// Copyright (C) MongoDB, Inc. 2014-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
//
// Based on github.com/golang/go by The Go Authors
// See cyclonedx.sbom.json for original license terms.

package json

import (
	"bytes"
	"math"
	"reflect"
	"testing"
	"unicode"

	"github.com/mongodb/mongo-tools/common/testtype"
)

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]any `json:"mr"`
	Mo map[string]any `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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	var o Optionals
	o.Sw = "something"
	o.Mr = map[string]any{}
	o.Mo = map[string]any{}

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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)
	}
}

func TestFloatSpecialValues(t *testing.T) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	_, err := Marshal(math.NaN())
	if err != nil {
		t.Errorf("Got error for NaN: %v", err)
	}

	_, err = Marshal(math.Inf(-1))
	if err != nil {
		t.Errorf("Got error for -Inf: %v", err)
	}

	_, err = Marshal(math.Inf(1))
	if err != nil {
		t.Errorf("Got error for +Inf: %v", err)
	}
}

// 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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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)
	}
}

// C1 implements Marshaler and returns unescaped JSON.
type C1 int

func (C1) 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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	var c C1
	want := `"\u003c\u0026\u003e"`
	b, err := Marshal(c)
	if err != nil {
		t.Fatalf("Marshal(c1): %v", err)
	}
	if got := string(b); got != want {
		t.Errorf("Marshal(c1) = %#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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	// Test that encodeState.stringBytes and encodeState.string use the same encoding.
	es := &encodeState{}
	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
	_, err := es.string(s)
	if err != nil {
		t.Fatal(err)
	}

	esBytes := &encodeState{}
	_, err = esBytes.stringBytes([]byte(s))
	if err != nil {
		t.Fatal(err)
	}

	enc := es.String()
	encBytes := esBytes.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("encodings differ at %#q vs %#q", enc, encBytes)
	}
}

func TestIssue6458(t *testing.T) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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 TestHTMLEscape(t *testing.T) {
	testtype.SkipUnlessTestType(t, testtype.UnitTestType)

	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())
	}
}
