tether/ios/MacTetherApp/Sources/MacTetherStore.swift

import AppKit
import Foundation
import enum TetherKit.RoomIdentity   // selective: avoids TetherKit.Message clashing
                                     // with the engine's Message (compiled into this target)
// Engine + Message + MessageHandler come from the generated tethercore.swift.

/// UI-facing clipboard item. Decouples the view from the FFI `Message` record.
struct FeedItem: Identifiable, Equatable {
    let id = UUID()
    let text: String
    let source: String
    let date: Date
}

/// macOS side: drives the shared `tethercore.Engine` (SSE + RTC). Unlike iOS we
/// CAN poll NSPasteboard in the background, so clipboard changes auto-send.
@MainActor @Observable
final class MacTetherStore {
    var serverURL: String = UserDefaults.standard.string(forKey: "serverURL") ?? "http://tether.lan:8765"
    var room: String = RoomIdentity.derive()
    var feed: [FeedItem] = []
    var connected = false
    var lastError: String?
    var hasAttemptedConnect = false

    private let deviceID = Host.current().localizedName ?? UUID().uuidString
    private var engine: Engine?
    private var bridge: EngineBridge?
    private var pollTask: Task<Void, Never>?
    private var lastChangeCount = NSPasteboard.general.changeCount

    func connectIfSaved() {
        guard UserDefaults.standard.string(forKey: "serverURL") != nil else { return }
        connect()
    }

    func connect() {
        let url = serverURL.trimmingCharacters(in: .whitespaces)
        guard !url.isEmpty else {
            hasAttemptedConnect = true
            lastError = "Invalid server URL."
            return
        }
        hasAttemptedConnect = true
        UserDefaults.standard.set(serverURL, forKey: "serverURL")
        disconnect()

        let b = EngineBridge(store: self)
        let e = Engine(server: url, room: room, from: deviceID, source: "macos")
        e.start(handler: b)
        engine = e
        bridge = b
        connected = true
        lastError = nil

        // Send: poll NSPasteboard for local changes → push to room.
        lastChangeCount = NSPasteboard.general.changeCount
        pollTask = Task { [weak self] in
            while !Task.isCancelled {
                try? await Task.sleep(for: .milliseconds(500))
                guard let self else { return }
                let count = NSPasteboard.general.changeCount
                guard count != self.lastChangeCount else { continue }
                self.lastChangeCount = count
                if let text = NSPasteboard.general.string(forType: .string), !text.isEmpty {
                    self.engine?.send(text: text)
                }
            }
        }
    }

    func disconnect() {
        engine?.stop()
        engine = nil
        bridge = nil
        pollTask?.cancel()
        pollTask = nil
        connected = false
    }

    func send(_ text: String) {
        engine?.send(text: text)
    }

    func copyToPasteboard(_ item: FeedItem) {
        writePasteboard(item.text)
    }

    private func writePasteboard(_ text: String) {
        NSPasteboard.general.clearContents()
        NSPasteboard.general.setString(text, forType: .string)
        lastChangeCount = NSPasteboard.general.changeCount // don't echo our own write back
    }

    // Called from the engine bridge, already on the main actor.
    fileprivate func ingest(_ item: FeedItem) {
        feed.insert(item, at: 0)
        if feed.count > 100 { feed.removeLast() }
        writePasteboard(item.text) // mirror received clipboard onto this Mac
    }

    fileprivate func setConnected(_ value: Bool) {
        connected = value
    }
}

/// Adapts the engine's callback interface (fired on the Rust runtime thread)
/// onto the main actor for SwiftUI.
private final class EngineBridge: MessageHandler {
    weak var store: MacTetherStore?
    init(store: MacTetherStore) { self.store = store }

    func onMessage(msg: Message) {
        // RTC-delivered messages carry ts=0 (no server stamp) — use now.
        let date = msg.ts > 0 ? Date(timeIntervalSince1970: Double(msg.ts) / 1000.0) : Date()
        let item = FeedItem(text: msg.text, source: msg.source.isEmpty ? "unknown" : msg.source, date: date)
        Task { @MainActor in self.store?.ingest(item) }
    }

    func onStatus(connected: Bool) {
        Task { @MainActor in self.store?.setConnected(connected) }
    }
}