package reflux

// 新实现(rfx)特有的行为验证: 未导出字段不可达、map 元素副本语义、
// 地址别名、自引用类型的描述符构建、并发安全。

import (
	"encoding/json"
	"reflect"
	"strings"
	"sync"
	"testing"
)

type uxInner struct {
	City   string
	Zip    int
	Active bool
	Ratio  float64
}

type uxMiddle struct {
	Inner    uxInner
	InnerPtr *uxInner
	Any      any
}

type uxOuter struct {
	Name    string
	Mid     uxMiddle
	Tags    []string
	Nums    [3]int
	Meta    map[string]string
	Objs    map[string]uxInner
	secret  string // 未导出字段, 必须无法读写
	Structs []uxInner
}

func newUxOuter() *uxOuter {
	return &uxOuter{
		Name: "root",
		Mid: uxMiddle{
			Inner:    uxInner{City: "Beijing", Zip: 100000, Active: true, Ratio: 1.5},
			InnerPtr: &uxInner{City: "Shanghai", Zip: 200000},
			Any:      uxInner{City: "Shenzhen", Zip: 518000},
		},
		Tags:    []string{"a", "b", "c"},
		Nums:    [3]int{10, 20, 30},
		Meta:    map[string]string{"k1": "v1", "k2": "v2"},
		Objs:    map[string]uxInner{"o1": {City: "Chengdu", Zip: 610000}},
		secret:  "should-not-be-reachable",
		Structs: []uxInner{{City: "Wuhan"}, {City: "Xian"}},
	}
}

// ---------------------------------------------------------------------------
// Get: 各种路径形态
// ---------------------------------------------------------------------------

func TestGetPaths(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	cases := []struct {
		name string
		path []string
		want string
	}{
		{"单层字段", []string{"Name"}, "root"},
		{"多层嵌套", []string{"Mid", "Inner", "City"}, "Beijing"},
		{"点号路径", []string{"Mid.Inner.City"}, "Beijing"},
		{"点号混合", []string{"Mid.Inner", "City"}, "Beijing"},
		{"指针自动解引用", []string{"Mid", "InnerPtr", "City"}, "Shanghai"},
		{"interface 自动解引用", []string{"Mid", "Any", "City"}, "Shenzhen"},
		{"slice 下标", []string{"Tags", "1"}, "b"},
		{"array 下标", []string{"Nums", "2"}, "30"},
		{"map 键", []string{"Meta", "k1"}, "v1"},
		{"map 里的 struct", []string{"Objs", "o1", "City"}, "Chengdu"},
		{"slice 里的 struct", []string{"Structs", "1", "City"}, "Xian"},
		{"首字母小写兼容", []string{"mid", "inner", "city"}, "Beijing"},
		{"前后多余点号", []string{".Mid..Inner.City."}, "Beijing"},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			got := r.Get(c.path...).String()
			if got != c.want {
				t.Fatalf("Get(%q) = %q, 期望 %q", c.path, got, c.want)
			}
			// 与 reflux 现有实现逐条对齐
			if want := newLegacy(o).Get(c.path...).String(); want != got {
				t.Fatalf("Get(%q): fastx=%q reflux=%q, 两者行为不一致", c.path, got, want)
			}
		})
	}
}

func TestGetMissing(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	missing := [][]string{
		{"NoSuchField"},
		{"Mid", "Inner", "NoSuchField"},
		{"Tags", "99"},
		{"Tags", "notanumber"},
		{"Nums", "5"},
		{"Meta", "nokey"},
		{"Name", "City"}, // 在标量上继续取路径
	}
	for _, p := range missing {
		got := r.Get(p...)
		if got.Exists() {
			t.Fatalf("Get(%q) 不应该存在, 却返回了 %v", p, got.Any())
		}
		if got.String() != "" {
			t.Fatalf("Get(%q).String() 应该是空串, 得到 %q", p, got.String())
		}
	}
}

// 未导出字段既不能读也不能写 —— 这是 unsafe 路径上最关键的安全断言。
func TestUnexportedFieldIsUnreachable(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	if r.Get("secret").Exists() {
		t.Fatal("未导出字段 secret 不应该可读")
	}

	err := uxMustPanic(t, func() { r.Set("secret", "hacked") })
	if err == nil {
		t.Fatal("向未导出字段写入应该 panic")
	}
	if o.secret != "should-not-be-reachable" {
		t.Fatalf("未导出字段被改写了: %q", o.secret)
	}
}

// ---------------------------------------------------------------------------
// Set
// ---------------------------------------------------------------------------

func TestUnsafeSet(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	r.Set("Name", "changed")
	if o.Name != "changed" {
		t.Fatalf("Set(Name) 失败: %q", o.Name)
	}

	r.Set("Mid.Inner.City", "Hangzhou")
	if o.Mid.Inner.City != "Hangzhou" {
		t.Fatalf("Set 嵌套字段失败: %q", o.Mid.Inner.City)
	}

	r.Set("Mid.Inner.Zip", 330000)
	if o.Mid.Inner.Zip != 330000 {
		t.Fatalf("Set int 失败: %d", o.Mid.Inner.Zip)
	}

	r.Set("Mid.Inner.Active", false)
	if o.Mid.Inner.Active {
		t.Fatal("Set bool 失败")
	}

	r.Set("Mid.Inner.Ratio", 2.5)
	if o.Mid.Inner.Ratio != 2.5 {
		t.Fatalf("Set float64 失败: %v", o.Mid.Inner.Ratio)
	}

	// 通过指针字段设置
	r.Set("Mid.InnerPtr.City", "Nanjing")
	if o.Mid.InnerPtr.City != "Nanjing" {
		t.Fatalf("经指针 Set 失败: %q", o.Mid.InnerPtr.City)
	}

	// slice 元素
	r.Set("Tags.0", "z")
	if o.Tags[0] != "z" {
		t.Fatalf("Set slice 元素失败: %v", o.Tags)
	}

	// array 元素
	r.Set("Nums.1", 99)
	if o.Nums[1] != 99 {
		t.Fatalf("Set array 元素失败: %v", o.Nums)
	}

	// map 键(新增 + 覆盖)
	r.Set("Meta.k1", "v1-new")
	r.Set("Meta.k3", "v3")
	if o.Meta["k1"] != "v1-new" || o.Meta["k3"] != "v3" {
		t.Fatalf("Set map 键失败: %v", o.Meta)
	}

	// slice 里的 struct 字段
	r.Set("Structs.0.City", "Changsha")
	if o.Structs[0].City != "Changsha" {
		t.Fatalf("Set slice 内 struct 字段失败: %v", o.Structs)
	}
}

// 类型不完全一致时应该走 cast 回退, 与 reflux 行为一致
func TestUnsafeSetTypeConversion(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	r.Set("Mid.Inner.Zip", "123456") // string -> int
	if o.Mid.Inner.Zip != 123456 {
		t.Fatalf("string->int 转换失败: %d", o.Mid.Inner.Zip)
	}

	r.Set("Name", 42) // int -> string
	if o.Name != "42" {
		t.Fatalf("int->string 转换失败: %q", o.Name)
	}

	r.Set("Mid.Inner.Ratio", 3) // int -> float64
	if o.Mid.Inner.Ratio != 3 {
		t.Fatalf("int->float64 转换失败: %v", o.Mid.Inner.Ratio)
	}
}

func TestUnsafeSetErrors(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	// 路径不存在
	if err := uxMustPanic(t, func() { r.Set("NoSuchField", 1) }); err == nil {
		t.Fatal("向不存在的字段写入应该 panic")
	}
	// 父路径不存在
	if err := uxMustPanic(t, func() { r.Set("NoSuch.Deep.Path", 1) }); err == nil {
		t.Fatal("父路径不存在时应该 panic")
	}
	// 空路径
	if err := uxMustPanic(t, func() { r.Set("", 1) }); err == nil {
		t.Fatal("空路径应该 panic")
	}
	// slice 越界
	if err := uxMustPanic(t, func() { r.Set("Tags.99", "x") }); err == nil {
		t.Fatal("slice 越界应该 panic")
	}
	// 无法转换的类型
	if err := uxMustPanic(t, func() { r.Set("Mid.Inner.Zip", struct{}{}) }); err == nil {
		t.Fatal("无法转换的类型应该 panic")
	}
}

// 从 map 里取出来的 struct 是副本, 对它的写入不应该影响原 map ——
// 这与 reflect 里 "map 元素不可寻址" 的语义一致。
func TestMapValueIsCopy(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	got := r.Get("Objs", "o1")
	if !got.Exists() {
		t.Fatal("Objs.o1 应该存在")
	}
	err := uxMustPanic(t, func() { got.Set("City", "Modified") })
	if err == nil {
		t.Log("对 map 元素副本的写入未 panic(落在副本上)")
	}
	if o.Objs["o1"].City != "Chengdu" {
		t.Fatalf("原 map 里的值被改写了: %q", o.Objs["o1"].City)
	}
}

// 传值(非指针)时不应该影响调用方的原始数据
func TestNewByValueDoesNotMutateOriginal(t *testing.T) {
	o := *newUxOuter()
	r := New(o)
	r.Set("Name", "changed")
	if o.Name != "root" {
		t.Fatalf("传值构造时原始数据被改写了: %q", o.Name)
	}
	if r.Get("Name").String() != "changed" {
		t.Fatal("副本上的写入没生效")
	}
}

// ---------------------------------------------------------------------------
// Accessor / JSON / 其它 R 方法
// ---------------------------------------------------------------------------

func TestAccessors(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	if got := r.Get("Mid.Inner.City").String(); got != "Beijing" {
		t.Fatalf("String() = %q", got)
	}
	if got := r.Get("Mid.Inner.Zip").Int(); got != 100000 {
		t.Fatalf("Int() = %d", got)
	}
	if got := r.Get("Mid.Inner.Zip").Int64(); got != 100000 {
		t.Fatalf("Int64() = %d", got)
	}
	if got := r.Get("Mid.Inner.Active").Bool(); !got {
		t.Fatal("Bool() = false")
	}
	if got := r.Get("Mid.Inner.Ratio").Float64(); got != 1.5 {
		t.Fatalf("Float64() = %v", got)
	}
	if got := r.Get("Mid.Inner.Ratio").Float32(); got != 1.5 {
		t.Fatalf("Float32() = %v", got)
	}
	if got := r.Get("Mid.Inner.Zip").String(); got != "100000" {
		t.Fatalf("int 转 String() = %q", got)
	}

	// Raw / Ptr
	raw := r.Get("Mid.Inner.City").Raw()
	if !raw.IsValid() || raw.Kind() != reflect.String || raw.String() != "Beijing" {
		t.Fatalf("Raw() = %v", raw)
	}
	ptr, ok := r.Get("Mid.Inner.City").Ptr().(*string)
	if !ok || *ptr != "Beijing" {
		t.Fatalf("Ptr() = %#v", r.Get("Mid.Inner.City").Ptr())
	}
	// Ptr 拿到的必须是原始数据的地址, 改它能反映到原对象上
	*ptr = "ViaPtr"
	if o.Mid.Inner.City != "ViaPtr" {
		t.Fatal("Ptr() 返回的不是原始数据的地址")
	}

	// Any
	if got := r.Get("Mid.Inner.Zip").Any(); got != 100000 {
		t.Fatalf("Any() = %#v", got)
	}

	// StringSlice / Slice
	if got := r.Get("Tags").StringSlice(); !reflect.DeepEqual(got, []string{"a", "b", "c"}) {
		t.Fatalf("StringSlice() = %v", got)
	}
	if got := r.Get("Meta").StringMapString(); got["k1"] != "v1" {
		t.Fatalf("StringMapString() = %v", got)
	}
}

func TestExistsKeysArray(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	if !r.Exists("Mid", "Inner", "City") {
		t.Fatal("Exists 应该为 true")
	}
	if r.Exists("Mid", "Nope") {
		t.Fatal("Exists 应该为 false")
	}

	keys := r.Keys()
	if len(keys) == 0 || keys[0] != "Name" {
		t.Fatalf("Keys() = %v", keys)
	}

	arr := r.Get("Tags").Array()
	if len(arr) != 3 || arr[2].String() != "c" {
		t.Fatalf("Array() = %v", arr)
	}
	// Array 返回的元素应该指向原始底层数组, 对它的写入能反映到原对象上
	objs := r.Get("Structs").Array()
	if len(objs) != 2 {
		t.Fatalf("Structs.Array() 长度 = %d", len(objs))
	}
	objs[0].Set("City", "Guiyang")
	if o.Structs[0].City != "Guiyang" {
		t.Fatalf("Array() 元素没有指向原始底层数组: %+v", o.Structs)
	}
}

func TestLookup(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	acc, ok := r.Lookup("Mid.Inner.City")
	if !ok || acc.String() != "Beijing" {
		t.Fatalf("Lookup = %v %v", acc, ok)
	}
	if _, ok := r.Lookup("Nope"); ok {
		t.Fatal("Lookup 不存在的路径应该返回 false")
	}
	if got := r.MustLookup("Nope").String(); got != "" {
		t.Fatalf("MustLookup 不存在时应该返回零值, 得到 %q", got)
	}
}

func TestJSON(t *testing.T) {
	o := newUxOuter()
	r := New(o)

	b, err := json.Marshal(r.Get("Mid", "Inner"))
	if err != nil {
		t.Fatalf("Marshal 失败: %v", err)
	}
	if !strings.Contains(string(b), `"City":"Beijing"`) {
		t.Fatalf("Marshal 结果不对: %s", b)
	}

	target := r.Get("Mid", "Inner")
	if err := json.Unmarshal([]byte(`{"City":"Kunming","Zip":650000}`), target); err != nil {
		t.Fatalf("Unmarshal 失败: %v", err)
	}
	if o.Mid.Inner.City != "Kunming" || o.Mid.Inner.Zip != 650000 {
		t.Fatalf("Unmarshal 没有写回原对象: %+v", o.Mid.Inner)
	}
}

// ---------------------------------------------------------------------------
// TypeDescriptor 本身
// ---------------------------------------------------------------------------

type uxSelfRef struct {
	Name string
	Next *uxSelfRef
	Kids []uxSelfRef
}

// 自引用类型不能让描述符构建无限递归
func TestSelfReferentialType(t *testing.T) {
	done := make(chan struct{})
	go func() {
		defer close(done)
		td := rfxDescriptorOf(reflect.TypeOf(uxSelfRef{}))
		if len(td.fields) != 3 {
			t.Errorf("字段数 = %d", len(td.fields))
		}
	}()
	<-done

	root := &uxSelfRef{Name: "a", Next: &uxSelfRef{Name: "b", Next: &uxSelfRef{Name: "c"}}}
	r := New(root)
	if got := r.Get("Next.Next.Name").String(); got != "c" {
		t.Fatalf("自引用类型路径遍历失败: %q", got)
	}
}

// ---------------------------------------------------------------------------
// 并发
// ---------------------------------------------------------------------------

type uxRaceA struct {
	X string
	B uxRaceB
}
type uxRaceB struct {
	Y string
	C uxRaceC
}
type uxRaceC struct{ Z string }

// 多个 goroutine 同时构建描述符 + 读写各自独立的实例
func TestConcurrentAccess(t *testing.T) {
	const n = 32
	var wg sync.WaitGroup
	wg.Add(n)
	for i := 0; i < n; i++ {
		go func(i int) {
			defer wg.Done()
			// 每个 goroutine 操作自己的实例, 但共享同一份全局描述符缓存
			a := &uxRaceA{X: "x", B: uxRaceB{Y: "y", C: uxRaceC{Z: "z"}}}
			r := New(a)
			for j := 0; j < 200; j++ {
				if got := r.Get("B.C.Z").String(); got != "z" && got != "changed" {
					t.Errorf("并发读到了意外的值: %q", got)
					return
				}
				r.Set("B.C.Z", "changed")
				r.Set("B.C.Z", "z")
			}
			// 也并发构建一些新类型的描述符
			switch i % 4 {
			case 0:
				rfxDescriptorOf(reflect.TypeOf(uxOuter{}))
			case 1:
				rfxDescriptorOf(reflect.TypeOf(uxSelfRef{}))
			case 2:
				rfxDescriptorOf(reflect.TypeOf(uxMiddle{}))
			case 3:
				rfxDescriptorOf(reflect.TypeOf(uxOuter{}))
			}
		}(i)
	}
	wg.Wait()
}

// 同一个实例被多个 goroutine 并发只读, 不应该有竞争
func TestConcurrentReadSameInstance(t *testing.T) {
	a := &uxRaceA{X: "x", B: uxRaceB{Y: "y", C: uxRaceC{Z: "z"}}}
	r := New(a)

	var wg sync.WaitGroup
	for i := 0; i < 16; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			for j := 0; j < 500; j++ {
				if got := r.Get("B", "C", "Z").String(); got != "z" {
					t.Errorf("并发只读得到 %q", got)
					return
				}
			}
		}()
	}
	wg.Wait()
}

// ---------------------------------------------------------------------------

func uxMustPanic(t *testing.T, f func()) (recovered any) {
	t.Helper()
	defer func() { recovered = recover() }()
	f()
	return nil
}