package cast_test

import (
	"reflect"
	"testing"

	"apigo.cc/go/cast"
)

// Matrix Test Entry
func TestConvertMatrix(t *testing.T) {
	type testCase struct {
		name     string
		from     any
		to       any // 传入指针的指针，用于接收结果
		expected any
	}

	// 1. 基础类型全互转矩阵
	cases := []testCase{
		{name: "int to string", from: 123, to: new(string), expected: "123"},
		{name: "string to int", from: "456", to: new(int), expected: 456},
		{name: "float to int", from: 123.45, to: new(int), expected: 123},
		{name: "bool to string", from: true, to: new(string), expected: "true"},
		{name: "string to bool", from: "1", to: new(bool), expected: true},
		{name: "string to bool (text)", from: "true", to: new(bool), expected: true},

		// 2. 容器与单值的自动包装/解包 (去摩擦)
		{name: "single to slice", from: 100, to: new([]int), expected: []int{100}},
		{name: "slice to single (len 1)", from: []int{200}, to: new(int), expected: 200},
		{name: "slice to single (len >1, take first)", from: []int{300, 400}, to: new(int), expected: 300},

		// 3. 字符串与切片的智能转换
		{name: "csv string to slice", from: "1, 2, 3", to: new([]int), expected: []int{1, 2, 3}},
		{name: "json string to slice", from: `[4, 5, 6]`, to: new([]int), expected: []int{4, 5, 6}},

		// 4. 指针转换 (深度穿透)
		{name: "deep pointer to val", from: ptr(ptr(789)), to: new(int), expected: 789},
		{name: "val to pointer", from: 999, to: new(*int), expected: ptr(999)},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			cast.Convert(tc.to, tc.from)
			// 获取 to 指针指向的实际值
			actual := reflect.ValueOf(tc.to).Elem().Interface()
			if !reflect.DeepEqual(actual, tc.expected) {
				t.Errorf("[%s] Failed: from(%v) expected(%v) but got(%v)", tc.name, tc.from, tc.expected, actual)
			}
		})
	}
}

func TestConvert_SelfAssignment(t *testing.T) {
	type User struct {
		Name string
	}
	u := &User{Name: "Tom"}
	// 应命中自我转换保护，不报错且不改变状态
	cast.Convert(u, u)
	if u.Name != "Tom" {
		t.Error("Self-assignment guard failed")
	}
}

// 5. 复杂映射与去摩擦 Key 匹配测试
func TestComplexFrictionlessMapping(t *testing.T) {
	// 场景：Map 键名非常混乱，Struct 嵌套，目标存在旧数据
	type Sub struct {
		Age int
	}
	type User struct {
		UserID   int
		UserName string
		SubInfo  Sub
	}

	from := map[string]any{
		"user_id":   1001,   // 下划线
		"USER-NAME": "Andy", // 中划线+大写
		"subinfo": map[string]any{ // 嵌套+全小写
			"age": "18", // 类型不一致 (string -> int)
		},
	}

	var to User
	to.UserID = 999 // 预设旧数据，验证是否被正确覆盖
	cast.Convert(&to, from)

	if to.UserID != 1001 {
		t.Errorf("UserID match failed: %d", to.UserID)
	}
	if to.UserName != "Andy" {
		t.Errorf("UserName match failed: %s", to.UserName)
	}
	if to.SubInfo.Age != 18 {
		t.Errorf("SubInfo.Age match failed: %d", to.SubInfo.Age)
	}
}

// 6. 函数转换测试 (Func to Func)
func TestFuncConversion(t *testing.T) {
	// 源函数：接收 int, string，返回 int, string
	f1 := func(a int, b string) (int, string) {
		return a + 1, b + "!"
	}

	// 目标函数：意图是接收 string, any，返回 string, any
	var f2 func(string, any) (string, any)
	cast.Convert(&f2, f1)

	if f2 == nil {
		t.Fatal("Converted function is nil")
	}

	r1, r2 := f2("10", "hello")
	if r1 != "11" || r2 != "hello!" {
		t.Errorf("Func conversion failed: r1=%v, r2=%v", r1, r2)
	}
}

// 8. 命名风格模糊匹配测试
func TestFuzzyNamingMapping(t *testing.T) {
	type TestStruct struct {
		JSONTag      string
		UserID       int
		UserName     string
		IsActiveFlag bool
	}

	// 测试用例：各种不规范输入到标准结构体的映射
	from := map[string]any{
		"jsontag":        "val1", // 小写
		"JSONTag":        "val2", // 原名
		"JSON_TAG":       "val3", // 下划线大写
		"user_id":        123,    // 下划线小写
		"USERID":         456,    // 全大写
		"userName":       "Andy", // 首字母小写
		"user-name":      "Bob",  // 中划线
		"is_active_flag": "true", // 模糊匹配 bool
	}

	var to TestStruct
	cast.Convert(&to, from)

	if to.UserID == 0 {
		t.Errorf("UserID should be matched and set")
	}
	if to.UserName == "" {
		t.Errorf("UserName should be matched and set")
	}
	if !to.IsActiveFlag {
		t.Errorf("IsActiveFlag should be set to true")
	}

	t.Logf("Conversion result: %+v", to)
}

// 9. 异常防御测试 (Panic Prevention)
func TestPanicPrevention(t *testing.T) {
	t.Run("nil destination", func(t *testing.T) {
		defer func() {
			if r := recover(); r != nil {
				t.Errorf("Panic occurred with nil destination: %v", r)
			}
		}()
		cast.Convert(nil, "data")
	})

	t.Run("nil pointer destination", func(t *testing.T) {
		// nil 指针目标应该是可以接受的，库应当忽略或优雅处理，不应 panic
		var p *int = nil
		cast.Convert(&p, 123) // 这里传入的是指针的指针
		if p == nil || *p != 123 {
			t.Errorf("Expected p to be initialized and set to 123, got %v", p)
		}
	})

	t.Run("read-only destination", func(t *testing.T) {
		const i = 1
		cast.Convert(i, 123)
	})
}

// 辅助函数
func ptr[T any](v T) *T { return &v }

// --- 性能测试 ---

func BenchmarkCastMatrixConvert(b *testing.B) {
	from := map[string]any{"id": "123", "name": "test"}
	type Target struct {
		ID   int
		Name string
	}
	var to Target
	for i := 0; i < b.N; i++ {
		cast.Convert(&to, from)
	}
}