// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package json

import (
	"bytes"
	"fmt"
	"log"
	"math"
	"reflect"
	"regexp"
	"strconv"
	"testing"
	"unicode"
)

type Optionals struct {
	Sr string `json:"sr"`
	So string `json:"so,omitempty"`
	Sw string `json:"-"`

	Ir int `json:"omitempty"` // actually named omitempty, not an option
	Io int `json:"io,omitempty"`

	Slr []string `json:"slr,random"`
	Slo []string `json:"slo,omitempty"`

	Mr map[string]interface{} `json:"mr"`
	Mo map[string]interface{} `json:",omitempty"`

	Fr float64 `json:"fr"`
	Fo float64 `json:"fo,omitempty"`

	Br bool `json:"br"`
	Bo bool `json:"bo,omitempty"`

	Ur uint `json:"ur"`
	Uo uint `json:"uo,omitempty"`

	Str struct{} `json:"str"`
	Sto struct{} `json:"sto,omitempty"`
}

var optionalsExpected = `{
 "sr": "",
 "omitempty": 0,
 "slr": null,
 "mr": {},
 "fr": 0,
 "br": false,
 "ur": 0,
 "str": {},
 "sto": {}
}`

func TestOmitEmpty(t *testing.T) {
	var o Optionals
	o.Sw = "something"
	o.Mr = map[string]interface{}{}
	o.Mo = map[string]interface{}{}

	got, err := MarshalIndent(&o, "", " ")
	if err != nil {
		t.Fatal(err)
	}
	if got := string(got); got != optionalsExpected {
		t.Errorf(" got: %s\nwant: %s\n", got, optionalsExpected)
	}
}

type StringTag struct {
	BoolStr bool   `json:",string"`
	IntStr  int64  `json:",string"`
	StrStr  string `json:",string"`
}

var stringTagExpected = `{
 "BoolStr": "true",
 "IntStr": "42",
 "StrStr": "\"xzbit\""
}`

func TestStringTag(t *testing.T) {
	var s StringTag
	s.BoolStr = true
	s.IntStr = 42
	s.StrStr = "xzbit"
	got, err := MarshalIndent(&s, "", " ")
	if err != nil {
		t.Fatal(err)
	}
	if got := string(got); got != stringTagExpected {
		t.Fatalf(" got: %s\nwant: %s\n", got, stringTagExpected)
	}

	// Verify that it round-trips.
	var s2 StringTag
	err = NewDecoder(bytes.NewReader(got)).Decode(&s2)
	if err != nil {
		t.Fatalf("Decode: %v", err)
	}
	if !reflect.DeepEqual(s, s2) {
		t.Fatalf("decode didn't match.\nsource: %#v\nEncoded as:\n%s\ndecode: %#v", s, string(got), s2)
	}
}

// byte slices are special even if they're renamed types.
type renamedByte byte
type renamedByteSlice []byte
type renamedRenamedByteSlice []renamedByte

func TestEncodeRenamedByteSlice(t *testing.T) {
	s := renamedByteSlice("abc")
	result, err := Marshal(s)
	if err != nil {
		t.Fatal(err)
	}
	expect := `"YWJj"`
	if string(result) != expect {
		t.Errorf(" got %s want %s", result, expect)
	}
	r := renamedRenamedByteSlice("abc")
	result, err = Marshal(r)
	if err != nil {
		t.Fatal(err)
	}
	if string(result) != expect {
		t.Errorf(" got %s want %s", result, expect)
	}
}

var unsupportedValues = []interface{}{
	math.NaN(),
	math.Inf(-1),
	math.Inf(1),
}

func TestUnsupportedValues(t *testing.T) {
	for _, v := range unsupportedValues {
		if _, err := Marshal(v); err != nil {
			if _, ok := err.(*UnsupportedValueError); !ok {
				t.Errorf("for %v, got %T want UnsupportedValueError", v, err)
			}
		} else {
			t.Errorf("for %v, expected error", v)
		}
	}
}

// Ref has Marshaler and Unmarshaler methods with pointer receiver.
type Ref int

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

func (r *Ref) UnmarshalJSON([]byte) error {
	*r = 12
	return nil
}

// Val has Marshaler methods with value receiver.
type Val int

func (Val) MarshalJSON() ([]byte, error) {
	return []byte(`"val"`), nil
}

// RefText has Marshaler and Unmarshaler methods with pointer receiver.
type RefText int

func (*RefText) MarshalText() ([]byte, error) {
	return []byte(`"ref"`), nil
}

func (r *RefText) UnmarshalText([]byte) error {
	*r = 13
	return nil
}

// ValText has Marshaler methods with value receiver.
type ValText int

func (ValText) MarshalText() ([]byte, error) {
	return []byte(`"val"`), nil
}

func TestRefValMarshal(t *testing.T) {
	var s = struct {
		R0 Ref
		R1 *Ref
		R2 RefText
		R3 *RefText
		V0 Val
		V1 *Val
		V2 ValText
		V3 *ValText
	}{
		R0: 12,
		R1: new(Ref),
		R2: 14,
		R3: new(RefText),
		V0: 13,
		V1: new(Val),
		V2: 15,
		V3: new(ValText),
	}
	const want = `{"R0":"ref","R1":"ref","R2":"\"ref\"","R3":"\"ref\"","V0":"val","V1":"val","V2":"\"val\"","V3":"\"val\""}`
	b, err := Marshal(&s)
	if err != nil {
		t.Fatalf("Marshal: %v", err)
	}
	if got := string(b); got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

// C implements Marshaler and returns unescaped JSON.
type C int

func (C) MarshalJSON() ([]byte, error) {
	return []byte(`"<&>"`), nil
}

// CText implements Marshaler and returns unescaped text.
type CText int

func (CText) MarshalText() ([]byte, error) {
	return []byte(`"<&>"`), nil
}

func TestMarshalerEscaping(t *testing.T) {
	var c C
	want := `"\u003c\u0026\u003e"`
	b, err := Marshal(c)
	if err != nil {
		t.Fatalf("Marshal(c): %v", err)
	}
	if got := string(b); got != want {
		t.Errorf("Marshal(c) = %#q, want %#q", got, want)
	}

	var ct CText
	want = `"\"\u003c\u0026\u003e\""`
	b, err = Marshal(ct)
	if err != nil {
		t.Fatalf("Marshal(ct): %v", err)
	}
	if got := string(b); got != want {
		t.Errorf("Marshal(ct) = %#q, want %#q", got, want)
	}
}

type IntType int

type MyStruct struct {
	IntType
}

func TestAnonymousNonstruct(t *testing.T) {
	var i IntType = 11
	a := MyStruct{i}
	const want = `{"IntType":11}`

	b, err := Marshal(a)
	if err != nil {
		t.Fatalf("Marshal: %v", err)
	}
	if got := string(b); got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

type BugA struct {
	S string
}

type BugB struct {
	BugA
	S string
}

type BugC struct {
	S string
}

// Legal Go: We never use the repeated embedded field (S).
type BugX struct {
	A int
	BugA
	BugB
}

// Issue 5245.
func TestEmbeddedBug(t *testing.T) {
	v := BugB{
		BugA{"A"},
		"B",
	}
	b, err := Marshal(v)
	if err != nil {
		t.Fatal("Marshal:", err)
	}
	want := `{"S":"B"}`
	got := string(b)
	if got != want {
		t.Fatalf("Marshal: got %s want %s", got, want)
	}
	// Now check that the duplicate field, S, does not appear.
	x := BugX{
		A: 23,
	}
	b, err = Marshal(x)
	if err != nil {
		t.Fatal("Marshal:", err)
	}
	want = `{"A":23}`
	got = string(b)
	if got != want {
		t.Fatalf("Marshal: got %s want %s", got, want)
	}
}

type BugD struct { // Same as BugA after tagging.
	XXX string `json:"S"`
}

// BugD's tagged S field should dominate BugA's.
type BugY struct {
	BugA
	BugD
}

// Test that a field with a tag dominates untagged fields.
func TestTaggedFieldDominates(t *testing.T) {
	v := BugY{
		BugA{"BugA"},
		BugD{"BugD"},
	}
	b, err := Marshal(v)
	if err != nil {
		t.Fatal("Marshal:", err)
	}
	want := `{"S":"BugD"}`
	got := string(b)
	if got != want {
		t.Fatalf("Marshal: got %s want %s", got, want)
	}
}

// There are no tags here, so S should not appear.
type BugZ struct {
	BugA
	BugC
	BugY // Contains a tagged S field through BugD; should not dominate.
}

func TestDuplicatedFieldDisappears(t *testing.T) {
	v := BugZ{
		BugA{"BugA"},
		BugC{"BugC"},
		BugY{
			BugA{"nested BugA"},
			BugD{"nested BugD"},
		},
	}
	b, err := Marshal(v)
	if err != nil {
		t.Fatal("Marshal:", err)
	}
	want := `{}`
	got := string(b)
	if got != want {
		t.Fatalf("Marshal: got %s want %s", got, want)
	}
}

func TestStringBytes(t *testing.T) {
	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
	var r []rune
	for i := '\u0000'; i <= unicode.MaxRune; i++ {
		r = append(r, i)
	}
	s := string(r) + "\xff\xff\xffhello" // some invalid UTF-8 too

	for _, escapeHTML := range []bool{true, false} {
		es := &encodeState{}
		es.string(s, escapeHTML)

		esBytes := &encodeState{}
		esBytes.stringBytes([]byte(s), escapeHTML)

		enc := es.Buffer.String()
		encBytes := esBytes.Buffer.String()
		if enc != encBytes {
			i := 0
			for i < len(enc) && i < len(encBytes) && enc[i] == encBytes[i] {
				i++
			}
			enc = enc[i:]
			encBytes = encBytes[i:]
			i = 0
			for i < len(enc) && i < len(encBytes) && enc[len(enc)-i-1] == encBytes[len(encBytes)-i-1] {
				i++
			}
			enc = enc[:len(enc)-i]
			encBytes = encBytes[:len(encBytes)-i]

			if len(enc) > 20 {
				enc = enc[:20] + "..."
			}
			if len(encBytes) > 20 {
				encBytes = encBytes[:20] + "..."
			}

			t.Errorf("with escapeHTML=%t, encodings differ at %#q vs %#q",
				escapeHTML, enc, encBytes)
		}
	}
}

func TestIssue6458(t *testing.T) {
	type Foo struct {
		M RawMessage
	}
	x := Foo{RawMessage(`"foo"`)}

	b, err := Marshal(&x)
	if err != nil {
		t.Fatal(err)
	}
	if want := `{"M":"foo"}`; string(b) != want {
		t.Errorf("Marshal(&x) = %#q; want %#q", b, want)
	}

	b, err = Marshal(x)
	if err != nil {
		t.Fatal(err)
	}

	if want := `{"M":"ImZvbyI="}`; string(b) != want {
		t.Errorf("Marshal(x) = %#q; want %#q", b, want)
	}
}

func TestIssue10281(t *testing.T) {
	type Foo struct {
		N Number
	}
	x := Foo{Number(`invalid`)}

	b, err := Marshal(&x)
	if err == nil {
		t.Errorf("Marshal(&x) = %#q; want error", b)
	}
}

func TestHTMLEscape(t *testing.T) {
	var b, want bytes.Buffer
	m := `{"M":"<html>foo &` + "\xe2\x80\xa8 \xe2\x80\xa9" + `</html>"}`
	want.Write([]byte(`{"M":"\u003chtml\u003efoo \u0026\u2028 \u2029\u003c/html\u003e"}`))
	HTMLEscape(&b, []byte(m))
	if !bytes.Equal(b.Bytes(), want.Bytes()) {
		t.Errorf("HTMLEscape(&b, []byte(m)) = %s; want %s", b.Bytes(), want.Bytes())
	}
}

// golang.org/issue/8582
func TestEncodePointerString(t *testing.T) {
	type stringPointer struct {
		N *int64 `json:"n,string"`
	}
	var n int64 = 42
	b, err := Marshal(stringPointer{N: &n})
	if err != nil {
		t.Fatalf("Marshal: %v", err)
	}
	if got, want := string(b), `{"n":"42"}`; got != want {
		t.Errorf("Marshal = %s, want %s", got, want)
	}
	var back stringPointer
	err = Unmarshal(b, &back)
	if err != nil {
		t.Fatalf("Unmarshal: %v", err)
	}
	if back.N == nil {
		t.Fatalf("Unmarshalled nil N field")
	}
	if *back.N != 42 {
		t.Fatalf("*N = %d; want 42", *back.N)
	}
}

var encodeStringTests = []struct {
	in  string
	out string
}{
	{"\x00", `"\u0000"`},
	{"\x01", `"\u0001"`},
	{"\x02", `"\u0002"`},
	{"\x03", `"\u0003"`},
	{"\x04", `"\u0004"`},
	{"\x05", `"\u0005"`},
	{"\x06", `"\u0006"`},
	{"\x07", `"\u0007"`},
	{"\x08", `"\u0008"`},
	{"\x09", `"\t"`},
	{"\x0a", `"\n"`},
	{"\x0b", `"\u000b"`},
	{"\x0c", `"\u000c"`},
	{"\x0d", `"\r"`},
	{"\x0e", `"\u000e"`},
	{"\x0f", `"\u000f"`},
	{"\x10", `"\u0010"`},
	{"\x11", `"\u0011"`},
	{"\x12", `"\u0012"`},
	{"\x13", `"\u0013"`},
	{"\x14", `"\u0014"`},
	{"\x15", `"\u0015"`},
	{"\x16", `"\u0016"`},
	{"\x17", `"\u0017"`},
	{"\x18", `"\u0018"`},
	{"\x19", `"\u0019"`},
	{"\x1a", `"\u001a"`},
	{"\x1b", `"\u001b"`},
	{"\x1c", `"\u001c"`},
	{"\x1d", `"\u001d"`},
	{"\x1e", `"\u001e"`},
	{"\x1f", `"\u001f"`},
}

func TestEncodeString(t *testing.T) {
	for _, tt := range encodeStringTests {
		b, err := Marshal(tt.in)
		if err != nil {
			t.Errorf("Marshal(%q): %v", tt.in, err)
			continue
		}
		out := string(b)
		if out != tt.out {
			t.Errorf("Marshal(%q) = %#q, want %#q", tt.in, out, tt.out)
		}
	}
}

type jsonbyte byte

func (b jsonbyte) MarshalJSON() ([]byte, error) { return tenc(`{"JB":%d}`, b) }

type textbyte byte

func (b textbyte) MarshalText() ([]byte, error) { return tenc(`TB:%d`, b) }

type jsonint int

func (i jsonint) MarshalJSON() ([]byte, error) { return tenc(`{"JI":%d}`, i) }

type textint int

func (i textint) MarshalText() ([]byte, error) { return tenc(`TI:%d`, i) }

func tenc(format string, a ...interface{}) ([]byte, error) {
	var buf bytes.Buffer
	fmt.Fprintf(&buf, format, a...)
	return buf.Bytes(), nil
}

// Issue 13783
func TestEncodeBytekind(t *testing.T) {
	testdata := []struct {
		data interface{}
		want string
	}{
		{byte(7), "7"},
		{jsonbyte(7), `{"JB":7}`},
		{textbyte(4), `"TB:4"`},
		{jsonint(5), `{"JI":5}`},
		{textint(1), `"TI:1"`},
		{[]byte{0, 1}, `"AAE="`},
		{[]jsonbyte{0, 1}, `[{"JB":0},{"JB":1}]`},
		{[][]jsonbyte{{0, 1}, {3}}, `[[{"JB":0},{"JB":1}],[{"JB":3}]]`},
		{[]textbyte{2, 3}, `["TB:2","TB:3"]`},
		{[]jsonint{5, 4}, `[{"JI":5},{"JI":4}]`},
		{[]textint{9, 3}, `["TI:9","TI:3"]`},
		{[]int{9, 3}, `[9,3]`},
	}
	for _, d := range testdata {
		js, err := Marshal(d.data)
		if err != nil {
			t.Error(err)
			continue
		}
		got, want := string(js), d.want
		if got != want {
			t.Errorf("got %s, want %s", got, want)
		}
	}
}

func TestTextMarshalerMapKeysAreSorted(t *testing.T) {
	b, err := Marshal(map[unmarshalerText]int{
		{"x", "y"}: 1,
		{"y", "x"}: 2,
		{"a", "z"}: 3,
		{"z", "a"}: 4,
	})
	if err != nil {
		t.Fatalf("Failed to Marshal text.Marshaler: %v", err)
	}
	const want = `{"a:z":3,"x:y":1,"y:x":2,"z:a":4}`
	if string(b) != want {
		t.Errorf("Marshal map with text.Marshaler keys: got %#q, want %#q", b, want)
	}
}

var re = regexp.MustCompile

// syntactic checks on form of marshalled floating point numbers.
var badFloatREs = []*regexp.Regexp{
	re(`p`),                     // no binary exponential notation
	re(`^\+`),                   // no leading + sign
	re(`^-?0[^.]`),              // no unnecessary leading zeros
	re(`^-?\.`),                 // leading zero required before decimal point
	re(`\.(e|$)`),               // no trailing decimal
	re(`\.[0-9]+0(e|$)`),        // no trailing zero in fraction
	re(`^-?(0|[0-9]{2,})\..*e`), // exponential notation must have normalized mantissa
	re(`e[0-9]`),                // positive exponent must be signed
	re(`e[+-]0`),                // exponent must not have leading zeros
	re(`e-[1-6]$`),              // not tiny enough for exponential notation
	re(`e+(.|1.|20)$`),          // not big enough for exponential notation
	re(`^-?0\.0000000`),         // too tiny, should use exponential notation
	re(`^-?[0-9]{22}`),          // too big, should use exponential notation
	re(`[1-9][0-9]{16}[1-9]`),   // too many significant digits in integer
	re(`[1-9][0-9.]{17}[1-9]`),  // too many significant digits in decimal
	// below here for float32 only
	re(`[1-9][0-9]{8}[1-9]`),  // too many significant digits in integer
	re(`[1-9][0-9.]{9}[1-9]`), // too many significant digits in decimal
}

func TestMarshalFloat(t *testing.T) {
	nfail := 0
	test := func(f float64, bits int) {
		vf := interface{}(f)
		if bits == 32 {
			f = float64(float32(f)) // round
			vf = float32(f)
		}
		bout, err := Marshal(vf)
		if err != nil {
			t.Errorf("Marshal(%T(%g)): %v", vf, vf, err)
			nfail++
			return
		}
		out := string(bout)

		// result must convert back to the same float
		g, err := strconv.ParseFloat(out, bits)
		if err != nil {
			t.Errorf("Marshal(%T(%g)) = %q, cannot parse back: %v", vf, vf, out, err)
			nfail++
			return
		}
		if f != g || fmt.Sprint(f) != fmt.Sprint(g) { // fmt.Sprint handles ±0
			t.Errorf("Marshal(%T(%g)) = %q (is %g, not %g)", vf, vf, out, float32(g), vf)
			nfail++
			return
		}

		bad := badFloatREs
		if bits == 64 {
			bad = bad[:len(bad)-2]
		}
		for _, re := range bad {
			if re.MatchString(out) {
				t.Errorf("Marshal(%T(%g)) = %q, must not match /%s/", vf, vf, out, re)
				nfail++
				return
			}
		}
	}

	var (
		bigger  = math.Inf(+1)
		smaller = math.Inf(-1)
	)

	var digits = "1.2345678901234567890123"
	for i := len(digits); i >= 2; i-- {
		for exp := -30; exp <= 30; exp++ {
			for _, sign := range "+-" {
				for bits := 32; bits <= 64; bits += 32 {
					s := fmt.Sprintf("%c%se%d", sign, digits[:i], exp)
					f, err := strconv.ParseFloat(s, bits)
					if err != nil {
						log.Fatal(err)
					}
					next := math.Nextafter
					if bits == 32 {
						next = func(g, h float64) float64 {
							return float64(math.Nextafter32(float32(g), float32(h)))
						}
					}
					test(f, bits)
					test(next(f, bigger), bits)
					test(next(f, smaller), bits)
					if nfail > 50 {
						t.Fatalf("stopping test early")
					}
				}
			}
		}
	}
	test(0, 64)
	test(math.Copysign(0, -1), 64)
	test(0, 32)
	test(math.Copysign(0, -1), 32)
}