionShowCount_minuscule() {
	bar := NewOptions(10000, OptionSetWidth(10), OptionShowCount(), OptionSetPredictTime(false))
	bar.Add(1)
	// Output:
	// 0% |          | (1/10000)
}

func ExampleOptionSetPredictTime() {
	bar := NewOptions(100, OptionSetWidth(10), OptionSetPredictTime(false))
	_ = bar.Add(10)
	// Output:
	// 10% |█         |
}

func ExampleOptionShowDescriptionAtLineEnd() {
	bar := NewOptions(100, OptionSetWidth(10), OptionShowDescriptionAtLineEnd(), OptionSetDescription("hello"))
	_ = bar.Add(10)
	// Output:
	// 10% |█         |  [0s:0s] hello
}

func ExampleOptionShowDescriptionAtLineEnd_spinner() {
	bar := NewOptions(-1, OptionSetWidth(10), OptionShowDescriptionAtLineEnd(), OptionSetDescription("hello"))
	_ = bar.Add(1)
	// Output:
	// |  [0s] hello
}

func ExampleDefault() {
	bar := Default(100)
	for i := 0; i < 50; i++ {
		bar.Add(1)
		time.Sleep(10 * time.Millisecond)
	}
	// Output:
	//
}

func ExampleProgressBar_ChangeMax() {
	bar := NewOptions(100, OptionSetWidth(10), OptionSetPredictTime(false))
	bar.ChangeMax(50)
	bar.Add(50)
	// Output:
	// 100% |██████████|
}

func ExampleProgressBar_AddMax() {
	bar := NewOptions(50, OptionSetWidth(10), OptionSetPredictTime(false))
	bar.AddMax(50)
	bar.Add(100)
	// Output:
	// 100% |██████████|
}

func ExampleOptionShowIts_spinner() {
	/*
		Spinner test with iteration count and iteration rate
	*/
	vt := virtualterm.NewDefault()
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionShowIts(),
		OptionShowCount(),
		OptionSetWriter(&vt),
	)
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(5)
	bar.lock.Lock()
	s, err := vt.String()
	bar.lock.Unlock()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Print(s)
	// Output:
	// -  (5/-, 5 it/s) [1s]
}

func TestSpinnerType(t *testing.T) {
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetDescription("indeterminate spinner"),
		OptionShowIts(),
		OptionShowCount(),
		OptionSpinnerType(9),
	)
	bar.Reset()
	for i := 0; i < 10; i++ {
		time.Sleep(120 * time.Millisecond)
		err := bar.Add(1)
		if err != nil {
			t.Errorf("Successfully tested one spinner option can be used.")
		}
	}
	if false {
		t.Errorf("error")
	}
}

func TestSpinnerCustom(t *testing.T) {
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetDescription("indeterminate spinner"),
		OptionShowIts(),
		OptionShowCount(),
		OptionSpinnerCustom([]string{"🐰", "🐰", "🥕", "🥕"}),
	)
	bar.Reset()
	for i := 0; i < 10; i++ {
		time.Sleep(120 * time.Millisecond)
		err := bar.Add(1)
		if err != nil {
			t.Errorf("Successfully tested one spinner option can be used.")
		}
	}
	if false {
		t.Errorf("error")
	}
}

func TestSpinnerTypeAndCustom(t *testing.T) {
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetDescription("indeterminate spinner"),
		OptionShowIts(),
		OptionShowCount(),
		OptionSpinnerCustom([]string{"🐰", "🐰", "🥕", "🥕"}),
		OptionSpinnerType(9),
	)
	bar.Reset()
	for i := 0; i < 10; i++ {
		time.Sleep(120 * time.Millisecond)
		err := bar.Add(1)
		if err == nil {
			t.Errorf("Successfully tested both spinner options cannot be used together.")
		}
	}
}

func Test_IsFinished(t *testing.T) {
	isCalled := false
	bar := NewOptions(72, OptionOnCompletion(func() {
		isCalled = true
	}))

	// Test1: If bar is not fully completed.
	bar.Add(5)
	if bar.IsFinished() || isCalled {
		t.Errorf("Successfully tested bar is not yet finished.")
	}

	// Test2: Bar fully completed.
	bar.Add(67)
	if !bar.IsFinished() || !isCalled {
		t.Errorf("Successfully tested bar is finished.")
	}

	// Test3: If increases maximum bytes error should be thrown and
	// bar finished will remain false.
	bar.Reset()
	err := bar.Add(73)
	if err == nil || bar.IsFinished() {
		t.Errorf("Successfully got error when bytes increases max bytes, bar finished: %v", bar.IsFinished())
	}
}

func ExampleOptionShowBytes_spinner() {
	/*
		Spinner test with iterations and count
	*/
	buf := strings.Builder{}
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionShowBytes(true),
		OptionSetWriter(&buf),
	)

	bar.Reset()
	time.Sleep(1 * time.Second)
	// since 10 is the width and we don't know the max bytes
	// it will do a infinite scrolling.
	bar.Add(11)
	bar.lock.Lock()
	result, _ := virtualterm.Process(buf.String())
	bar.lock.Unlock()
	fmt.Print(result)
	// Output:
	// -  (11 B/s) [1s]
}

func TestBarSlowAdd(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(100, OptionSetWidth(10), OptionShowIts(), OptionSetWriter(&buf))
	bar.Reset()
	time.Sleep(3 * time.Second)
	bar.Add(1)
	if !strings.Contains(buf.String(), "1%") {
		t.Errorf("wrong string: %s", buf.String())
	}
	if !strings.Contains(buf.String(), "20 it/min") {
		t.Errorf("wrong string: %s", buf.String())
	}
	if !strings.Contains(buf.String(), "[3s:") {
		t.Errorf("wrong string: %s", buf.String())
	}
	// Output:
	// 1% |          | (20 it/min) [3s:4m57s]
}

func TestBarSmallBytes(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions64(100000000, OptionShowBytes(true), OptionShowCount(), OptionSetWidth(10), OptionSetWriter(&buf))
	for i := 1; i < 10; i++ {
		time.Sleep(100 * time.Millisecond)
		bar.Add(1000)
	}
	if !strings.Contains(buf.String(), "9.0 kB/100 MB") {
		t.Errorf("wrong string: %s", buf.String())
	}
	for i := 1; i < 10; i++ {
		time.Sleep(10 * time.Millisecond)
		bar.Add(1000000)
	}
	if !strings.Contains(buf.String(), "9.0/100 MB") {
		t.Errorf("wrong string: %s", buf.String())
	}
}

func TestBarFastBytes(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions64(1e8, OptionShowBytes(true), OptionShowCount(), OptionSetWidth(10), OptionSetWriter(&buf))
	bar.StartWithoutRender()
	time.Sleep(time.Millisecond)
	bar.Add(1e7)
	if !strings.Contains(buf.String(), " GB/s)") {
		t.Errorf("wrong string: %s", buf.String())
	}
}

func TestBar(t *testing.T) {
	bar := New(0)
	if err := bar.Add(1); err == nil {
		t.Error("should have an error for 0 bar")
	}
	bar = New(10)
	if err := bar.Add(11); err == nil {
		t.Error("should have an error for adding > bar")
	}
}

func TestAddExceedsMaxDoesNotCorruptState(t *testing.T) {
	bar := NewOptions(100, OptionSetWriter(io.Discard))

	if err := bar.Add(95); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if err := bar.Add(10); err == nil {
		t.Error("should have an error for adding past max")
	}

	// A rejected Add must leave state exactly as it was before the call,
	// not partially applied, so the bar is not left stuck above 100%.
	if bar.state.currentNum != 95 {
		t.Errorf("expected currentNum to stay at 95 after a rejected Add, got %d", bar.state.currentNum)
	}
	if bar.state.currentPercent != 95 {
		t.Errorf("expected currentPercent to stay at 95 after a rejected Add, got %d", bar.state.currentPercent)
	}

	// The bar must still accept further, non-overshooting progress afterwards.
	if err := bar.Add(5); err != nil {
		t.Errorf("bar should still accept progress after a rejected Add, got error: %v", err)
	}
	if bar.state.currentNum != 100 {
		t.Errorf("expected currentNum to reach 100, got %d", bar.state.currentNum)
	}
}

func TestState(t *testing.T) {
	bar := NewOptions(100, OptionSetWidth(10))
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	s := bar.State()
	if s.CurrentPercent != 0.1 {
		t.Error(s)
	}
}

func TestStartingBytes(t *testing.T) {
	bar := NewOptions64(100, OptionSetWidth(10), OptionSetStartingBytes(80))
	s := bar.State()
	if s.CurrentBytes != 80 {
		t.Errorf("expected CurrentBytes 80, got %v", s.CurrentBytes)
	}
	if s.CurrentPercent != 0.8 {
		t.Errorf("expected CurrentPercent 0.8, got %v", s.CurrentPercent)
	}

	// Transfer 10 more over ~0.2s: the rate must reflect only those 10 units,
	// not the 80 seeded ones. Without the offset the fallback rate would be
	// 90/0.2 = 450/s; with it, ~50/s.
	bar = NewOptions64(100, OptionSetWidth(10), OptionSetStartingBytes(80), OptionSetWriter(io.Discard))
	bar.Add(0) // start the clock at the seeded position
	time.Sleep(200 * time.Millisecond)
	bar.Add(10)
	s = bar.State()
	if rate := s.KBsPerSecond * 1024; rate > 200 {
		t.Errorf("rate should exclude seeded bytes, got %v/s", rate)
	}
}

func ExampleOptionSetRenderBlankState() {
	NewOptions(10, OptionSetWidth(10), OptionSetRenderBlankState(true))
	// Output:
	// 0% |          |  [0s:0s]
}

func TestBasicSets(t *testing.T) {
	b := NewOptions(
		999,
		OptionSetWidth(888),
		OptionSetRenderBlankState(true),
		OptionSetWriter(io.Discard), // suppressing output for this test
	)

	tc := b.config

	if tc.max != 999 {
		t.Errorf("Expected %s to be %d, instead I got %d\n%+v", "max", 999, tc.max, b)
	}

	if tc.width != 888 {
		t.Errorf("Expected %s to be %d, instead I got %d\n%+v", "width", 999, tc.max, b)
	}

	if !tc.renderWithBlankState {
		t.Errorf("Expected %s to be %t, instead I got %t\n%+v", "renderWithBlankState", true, tc.renderWithBlankState, b)
	}
}

func TestOptionSetTheme(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(
		10,
		OptionSetTheme(
			Theme{Saucer: "#", SaucerPadding: "-",
				BarStart: ">", BarEnd: "<"}),
		OptionSetWidth(10),
		OptionSetWriter(&buf),
	)
	bar.RenderBlank()
	result := strings.TrimSpace(buf.String())
	expect := "0% >----------<"
	if !strings.Contains(result, expect) {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
	buf.Reset()

	bar.Add(5)
	result = strings.TrimSpace(buf.String())
	expect = "50% >#####-----<  [0s:0s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
	buf.Reset()

	bar.Finish()
	result = strings.TrimSpace(buf.String())
	expect = "100% >##########<"
	if !strings.Contains(result, expect) {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestOptionSetThemeFilled(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(
		10,
		OptionSetTheme(
			Theme{Saucer: "#", SaucerPadding: "-",
				BarStart: ">", BarStartFilled: "]",
				BarEnd: "<", BarEndFilled: "["}),
		OptionSetWidth(10),
		OptionSetWriter(&buf),
	)
	bar.RenderBlank()
	result := strings.TrimSpace(buf.String())
	expect := "0% >----------<"
	if !strings.Contains(result, expect) {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
	buf.Reset()

	bar.Add(5)
	result = strings.TrimSpace(buf.String())
	expect = "50% ]#####-----<  [0s:0s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
	buf.Reset()

	bar.Finish()
	result = strings.TrimSpace(buf.String())
	expect = "100% ]##########["
	if !strings.Contains(result, expect) {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

// TestOptionSetPredictTime ensures that when predict time is turned off, the progress
// bar is showing the total steps completed of the given max, otherwise the predicted
// time in seconds is specified.
func TestOptionSetPredictTime(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(
		10,
		OptionSetPredictTime(false),
		OptionSetWidth(10),
		OptionSetWriter(&buf),
	)

	_ = bar.Add(2)
	result := strings.TrimSpace(buf.String())
	expect := "20% |██        |"

	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}

	bar.Reset()
	bar.config.predictTime = true
	buf.Reset()

	_ = bar.Add(7)
	result = strings.TrimSpace(buf.String())
	expect = "70% |███████   |  [0s:0s]"

	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestOptionSetElapsedTime_spinner(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetWriter(&buf),
		OptionShowIts(),
		OptionShowCount(),
		OptionSetElapsedTime(false),
	)
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(5)
	bar.lock.Lock()
	result, err := virtualterm.Process(buf.String())
	bar.lock.Unlock()
	result = strings.TrimSpace(result)
	if err != nil {
		t.Fatal(err)
	}
	expect := "-  (5/-, 5 it/s)"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestOptionSetElapsedTime(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(
		10,
		OptionSetElapsedTime(false),
		OptionSetPredictTime(false),
		OptionSetWidth(10),
		OptionSetWriter(&buf),
	)

	_ = bar.Add(2)
	result := strings.TrimSpace(buf.String())
	expect := "20% |██        |"

	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}

	bar.Reset()
	bar.config.elapsedTime = true
	buf.Reset()

	_ = bar.Add(7)
	result = strings.TrimSpace(buf.String())
	expect = "70% |███████   |  [0s]"

	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestShowElapsedTimeOnFinish(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(10,
		OptionShowElapsedTimeOnFinish(),
		OptionSetWidth(10),
		OptionSetWriter(&buf),
	)
	bar.Reset()
	time.Sleep(3 * time.Second)
	bar.Add(10)
	result := strings.TrimSpace(buf.String())
	expect := "100% |██████████|  [3s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestSpinnerState(t *testing.T) {
	bar := NewOptions(
		-1,
		OptionSetWidth(100),
	)
	bar.Reset()
	time.Sleep(1 * time.Second)
	bar.Add(10)

	state := bar.State()
	if state.Max != -1 {
		t.Errorf("Max mismatched gotMax %d wantMax %d", state.Max, -1)
	}
	if state.CurrentNum != 10 {
		t.Errorf("Number mismatched gotNum %d wantNum %d", state.CurrentNum, 10)
	}
	if state.CurrentBytes != 10.0 {
		t.Errorf("Number of bytes mismatched gotBytes %f wantBytes %f", state.CurrentBytes, 10.0)
	}
	if state.CurrentPercent != 0.1 {
		t.Errorf("Percent of bar mismatched got %f want %f", state.CurrentPercent, 0.1)
	}

	kbPerSec := fmt.Sprintf("%2.2f", state.KBsPerSecond)
	if kbPerSec != "0.01" {
		t.Errorf("Speed mismatched got %s want %s", kbPerSec, "0.01")
	}
}

func TestReaderToBuffer(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}

	urlToGet := "https://dl.google.com/go/go1.14.1.src.tar.gz"
	req, err := http.NewRequest("GET", urlToGet, nil)
	assert.Nil(t, err)
	resp, err := http.DefaultClient.Do(req)
	assert.Nil(t, err)
	defer resp.Body.Close()

	buf := new(bytes.Buffer)
	bar := NewOptions(int(resp.ContentLength), OptionShowBytes(true), OptionShowCount())
	out := io.MultiWriter(buf, bar)
	_, err = io.Copy(out, resp.Body)
	assert.Nil(t, err)

	md5, err := md5sum(buf)
	assert.Nil(t, err)
	assert.Equal(t, "d441819a800f8c90825355dfbede7266", md5)
}

func TestReaderToFile(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}

	urlToGet := "https://dl.google.com/go/go1.14.1.src.tar.gz"
	req, err := http.NewRequest("GET", urlToGet, nil)
	assert.Nil(t, err)
	resp, err := http.DefaultClient.Do(req)
	assert.Nil(t, err)
	defer resp.Body.Close()

	f, err := os.CreateTemp("", "progressbar_testfile")
	if err != nil {
		t.Fatal()
	}
	defer os.Remove(f.Name())
	defer f.Close()

	realStdout := os.Stdout
	defer func() { os.Stdout = realStdout }()
	r, fakeStdout, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}
	os.Stdout = fakeStdout

	bar := DefaultBytes(resp.ContentLength)
	out := io.MultiWriter(f, bar)
	_, err = io.Copy(out, resp.Body)
	assert.Nil(t, err)
	f.Sync()
	f.Seek(0, 0)

	if err := fakeStdout.Close(); err != nil {
		t.Fatal(err)
	}

	b, err := io.ReadAll(r)
	if err != nil {
		t.Fatal(err)
	}

	if err := r.Close(); err != nil {
		t.Fatal(err)
	}

	assert.Equal(t, "", string(b))

	md5, err := md5sum(f)
	assert.Nil(t, err)
	assert.Equal(t, "d441819a800f8c90825355dfbede7266", md5)
}

func TestReaderToFileUnknownLength(t *testing.T) {
	if testing.Short() {
		t.SkipNow()
	}

	urlToGet := "https://dl.google.com/go/go1.14.1.src.tar.gz"
	req, err := http.NewRequest("GET", urlToGet, nil)
	assert.Nil(t, err)
	resp, err := http.DefaultClient.Do(req)
	assert.Nil(t, err)
	defer resp.Body.Close()

	f, err := os.CreateTemp("", "progressbar_testfile")
	if err != nil {
		t.Fatal()
	}
	defer os.Remove(f.Name())
	defer f.Close()

	realStdout := os.Stdout
	defer func() { os.Stdout = realStdout }()
	r, fakeStdout, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}
	os.Stdout = fakeStdout

	bar := DefaultBytes(-1, " downloading")
	out := io.MultiWriter(f, bar)
	_, err = io.Copy(out, resp.Body)
	assert.Nil(t, err)
	f.Sync()
	f.Seek(0, 0)

	if err := fakeStdout.Close(); err != nil {
		t.Fatal(err)
	}

	b, err := io.ReadAll(r)
	if err != nil {
		t.Fatal(err)
	}

	if err := r.Close(); err != nil {
		t.Fatal(err)
	}

	assert.Equal(t, "", string(b))

	md5, err := md5sum(f)
	assert.Nil(t, err)
	assert.Equal(t, "d441819a800f8c90825355dfbede7266", md5)
}

func TestConcurrency(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(
		1000,
		OptionSetWriter(&buf),
	)
	var wg sync.WaitGroup
	for i := 0; i < 900; i++ {
		wg.Add(1)
		go func(b *ProgressBar, wg *sync.WaitGroup) {
			bar.Add(1)
			wg.Done()
		}(bar, &wg)
	}
	wg.Wait()
	result := bar.state.currentNum
	expect := int64(900)
	assert.Equal(t, expect, result)
}

func TestIterationNames(t *testing.T) {
	b := Default(20)
	tc := b.config

	// Checking for the default iterations per second or "it/s"
	if tc.iterationString != "it" {
		t.Errorf("Expected %s to be %s, instead I got %s", "iterationString", "it", tc.iterationString)
	}

	// Change the default "it/s" to provide context, downloads per second or "dl/s"
	b = NewOptions(20, OptionSetItsString("dl"))
	tc = b.config

	if tc.iterationString != "dl" {
		t.Errorf("Expected %s to be %s, instead I got %s", "iterationString", "dl", tc.iterationString)
	}
}

func md5sum(r io.Reader) (string, error) {
	hash := md5.New()
	_, err := io.Copy(hash, r)
	return hex.EncodeToString(hash.Sum(nil)), err
}

func TestProgressBar_Describe(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(100, OptionSetWidth(10), OptionSetWriter(&buf))
	bar.Describe("performing axial adjustments")
	bar.Add(10)
	result := buf.String()
	expect := "" +
		"\rperforming axial adjustments   0% |          |  [0s:0s]" +
		"\r                                                       \r" +
		"\rperforming axial adjustments  10% |█         |  [0s:0s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestProgressBar_DescribeAfterFinish(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(100,
		OptionSetDescription("Uploading files"),
		OptionShowCount(),
		OptionSetWriter(&buf),
		OptionSetWidth(10),
	)
	for i := 0; i < 100; i++ {
		bar.Add(1)
	}
	bar.Describe("Upload complete")
	result := buf.String()
	assert.Contains(t, result, "Upload complete")
}

func TestRenderBlankStateWithThrottle(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(100, OptionSetWidth(10), OptionSetRenderBlankState(true), OptionThrottle(time.Millisecond), OptionSetWriter(&buf))
	result := strings.TrimSpace(buf.String())
	expect := "0% |          |  [0s:0s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestOptionFullWidth(t *testing.T) {
	var tests = []struct {
		opts     []Option
		expected string
	}{
		{ // 1
			[]Option{},
			"" +
				"\r  10% |██████                                                        |  [1s:9s]" +
				"\r                                                                               \r" +
				"\r 100% |██████████████████████████████████████████████████████████████| ",
		},
		{ // 2
			[]Option{OptionSetDescription("Progress:")},
			"" +
				"\rProgress:  10% |█████                                                |  [1s:9s]" +
				"\r                                                                               \r" +
				"\rProgress: 100% |█████████████████████████████████████████████████████| ",
		},
		{ // 3
			[]Option{OptionSetDescription("<1/5>"), OptionShowDescriptionAtLineEnd()},
			"" +
				"\r  10% |█████                                                   |  [1s:9s] <1/5>" +
				"\r                                                                               \r" +
				"\r 100% |████████████████████████████████████████████████████████|  <1/5>",
		},
		{ // 4
			[]Option{OptionSetPredictTime(false)},
			"" +
				"\r  10% |██████                                                               |  " +
				"\r                                                                               \r" +
				"\r 100% |█████████████████████████████████████████████████████████████████████|  ",
		},
		{ // 5
			[]Option{OptionSetPredictTime(false), OptionShowElapsedTimeOnFinish()},
			"" +
				"\r  10% |██████                                                          |  " +
				"\r                                                                          \r" +
				"\r 100% |████████████████████████████████████████████████████████████████|  [2s] ",
		},
		{ // 6
			[]Option{OptionSetPredictTime(false), OptionSetElapsedTime(false)},
			"" +
				"\r  10% |██████                                                               |  " +
				"\r                                                                               \r" +
				"\r 100% |█████████████████████████████████████████████████████████████████████|  ",
		},
		{ // 7
			[]Option{OptionShowIts()},
			"" +
				"\r  10% |█████                                                | (10 it/s) [1s:9s]" +
				"\r                                                                               \r" +
				"\r 100% |█████████████████████████████████████████████████████| (50 it/s)",
		},
		{ // 8
			[]Option{OptionShowCount()},
			"" +
				"\r  10% |█████                                                 | (10/100) [1s:9s]" +
				"\r                                                                               \r" +
				"\r 100% |█████████████████████████████████████████████████████| (100/100)",
		},
		{ // 9
			[]Option{OptionShowIts(), OptionShowCount(), OptionShowElapsedTimeOnFinish()},
			"" +
				"\r  10% |████                                         | (10/100, 10 it/s) [1s:9s]" +
				"\r                                                                               \r" +
				"\r 100% |████████████████████████████████████████████| (100/100, 50 it/s) [2s]",
		},
		{ // 10
			[]Option{OptionSetDescription("Progress:"), OptionShowIts(), OptionShowCount()},
			"" +
				"\rProgress:  10% |███                                 | (10/100, 10 it/s) [1s:9s]" +
				"\r                                                                               \r" +
				"\rProgress: 100% |███████████████████████████████████| (100/100, 50 it/s)",
		},
		{ // 11
			[]Option{OptionSetDescription("<3/5>"), OptionShowIts(), OptionShowCount(), OptionShowElapsedTimeOnFinish(), OptionShowDescriptionAtLineEnd()},
			"" +
				"\r  10% |███                                    | (10/100, 10 it/s) [1s:9s] <3/5>" +
				"\r                                                                               \r" +
				"\r 100% |██████████████████████████████████████| (100/100, 50 it/s) [2s] <3/5>",
		},
		{ // 12
			[]Option{OptionShowIts(), OptionShowCount(), OptionSetPredictTime(false)},
			"" +
				"\r  10% |█████                                               | (10/100, 10 it/s) " +
				"\r                                                                               \r" +
				"\r 100% |███████████████████████████████████████████████████| (100/100, 50 it/s) ",
		},
		{ // 13
			[]Option{OptionShowIts(), OptionShowCount(), OptionSetPredictTime(false), OptionShowElapsedTimeOnFinish()},
			"" +
				"\r  10% |████                                           | (10/100, 10 it/s) " +
				"\r                                                                          \r" +
				"\r 100% |██████████████████████████████████████████████| (100/100, 50 it/s) [2s] ",
		},
		{ // 14
			[]Option{OptionShowIts(), OptionShowCount(), OptionSetPredictTime(false), OptionSetElapsedTime(false)},
			"" +
				"\r  10% |█████                                               | (10/100, 10 it/s) " +
				"\r                                                                               \r" +
				"\r 100% |███████████████████████████████████████████████████| (100/100, 50 it/s) ",
		},
	}

	for i, test := range tests {
		test := test
		t.Run(fmt.Sprintf("%d", i+1), func(t *testing.T) {
			t.Parallel()
			buf := strings.Builder{}
			bar := NewOptions(100, append(test.opts, []Option{OptionFullWidth(), OptionSetWriter(&buf)}...)...)
			bar.StartWithoutRender()
			time.Sleep(1 * time.Second)
			bar.Add(10)
			time.Sleep(1 * time.Second)
			bar.Add(90)
			assert.Equal(t, test.expected, buf.String())
		})
	}
}

func TestFixedWidthBarFitsTerminal(t *testing.T) {
	oldTermWidth := termWidth
	termWidth = func(w io.Writer) (int, error) {
		return 50, nil
	}
	defer func() {
		termWidth = oldTermWidth
	}()

	buf := strings.Builder{}
	bar := NewOptions(
		100,
		OptionSetWriter(&buf),
		OptionSetDescription("really-long-file-name.bin "),
		OptionSetWidth(20),
		OptionShowCount(),
		OptionSetPredictTime(false),
	)
	bar.Add(1)

	assert.LessOrEqual(t, getStringWidth(bar.config, bar.String()), 50)
	assert.NotContains(t, bar.String(), "|                    |")
}

func TestHumanizeBytesSI(t *testing.T) {
	amount, suffix := humanizeBytes(float64(12.34)*1000*1000, false)
	assert.Equal(t, "12 MB", fmt.Sprintf("%s%s", amount, suffix))

	amount, suffix = humanizeBytes(float64(56.78)*1000*1000*1000, false)
	assert.Equal(t, "57 GB", fmt.Sprintf("%s%s", amount, suffix))
}

func TestHumanizeBytesIEC(t *testing.T) {
	amount, suffix := humanizeBytes(float64(12.34)*1024*1024, true)
	assert.Equal(t, "12 MiB", fmt.Sprintf("%s%s", amount, suffix))

	amount, suffix = humanizeBytes(float64(56.78)*1024*1024*1024, true)
	assert.Equal(t, "57 GiB", fmt.Sprintf("%s%s", amount, suffix))
}

func TestProgressBar_StartWithoutRender(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(100, OptionSetWriter(&buf))
	time.Sleep(1 * time.Second)
	bar.StartWithoutRender()
	time.Sleep(1 * time.Second)
	bar.Add(10)
	result := strings.TrimSpace(buf.String())
	expect := "10% |████                                    |  [1s:9s]"
	if result != expect {
		t.Errorf("Render miss-match\nResult: '%s'\nExpect: '%s'\n%+v", result, expect, bar)
	}
}

func TestOptionSetSpinnerChangeInterval(t *testing.T) {
	interval := 1000 * time.Millisecond
	vt := virtualterm.NewDefault()
	actuals := make([]string, 0, 8)
	expecteds := []string{
		"◐ test  [0s]",
		"◓ test  [1s]",
		"◑ test  [2s]",
		"◒ test  [3s]",
		"◐ test  [4s]",
		"◓ test  [5s]",
		"◑ test  [6s]",
		"◒ test  [7s]",
	}
	bar := NewOptions(-1,
		OptionSetDescription("test"),
		OptionSpinnerType(7),
		OptionSetWriter(&vt),
		OptionSetSpinnerChangeInterval(interval))
	bar.Add(1)
	for i := 0; i < 8; i++ {
		bar.lock.Lock()
		s, _ := vt.String()
		bar.lock.Unlock()
		s = strings.TrimSpace(s)
		actuals = append(actuals, s)
		// sleep 50 ms more to make sure to go to next interval each time
		time.Sleep(1050 * time.Millisecond)
	}
	for i := range actuals {
		assert.Equal(t, expecteds[i], actuals[i])
	}
}

func TestOptionSetSpinnerChangeIntervalZero(t *testing.T) {
	vt := virtualterm.NewDefault()
	bar := NewOptions(-1,
		OptionSetDescription("test"),
		OptionSpinnerType(7),
		OptionSetWriter(&vt),
		OptionSetSpinnerChangeInterval(0))
	actuals := make([]string, 0, 5)
	expected := []string{
		"◐ test  [0s]",
		"◓ test  [1s]",
		"◑ test  [2s]",
		"◒ test  [3s]",
		"◐ test  [4s]",
	}
	for i := 0; i < 5; i++ {
		bar.Add(1)
		bar.lock.Lock()
		s, _ := vt.String()
		bar.lock.Unlock()
		_ = strings.TrimSpace(s)
	}
	for i := range actuals {
		assert.Equal(t, expected[i], actuals[i])
	}
}

func TestOptionShowTotalFalseDeterminate(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions64(
		100000000,
		OptionShowBytes(true),
		OptionShowCount(),
		OptionSetWidth(10),
		OptionShowTotalBytes(false),
		OptionSetWriter(&buf),
	)

	bar.Add(10000)
	if !strings.Contains(buf.String(), "10 kB, ") {
		t.Errorf("wrong string: %s", buf.String())
	}
}

func TestOptionShowTotalFalseIndeterminate(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetDescription("indeterminate spinner"),
		OptionShowIts(),
		OptionShowCount(),
		OptionSpinnerType(9),
		OptionShowTotalBytes(false),
		OptionSetWriter(&buf),
	)
	bar.Add(10)
	if !strings.Contains(buf.String(), "10, ") {
		t.Errorf("wrong string: %s", buf.String())
	}
}

func TestOptionShowTotalTrueIndeterminate(t *testing.T) {
	buf := strings.Builder{}
	bar := NewOptions(-1,
		OptionSetWidth(10),
		OptionSetDescription("indeterminate spinner"),
		OptionShowIts(),
		OptionShowCount(),
		OptionSpinnerType(9),
		OptionShowTotalBytes(true),
		OptionSetWriter(&buf),
	)
	bar.Add(10)
	if !strings.Contains(buf.String(), "10/-, ") {
		t.Errorf("wrong string: %s", buf.String())
	}
}

func freeTestHTTPAddr(t *testing.T) string {
	t.Helper()

	listener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("listen for free port: %v", err)
	}
	defer listener.Close()

	return listener.Addr().String()
}

func getHTTPWithRetry(t *testing.T, url string) *http.Response {
	t.Helper()

	var lastErr error
	deadline := time.Now().Add(time.Second)
	for time.Now().Before(deadline) {
		resp, err := http.Get(url)
		if err == nil {
			return resp
		}
		lastErr = err
		time.Sleep(10 * time.Millisecond)
	}

	t.Fatalf("GET %s: %v", url, lastErr)
	return nil
}

func TestStartHTTPServer(t *testing.T) {
	bar := Default(10, "test")
	bar.Add(1)

	hostPort := freeTestHTTPAddr(t)
	svr := bar.StartHTTPServer(hostPort)

	// check plain text
	resp := getHTTPWithRetry(t, fmt.Sprintf("http://%s/desc", hostPort))
	got, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Error(err)
	}
	if string(got) != "1/10, 10.00%, 0s left" {
		t.Errorf("wrong string: %s", string(got))
	}

	// check json
	resp = getHTTPWithRetry(t, fmt.Sprintf("http://%s/state", hostPort))
	got, err = io.ReadAll(resp.Body)
	if err != nil {
		t.Error(err)
	}
	var result State
	err = json.Unmarshal(got, &result)
	if err != nil {
		t.Error(err)
	}
	if result.Max != bar.State().Max || result.CurrentNum != bar.State().CurrentNum {
		t.Errorf("wrong state: %v", result)
	}

	// shutdown server
	err = svr.Shutdown(context.Background())
	if err != nil {
		t.Errorf("shutdown server failed: %v", err)
	}

	// start new bar server
	bar = Default(10, "test")
	bar.Add(1)
	svr = bar.StartHTTPServer(hostPort)
	err = svr.Close()
	if err != nil {
		t.Errorf("shutdown server failed: %v", err)
	}
}

func TestTrimRateSamples(t *testing.T) {
	base := time.Now()
	times := []time.Time{
		base.Add(-10 * time.Second),
		base.Add(-5 * time.Second),
		base.Add(-2 * time.Second),
		base,
	}
	rates := []float64{1, 2, 3, 4}

	clone := func() ([]float64, []time.Time) {
		return append([]float64{}, rates...), append([]time.Time{}, times...)
	}

	// A 6s window keeps only the samples collected within the last 6 seconds.
	r, tt := clone()
	gotRates, gotTimes := trimRateSamples(r, tt, 6*time.Second, base)
	if len(gotRates) != 3 || gotRates[0] != 2 {
		t.Errorf("window trim: expected 3 samples starting at 2, got %v", gotRates)
	}
	if len(gotTimes) != len(gotRates) {
		t.Errorf("window trim: rates/times length mismatch: %d vs %d", len(gotRates), len(gotTimes))
	}

	// A window shorter than the gap between samples keeps only the newest sample.
	r, tt = clone()
	gotRates, _ = trimRateSamples(r, tt, time.Nanosecond, base)
	if len(gotRates) != 1 || gotRates[0] != 4 {
		t.Errorf("tiny window: expected only the newest sample 4, got %v", gotRates)
	}

	// Without a window, at most maxLegacyRateSamples samples are kept.
	manyRates := make([]float64, maxLegacyRateSamples+5)
	manyTimes := make([]time.Time, maxLegacyRateSamples+5)
	for i := range manyRates {
		manyRates[i] = float64(i)
		manyTimes[i] = base.Add(time.Duration(i) * time.Second)
	}
	gotRates, _ = trimRateSamples(manyRates, manyTimes, 0, base)
	if len(gotRates) != maxLegacyRateSamples {
		t.Errorf("legacy trim: expected %d samples, got %d", maxLegacyRateSamples, len(gotRates))
	}
	if gotRates[0] != 5 {
		t.Errorf("legacy trim: expected to keep the newest samples, first kept = %v", gotRates[0])
	}
}

func TestRateAveragingWindow(t *testing.T) {
	forceSamples := func(bar *ProgressBar, n int) {
		for i := 0; i < n; i++ {
			// backdate the counter so each Add records a new rate sample
			bar.state.counterTime = time.Now().Add(-time.Second)
			if err := bar.Add(1); err != nil {
				t.Fatal(err)
			}
		}
	}

	// Without a window the number of retained rate samples is capped.
	legacy := NewOptions(1000000, OptionSetWriter(io.Discard))
	forceSamples(legacy, maxLegacyRateSamples+15)
	if got := len(legacy.state.counterLastTenRates); got != maxLegacyRateSamples {
		t.Errorf("legacy: expected %d retained rate samples, got %d", maxLegacyRateSamples, got)
	}

	// With a window covering the whole test, every sample is retained, so the
	// count exceeds the legacy cap.
	windowed := NewOptions(1000000, OptionSetWriter(io.Discard), OptionSetRateAveragingWindow(time.Hour))
	forceSamples(windowed, maxLegacyRateSamples+15)
	if got := len(windowed.state.counterLastTenRates); got <= maxLegacyRateSamples {
		t.Errorf("windowed: expected more than %d retained samples, got %d", maxLegacyRateSamples, got)
	}
}