package reflux

import (
	"encoding/json"
	"fmt"
	"testing"
)

// Scope 必须返回快实现(*rfx), 否则它之后的所有 Get/Set 都退回逐次反射。
// 这一条很容易在重构里悄悄失守: 交回 refx 功能完全正常, 只是慢 3 倍,
// 测试不看类型就发现不了。
func TestScopeReturnsFastImpl(t *testing.T) {
	type leaf struct{ V string }
	type doc struct {
		A    leaf
		Tags []string
		M    map[string]any
	}
	d := &doc{A: leaf{V: "v"}, Tags: []string{"t"}, M: map[string]any{"k": "v"}}
	r := New(d)

	for _, p := range [][]string{nil, {"A"}, {"Tags"}, {"M"}} {
		got := r.Scope(p...)
		if _, ok := got.(*rfx); !ok {
			t.Fatalf("Scope(%v) 返回了 %T, 应当是 *rfx —— 慢实现会让后续操作退回逐次反射", p, got)
		}
		// 链下去也必须还是快实现
		if inner := got.Get("V"); p != nil && len(p) == 1 && p[0] == "A" {
			if _, ok := inner.(*rfx); !ok {
				t.Fatalf("Scope(%v).Get() 返回了 %T", p, inner)
			}
		}
	}
}

// 语义不能变: Scope 仍然是深度克隆, 改副本不影响原数据
func TestScopeStillIsolates(t *testing.T) {
	type inner struct {
		Name string
		Tags []string
	}
	type doc struct {
		In   inner
		M    map[string]string
		Pure struct{ A, B string }
	}
	mk := func() *doc {
		return &doc{
			In:   inner{Name: "n", Tags: []string{"t0", "t1"}},
			M:    map[string]string{"k": "v"},
			Pure: struct{ A, B string }{"a", "b"},
		}
	}

	t.Run("含引用的子树", func(t *testing.T) {
		d := mk()
		s := New(d).Scope("In")
		s.Set("Name", "changed")
		s.Set("Tags.0", "changed")
		if d.In.Name != "n" || d.In.Tags[0] != "t0" {
			t.Fatalf("原数据被改写了: %+v", d.In)
		}
		if s.Get("Name").String() != "changed" || s.Get("Tags.0").String() != "changed" {
			t.Fatal("副本上的写入没生效")
		}
	})

	t.Run("纯值子树(走浅拷贝分支)", func(t *testing.T) {
		d := mk()
		s := New(d).Scope("Pure")
		s.Set("A", "changed")
		if d.Pure.A != "a" {
			t.Fatalf("原数据被改写了: %+v", d.Pure)
		}
	})

	t.Run("map 子树", func(t *testing.T) {
		d := mk()
		s := New(d).Scope("M")
		s.Set("k", "changed")
		if d.M["k"] != "v" {
			t.Fatalf("原 map 被改写了: %v", d.M)
		}
	})

	t.Run("无参数克隆整个对象", func(t *testing.T) {
		d := mk()
		s := New(d).Scope()
		s.Set("In.Name", "changed")
		if d.In.Name != "n" {
			t.Fatalf("原数据被改写了: %+v", d.In)
		}
	})
}

// 与旧实现逐格对拍
func TestScopeMatchesLegacy(t *testing.T) {
	type inner struct {
		Name string
		Tags []string
	}
	type doc struct {
		In inner
		M  map[string]any
		S  []inner
	}
	mk := func() *doc {
		return &doc{
			In: inner{Name: "n", Tags: []string{"t"}},
			M:  map[string]any{"k": map[string]any{"deep": "d"}},
			S:  []inner{{Name: "s0"}},
		}
	}

	paths := [][]string{
		nil, {"In"}, {"In", "Name"}, {"In", "Tags"}, {"In", "Tags", "0"},
		{"M"}, {"M", "k"}, {"M", "k", "deep"},
		{"S"}, {"S", "0"}, {"S", "0", "Name"},
		{"nosuch"}, {"In", "nosuch"},
	}
	ops := []struct {
		name string
		f    func(R) any
	}{
		{"String", func(r R) any { return r.String() }},
		{"Exists", func(r R) any { return r.Exists() }},
		{"Keys", func(r R) any { return fmt.Sprintf("%v", r.Keys()) }},
		{"RawKind", func(r R) any { return r.Raw().Kind().String() }},
		{"JSON", func(r R) any { b, e := json.Marshal(r); return fmt.Sprintf("%s/%v", b, e) }},
		{"再取一层", func(r R) any { return r.Get("Name").String() }},
	}

	for _, p := range paths {
		for _, op := range ops {
			t.Run(fmt.Sprintf("%v/%s", p, op.name), func(t *testing.T) {
				want := call(newLegacy(mk()).Scope(p...), op.f)
				got := call(New(mk()).Scope(p...), op.f)
				if want != got {
					t.Fatalf("行为不一致\n  旧 = %s\n  新 = %s", want, got)
				}
			})
		}
	}
}