import XCTest
@testable import Voice

private final class FeatureParityURLProtocol: URLProtocol {
    static var handler: ((URLRequest) throws -> (Int, Data))?
    override class func canInit(with request: URLRequest) -> Bool { true }
    override class func canonicalRequest(for request: URLRequest) -> URLRequest { request }
    override func startLoading() {
        do {
            let (status, data) = try Self.handler!(request)
            client?.urlProtocol(self, didReceive: HTTPURLResponse(url: request.url!, statusCode: status, httpVersion: nil, headerFields: nil)!, cacheStoragePolicy: .notAllowed)
            client?.urlProtocol(self, didLoad: data)
            client?.urlProtocolDidFinishLoading(self)
        } catch { client?.urlProtocol(self, didFailWithError: error) }
    }
    override func stopLoading() {}
}

private final class SuspendedFeatureTransport: ChatTransport {
    var handler: (@MainActor (String) async throws -> Data)?
    func request(_ path: String, method: String, body: [String: Any]?, query: [URLQueryItem]) async throws -> Data { try await handler!(path) }
    func events(run: String, after: Int, receive: @escaping @MainActor (ChatEvent) throws -> Void) async throws {}
    func cancel() {}
}

@MainActor
final class ChatFeatureParityTests: XCTestCase {
    private func makeStore() throws -> (ChatFeatureStore, ChatAPI) {
        guard case .success(let config) = ServerConfig.parse("https://hope.example") else { throw ChatFailure.invalidResponse }
        let configuration = URLSessionConfiguration.ephemeral
        configuration.protocolClasses = [FeatureParityURLProtocol.self]
        let api = ChatAPI(config: config, token: "offline-fixture", session: URLSession(configuration: configuration))
        return (ChatFeatureStore(api: api), api)
    }
    private func attachment(status: String = "ready", mime: String = "text/plain") -> ChatAttachment {
        ChatAttachment(id: String(repeating: "a", count: 32), filename: "notes.txt", mime: mime, size: 5, extractionStatus: status, createdAt: 1)
    }
    private func envelope(_ item: ChatAttachment) throws -> Data {
        try JSONSerialization.data(withJSONObject: ["attachment": ["id": item.id, "filename": item.filename, "mime": item.mime, "size": item.size, "extraction_status": item.extractionStatus, "created_at": item.createdAt]])
    }
    func testMetadataRevalidationRejectsUnavailableAndDeletedFiles() async throws {
        let (store, api) = try makeStore(); defer { api.cancel(); FeatureParityURLProtocol.handler = nil }
        let old = attachment()
        let unavailable = try envelope(attachment(status: "unavailable"))
        var metadataStatus = 200
        FeatureParityURLProtocol.handler = { request in
            if request.url?.path == "/api/capabilities" { return (200, Data("{\"features\":{\"attachments\":true}}".utf8)) }
            XCTAssertEqual(request.url?.path, "/api/attachments/\(old.id)")
            return (metadataStatus, unavailable)
        }
        let blocked = await store.validatedAttachment(old)
        XCTAssertNil(blocked)
        XCTAssertTrue(store.error?.contains("unavailable") == true)
        metadataStatus = 404
        let deleted = await store.validatedAttachment(old)
        XCTAssertNil(deleted)
        XCTAssertTrue(store.error?.contains("no longer available") == true)
    }
    func testCapabilityRefreshFailsClosedAndImagesCannotUpload() async throws {
        let (store, api) = try makeStore(); defer { api.cancel(); FeatureParityURLProtocol.handler = nil }
        store.enabled = ["attachments", "image_input"]
        FeatureParityURLProtocol.handler = { _ in (503, Data()) }
        let refreshed = await store.refreshCapabilities()
        XCTAssertFalse(refreshed)
        XCTAssertTrue(store.enabled.isEmpty)
        FeatureParityURLProtocol.handler = { request in
            XCTAssertEqual(request.url?.path, "/api/capabilities", "Unqualified images must never reach upload")
            return (200, Data("{\"features\":{\"attachments\":true,\"image_input\":false}}".utf8))
        }
        let uploaded = await store.upload(Data([1, 2, 3]), filename: "photo.jpg", mime: "image/jpeg")
        XCTAssertNil(uploaded)
        XCTAssertTrue(store.error?.contains("Image input") == true)
    }
    func testLateCapabilityResponseCannotRestoreOldImageQualification() async throws {
        let api = SuspendedFeatureTransport()
        let store = ChatFeatureStore(api: api)
        let firstStarted = expectation(description: "First capability request suspended")
        var firstResponse: CheckedContinuation<Data, Error>?
        var requests = 0
        api.handler = { _ in
            requests += 1
            if requests == 1 {
                return try await withCheckedThrowingContinuation { continuation in
                    firstResponse = continuation
                    firstStarted.fulfill()
                }
            }
            return Data("{\"features\":{\"attachments\":true,\"image_input\":false}}".utf8)
        }
        let first = Task { await store.refreshCapabilities() }
        await fulfillment(of: [firstStarted], timeout: 2)
        let latest = await store.refreshCapabilities()
        XCTAssertTrue(latest)
        firstResponse?.resume(returning: Data("{\"features\":{\"attachments\":true,\"image_input\":true}}".utf8))
        let stale = await first.value
        XCTAssertFalse(stale)
        XCTAssertFalse(store.enabled.contains("image_input"))
    }
    func testBlockedStatusesIncludeUnknownAndImageQualification() {
        for status in ["failed", "encrypted", "unavailable", "pending"] {
            XCTAssertNotNil(ChatFeatureStore.blockedReason(attachment(status: status), imageInput: true))
        }
        XCTAssertNil(ChatFeatureStore.blockedReason(attachment(status: "truncated"), imageInput: false))
        XCTAssertNotNil(ChatFeatureStore.blockedReason(attachment(status: "image", mime: "image/png"), imageInput: false))
    }
    func testPausedTaskAndOptionalRepeatUseContractFields() async throws {
        let (store, api) = try makeStore(); defer { api.cancel(); FeatureParityURLProtocol.handler = nil }
        FeatureParityURLProtocol.handler = { request in
            XCTAssertEqual(request.url?.path, "/api/tasks")
            XCTAssertEqual(request.httpMethod, "POST")
            var bytes = request.httpBody ?? Data()
            if bytes.isEmpty, let stream = request.httpBodyStream {
                stream.open(); defer { stream.close() }
                var buffer = [UInt8](repeating: 0, count: 1024)
                while stream.hasBytesAvailable { let count = stream.read(&buffer, maxLength: buffer.count); if count <= 0 { break }; bytes.append(contentsOf: buffer.prefix(count)) }
            }
            let body = try XCTUnwrap(JSONSerialization.jsonObject(with: bytes) as? [String: Any])
            XCTAssertEqual(body["paused"] as? Bool, true)
            XCTAssertEqual(body["repeat"] as? Int, 3)
            XCTAssertEqual(body["schedule"] as? String, "0 9 * * *")
            return (201, Data("{\"task\":{\"id\":\"aaaaaaaaaaaa\",\"enabled\":false,\"repeat\":3}}".utf8))
        }
        await store.saveTask(nil, name: "Daily", schedule: "0 9 * * *", prompt: "Review", repeatCount: 3, paused: true)
        XCTAssertNil(store.error)
        XCTAssertEqual(store.tasks.first?.enabled, false)
        XCTAssertEqual(store.tasks.first?.repeat, 3)
    }
    func testMemoryConflictRequiresExplicitLatestRevisionAndKeepsDraft() async throws {
        let api = OfflineChatAPI()
        let store = ChatFeatureStore(api: api)
        await store.load()
        let original = try XCTUnwrap(store.memory.first)
        let first = await store.saveMemory(original, content: "Server update")
        XCTAssertTrue(first)
        let localDraft = "Keep my draft"
        let stale = await store.saveMemory(original, content: localDraft)
        XCTAssertFalse(stale)
        XCTAssertTrue(store.error?.contains("Compare") == true)
        let fetched = await store.latestMemory(original)
        let latest = try XCTUnwrap(fetched)
        XCTAssertEqual(latest.content, "Server update")
        XCTAssertEqual(localDraft, "Keep my draft")
        let accepted = await store.saveMemory(latest, content: localDraft)
        XCTAssertTrue(accepted)
        XCTAssertEqual(store.memory.first?.content, localDraft)
    }
    func testClosedStoreCannotReloadOrPreviewAccountData() async throws {
        let (store, api) = try makeStore(); defer { api.cancel(); FeatureParityURLProtocol.handler = nil }
        FeatureParityURLProtocol.handler = { _ in XCTFail("Closed account must not request private data"); return (200, Data()) }
        store.close()
        await store.load()
        await store.preview(attachment())
        XCTAssertTrue(store.enabled.isEmpty)
        XCTAssertNil(store.previewAttachment)
    }
}