import Foundation
#if canImport(FoundationNetworking)
import FoundationNetworking
#endif
import ForgeCamera
import ForgeGrade
import ForgeColor

/// Sony CNA endpoint paths — single source of truth. Correct against Sony
/// protocol docs in hardware phase; sim mirrors these.
enum SonyPaths {
    static let cameraInfo = "/cna/v1/camera/info"
    static let status = "/cna/v1/camera/status"
    static let userLut = "/cna/v1/monitoring/lut"
}

/// Venice 2 driver: REST over IP. Capability-narrow — user 3D LUT push only,
/// no native CDL (grade pipeline must full-bake for this camera).
public actor SonyDriver: CameraDriver {
    public nonisolated let capabilities = CameraCapabilities(
        vendor: .sony,
        supportsNativeCDL: false,
        lut3dSizes: [17, 33],
        metadataFields: [.clipName, .exposureIndex, .whiteBalance, .tint, .fps, .timecode])

    private let host: String
    private let port: Int
    private let pollInterval: Duration
    private let session: URLSession

    private var pollTask: Task<Void, Never>?
    private var lastState = CameraState(connection: .disconnected)
    // Async registration OK here — poll loop re-emits on change (see ArriDriver note).
    private var stateContinuations: [UUID: AsyncStream<CameraState>.Continuation] = [:]

    public init(host: String, port: Int, pollInterval: Duration = .milliseconds(150)) {
        self.host = host
        self.port = port
        self.pollInterval = pollInterval
        let config = URLSessionConfiguration.ephemeral
        config.timeoutIntervalForRequest = 3
        session = URLSession(configuration: config)
    }

    public nonisolated var state: AsyncStream<CameraState> {
        AsyncStream { continuation in
            let id = UUID()
            Task { await self.register(id: id, continuation: continuation) }
            continuation.onTermination = { _ in
                Task { await self.unregister(id: id) }
            }
        }
    }

    private func register(id: UUID, continuation: AsyncStream<CameraState>.Continuation) {
        stateContinuations[id] = continuation
    }

    private func unregister(id: UUID) {
        stateContinuations.removeValue(forKey: id)
    }

    private func emit(_ s: CameraState) {
        lastState = s
        for c in stateContinuations.values {
            c.yield(s)
        }
    }

    // MARK: HTTP (completion-handler path — async URLSession hangs on Linux)

    private func url(_ path: String) -> URL {
        URL(string: "http://\(host):\(port)\(path)")!
    }

    private func perform(_ req: URLRequest) async throws -> (Data, HTTPURLResponse) {
        try await withCheckedThrowingContinuation { cont in
            let task = session.dataTask(with: req) { data, resp, err in
                if let err {
                    cont.resume(throwing: err)
                    return
                }
                guard let http = resp as? HTTPURLResponse else {
                    cont.resume(throwing: CameraError.connectionFailed("no HTTP response"))
                    return
                }
                cont.resume(returning: (data ?? Data(), http))
            }
            task.resume()
        }
    }

    private func getJSON(_ path: String) async throws -> [String: Any] {
        let (data, http) = try await perform(URLRequest(url: url(path)))
        guard http.statusCode == 200,
              let obj = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
            throw CameraError.connectionFailed("GET \(path) failed")
        }
        return obj
    }

    // MARK: CameraDriver

    public func connect() async throws {
        do {
            _ = try await getJSON(SonyPaths.cameraInfo)
        } catch {
            throw CameraError.connectionFailed("camera info unreachable: \(error)")
        }
        emit(CameraState(connection: .connected))
        startPolling()
    }

    public func disconnect() async {
        pollTask?.cancel()
        pollTask = nil
        emit(CameraState(connection: .disconnected))
    }

    public func push(look: FlattenedLook) async throws {
        guard look.cdl == nil else {
            throw CameraError.unsupportedLook("Venice has no native CDL — re-flatten with splitLeadingCDL=false")
        }
        guard let lut = look.lut else {
            throw CameraError.unsupportedLook("nothing to push")
        }
        guard capabilities.lut3dSizes.contains(lut.size) else {
            throw CameraError.unsupportedLook("LUT size \(lut.size) not in \(capabilities.lut3dSizes)")
        }
        let payload = try JSONSerialization.data(
            withJSONObject: ["size": lut.size, "table": lut.table],
            options: [.sortedKeys])
        var req = URLRequest(url: url(SonyPaths.userLut))
        req.httpMethod = "PUT"
        req.httpBody = payload
        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
        let (_, http) = try await perform(req)
        guard http.statusCode == 200 else {
            throw CameraError.pushFailed("LUT upload -> \(http.statusCode)")
        }
    }

    // MARK: Polling

    private func startPolling() {
        pollTask?.cancel()
        pollTask = Task {
            while !Task.isCancelled {
                await pollOnce()
                try? await Task.sleep(for: pollInterval)
            }
        }
    }

    private func pollOnce() async {
        do {
            let s = try await getJSON(SonyPaths.status)
            let newState = CameraState(
                connection: .connected,
                isRecording: s["recording"] as? Bool ?? false,
                clipName: s["clipName"] as? String,
                metadata: CameraMetadata(
                    exposureIndex: s["exposureIndex"] as? Int,
                    whiteBalance: s["whiteBalance"] as? Int,
                    tint: s["tint"] as? Int,
                    fps: s["fps"] as? Double,
                    timecode: s["timecode"] as? String))
            if newState != lastState {
                emit(newState)
            }
        } catch {
            if lastState.connection == .connected {
                emit(CameraState(connection: .disconnected))
            }
        }
    }
}