package skills

import (
	"strings"
	"testing"
)

// 本文件专测 design/09 §6.4-3 的能力收缩：**只收不放**。

func TestResolveToolSurface_表驱动(t *testing.T) {
	t.Parallel()
	registered := []string{"alpha", "beta", "gamma"}
	cases := []struct {
		name       string
		allowed    []string
		disallowed []string
		gate       Gate
		want       string
	}{
		{
			name: "未声明上限时不额外收窄（仍受安全闸约束）",
			gate: NewNameSet([]string{"alpha", "beta", "gamma"}),
			want: "alpha,beta,gamma",
		},
		{
			name:    "allowed 是上限：列表外的工具不可见",
			allowed: []string{"alpha"},
			gate:    NewNameSet([]string{"alpha", "beta", "gamma"}),
			want:    "alpha",
		},
		{
			name:       "disallowed 从上限里剔除",
			allowed:    []string{"alpha", "beta"},
			disallowed: []string{"beta"},
			gate:       NewNameSet([]string{"alpha", "beta", "gamma"}),
			want:       "alpha",
		},
		{
			name:    "安全闸拒绝的工具即使被技能允许也不可用",
			allowed: []string{"alpha", "beta"},
			gate:    NewNameSet([]string{"alpha"}),
			want:    "alpha",
		},
		{
			name:    "allowed 里的幽灵工具不会凭空出现（∩ 注册表）",
			allowed: []string{"alpha", "ghost"},
			gate:    NewNameSet([]string{"alpha", "ghost"}),
			want:    "alpha",
		},
		{
			name: "缺安全闸 ⇒ 全拒（fail-closed）",
			gate: nil,
			want: "",
		},
		{
			name: "空注册表 ⇒ 空面",
			gate: NewNameSet([]string{"alpha"}),
			want: "",
		},
	}
	for _, tc := range cases {
		tc := tc
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()
			tools := registered
			if tc.name == "空注册表 ⇒ 空面" {
				tools = nil
			}
			got := ResolveToolSurface(tools, tc.allowed, tc.disallowed, tc.gate)
			if strings.Join(got, ",") != tc.want {
				t.Fatalf("ResolveToolSurface = %q, want %q", strings.Join(got, ","), tc.want)
			}
		})
	}
}

// TestResolveToolSurface_只收不放 是本片的核心不变式：无论技能怎么声明，结果永远
// 是「注册表 ∩ 安全闸」的子集 —— 技能**加不进**任何东西。
func TestResolveToolSurface_只收不放(t *testing.T) {
	t.Parallel()
	registered := []string{"alpha", "beta"}
	gate := NewNameSet([]string{"alpha", "beta"})
	// 技能把 allowed-tools 写成注册表之外的、或安全闸之外的，都不该出现在结果里。
	got := ResolveToolSurface(registered, []string{"ghost", "secret"}, nil, gate)
	if len(got) != 0 {
		t.Fatalf("ResolveToolSurface = %v, want 空（技能不得放宽任何工具）", got)
	}
	// 反过来：技能把*所有*注册表工具都写进 allowed，也只能拿到安全闸允许的那些。
	got = ResolveToolSurface(registered, registered, nil, NewNameSet([]string{"beta"}))
	if strings.Join(got, ",") != "beta" {
		t.Fatalf("ResolveToolSurface = %v, want [beta]", got)
	}
}

func TestResolveToolSurface_去重与保序(t *testing.T) {
	t.Parallel()
	got := ResolveToolSurface([]string{"b", "a", "b", "  ", "c"}, nil, nil, NewNameSet([]string{"a", "b", "c"}))
	if strings.Join(got, ",") != "b,a,c" {
		t.Fatalf("ResolveToolSurface = %q, want b,a,c（保注册表序 + 去重 + 跳空白）", strings.Join(got, ","))
	}
}

func TestAllOf_全允许才允许(t *testing.T) {
	t.Parallel()
	allowAll := NewNameSet([]string{"a", "b"})
	onlyA := NewNameSet([]string{"a"})
	if !AllOf(allowAll, onlyA).Allow("a") {
		t.Fatal("AllOf(allowAll, onlyA).Allow(a) = false, want true")
	}
	if AllOf(allowAll, onlyA).Allow("b") {
		t.Fatal("AllOf(allowAll, onlyA).Allow(b) = true, want false")
	}
	if AllOf(allowAll, GateFunc(nil)).Allow("a") {
		t.Fatal("含 nil 函数闸时应当全拒")
	}
	// 没有任何有效闸 ⇒ 全拒（绝不给出无人看守的工具面）。
	if AllOf(nil, nil).Allow("a") {
		t.Fatal("AllOf() 全 nil 时应当全拒")
	}
	if AllOf().Allow("a") {
		t.Fatal("AllOf() 无参时应当全拒")
	}
}

func TestNameSet_语义(t *testing.T) {
	t.Parallel()
	set := NewNameSet([]string{" a ", "", "b"})
	if !set.Allow("a") || !set.Allow("b") {
		t.Fatalf("NameSet = %v, want 含 a/b（并去掉空白）", set)
	}
	if set.Allow("") || set.Allow("c") {
		t.Fatal("NameSet 不该放行未登记的名字")
	}
	var nilSet NameSet
	if nilSet.Allow("a") {
		t.Fatal("nil NameSet 必须全拒")
	}
}

func TestSortedCopy_不改原切片(t *testing.T) {
	t.Parallel()
	in := []string{"b", "a"}
	got := SortedCopy(in)
	if strings.Join(got, ",") != "a,b" {
		t.Fatalf("SortedCopy = %v, want [a b]", got)
	}
	if in[0] != "b" {
		t.Fatalf("SortedCopy 改动了入参：%v", in)
	}
}