package json

import (
	"bytes"
	"compress/gzip"
	"encoding"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"math"
	"os"
	"path/filepath"
	"reflect"
	"runtime"
	"strconv"
	"strings"
	"testing"
	"time"
)

// The encoding/json package does not export the msg field of json.SyntaxError,
// so we use this replacement type in tests.
type testSyntaxError struct {
	msg    string
	Offset int64
}

func (e *testSyntaxError) Error() string { return e.msg }

var (
	marshal    func([]byte, interface{}) ([]byte, error)
	unmarshal  func([]byte, interface{}) error
	escapeHTML bool
)

func TestMain(m *testing.M) {
	var pkg string
	flag.StringVar(&pkg, "package", ".", "The name of the package to test (encoding/json, or default to this package)")
	flag.BoolVar(&escapeHTML, "escapehtml", false, "Whether to enable HTML escaping or not")
	flag.Parse()

	switch pkg {
	case "encoding/json":
		buf := &buffer{}
		enc := json.NewEncoder(buf)
		enc.SetEscapeHTML(escapeHTML)

		marshal = func(b []byte, v interface{}) ([]byte, error) {
			buf.data = b
			err := enc.Encode(v)
			return buf.data, err
		}

		unmarshal = json.Unmarshal

	default:
		flags := AppendFlags(0)
		if escapeHTML {
			flags |= EscapeHTML
		}

		marshal = func(b []byte, v interface{}) ([]byte, error) {
			return Append(b, v, flags)
		}

		unmarshal = func(b []byte, v interface{}) error {
			_, err := Parse(b, v, ZeroCopy)
			return err
		}
	}

	os.Exit(m.Run())
}

type point struct {
	X int `json:"x"`
	Y int `json:"y"`
}

type tree struct {
	Value string
	Left  *tree
	Right *tree
}

var testValues = [...]interface{}{
	// constants
	nil,
	false,
	true,

	// int
	int(0),
	int(1),
	int(42),
	int(-1),
	int(-42),
	int8(math.MaxInt8),
	int8(math.MinInt8),
	int16(math.MaxInt16),
	int16(math.MinInt16),
	int32(math.MaxInt32),
	int32(math.MinInt32),
	int64(math.MaxInt64),
	int64(math.MinInt64),

	// uint
	uint(0),
	uint(1),
	uintptr(0),
	uintptr(1),
	uint8(math.MaxUint8),
	uint16(math.MaxUint16),
	uint32(math.MaxUint32),
	uint64(math.MaxUint64),

	// float
	float32(0),
	float32(0.5),
	float32(math.SmallestNonzeroFloat32),
	float32(math.MaxFloat32),
	float64(0),
	float64(0.5),
	float64(math.SmallestNonzeroFloat64),
	float64(math.MaxFloat64),

	// number
	Number("0"),
	Number("1234567890"),
	Number("-0.5"),
	Number("-1e+2"),

	// string
	"",
	"Hello World!",
	"Hello\"World!",
	"Hello\\World!",
	"Hello\nWorld!",
	"Hello\rWorld!",
	"Hello\tWorld!",
	"Hello\bWorld!",
	"Hello\fWorld!",
	"你好",
	"<",
	">",
	"&",
	"\u001944",
	"\u00c2e>",
	"\u00c2V?",
	"\u000e=8",
	"\u001944\u00c2e>\u00c2V?\u000e=8",
	"ir\u001bQJ\u007f\u0007y\u0015)",
	strings.Repeat("A", 32),
	strings.Repeat("A", 250),
	strings.Repeat("A", 1020),

	// bytes
	[]byte(""),
	[]byte("Hello World!"),
	bytes.Repeat([]byte("A"), 250),
	bytes.Repeat([]byte("A"), 1020),

	// time
	time.Unix(0, 0).In(time.UTC),
	time.Unix(1, 42).In(time.UTC),
	time.Unix(17179869184, 999999999).In(time.UTC),
	time.Date(2016, 12, 20, 0, 20, 1, 0, time.UTC),

	// array
	[...]int{},
	[...]int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9},

	// slice
	[]int{},
	[]int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
	makeSlice(250),
	makeSlice(1020),
	[]string{"A", "B", "C"},
	[]interface{}{nil, true, false, 0.5, "Hello World!"},

	// map
	makeMapStringBool(0),
	makeMapStringBool(15),
	makeMapStringBool(1020),
	makeMapStringInterface(0),
	makeMapStringInterface(15),
	makeMapStringInterface(1020),
	map[int]bool{1: false, 42: true},
	map[textValue]bool{{1, 2}: true, {3, 4}: false},
	map[string]*point{
		"A": {1, 2},
		"B": {3, 4},
		"C": {5, 6},
	},
	map[string]RawMessage{
		"A": RawMessage(`{}`),
		"B": RawMessage(`null`),
		"C": RawMessage(`42`),
	},

	// struct
	struct{}{},
	struct{ A int }{42},
	struct{ A, B, C int }{1, 2, 3},
	struct {
		A int
		T time.Time
		S string
	}{42, time.Date(2016, 12, 20, 0, 20, 1, 0, time.UTC), "Hello World!"},
	// These types are interesting because they fit in a pointer so the compiler
	// puts their value directly into the pointer field of the interface{} that
	// is passed to Marshal.
	struct{ X *int }{},
	struct{ X *int }{new(int)},
	struct{ X **int }{},
	// Struct types with more than one pointer, those exercise the regular
	// pointer handling with code that dereferences the fields.
	struct{ X, Y *int }{},
	struct{ X, Y *int }{new(int), new(int)},
	struct {
		A string                 `json:"name"`
		B string                 `json:"-"`
		C string                 `json:",omitempty"`
		D map[string]interface{} `json:",string"`
		e string
	}{A: "Luke", D: map[string]interface{}{"answer": float64(42)}},
	struct{ point }{point{1, 2}},
	tree{
		Value: "T",
		Left:  &tree{Value: "L"},
		Right: &tree{Value: "R", Left: &tree{Value: "R-L"}},
	},

	// pointer
	(*string)(nil),
	new(int),

	// Marshaler/Unmarshaler
	jsonValue{},
	jsonValue{1, 2},

	// encoding.TextMarshaler/encoding.TextUnmarshaler
	textValue{},
	textValue{1, 2},

	// RawMessage
	RawMessage(`{
	"answer": 42,
	"hello": "world"
}`),

	// fixtures
	loadTestdata(filepath.Join(runtime.GOROOT(), "src/encoding/json/testdata/code.json.gz")),
}

var durationTestValues = []interface{}{
	// duration
	time.Nanosecond,
	time.Microsecond,
	time.Millisecond,
	time.Second,
	time.Minute,
	time.Hour,

	// struct with duration
	struct{ D1, D2 time.Duration }{time.Millisecond, time.Hour},
}

func makeSlice(n int) []int {
	s := make([]int, n)
	for i := range s {
		s[i] = i
	}
	return s
}

func makeMapStringBool(n int) map[string]bool {
	m := make(map[string]bool, n)
	for i := 0; i != n; i++ {
		m[strconv.Itoa(i)] = true
	}
	return m
}

func makeMapStringInterface(n int) map[string]interface{} {
	m := make(map[string]interface{}, n)
	for i := 0; i != n; i++ {
		m[strconv.Itoa(i)] = nil
	}
	return m
}

func testName(v interface{}) string {
	return fmt.Sprintf("%T", v)
}

type codeResponse2 struct {
	Tree     *codeNode2 `json:"tree"`
	Username string     `json:"username"`
}

type codeNode2 struct {
	Name     string      `json:"name"`
	Kids     []*codeNode `json:"kids"`
	CLWeight float64     `json:"cl_weight"`
	Touches  int         `json:"touches"`
	MinT     int64       `json:"min_t"`
	MaxT     int64       `json:"max_t"`
	MeanT    int64       `json:"mean_t"`
}

func loadTestdata(path string) interface{} {
	f, err := os.Open(path)
	if err != nil {
		return err.Error()
	}
	defer f.Close()

	r, err := gzip.NewReader(f)
	if err != nil {
		return err.Error()
	}
	defer r.Close()

	testdata := new(codeResponse2)
	if err := json.NewDecoder(r).Decode(testdata); err != nil {
		return err.Error()
	}
	return testdata
}

func TestCodec(t *testing.T) {
	for _, v1 := range testValues {
		t.Run(testName(v1), func(t *testing.T) {
			v2 := newValue(v1)

			a, err := json.MarshalIndent(v1, "", "\t")
			if err != nil {
				t.Error(err)
				return
			}
			a = append(a, '\n')

			buf := &bytes.Buffer{}
			enc := NewEncoder(buf)
			enc.SetIndent("", "\t")

			if err := enc.Encode(v1); err != nil {
				t.Error(err)
				return
			}
			b := buf.Bytes()

			if !Valid(b) {
				t.Error("invalid JSON representation")
			}

			if !bytes.Equal(a, b) {
				t.Error("JSON representations mismatch")
				t.Log("expected:", string(a))
				t.Log("found:   ", string(b))
			}

			dec := NewDecoder(bytes.NewBuffer(b))

			if err := dec.Decode(v2.Interface()); err != nil {
				t.Errorf("%T: %v", err, err)
				return
			}

			x1 := v1
			x2 := v2.Elem().Interface()

			if !reflect.DeepEqual(x1, x2) {
				t.Error("values mismatch")
				t.Logf("expected: %#v", x1)
				t.Logf("found:    %#v", x2)
			}

			if b, err := ioutil.ReadAll(dec.Buffered()); err != nil {
				t.Error(err)
			} else if len(b) != 0 {
				t.Errorf("leftover trailing bytes in the decoder: %q", b)
			}
		})
	}
}

// TestCodecDuration isolates testing of time.Duration.  The stdlib un/marshals
// this type as integers whereas this library un/marshals formatted string
// values.  Therefore, plugging durations into TestCodec would cause fail since
// it checks equality on the marshaled strings from the two libraries.
func TestCodecDuration(t *testing.T) {
	for _, v1 := range durationTestValues {
		t.Run(testName(v1), func(t *testing.T) {
			v2 := newValue(v1)

			// encode using stdlib. (will be an int)
			std, err := json.MarshalIndent(v1, "", "\t")
			if err != nil {
				t.Error(err)
				return
			}
			std = append(std, '\n')

			// decode using our decoder. (reads int to duration)
			dec := NewDecoder(bytes.NewBuffer([]byte(std)))

			if err := dec.Decode(v2.Interface()); err != nil {
				t.Errorf("%T: %v", err, err)
				return
			}

			x1 := v1
			x2 := v2.Elem().Interface()

			if !reflect.DeepEqual(x1, x2) {
				t.Error("values mismatch")
				t.Logf("expected: %#v", x1)
				t.Logf("found:    %#v", x2)
			}

			// encoding using our encoder. (writes duration as string)
			buf := &bytes.Buffer{}
			enc := NewEncoder(buf)
			enc.SetIndent("", "\t")

			if err := enc.Encode(v1); err != nil {
				t.Error(err)
				return
			}
			b := buf.Bytes()

			if !Valid(b) {
				t.Error("invalid JSON representation")
			}

			if reflect.DeepEqual(std, b) {
				t.Error("encoded durations should not match stdlib")
				t.Logf("got: %s", b)
			}

			// decode using our decoder. (reads string to duration)
			dec = NewDecoder(bytes.NewBuffer([]byte(std)))

			if err := dec.Decode(v2.Interface()); err != nil {
				t.Errorf("%T: %v", err, err)
				return
			}

			x1 = v1
			x2 = v2.Elem().Interface()

			if !reflect.DeepEqual(x1, x2) {
				t.Error("values mismatch")
				t.Logf("expected: %#v", x1)
				t.Logf("found:    %#v", x2)
			}
		})
	}
}

func newValue(model interface{}) reflect.Value {
	if model == nil {
		return reflect.New(reflect.TypeOf(&model).Elem())
	}
	return reflect.New(reflect.TypeOf(model))
}

// func BenchmarkMarshal(b *testing.B) {
// 	j := make([]byte, 0, 128*1024)

// 	for _, v := range testValues {
// 		b.Run(testName(v), func(b *testing.B) {
// 			if marshal == nil {
// 				return
// 			}

// 			for i := 0; i != b.N; i++ {
// 				j, _ = marshal(j[:0], v)
// 			}

// 			b.SetBytes(int64(len(j)))
// 		})
// 	}
// }

// func BenchmarkUnmarshal(b *testing.B) {
// 	for _, v := range testValues {
// 		b.Run(testName(v), func(b *testing.B) {
// 			if unmarshal == nil {
// 				return
// 			}

// 			x := v
// 			if d, ok := x.(time.Duration); ok {
// 				x = duration(d)
// 			}

// 			j, _ := json.Marshal(x)
// 			x = newValue(v).Interface()

// 			for i := 0; i != b.N; i++ {
// 				unmarshal(j, x)
// 			}

// 			b.SetBytes(int64(len(j)))
// 		})
// 	}
// }

type buffer struct{ data []byte }

func (buf *buffer) Write(b []byte) (int, error) {
	buf.data = append(buf.data, b...)
	return len(b), nil
}

func (buf *buffer) WriteString(s string) (int, error) {
	buf.data = append(buf.data, s...)
	return len(s), nil
}

type jsonValue struct {
	x int32
	y int32
}

func (v jsonValue) MarshalJSON() ([]byte, error) {
	return Marshal([2]int32{v.x, v.y})
}

func (v *jsonValue) UnmarshalJSON(b []byte) error {
	var a [2]int32
	err := Unmarshal(b, &a)
	v.x = a[0]
	v.y = a[1]
	return err
}

type textValue struct {
	x int32
	y int32
}

func (v textValue) MarshalText() ([]byte, error) {
	return []byte(fmt.Sprintf("(%d,%d)", v.x, v.y)), nil
}

func (v *textValue) UnmarshalText(b []byte) error {
	_, err := fmt.Sscanf(string(b), "(%d,%d)", &v.x, &v.y)
	return err
}

type duration time.Duration

func (d duration) MarshalJSON() ([]byte, error) {
	return []byte(`"` + time.Duration(d).String() + `"`), nil
}

func (d *duration) UnmarshalJSON(b []byte) error {
	var s string
	if err := json.Unmarshal(b, &s); err != nil {
		return err
	}
	x, err := time.ParseDuration(s)
	*d = duration(x)
	return err
}

var (
	_ Marshaler = jsonValue{}
	_ Marshaler = duration(0)

	_ encoding.TextMarshaler = textValue{}

	_ Unmarshaler = (*jsonValue)(nil)
	_ Unmarshaler = (*duration)(nil)

	_ encoding.TextUnmarshaler = (*textValue)(nil)
)

func TestDecodeStructFieldCaseInsensitive(t *testing.T) {
	b := []byte(`{ "type": "changed" }`)
	s := struct {
		Type string
	}{"unchanged"}

	if err := Unmarshal(b, &s); err != nil {
		t.Error(err)
	}

	if s.Type != "changed" {
		t.Error("s.Type: expected to be changed but found", s.Type)
	}
}

func TestDecodeLines(t *testing.T) {
	tests := []struct {
		desc        string
		reader      io.Reader
		expectCount int
	}{

		// simple

		{
			desc:        "bare object",
			reader:      strings.NewReader("{\"Good\":true}"),
			expectCount: 1,
		},
		{
			desc:        "multiple objects on one line",
			reader:      strings.NewReader("{\"Good\":true}{\"Good\":true}\n"),
			expectCount: 2,
		},
		{
			desc:        "object spanning multiple lines",
			reader:      strings.NewReader("{\n\"Good\":true\n}\n"),
			expectCount: 1,
		},

		// whitespace handling

		{
			desc:        "trailing newline",
			reader:      strings.NewReader("{\"Good\":true}\n{\"Good\":true}\n"),
			expectCount: 2,
		},
		{
			desc:        "multiple trailing newlines",
			reader:      strings.NewReader("{\"Good\":true}\n{\"Good\":true}\n\n"),
			expectCount: 2,
		},
		{
			desc:        "blank lines",
			reader:      strings.NewReader("{\"Good\":true}\n\n{\"Good\":true}"),
			expectCount: 2,
		},
		{
			desc:        "no trailing newline",
			reader:      strings.NewReader("{\"Good\":true}\n{\"Good\":true}"),
			expectCount: 2,
		},
		{
			desc:        "leading whitespace",
			reader:      strings.NewReader("  {\"Good\":true}\n\t{\"Good\":true}"),
			expectCount: 2,
		},

		// multiple reads

		{
			desc: "one object, multiple reads",
			reader: io.MultiReader(
				strings.NewReader("{"),
				strings.NewReader("\"Good\": true"),
				strings.NewReader("}\n"),
			),
			expectCount: 1,
		},

		// EOF reads

		{
			desc:        "one object + EOF",
			reader:      &eofReader{"{\"Good\":true}\n"},
			expectCount: 1,
		},
		{
			desc:        "leading whitespace + EOF",
			reader:      &eofReader{"\n{\"Good\":true}\n"},
			expectCount: 1,
		},
		{
			desc:        "multiple objects + EOF",
			reader:      &eofReader{"{\"Good\":true}\n{\"Good\":true}\n"},
			expectCount: 2,
		},
		{
			desc: "one object + multiple reads + EOF",
			reader: io.MultiReader(
				strings.NewReader("{"),
				strings.NewReader("  \"Good\": true"),
				&eofReader{"}\n"},
			),
			expectCount: 1,
		},
		{
			desc: "multiple objects + multiple reads + EOF",
			reader: io.MultiReader(
				strings.NewReader("{"),
				strings.NewReader("  \"Good\": true}{\"Good\": true}"),
				&eofReader{"\n"},
			),
			expectCount: 2,
		},

		{
			// the 2nd object should be discarded, as 42 cannot be cast to bool
			desc:        "unmarshal error while decoding",
			reader:      strings.NewReader("{\"Good\":true}\n{\"Good\":42}\n{\"Good\":true}\n"),
			expectCount: 2,
		},
		{
			// the 2nd object should be discarded, as 42 cannot be cast to bool
			desc:        "unmarshal error while decoding last object",
			reader:      strings.NewReader("{\"Good\":true}\n{\"Good\":42}\n"),
			expectCount: 1,
		},
	}

	type obj struct {
		Good bool
	}

	for _, test := range tests {
		t.Run(test.desc, func(t *testing.T) {
			d := NewDecoder(test.reader)
			var count int
			var err error
			for {
				var o obj
				err = d.Decode(&o)
				if err != nil {
					if err == io.EOF {
						break
					}

					switch err.(type) {
					case *SyntaxError, *UnmarshalTypeError, *UnmarshalFieldError:
						t.Log("unmarshal error", err)
						continue
					}

					t.Error("decode error", err)
					break
				}
				if !o.Good {
					t.Errorf("object was not unmarshaled correctly: %#v", o)
				}
				count++
			}

			if err != nil && err != io.EOF {
				t.Error(err)
			}

			if count != test.expectCount {
				t.Errorf("expected %d objects, got %d", test.expectCount, count)
			}
		})
	}
}

// eofReader is a simple io.Reader that reads its full contents _and_ returns
// and EOF in the first call. Subsequent Read calls only return EOF.
type eofReader struct {
	s string
}

func (r *eofReader) Read(p []byte) (n int, err error) {
	n = copy(p, r.s)
	r.s = r.s[n:]
	if r.s == "" {
		err = io.EOF
	}
	return
}

func TestDontMatchCaseIncensitiveStructFields(t *testing.T) {
	b := []byte(`{ "type": "changed" }`)
	s := struct {
		Type string
	}{"unchanged"}

	if _, err := Parse(b, &s, DontMatchCaseInsensitiveStructFields); err != nil {
		t.Error(err)
	}

	if s.Type != "unchanged" {
		t.Error("s.Type: expected to be unchanged but found", s.Type)
	}
}

func TestMarshalFuzzBugs(t *testing.T) {
	tests := []struct {
		value  interface{}
		output string
	}{
		{ // html sequences are escaped even in RawMessage
			value: struct {
				P RawMessage
			}{P: RawMessage(`"<"`)},
			output: "{\"P\":\"\\u003c\"}",
		},
		{ // raw message output is compacted
			value: struct {
				P RawMessage
			}{P: RawMessage(`{"" :{}}`)},
			output: "{\"P\":{\"\":{}}}",
		},
	}

	for _, test := range tests {
		t.Run("", func(t *testing.T) {
			b, err := Marshal(test.value)
			if err != nil {
				t.Fatal(err)
			}

			if string(b) != test.output {
				t.Error("values mismatch")
				t.Logf("expected: %#v", test.output)
				t.Logf("found:    %#v", string(b))
			}
		})
	}
}

func TestUnmarshalFuzzBugs(t *testing.T) {
	tests := []struct {
		input string
		value interface{}
	}{
		{ // non-UTF8 sequences must be converted to the utf8.RuneError character.
			input: "[\"00000\xef\"]",
			value: []interface{}{"00000�"},
		},
		{ // UTF16 surrogate followed by null character
			input: "[\"\\ud800\\u0000\"]",
			value: []interface{}{"�\x00"},
		},
		{ // UTF16 surrogate followed by ascii character
			input: "[\"\\uDF00\\u000e\"]",
			value: []interface{}{"�\x0e"},
		},
		{ // UTF16 surrogate followed by unicode character
			input: "[[\"\\uDF00\\u0800\"]]",
			value: []interface{}{[]interface{}{"�ࠀ"}},
		},
		{ // invalid UTF16 surrogate sequenced followed by a valid UTF16 surrogate sequence
			input: "[\"\\udf00\\udb00\\udf00\"]",
			value: []interface{}{"�\U000d0300"},
		},
		{ // decode single-element slice into []byte field
			input: "{\"f\":[0],\"0\":[0]}",
			value: struct{ F []byte }{F: []byte{0}},
		},
		{ // decode multi-element slice into []byte field
			input: "{\"F\":[3,1,1,1,9,9]}",
			value: struct{ F []byte }{F: []byte{3, 1, 1, 1, 9, 9}},
		},
		{ // decode string with escape sequence into []byte field
			input: "{\"F\":\"0p00\\r\"}",
			value: struct{ F []byte }{F: []byte("ҝ4")},
		},
		{ // decode unicode code points which fold into ascii characters
			input: "{\"ſ\":\"8\"}",
			value: struct {
				S int `json:",string"`
			}{S: 8},
		},
		{ // decode unicode code points which don't fold into ascii characters
			input: "{\"İ\":\"\"}",
			value: struct{ I map[string]string }{I: nil},
		},
		{ // override pointer-to-pointer field clears the inner pointer only
			input: "{\"o\":0,\"o\":null}",
			value: struct{ O **int }{O: new(*int)},
		},
		{ // subsequent occurrences of a map field retain keys previously loaded
			input: "{\"i\":{\"\":null},\"i\":{}}",
			value: struct{ I map[string]string }{I: map[string]string{"": ""}},
		},
		{ // an empty string is an invalid JSON input
			input: "",
		},
		{ // ASCII character below 0x20 are invalid JSON input
			input: "[\"\b\"]",
		},
		{ // random byte before any value
			input: "\xad",
		},
		{ // cloud be the beginning of a false value but not
			input: "f",
			value: false,
		},
		{ // random ASCII character
			input: "}",
			value: []interface{}{},
		},
		{ // random byte after valid JSON, decoded to a nil type
			input: "0\x93",
		},
		{ // random byte after valid JSON, decoded to a int type
			input: "0\x93",
			value: 0,
		},
		{ // random byte after valid JSON, decoded to a slice type
			input: "0\x93",
			value: []interface{}{},
		},
		{ // decode integer into slice
			input: "0",
			value: []interface{}{},
		},
		{ // decode integer with trailing space into slice
			input: "0\t",
			value: []interface{}{},
		},
		{ // decode integer with leading random bytes into slice
			input: "\b0",
			value: []interface{}{},
		},
		{ // decode string into slice followed by number
			input: "\"\"0",
			value: []interface{}{},
		},
		{ // decode what looks like an object followed by a number into a string
			input: "{0",
			value: "",
		},
		{ // decode what looks like an object followed by a number into a map
			input: "{0",
			value: map[string]string{},
		},
		{ // decode string into string with trailing random byte
			input: "\"\"\f",
			value: "",
		},
		{ // decode weird number value into nil
			input: "-00",
		},
		{ // decode an invalid escaped sequence
			input: "\"\\0\"",
			value: "",
		},
		{ // decode what looks like an array followed by a number into a slice
			input: "[9E600",
			value: []interface{}{},
		},
		{ // decode a number which is too large to fit in a float64
			input: "[1e900]",
			value: []interface{}{},
		},
		{ // many nested arrays openings
			input: "[[[[[[",
			value: []interface{}{},
		},
		{ // decode a map with value type mismatch and missing closing character
			input: "{\"\":0",
			value: map[string]string{},
		},
		{ // decode a struct with value type mismatch and missing closing character
			input: "{\"E\":\"\"",
			value: struct{ E uint8 }{},
		},
		{ // decode a map with value type mismatch
			input: "{\"\":0}",
			value: map[string]string{},
		},
		{ // decode number with exponent into integer field
			input: "{\"e\":0e0}",
			value: struct{ E uint8 }{},
		},
		{ // decode invalid integer representation into integer field
			input: "{\"e\":00}",
			value: struct{ E uint8 }{},
		},
		{ // decode unterminated array into byte slice
			input: "{\"F\":[",
			value: struct{ F []byte }{},
		},
		{ // attempt to decode string into in
			input: "{\"S\":\"\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode object with null key into map
			input: "{null:0}",
			value: map[string]interface{}{},
		},
		{ // decode unquoted integer into struct field with string tag
			input: "{\"S\":0}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // invalid base64 content when decoding string into byte slice
			input: "{\"F\":\"0\"}",
			value: struct{ F []byte }{},
		},
		{ // decode an object with a "null" string as key
			input: "{\"null\":null}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode an invalid floating point number representation into an integer field with string tag
			input: "{\"s\":8e800}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode a string with leading zeroes into an integer field with string tag
			input: "{\"S\":\"00\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode a string with invalid leading sign and zeroes into an integer field with string tag
			input: "{\"S\":\"+00\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode a string with valid leading sign and zeroes into an integer field with string tag
			input: "{\"S\":\"-00\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode non-ascii string into integer field with string tag
			input: "{\"ſ\":\"\xbf\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode a valid floating point number representation into an integer field with string tag
			input: "{\"S\":0.0}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with invalid leading sign to integer field with string tag
			input: "{\"S\":\"+0\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with valid leading sign to integer field with string tag
			input: "{\"S\":\"-0\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with object representation to integer field with string tag
			input: "{\"s\":{}}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decoding integer with leading zeroes
			input: "{\"o\":00}",
			value: struct{ O **int }{},
		},
		{ // codeding string with invalid float representation into integer field with string tag
			input: "{\"s\":\"0.\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // malformed negative integer in object value
			input: "{\"N\":-00}",
			value: struct{ N *int }{},
		},
		{ // integer overflow
			input: "{\"a\":9223372036854775808}",
			value: struct {
				A int `json:",omitempty"`
			}{},
		},
		{ // decode string with number followed by random byte into integer field with string tag
			input: "{\"s\":\"0]\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode object into integer field
			input: "{\"n\":{}}",
			value: struct{ N *int }{},
		},
		{ // decode negative integer into unsigned type
			input: "{\"E\":-0}",
			value: struct{ E uint8 }{},
		},
		{ // decode string with number followed by random byte into integer field with string tag
			input: "{\"s\":\"03�\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with leading zeroes into integer field with string tag
			input: "{\"s\":\"03\"}",
			value: struct {
				S int `json:",string"`
			}{S: 3},
		},
		{ // decode string containing what looks like an object into integer field with string tag
			input: "{\"S\":\"{}\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode an empty string followed by the same field with a null value into a byte slice
			input: "{\"F\":\"\",\"F\":null}",
			value: struct{ F []byte }{},
		},
		{ // decode string containing a float into an integer field with string tag
			input: "{\"S\":\"0e0\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with negative sign into a an integer field with string tag
			input: "{\"s\":\"-\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode string with positive sign into a an integer field with string tag
			input: "{\"s\":\"+\"}",
			value: struct {
				S int `json:",string"`
			}{},
		},
		{ // decode an integer into a json unmarshaler
			input: "{\"q\":0}",
			value: struct {
				Q testMarshaller
			}{},
		},
		// This test fails because it appears that the encoding/json package
		// will decode "q" before "s", so it returns an error about "q" being of
		// the wrong type while this package will prase object keys in the order
		// that they appear in the JSON input, so it detects the error from "s"
		// first.
		//
		//{
		//	input: "{\"s\":0,\"q\":0}",
		//	value: struct {
		//		Q testMarshaller
		//		S int `json:",string"`
		//	}{},
		//},
	}

	for _, test := range tests {
		t.Run("", func(t *testing.T) {
			var ptr1 interface{}
			var ptr2 interface{}

			if test.value != nil {
				ptr1 = reflect.New(reflect.TypeOf(test.value)).Interface()
				ptr2 = reflect.New(reflect.TypeOf(test.value)).Interface()
			}

			err1 := json.Unmarshal([]byte(test.input), ptr1)
			err2 := Unmarshal([]byte(test.input), ptr2)

			if reflect.TypeOf(err1) != reflect.TypeOf(err2) {
				t.Error("errors mismatch")
				t.Logf("expected: %T: %v", err1, err1)
				t.Logf("found:    %T: %v", err2, err2)
			} else if err1 == nil && test.value != nil {
				if value := reflect.ValueOf(ptr2).Elem().Interface(); !reflect.DeepEqual(test.value, value) {
					t.Error("values mismatch")
					t.Logf("expected: %#v", test.value)
					t.Logf("found:    %#v", value)
				}
			}
		})
	}
}

// func BenchmarkEasyjsonUnmarshalSmallStruct(b *testing.B) {
// 	type Hashtag struct {
// 		Indices []int  `json:"indices"`
// 		Text    string `json:"text"`
// 	}

// 	//easyjson:json
// 	type Entities struct {
// 		Hashtags     []Hashtag `json:"hashtags"`
// 		Urls         []*string `json:"urls"`
// 		UserMentions []*string `json:"user_mentions"`
// 	}

// 	var json = []byte(`{"hashtags":[{"indices":[5, 10],"text":"some-text"}],"urls":[],"user_mentions":[]}`)

// 	for i := 0; i < b.N; i++ {
// 		var value Entities
// 		if err := Unmarshal(json, &value); err != nil {
// 			b.Fatal(err)
// 		}
// 	}
// }

type testMarshaller struct {
	v string
}

func (m *testMarshaller) MarshalJSON() ([]byte, error) {
	return Marshal(m.v)
}

func (m *testMarshaller) UnmarshalJSON(data []byte) error {
	return Unmarshal(data, &m.v)
}

func TestGithubIssue11(t *testing.T) {
	// https://github.com/segmentio/encoding/issues/11
	v := struct{ F float64 }{
		F: math.NaN(),
	}

	_, err := Marshal(v)
	if err == nil {
		t.Error("no error returned when marshalling NaN value")
	} else if s := err.Error(); !strings.Contains(s, "NaN") {
		t.Error("error returned when marshalling NaN value does not mention 'NaN':", s)
	} else {
		t.Log(s)
	}
}

type Issue13 struct {
	Stringer fmt.Stringer
	Field    int `json:"MyInt"`
}

type S string

func (s S) String() string { return string(s) }

func TestGithubIssue13(t *testing.T) {
	// https://github.com/segmentio/encoding/issues/13
	v := Issue13{}

	b, err := Marshal(v)
	if err != nil {
		t.Error("unexpected errror:", err)
	} else {
		t.Log(string(b))
	}

	v = Issue13{Stringer: S("")}
	if err := Unmarshal([]byte(`{"Stringer":null}`), &v); err != nil {
		t.Error("unexpected error:", err)
	}
	if v.Stringer != nil {
		t.Error("Stringer field was not overwritten")
	}

	v = Issue13{}
	if err := Unmarshal([]byte(`{"Stringer":"whatever"}`), &v); err == nil {
		t.Error("expected error but decoding string value into nil fmt.Stringer but got <nil>")
	}

	v = Issue13{Stringer: S("")}
	if err := Unmarshal([]byte(`{"Stringer":"whatever"}`), &v); err == nil {
		t.Error("expected error but decoding string value into non-pointer fmt.Stringer but got <nil>")
	}

	s := S("")
	v = Issue13{Stringer: &s}
	if err := Unmarshal([]byte(`{"Stringer":"whatever"}`), &v); err != nil {
		t.Error("unexpected error decoding string value into pointer fmt.Stringer:", err)
	}
}

func TestGithubIssue15(t *testing.T) {
	// https://github.com/segmentio/encoding/issues/15
	tests := []struct {
		m interface{}
		s string
	}{
		{
			m: map[uint]bool{1: true, 123: true, 333: true, 42: true},
			s: `{"1":true,"123":true,"333":true,"42":true}`,
		},
		{
			m: map[int]bool{-1: true, -123: true, 333: true, 42: true},
			s: `{"-1":true,"-123":true,"333":true,"42":true}`,
		},
	}

	for _, test := range tests {
		b, _ := Marshal(test.m)

		if string(b) != test.s {
			t.Error("map with integer keys must be ordered by their string representation, got", string(b))
		}

	}
}

type sliceA []byte

func (sliceA) MarshalJSON() ([]byte, error) {
	return []byte(`"A"`), nil
}

type sliceB []byte

func (sliceB) MarshalText() ([]byte, error) {
	return []byte("B"), nil
}

type mapA map[string]string

func (mapA) MarshalJSON() ([]byte, error) {
	return []byte(`"A"`), nil
}

type mapB map[string]string

func (mapB) MarshalText() ([]byte, error) {
	return []byte("B"), nil
}

type intPtrA int

func (*intPtrA) MarshalJSON() ([]byte, error) {
	return []byte(`"A"`), nil
}

type intPtrB int

func (*intPtrB) MarshalText() ([]byte, error) {
	return []byte("B"), nil
}

type structA struct{ I intPtrA }
type structB struct{ I intPtrB }
type structC struct{ M Marshaler }
type structD struct{ M encoding.TextMarshaler }

func TestGithubIssue16(t *testing.T) {
	// https://github.com/segmentio/encoding/issues/16
	tests := []struct {
		value  interface{}
		output string
	}{
		{value: sliceA(nil), output: `"A"`},
		{value: sliceB(nil), output: `"B"`},
		{value: mapA(nil), output: `"A"`},
		{value: mapB(nil), output: `"B"`},
		{value: intPtrA(1), output: `1`},
		{value: intPtrB(2), output: `2`},
		{value: new(intPtrA), output: `"A"`},
		{value: new(intPtrB), output: `"B"`},
		{value: (*intPtrA)(nil), output: `null`},
		{value: (*intPtrB)(nil), output: `null`},
		{value: structA{I: 1}, output: `{"I":1}`},
		{value: structB{I: 2}, output: `{"I":2}`},
		{value: structC{}, output: `{"M":null}`},
		{value: structD{}, output: `{"M":null}`},
		{value: &structA{I: 1}, output: `{"I":"A"}`},
		{value: &structB{I: 2}, output: `{"I":"B"}`},
		{value: &structC{}, output: `{"M":null}`},
		{value: &structD{}, output: `{"M":null}`},
	}

	for _, test := range tests {
		t.Run(fmt.Sprintf("%T", test.value), func(t *testing.T) {
			if b, _ := Marshal(test.value); string(b) != test.output {
				t.Errorf(`%s != %s`, string(b), test.output)
			}
		})
	}
}

func TestDecoderInputOffset(t *testing.T) {
	checkOffset := func(o, expected int64) {
		if o != expected {
			t.Error("unexpected input offset", o, expected)
		}
	}

	b := []byte(`{"userId": "blah"}{"userId": "blah"}
	{"userId": "blah"}{"num": 0}`)
	d := NewDecoder(bytes.NewReader(b))

	var expected int64
	checkOffset(d.InputOffset(), expected)

	var a struct {
		UserId string `json:"userId"`
	}

	if err := d.Decode(&a); err != nil {
		t.Error("unexpected decode error", err)
	}
	expected = int64(18)
	checkOffset(d.InputOffset(), expected)

	if err := d.Decode(&a); err != nil {
		t.Error("unexpected decode error", err)
	}
	expected = int64(38)
	checkOffset(d.InputOffset(), expected)

	if err := d.Decode(&a); err != nil {
		t.Error("unexpected decode error", err)
	}
	expected = int64(56)
	checkOffset(d.InputOffset(), expected)

	var z struct {
		Num int64 `json:"num"`
	}
	if err := d.Decode(&z); err != nil {
		t.Error("unexpected decode error", err)
	}
	expected = int64(66)
	checkOffset(d.InputOffset(), expected)
}

func TestGithubIssue18(t *testing.T) {
	// https://github.com/segmentio/encoding/issues/18
	b := []byte(`{
	"userId": "blah",
	}`)

	d := NewDecoder(bytes.NewReader(b))

	var a struct {
		UserId string `json:"userId"`
	}
	switch err := d.Decode(&a).(type) {
	case *SyntaxError:
	default:
		t.Error("expected syntax error but found:", err)
	}

	for i := 1; i <= 18; i++ { // up to the invalid ',' character
		d := NewDecoder(bytes.NewReader(b[:i])) // cut somewhere in the middle
		switch err := d.Decode(&a); err {
		case io.ErrUnexpectedEOF:
		default:
			t.Error("expected 'unexpected EOF' error but found:", err)
		}
	}
}

func TestGithubIssue23(t *testing.T) {
	t.Run("marshal-1", func(t *testing.T) {
		type d struct{ S map[string]string }

		b, _ := Marshal(map[string]d{"1": {S: map[string]string{"2": "3"}}})
		if string(b) != `{"1":{"S":{"2":"3"}}}` {
			t.Error(string(b))
		}
	})

	t.Run("marshal-2", func(t *testing.T) {
		type testInner struct {
			InnerMap map[string]string `json:"inner_map"`
		}

		type testOuter struct {
			OuterMap map[string]testInner `json:"outer_map"`
		}

		b, _ := Marshal(testOuter{
			OuterMap: map[string]testInner{
				"outer": {
					InnerMap: map[string]string{"inner": "value"},
				},
			},
		})

		if string(b) != `{"outer_map":{"outer":{"inner_map":{"inner":"value"}}}}` {
			t.Error(string(b))
		}
	})

	t.Run("marshal-3", func(t *testing.T) {
		type A struct{ A map[string]string }
		type B struct{ B map[string]A }
		type C struct{ C map[string]B }

		b, _ := Marshal(C{
			C: map[string]B{
				"1": B{
					B: map[string]A{
						"2": A{
							A: map[string]string{"3": "!"},
						},
					},
				},
			},
		})

		if string(b) != `{"C":{"1":{"B":{"2":{"A":{"3":"!"}}}}}}` {
			t.Error(string(b))
		}
	})

	t.Run("unmarshal-1", func(t *testing.T) {
		var d struct{ S map[string]string }

		if err := Unmarshal([]byte(`{"1":{"S":{"2":"3"}}}`), &d); err != nil {
			t.Error(err)
		}
	})
}

func TestGithubIssue26(t *testing.T) {
	type interfaceType interface{}

	var value interfaceType
	var data = []byte(`{}`)

	if err := Unmarshal(data, &value); err != nil {
		t.Error(err)
	}
}

func TestGithubIssue28(t *testing.T) {
	type A struct {
		Err error `json:"err"`
	}

	if b, err := Marshal(&A{Err: errors.New("ABC")}); err != nil {
		t.Error(err)
	} else if string(b) != `{"err":{}}` {
		t.Error(string(b))
	}

}

func TestGithubIssue41(t *testing.T) {
	expectedString := `{"Zero":0,"Three":3}`
	type M struct {
		One int
		Two int
	}
	type N struct {
		Zero int
		*M
		Three int
	}

	if b, err := Marshal(N{Three: 3}); err != nil {
		t.Error(err)
	} else if string(b) != expectedString {
		t.Error(
			"got: ", string(b),
			"expected: ", expectedString,
		)
	}

}

func TestGithubIssue44(t *testing.T) {
	var out rawJsonString
	if err := Unmarshal([]byte("null"), &out); err != nil {
		t.Fatal(err)
	}
	if out != "null" {
		t.Errorf("wanted \"null\" but got %q", out)
	}
}

type rawJsonString string

func (r *rawJsonString) UnmarshalJSON(b []byte) error {
	if len(b) == 0 {
		*r = "null"
	} else {
		*r = rawJsonString(b)
	}
	return nil
}

func TestSetTrustRawMessage(t *testing.T) {
	buf := &bytes.Buffer{}
	enc := NewEncoder(buf)
	enc.SetTrustRawMessage(true)

	// "Good" values are encoded in the regular way
	m := map[string]json.RawMessage{
		"k": json.RawMessage(`"value"`),
	}
	if err := enc.Encode(m); err != nil {
		t.Error(err)
	}

	b := buf.Bytes()
	exp := []byte(`{"k":"value"}`)
	exp = append(exp, '\n')
	if bytes.Compare(exp, b) != 0 {
		t.Error(
			"unexpected encoding:",
			"expected", exp,
			"got", b,
		)
	}

	// "Bad" values are encoded without checking and throwing an error
	buf.Reset()
	m = map[string]json.RawMessage{
		"k": json.RawMessage(`bad"value`),
	}
	if err := enc.Encode(m); err != nil {
		t.Error(err)
	}

	b = buf.Bytes()
	exp = []byte(`{"k":bad"value}`)
	exp = append(exp, '\n')
	if bytes.Compare(exp, b) != 0 {
		t.Error(
			"unexpected encoding:",
			"expected", exp,
			"got", b,
		)
	}
}
