package execenv

import (
	"strings"
	"testing"
)

// envToMap 把 []string 形式的 env 转成 map 方便断言.
func envToMap(env []string) map[string]string {
	m := make(map[string]string, len(env))
	for _, kv := range env {
		i := strings.IndexByte(kv, '=')
		if i < 0 {
			continue
		}
		m[kv[:i]] = kv[i+1:]
	}
	return m
}

// TestMinimalEnv_WhitelistOnly 验证纯白名单模式下, 敏感 env 不会泄漏.
//
// 这是本包存在的唯一理由 - 如果这个测试挂了, Flyto 的整个插件/MCP 隔离
// 机制等于没有. 测试命名和 plugin_tool_test.go 的 TestPluginShellTool_NoOsEnvLeak
// 对齐, 方便未来 grep "NoOsEnvLeak" 找到所有 env 隔离测试.
func TestMinimalEnv_WhitelistOnly(t *testing.T) {
	t.Setenv("FLYTO_EXECENV_CANARY_XYZ", "supersecret-should-never-leak")

	env := MinimalEnv(nil)
	m := envToMap(env)

	if _, ok := m["FLYTO_EXECENV_CANARY_XYZ"]; ok {
		t.Errorf("SECURITY: canary env leaked into MinimalEnv output: %v", m)
	}
	if _, ok := m["PATH"]; !ok {
		t.Error("PATH should be in whitelist output")
	}
}

// TestMinimalEnv_ExtraOverride 验证 extra 参数能覆盖白名单默认值.
func TestMinimalEnv_ExtraOverride(t *testing.T) {
	env := MinimalEnv(map[string]string{"HOME": "/custom/sandbox"})
	m := envToMap(env)

	if got := m["HOME"]; got != "/custom/sandbox" {
		t.Errorf("HOME = %q, want /custom/sandbox", got)
	}
}

// TestMinimalEnv_ExtraInjection 验证 extra 能注入新 key.
func TestMinimalEnv_ExtraInjection(t *testing.T) {
	env := MinimalEnv(map[string]string{"MY_API_KEY": "k123"})
	m := envToMap(env)

	if got := m["MY_API_KEY"]; got != "k123" {
		t.Errorf("MY_API_KEY = %q, want k123", got)
	}
}

// TestMinimalEnv_NilExtra 验证 nil extra 不 panic.
func TestMinimalEnv_NilExtra(t *testing.T) {
	env := MinimalEnv(nil)
	if len(env) == 0 {
		t.Error("nil extra should still produce whitelist env")
	}
}

// TestMinimalEnv_NoWhitelistLeakWhenCleared 验证 extra 传空字符串能清掉
// 白名单项 (场景: plugin 想要一个最小 sandbox, 连 PATH 都不要).
func TestMinimalEnv_NoWhitelistLeakWhenCleared(t *testing.T) {
	env := MinimalEnv(map[string]string{"PATH": ""})
	m := envToMap(env)
	if got, ok := m["PATH"]; !ok || got != "" {
		t.Errorf("PATH = %q, ok=%v, want empty string", got, ok)
	}
}

// TestExpandEnvMap_Literal 验证无 ${VAR} 的值保持不变.
func TestExpandEnvMap_Literal(t *testing.T) {
	out, err := ExpandEnvMap(map[string]string{
		"PLAIN":   "hello world",
		"NUMERIC": "42",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if out["PLAIN"] != "hello world" {
		t.Errorf("PLAIN = %q", out["PLAIN"])
	}
	if out["NUMERIC"] != "42" {
		t.Errorf("NUMERIC = %q", out["NUMERIC"])
	}
}

// TestExpandEnvMap_BracesSyntax 验证 ${VAR} 展开.
func TestExpandEnvMap_BracesSyntax(t *testing.T) {
	t.Setenv("FLYTO_TEST_BRAVE_KEY", "brave-abc")

	out, err := ExpandEnvMap(map[string]string{
		"BRAVE_API_KEY": "${FLYTO_TEST_BRAVE_KEY}",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if out["BRAVE_API_KEY"] != "brave-abc" {
		t.Errorf("BRAVE_API_KEY = %q, want brave-abc", out["BRAVE_API_KEY"])
	}
}

// TestExpandEnvMap_BareDollarSyntax 验证 $VAR (无大括号) 展开.
// Go os.Expand 支持两种语法; 行业 (Docker/K8s) 偏好大括号, 但没有理由禁止
// 裸形式, 保留 Go 标准行为.
func TestExpandEnvMap_BareDollarSyntax(t *testing.T) {
	t.Setenv("FLYTO_TEST_BARE", "bare-value")

	out, err := ExpandEnvMap(map[string]string{
		"KEY": "$FLYTO_TEST_BARE",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if out["KEY"] != "bare-value" {
		t.Errorf("KEY = %q, want bare-value", out["KEY"])
	}
}

// TestExpandEnvMap_MissingVariableIsError 验证引用未设置变量时返回 error.
// 这是"显式 >  静默降级"设计的核心测试.
func TestExpandEnvMap_MissingVariableIsError(t *testing.T) {
	_, err := ExpandEnvMap(map[string]string{
		"X": "${FLYTO_DEFINITELY_NOT_SET_XYZ_12345}",
	})
	if err == nil {
		t.Fatal("expected error for missing env var, got nil")
	}
	if !strings.Contains(err.Error(), "FLYTO_DEFINITELY_NOT_SET_XYZ_12345") {
		t.Errorf("error message should name the missing var, got: %v", err)
	}
	if !strings.Contains(err.Error(), `"X"`) {
		t.Errorf("error message should name the config key, got: %v", err)
	}
}

// TestExpandEnvMap_ExplicitEmptyIsNotMissing 验证显式 set 为空字符串
// (export FOO=) 与未设置不同, 前者合法.
//
// 这依赖 os.LookupEnv 能区分两种情况, os.Getenv 不能.
func TestExpandEnvMap_ExplicitEmptyIsNotMissing(t *testing.T) {
	t.Setenv("FLYTO_TEST_EMPTY", "")

	out, err := ExpandEnvMap(map[string]string{
		"X": "${FLYTO_TEST_EMPTY}",
	})
	if err != nil {
		t.Fatalf("empty env var should not be treated as missing: %v", err)
	}
	if out["X"] != "" {
		t.Errorf("X = %q, want empty string", out["X"])
	}
}

// TestExpandEnvMap_Interpolation 验证一个 value 里能混合字面和 ${VAR}.
func TestExpandEnvMap_Interpolation(t *testing.T) {
	t.Setenv("FLYTO_TEST_HOST", "api.example.com")

	out, err := ExpandEnvMap(map[string]string{
		"URL": "https://${FLYTO_TEST_HOST}/v1",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if out["URL"] != "https://api.example.com/v1" {
		t.Errorf("URL = %q", out["URL"])
	}
}

// TestExpandEnvMap_DollarEscape 验证 $$ 转义为字面 $.
func TestExpandEnvMap_DollarEscape(t *testing.T) {
	out, err := ExpandEnvMap(map[string]string{
		"PRICE": "$$5.00",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if out["PRICE"] != "$5.00" {
		t.Errorf("PRICE = %q, want $5.00", out["PRICE"])
	}
}

// TestExpandEnvMap_NilInput 验证 nil 和空 map 返回 nil.
func TestExpandEnvMap_NilInput(t *testing.T) {
	out, err := ExpandEnvMap(nil)
	if err != nil {
		t.Fatal(err)
	}
	if out != nil {
		t.Errorf("nil input should return nil map, got %v", out)
	}

	out, err = ExpandEnvMap(map[string]string{})
	if err != nil {
		t.Fatal(err)
	}
	if out != nil {
		t.Errorf("empty input should return nil map, got %v", out)
	}
}