import Foundation
import Security
import Testing
@testable import ClientTLS

// B4 · The Secure-Enclave enrollment half of `KeychainClientIdentityStore`:
// `enroll`, `renew`, `renewalState`. What is pinned here is the ORCHESTRATION —
// which key signs the CSR, which endpoint it goes to, what the request body is
// allowed to contain, and what happens to local state when the server's answer
// is unusable. The signing key is injected (`keyProvider`) or pre-installed
// under the store's derived tag, so no Secure Enclave is needed.
//
// Every test stops at the leaf-installation step by having the server return an
// undecodable certificate (`undecodableCertificateDER`) — see the note there for
// why installing a real leaf is not possible in a macOS `swift test` run. The
// happy-path leaf install + `SecItemCopyMatching(kSecClassIdentity)` assembly
// stays a device/simulator concern.

private let controlPlaneURL = URL(string: "https://cp.terminal.yaojia.wang")!

@Test("renewalState is nil before any enrollment", .keychainSerialized)
func renewalStateNilWhenNotEnrolled() async throws {
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)

    #expect(try store.renewalState() == nil)
}

@Test("renewalState reads back the persisted enrollment record verbatim", .keychainSerialized)
func renewalStateReadsPersistedRecord() async throws {
    // Arrange — the record layout is a migration contract, so it is seeded
    // directly and read back through the public API.
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let notAfter = Date(timeIntervalSinceReferenceDate: 800_000_000)
    let renewAfter = Date(timeIntervalSinceReferenceDate: 790_000_000)
    KeychainProbe.write(
        service: keys.service, account: keys.enrollmentAccount,
        data: storedEnrollmentJSON(
            deviceId: "dev-42", deviceName: "Yaojia iPhone",
            caChain: [Data([0x30, 0xAA])], notAfter: notAfter, renewAfter: renewAfter
        )
    )
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)

    // Act
    let state = try #require(try store.renewalState())

    // Assert — deviceId drives POST /device/:id/renew; the dates drive the
    // scheduler's decision.
    #expect(state.deviceId == "dev-42")
    #expect(state.notAfter == notAfter)
    #expect(state.renewAfter == renewAfter)
    #expect(state.isRenewalDue(asOf: renewAfter.addingTimeInterval(1)))
    #expect(state.isRenewalDue(asOf: renewAfter.addingTimeInterval(-1)) == false)
}

@Test("a record with no renewAfter never reports renewal due (fail-safe)", .keychainSerialized)
func renewalStateWithoutRenewAfterNeverDue() async throws {
    // Arrange — an older server that omitted the advisory field.
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    KeychainProbe.write(
        service: keys.service, account: keys.enrollmentAccount,
        data: storedEnrollmentJSON(deviceId: "dev-legacy", deviceName: "iPad")
    )
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)

    // Act
    let state = try #require(try store.renewalState())

    // Assert — the TLS stack stays the real gate; the scheduler must not guess.
    #expect(state.notAfter == nil)
    #expect(state.renewAfter == nil)
    #expect(state.isRenewalDue(asOf: Date.distantFuture) == false)
}

@Test("an undecodable enrollment record surfaces .corruptStoredBlob", .keychainSerialized)
func renewalStateCorruptRecord() async throws {
    // Arrange
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    KeychainProbe.write(
        service: keys.service, account: keys.enrollmentAccount,
        data: Data("{\"deviceId\":".utf8) // truncated JSON
    )
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)

    // Act / Assert — never a silent "not enrolled" (that would make the
    // scheduler skip rotation forever on a device that IS enrolled).
    #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try store.renewalState()
    }
}

@Test("enroll signs the CSR with the injected key and posts it to /device/enroll", .keychainSerialized)
func enrollPostsCSRSignedByTheDeviceKey() async throws {
    // Arrange
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let deviceKey = try SecureEnclaveKeyFactory.generateSoftware()
    let transport = RecordingEnrollmentTransport(status: 201, body: enrollmentResponseJSON())
    let client = DeviceEnrollmentClient(
        baseURL: controlPlaneURL, bearerToken: "enroll-bearer", transport: transport
    )

    // Act — the response's leaf is undecodable, so persistence fails; the CSR has
    // already been built and sent, which is what this test is about.
    await #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try await store.enroll(
            using: client, subdomain: "yaojia", deviceName: "Yaojia iPhone",
            keyProvider: { deviceKey }
        )
    }

    // Assert — one request, to the enroll endpoint, carrying the A4 body.
    #expect(transport.callCount == 1)
    let request = try #require(transport.requests.first)
    #expect(request.url?.absoluteString == "https://cp.terminal.yaojia.wang/device/enroll")
    let body = try #require(transport.jsonBody(at: 0))
    #expect(body["subdomain"] as? String == "yaojia")
    #expect(body["deviceName"] as? String == "Yaojia iPhone")
    #expect(body["keyAlg"] as? String == "ec-p256")

    // …and the CSR is bound to the injected key, with the device name as CN.
    let csrDER = try #require(transport.csrDER(at: 0))
    let csr = try #require(parseCSR(csrDER))
    #expect(csr.subjectCommonName == "Yaojia iPhone")
    #expect(csr.publicPointX963 == (try deviceKey.publicKeyX963()))
}

@Test("an undecodable leaf leaves NO enrollment record behind", .keychainSerialized)
func enrollDoesNotPersistOnUndecodableLeaf() async throws {
    // Arrange
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let transport = RecordingEnrollmentTransport(status: 201, body: enrollmentResponseJSON())
    let client = DeviceEnrollmentClient(
        baseURL: controlPlaneURL, bearerToken: "enroll-bearer", transport: transport
    )

    // Act
    await #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try await store.enroll(
            using: client, subdomain: "yaojia", deviceName: "iPhone",
            keyProvider: { try SecureEnclaveKeyFactory.generateSoftware() }
        )
    }

    // Assert — a half-written record would make `renewalState` claim an
    // enrollment that has no leaf, and the scheduler would renew a phantom.
    #expect(KeychainProbe.count(service: keys.service, account: keys.enrollmentAccount) == 0)
    #expect(try store.renewalState() == nil)
}

@Test("a rejected enrollment (403) propagates the server error and stores nothing", .keychainSerialized)
func enrollPropagatesServerRejection() async throws {
    // Arrange — subdomain not owned by the account.
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let body = try JSONSerialization.data(withJSONObject: ["error": "subdomain_not_owned"])
    let transport = RecordingEnrollmentTransport(status: 403, body: body)
    let client = DeviceEnrollmentClient(
        baseURL: controlPlaneURL, bearerToken: "enroll-bearer", transport: transport
    )

    // Act / Assert
    await #expect(
        throws: DeviceEnrollmentError.http(status: 403, code: "subdomain_not_owned")
    ) {
        _ = try await store.enroll(
            using: client, subdomain: "someone-else", deviceName: "iPhone",
            keyProvider: { try SecureEnclaveKeyFactory.generateSoftware() }
        )
    }
    #expect(KeychainProbe.count(service: keys.service, account: keys.enrollmentAccount) == 0)
}

@Test("renew without an enrollment record fails locally and never calls the server", .keychainSerialized)
func renewWithoutRecordDoesNotCallServer() async throws {
    // Arrange
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let transport = RecordingEnrollmentTransport(status: 201, body: enrollmentResponseJSON())
    let client = DeviceEnrollmentClient(baseURL: controlPlaneURL, transport: transport)

    // Act / Assert — nothing to renew: a fresh install or a legacy .p12-only
    // device. The scheduler must not fire a request it cannot authenticate.
    await #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try await store.renew(using: client)
    }
    #expect(transport.callCount == 0)
}

@Test("renew without the device key fails locally and never calls the server", .keychainSerialized)
func renewWithoutDeviceKeyDoesNotCallServer() async throws {
    // Arrange — a record exists but the Secure-Enclave key is gone (restored
    // backup / manually cleared keychain).
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    KeychainProbe.write(
        service: keys.service, account: keys.enrollmentAccount,
        data: storedEnrollmentJSON(deviceId: "dev-99", deviceName: "iPhone")
    )
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let transport = RecordingEnrollmentTransport(status: 201, body: enrollmentResponseJSON())
    let client = DeviceEnrollmentClient(baseURL: controlPlaneURL, transport: transport)

    // Act / Assert — a renew CSR signed by a NEW key would be rejected by the
    // server (PoP against the enrolled key), so it must not be attempted.
    await #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try await store.renew(using: client)
    }
    #expect(transport.callCount == 0)
}

@Test("renew re-signs with the SAME device key and posts a csr-only body to /device/:id/renew", .keychainSerialized)
func renewReusesTheEnrolledDeviceKey() async throws {
    // Arrange — an enrolled device: record + the permanent key under the store's
    // derived tag (the shape `enroll` leaves behind).
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let enrolledKey = try SecureEnclaveKeyFactory.generateSoftware(
        tag: keys.deviceKeyTag, permanent: true
    )
    let originalRecord = storedEnrollmentJSON(
        deviceId: "dev-77", deviceName: "Yaojia iPad",
        notAfter: Date(timeIntervalSinceReferenceDate: 800_000_000),
        renewAfter: Date(timeIntervalSinceReferenceDate: 790_000_000)
    )
    KeychainProbe.write(
        service: keys.service, account: keys.enrollmentAccount, data: originalRecord
    )
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let transport = RecordingEnrollmentTransport(status: 201, body: enrollmentResponseJSON())
    // Nil bearer: the renew endpoint authenticates by the CURRENT client cert.
    let client = DeviceEnrollmentClient(baseURL: controlPlaneURL, transport: transport)

    // Act
    await #expect(throws: ClientIdentityStoreError.corruptStoredBlob) {
        _ = try await store.renew(using: client)
    }

    // Assert — the endpoint carries the stored deviceId…
    #expect(transport.callCount == 1)
    let request = try #require(transport.requests.first)
    #expect(request.url?.absoluteString == "https://cp.terminal.yaojia.wang/device/dev-77/renew")
    #expect(request.value(forHTTPHeaderField: "Authorization") == nil)

    // …the body is `{ csr }` ONLY (a stray field 400s every silent renewal)…
    let body = try #require(transport.jsonBody(at: 0))
    #expect(Set(body.keys) == ["csr"])

    // …and the CSR re-uses the ENROLLED key (a new key would fail the server's
    // PoP-against-the-enrolled-key check) with the stored device name as CN.
    let csrDER = try #require(transport.csrDER(at: 0))
    let csr = try #require(parseCSR(csrDER))
    #expect(csr.publicPointX963 == (try enrolledKey.publicKeyX963()))
    #expect(csr.subjectCommonName == "Yaojia iPad")

    // …and a failed rotation leaves the EXISTING enrollment intact.
    let state = try #require(try store.renewalState())
    #expect(state.deviceId == "dev-77")
    #expect(state.renewAfter == Date(timeIntervalSinceReferenceDate: 790_000_000))
}

@Test("the flow's production install step is wired to the keychain store's SE enroll", .keychainSerialized)
func enrollmentFlowWiresTheKeychainStore() async throws {
    // Arrange — the `store:` convenience initializer is the composition the app
    // uses: login → bearer → enroll → install. Its install step deliberately
    // takes NO keyProvider, i.e. it always asks for a real Secure-Enclave key.
    let keys = StoreKeychainKeys.unique()
    defer { KeychainProbe.purge(keys) }
    let store = KeychainClientIdentityStore(service: keys.service, account: keys.account)
    let loginBody = try JSONSerialization.data(withJSONObject: [
        "enrollToken": "enroll-bearer", "accountId": "acct-1", "expiresIn": 300,
    ])
    let transport = RecordingEnrollmentTransport(replies: [
        .init(status: 201, body: loginBody),
        .init(status: 201, body: enrollmentResponseJSON()),
    ])
    let flow = DeviceEnrollmentFlow(
        baseURL: controlPlaneURL, transport: transport, store: store
    )

    // Act
    var thrown: Error?
    do {
        _ = try await flow.run(
            password: "account-password", subdomain: "yaojia", deviceName: "iPhone"
        )
    } catch {
        thrown = error
    }

    // Assert — login happened first, with the password and nothing else…
    let loginRequest = try #require(transport.requests.first)
    #expect(loginRequest.url?.path == "/auth/login")
    #expect(Set(try #require(transport.jsonBody(at: 0)).keys) == ["password"])

    // …and the failure came from the INSTALL step, not the login step: the
    // convenience initializer really does route into the keychain store. Off
    // device (macOS `swift test`, Simulator) `generateSecureEnclave` cannot mint
    // a key, so `.secureEnclaveUnavailable` is the expected stop; an entitled
    // host gets as far as the undecodable leaf (`.corruptStoredBlob`).
    let error = try #require(thrown)
    #expect(error is SecureEnclaveKeyError || error is ClientIdentityStoreError)
    #expect(error is ControlPlaneLoginError == false)
    #expect(KeychainProbe.count(service: keys.service, account: keys.enrollmentAccount) == 0)
}