import SystemConfiguration
import XCTest

@testable import ShadowsocksX_NG2

/// 生产本机接口事实来源的真实主机非视觉验证：替身测试证明策略
/// 行为，本组用例证明系统适配器整合——接口名称与类型映射、回环识别、地址
/// 规范化与链路本地判定均来自真实 macOS。候选枚举本身不证明跨设备可达。
@MainActor
final class SystemInterfaceFactsProviderTests: XCTestCase {
  private var provider: SystemInterfaceFactsProvider!
  private var interfaces: [LocalInterfaceFacts]!

  override func setUp() async throws {
    try await super.setUp()
    provider = SystemInterfaceFactsProvider()
    guard let interfaces = provider.interfaces else {
      self.interfaces = []
      XCTFail("真实主机 getifaddrs 枚举不应失败")
      return
    }
    self.interfaces = interfaces
  }

  private func fact(_ bsdName: String) -> LocalInterfaceFacts? {
    interfaces.first { $0.bsdName == bsdName }
  }

  func testLoopbackIsIdentifiedWithNormalizedAddresses() {
    guard let lo0 = fact("lo0") else {
      return XCTFail("真实主机必有 lo0：\(interfaces.map(\.bsdName))")
    }
    XCTAssertTrue(lo0.isLoopback, "回环以 IFF_LOOPBACK 识别")
    XCTAssertNil(lo0.interfaceType, "回环无 SystemConfiguration 类型映射")
    XCTAssertTrue(
      lo0.addresses.contains(
        LocalInterfaceAddress(
          address: "127.0.0.1", family: .ipv4, isIPv6LinkLocal: false, v6Flags: nil)),
      "回环单播含规范化 127.0.0.1")
  }

  func testInterfaceTypeMappingCoversRealSystemInterfaces() {
    let mapped = interfaces.filter { $0.interfaceType != nil }
    XCTAssertFalse(
      mapped.isEmpty, "真实主机至少有一个 SystemConfiguration 可见接口：\(String(describing: interfaces))")
    for interface in mapped {
      if let localizedName = interface.localizedName {
        XCTAssertFalse(localizedName.isEmpty, "\(interface.bsdName) 本地化名称非空")
      }
    }
  }

  func testAddressTextIsNormalizedWithoutScopeOrEmptiness() {
    for interface in interfaces {
      for address in interface.addresses {
        XCTAssertFalse(address.address.isEmpty)
        XCTAssertFalse(
          address.address.contains("%"),
          "\(interface.bsdName) 地址不含作用域后缀：\(address.address)")
        if address.family == .ipv6 {
          XCTAssertNotNil(
            address.v6Flags, "\(interface.bsdName) IPv6 地址标志查询不应失败")
          if address.address.hasPrefix("fe80") {
            XCTAssertTrue(address.isIPv6LinkLocal, "fe80 地址必须标记链路本地")
          } else {
            XCTAssertFalse(address.isIPv6LinkLocal, "非 fe80 地址不应标记链路本地")
          }
        } else {
          XCTAssertNil(address.v6Flags, "IPv4 地址不携带 IPv6 标志")
        }
      }
    }
  }

  func testPolicyAppliedToRealFactsYieldsLoopbackFirstAndAllowedTypesOnly() {
    let candidates = TerminalCommandAddressPolicy.candidates(
      for: .allIPv4AndIPv6Interfaces, interfaces: interfaces)

    XCTAssertEqual(
      candidates.prefix(1).map(\.address), ["127.0.0.1"],
      "本地 IPv4 回环置顶且来自真实主机")
    let nonLoopback = candidates.dropFirst(1)
    XCTAssertFalse(nonLoopback.isEmpty, "真实主机存在可列出的接口地址候选")
    for candidate in nonLoopback {
      let fact = interfaces.first { $0.bsdName == candidate.bsdName }?
        .addresses.first { $0.address == candidate.address }
      let type = interfaces.first { $0.bsdName == candidate.bsdName }?.interfaceType
      XCTAssertTrue(
        type == kSCNetworkInterfaceTypeIEEE80211 as String
          || type == kSCNetworkInterfaceTypeEthernet as String,
        "候选 \(candidate.address) 必须来自允许类型接口（实际类型 \(type ?? "nil")）")
      XCTAssertFalse(candidate.address.contains("%"), "候选地址已规范化")
      XCTAssertFalse(
        fact?.v6Flags?.contains(.temporary) ?? false,
        "临时地址（会轮换）不进候选：\(candidate.address)")
      let knownAnnotations: Set<String?> = ["autoconf secured", "autoconf", "dynamic", nil]
      XCTAssertTrue(
        knownAnnotations.contains(candidate.annotation),
        "IPv6 候选注记只能来自 ifconfig 同源闭集：\(candidate.address)")
    }
  }
}