package little

import (
	"bytes"
	"fmt"
	"math"
	"math/rand"
	"testing"
)

func TestContants(t *testing.T) {
	fmt.Println(MinInt24 == -8388608)
	fmt.Println(MaxInt24 == 8388607)
	fmt.Println(MinInt48 == -140737488355328)
	fmt.Println(MaxInt48 == 140737488355327)
	fmt.Println(MaxUint24 == 16777215)
	fmt.Println(MaxUint48 == 281474976710655)
}

// PUT/GET INT
func TestPutGetInt16(t *testing.T) {
	nums := []int16{
		math.MinInt16,
		0,
		math.MaxInt16,
	}
	for _, num := range nums {
		a := make([]byte, 2)
		PutInt16(a, num)
		decoded, err := GetInt16(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetInt24(t *testing.T) {
	nums := []int32{
		MinInt24,
		0,
		MaxInt24,
	}
	for _, num := range nums {
		a := make([]byte, 3)
		PutInt24(a, num)
		decoded, err := GetInt24(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetInt32(t *testing.T) {
	nums := []int32{
		math.MinInt32,
		0,
		math.MaxInt32,
	}
	for _, num := range nums {
		a := make([]byte, 4)
		PutInt32(a, num)
		decoded, err := GetInt32(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetInt48(t *testing.T) {
	nums := []int64{
		MinInt48,
		0,
		MaxInt48,
	}
	for _, num := range nums {
		a := make([]byte, 6)
		PutInt48(a, num)
		decoded, err := GetInt48(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetInt64(t *testing.T) {
	nums := []int64{
		math.MinInt64,
		0,
		math.MaxInt64,
	}
	for _, num := range nums {
		a := make([]byte, 8)
		PutInt64(a, num)
		decoded, err := GetInt64(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

// PUT/GET UINT
func TestPutGetUint16(t *testing.T) {
	nums := []uint16{
		0,
		math.MaxUint16,
	}
	for _, num := range nums {
		a := make([]byte, 2)
		PutUint16(a, num)
		decoded, err := GetUint16(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetUint24(t *testing.T) {
	nums := []uint32{
		0,
		MaxUint24,
	}
	for _, num := range nums {
		a := make([]byte, 3)
		PutUint24(a, num)
		decoded, err := GetUint24(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetUint32(t *testing.T) {
	nums := []uint32{
		0,
		math.MaxUint32,
	}
	for _, num := range nums {
		a := make([]byte, 4)
		PutUint32(a, num)
		decoded, err := GetUint32(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetUint48(t *testing.T) {
	nums := []uint64{
		0,
		MaxUint48,
	}
	for _, num := range nums {
		a := make([]byte, 6)
		PutUint48(a, num)
		decoded, err := GetUint48(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestPutGetUint64(t *testing.T) {
	nums := []uint64{
		0,
		math.MaxUint64,
	}
	for _, num := range nums {
		a := make([]byte, 8)
		PutUint64(a, num)
		decoded, err := GetUint64(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

// PUT/GET FLOAT

func TestPutGetFloat32(t *testing.T) {
	nums := []float32{
		-math.SmallestNonzeroFloat32,
		math.SmallestNonzeroFloat32,
		-1,
		0,
		1,
		-math.MaxFloat32,
		math.MaxFloat32,
	}
	for _, num := range nums {
		a := make([]byte, 4)
		PutFloat32(a, num)
		decoded, err := GetFloat32(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %v not equal decoded %v", num, decoded)
		}
	}
}

func TestPutGetFloat64(t *testing.T) {
	nums := []float64{
		-math.SmallestNonzeroFloat64,
		math.SmallestNonzeroFloat64,
		-1,
		0,
		1,
		-math.MaxFloat64,
		math.MaxFloat64,
	}
	for _, num := range nums {
		a := make([]byte, 8)
		PutFloat64(a, num)
		decoded, err := GetFloat64(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %v not equal decoded %v", num, decoded)
		}
	}
}

// PUT/GET STRING

func TestPutGetString8(t *testing.T) {
	pSize := 1 // размер префикса, в котором закодирована длина строки
	items := []string{
		"",
		RandString(60),
		RandString(150),
		RandString(math.MaxUint8),
	}
	for _, origin := range items {
		a := make([]byte, pSize+len(origin))
		err := PutString8(a, origin)
		if err != nil {
			t.Fatal(err)
		}
		decoded, err := GetString8(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != origin {
			t.Fatalf("origin %q not equal decoded %q", origin, decoded)
		}
	}
	// запись слишком большой строки
	tooLongStr := RandString(math.MaxUint8 + 1)
	a := make([]byte, pSize+len(tooLongStr))
	err := PutString8(a, tooLongStr)
	if err != ErrTooLong {
		t.Fatal("too long string put did not return ErrTooLong")
	}
	// запись, когда в массиве недостаточно места
	someStr := RandString(10)
	a = make([]byte, 10)
	err = PutString8(a, someStr)
	if err != ErrNoSpace {
		t.Fatal("put string longer then slice did not return ErrNoSpace")
	}
}

func TestPutGetString16(t *testing.T) {
	pSize := 2 // размер префикса, в котором закодирована длина строки
	items := []string{
		"",
		RandString(255),
		RandString(256),
		RandString(math.MaxUint16),
	}
	for _, origin := range items {
		a := make([]byte, pSize+len(origin))
		err := PutString16(a, origin)
		if err != nil {
			t.Fatal(err)
		}
		decoded, err := GetString16(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != origin {
			t.Fatalf("origin %q not equal decoded %q", origin, decoded)
		}
	}
	// запись слишком большой строки
	tooLongStr := RandString(math.MaxUint16 + 1)
	a := make([]byte, pSize+len(tooLongStr))
	err := PutString16(a, tooLongStr)
	if err != ErrTooLong {
		t.Fatal("too long string put did not return ErrTooLong")
	}
	// запись, когда в массиве недостаточно места
	someStr := RandString(10)
	a = make([]byte, 11)
	err = PutString16(a, someStr)
	if err != ErrNoSpace {
		t.Fatal("put string longer then slice did not return ErrNoSpace")
	}
}

// PUT/GET BOOL
func TestPutGetBool(t *testing.T) {
	flags := []bool{
		true,
		false,
	}
	for _, flag := range flags {
		a := make([]byte, 1)
		PutBool(a, flag)
		decoded, err := GetBool(a)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != flag {
			t.Fatalf("flag %t not equal decoded %t", flag, decoded)
		}
	}
}

// WRITE/READ INT

func TestWriteReadInt16(t *testing.T) {
	nums := []int16{
		math.MinInt16,
		0,
		math.MaxInt16,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteInt16(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadInt16(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadInt24(t *testing.T) {
	nums := []int32{
		MinInt24,
		0,
		MaxInt24,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteInt24(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadInt24(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadInt32(t *testing.T) {
	nums := []int32{
		math.MinInt32,
		0,
		math.MaxInt32,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteInt32(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadInt32(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadInt48(t *testing.T) {
	nums := []int64{
		MinInt48,
		0,
		MaxInt48,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteInt48(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadInt48(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadInt64(t *testing.T) {
	nums := []int64{
		math.MinInt64,
		0,
		math.MaxInt64,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteInt64(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadInt64(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

// WRITE/READ UINT
func TestWriteReadUint16(t *testing.T) {
	nums := []uint16{
		0,
		math.MaxUint16,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteUint16(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadUint16(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadUint24(t *testing.T) {
	nums := []uint32{
		0,
		MaxUint24,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteUint24(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadUint24(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadUint32(t *testing.T) {
	nums := []uint32{
		0,
		math.MaxUint32,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteUint32(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadUint32(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadUint48(t *testing.T) {
	nums := []uint64{
		0,
		MaxUint48,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteUint48(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadUint48(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

func TestWriteReadUint64(t *testing.T) {
	nums := []uint64{
		0,
		math.MaxUint64,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteUint64(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadUint64(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %d not equal decoded %d", num, decoded)
		}
	}
}

// WRITE/READ FLOAT
func TestWriteReadFloat32(t *testing.T) {
	nums := []float32{
		-math.SmallestNonzeroFloat32,
		math.SmallestNonzeroFloat32,
		-1,
		0,
		1,
		-math.MaxFloat32,
		math.MaxFloat32,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteFloat32(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadFloat32(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %v not equal decoded %v", num, decoded)
		}
	}
}

func TestWriteReadFloat64(t *testing.T) {
	nums := []float64{
		-math.SmallestNonzeroFloat64,
		math.SmallestNonzeroFloat64,
		-1,
		0,
		1,
		-math.MaxFloat64,
		math.MaxFloat64,
	}
	for _, num := range nums {
		w := bytes.NewBuffer(nil)
		err := WriteFloat64(w, num)
		if err != nil {
			return
		}
		decoded, err := ReadFloat64(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != num {
			t.Fatalf("num %v not equal decoded %v", num, decoded)
		}
	}
}

// WRITE/READ STRING

func TestWriteReadString8(t *testing.T) {
	items := []string{
		"",
		RandString(60),
		RandString(150),
		RandString(255),
	}
	for _, origin := range items {
		w := bytes.NewBuffer(nil)
		err := WriteString8(w, origin)
		if err != nil {
			return
		}
		decoded, err := ReadString8(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != origin {
			t.Fatalf("origin %q not equal decoded %q", origin, decoded)
		}
	}
	// запись слишком большой строки
	w := bytes.NewBuffer(nil)
	err := WriteString8(w, RandString(256))
	if err != ErrTooLong {
		t.Fatal("too long string write did not return ErrTooLong")
	}
}

func TestWriteReadString16(t *testing.T) {
	items := []string{
		"",
		RandString(255),
		RandString(256),
		RandString(math.MaxUint16),
	}
	for _, origin := range items {
		w := bytes.NewBuffer(nil)
		err := WriteString16(w, origin)
		if err != nil {
			return
		}
		decoded, err := ReadString16(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != origin {
			t.Fatalf("origin %q not equal decoded %q", origin, decoded)
		}
	}
	// запись слишком большой строки
	w := bytes.NewBuffer(nil)
	err := WriteString8(w, RandString(math.MaxUint16+1))
	if err != ErrTooLong {
		t.Fatal("too long string write did not return ErrTooLong")
	}
}

// WRITE/READ BOOL

func TestWriteReadBool(t *testing.T) {
	flags := []bool{
		true,
		false,
	}
	for _, flag := range flags {
		w := bytes.NewBuffer(nil)
		err := WriteBool(w, flag)
		if err != nil {
			return
		}
		decoded, err := ReadBool(w)
		if err != nil {
			t.Fatal(err)
		}
		if decoded != flag {
			t.Fatalf("flag %t not equal decoded %t", flag, decoded)
		}
	}
}

// VAR SIZE COUNT

func TestCountVarUint32(t *testing.T) {
	var testCases = []struct {
		Num   uint32
		Count int
	}{
		{Num: (1 << 7) - 1, Count: 1},
		{Num: (1 << 7), Count: 2},
		{Num: (1 << 14) - 1, Count: 2},
		{Num: (1 << 14), Count: 3},
		{Num: (1 << 21) - 1, Count: 3},
		{Num: (1 << 21), Count: 4},
		{Num: (1 << 28) - 1, Count: 4},
		{Num: (1 << 28), Count: 5},
		{Num: (1 << 32) - 1, Count: 5},
	}
	for _, testCase := range testCases {
		count := CountVarUint32(testCase.Num)
		if count != testCase.Count {
			t.Fatalf("calculated count %d is not equal %d for num %d\n",
				count, testCase.Count, testCase.Num)
		}
	}
}

func TestCountVarUint64(t *testing.T) {
	var testCases = []struct {
		Num   uint64
		Count int
	}{
		{Num: (1 << 7) - 1, Count: 1},
		{Num: (1 << 7), Count: 2},
		{Num: (1 << 14) - 1, Count: 2},
		{Num: (1 << 14), Count: 3},
		{Num: (1 << 21) - 1, Count: 3},
		{Num: (1 << 21), Count: 4},
		{Num: (1 << 28) - 1, Count: 4},
		{Num: (1 << 28), Count: 5},
		{Num: (1 << 35) - 1, Count: 5},
		{Num: (1 << 35), Count: 6},
		{Num: (1 << 42) - 1, Count: 6},
		{Num: (1 << 42), Count: 7},
		{Num: (1 << 49) - 1, Count: 7},
		{Num: (1 << 49), Count: 8},
		{Num: (1 << 56) - 1, Count: 8},
		{Num: (1 << 56), Count: 9},
		{Num: (1 << 64) - 1, Count: 9},
	}
	for _, testCase := range testCases {
		count := CountVarUint64(testCase.Num)
		if count != testCase.Count {
			t.Fatalf("calculated count %d is not equal %d for num %d\n",
				count, testCase.Count, testCase.Num)
		}
	}
}

func TestCountVarSize(t *testing.T) {
	var testCases = []struct {
		Num   int
		Count int
	}{
		{Num: (1 << 7) - 1, Count: 1},
		{Num: (1 << 7), Count: 2},
		{Num: (1 << 14) - 1, Count: 2},
		{Num: (1 << 14), Count: 3},
		{Num: (1 << 21) - 1, Count: 3},
		{Num: (1 << 21), Count: 4},
		{Num: (1 << 28) - 1, Count: 4},
		{Num: (1 << 28), Count: 5},
		{Num: (1 << 35) - 1, Count: 5},
		{Num: (1 << 35), Count: 6},
		{Num: (1 << 42) - 1, Count: 6},
		{Num: (1 << 42), Count: 7},
		{Num: (1 << 49) - 1, Count: 7},
		{Num: (1 << 49), Count: 8},
		{Num: (1 << 56) - 1, Count: 8},
		{Num: (1 << 56), Count: 9},
		{Num: (1 << 63) - 1, Count: 9},
	}
	for _, testCase := range testCases {
		count := CountVarSize(testCase.Num)
		if count != testCase.Count {
			t.Fatalf("calculated count %d is not equal %d for num %d\n",
				count, testCase.Count, testCase.Num)
		}
	}
}

// HELPERS

const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

func RandString(n int) string {
	b := make([]byte, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}