import Foundation
import Testing
import WireProtocol
import HostRegistry

// 迁移安全 + 持久化形状(B2)。
// 已配对的主机是**当前线上构建**写进 Keychain 的旧形状记录(没有 accessToken 字段);
// 新构建必须照常读出它们 —— 缺字段 = nil,绝不是解码失败(否则用户的主机列表整体变
// .corruptedData,等于要求重新配对所有主机)。

/// 上一版 `Host` 的编码形状:只有 id/name/endpoint,合成 Codable。
/// 用它来生成"旧记录",比手写 JSON 更能保真上一版编码器的输出。
private struct LegacyHostRecord: Encodable {
    let id: UUID
    let name: String
    let endpoint: HostEndpoint
}

private func encodedLegacyPayload(_ host: Host) throws -> Data {
    try JSONEncoder().encode([
        LegacyHostRecord(id: host.id, name: host.name, endpoint: host.endpoint),
    ])
}

// MARK: - 旧形状读取(迁移回归)

@Test("迁移:旧形状记录(无 accessToken 字段)照常读出,令牌为 nil")
func legacyRecordWithoutTokenFieldStillLoads() async throws {
    // Arrange
    let legacy = Fixtures.makeHost(name: "paired-before-tokens")
    let shim = FakeSecItemShim()
    shim.forceCopyData(try encodedLegacyPayload(legacy))
    let store = KeychainHostStore(shim: shim)

    // Act
    let loaded = try await store.loadAll()

    // Assert
    #expect(loaded.count == 1)
    #expect(loaded.first?.id == legacy.id)
    #expect(loaded.first?.name == "paired-before-tokens")
    #expect(loaded.first?.endpoint == legacy.endpoint)
    #expect(loaded.first?.accessToken == nil)
    #expect(loaded == [legacy]) // 旧记录 == 令牌为 nil 的新值
}

@Test("迁移:逐字旧 JSON(键名钉死 id/name/endpoint.baseURL)解码成功且令牌为 nil")
func literalLegacyJSONDecodesWithNilToken() throws {
    // Arrange —— 逐字旧形状,钉死上一版的键名(键名一改就红)
    let json = """
    [{"id":"E621E1F8-C36C-495A-93FC-0C247A3E6E5F",\
    "name":"mac-studio","endpoint":{"baseURL":"http://192.168.1.5:3000"}}]
    """

    // Act
    let hosts = try JSONDecoder().decode([Host].self, from: Data(json.utf8))

    // Assert
    #expect(hosts.count == 1)
    #expect(hosts.first?.name == "mac-studio")
    #expect(hosts.first?.endpoint.originHeader == "http://192.168.1.5:3000")
    #expect(hosts.first?.accessToken == nil)
}

@Test("被篡改的非法令牌值:降级为 nil,不把整张主机表打成 .corruptedData")
func tamperedTokenValueDegradesToNilInsteadOfCorruptingTheList() async throws {
    // Arrange —— 只有外部篡改才可能出现非法值(写路径已在边界校验)
    let json = """
    [{"id":"E621E1F8-C36C-495A-93FC-0C247A3E6E5F","name":"mac-studio",\
    "endpoint":{"baseURL":"http://192.168.1.5:3000"},"accessToken":"short!"}]
    """
    let shim = FakeSecItemShim()
    shim.forceCopyData(Data(json.utf8))
    let store = KeychainHostStore(shim: shim)

    // Act
    let loaded = try await store.loadAll()

    // Assert
    #expect(loaded.count == 1)
    #expect(loaded.first?.name == "mac-studio")
    #expect(loaded.first?.accessToken == nil)
}

@Test("accessToken 为 JSON null:等同缺字段,令牌为 nil")
func explicitNullTokenDecodesAsNil() throws {
    // Arrange
    let json = """
    [{"id":"E621E1F8-C36C-495A-93FC-0C247A3E6E5F","name":"mac-studio",\
    "endpoint":{"baseURL":"http://192.168.1.5:3000"},"accessToken":null}]
    """

    // Act
    let hosts = try JSONDecoder().decode([Host].self, from: Data(json.utf8))

    // Assert
    #expect(hosts.first?.accessToken == nil)
}

@Test("endpoint 仍是硬校验:非 http(s) 的 baseURL → 解码失败(令牌宽松不放宽 endpoint)")
func endpointRemainsStrictlyValidatedOnDecode() {
    // Arrange
    let json = """
    [{"id":"E621E1F8-C36C-495A-93FC-0C247A3E6E5F","name":"bad",\
    "endpoint":{"baseURL":"ftp://192.168.1.5"}}]
    """

    // Act / Assert
    #expect(throws: (any Error).self) {
        _ = try JSONDecoder().decode([Host].self, from: Data(json.utf8))
    }
}

// MARK: - 新形状

@Test("新形状:令牌以纯字符串存在 accessToken 键下(键名/形状钉死)")
func tokenIsPersistedAsAPlainStringUnderAccessTokenKey() throws {
    // Arrange
    let host = Fixtures.makeHost().withAccessToken(Fixtures.makeToken())

    // Act
    let data = try JSONEncoder().encode(host)
    let object = try #require(
        JSONSerialization.jsonObject(with: data) as? [String: Any]
    )

    // Assert
    #expect(object["accessToken"] as? String == Fixtures.validTokenString)
}

@Test("新形状:令牌为 nil 时不写 accessToken 键(不留空字段)")
func nilTokenIsOmittedFromTheEncodedForm() throws {
    // Arrange
    let host = Fixtures.makeHost()

    // Act
    let data = try JSONEncoder().encode(host)
    let object = try #require(
        JSONSerialization.jsonObject(with: data) as? [String: Any]
    )

    // Assert
    #expect(object.keys.contains("accessToken") == false)
    #expect(object.keys.sorted() == ["endpoint", "id", "name"])
}

@Test("Codable 往返:带令牌的 Host 全字段保真")
func codableRoundTripPreservesTheToken() throws {
    // Arrange
    let host = Fixtures.makeHost(name: "studio", urlString: "https://mac.ts.net:8443")
        .withAccessToken(Fixtures.makeToken())

    // Act
    let decoded = try JSONDecoder().decode(Host.self, from: JSONEncoder().encode(host))

    // Assert
    #expect(decoded == host)
    #expect(decoded.accessToken == Fixtures.makeToken())
    #expect(decoded.endpoint.originHeader == "https://mac.ts.net:8443")
}

// MARK: - 不可变性

@Test("withAccessToken 不可变:返回新值,原 Host 不变")
func withAccessTokenReturnsANewValueWithoutMutatingTheOriginal() {
    // Arrange
    let original = Fixtures.makeHost()

    // Act
    let withToken = original.withAccessToken(Fixtures.makeToken())
    let cleared = withToken.withAccessToken(nil)

    // Assert
    #expect(original.accessToken == nil)
    #expect(withToken.accessToken == Fixtures.makeToken())
    #expect(cleared.accessToken == nil)
    #expect(withToken.id == original.id)
    #expect(withToken.name == original.name)
    #expect(withToken.endpoint == original.endpoint)
    #expect(cleared == original)
}

@Test("Equatable 含令牌:令牌不同的同 id 主机不相等(UI 才能感知令牌变化)")
func hostsDifferingOnlyByTokenAreNotEqual() {
    // Arrange
    let base = Fixtures.makeHost()

    // Act / Assert
    #expect(base.withAccessToken(Fixtures.makeToken()) != base)
    #expect(base.withAccessToken(Fixtures.makeToken())
        != base.withAccessToken(Fixtures.makeToken(Fixtures.otherValidTokenString)))
}