// Keeps the menu bar in sync with reality without ever polling. Registers
// NSWorkspace notifications for launch/terminate/activate/hide/unhide,
// filtered to Claude's own binary, and reconciles an in-memory
// [ProfileInfo] the instant one fires (sub-second, push-based) — this is
// what makes external changes (Force Quit, Spotlight, Dock, a hand quit)
// show up immediately instead of needing a menu click or an app restart.
import AppKit
import Foundation

struct ProfileInfo {
    let profile: ResolvedProfile
    let running: Bool
    let pid: pid_t?
}

protocol LiveStateDelegate: AnyObject {
    func liveStateDidChange(_ infos: [ProfileInfo])
    func liveStateFoundCollisions(_ collisions: [ProfileStore.DirCollision])
}

final class LiveState {
    weak var delegate: LiveStateDelegate?

    // Best-effort "last switched to" pointer for the ⇆ marker in the menu —
    // reflects profiles opened/switched through this app; there's no
    // ordered history to fall back through if that one gets hand-quit
    // (matches the "don't overdo it" brief — reality-vs-stopped state is
    // still always ground-truth, this only affects the ⇆ hint).
    private(set) var lastActiveName = "default"

    private var observers: [NSObjectProtocol] = []

    init() {
        let center = NSWorkspace.shared.notificationCenter
        let names: [Notification.Name] = [
            NSWorkspace.didLaunchApplicationNotification,
            NSWorkspace.didTerminateApplicationNotification,
            NSWorkspace.didActivateApplicationNotification,
            NSWorkspace.didHideApplicationNotification,
            NSWorkspace.didUnhideApplicationNotification,
        ]
        observers = names.map { name in
            center.addObserver(forName: name, object: nil, queue: .main) { [weak self] note in
                self?.handle(note)
            }
        }
        // Deliberately not calling reconcile() here — `delegate` is set by
        // the caller right after init, and the caller does the first
        // reconcile itself once it's ready to receive the callback.
    }

    deinit {
        let center = NSWorkspace.shared.notificationCenter
        observers.forEach { center.removeObserver($0) }
    }

    private func handle(_ note: Notification) {
        guard let app = note.userInfo?[NSWorkspace.applicationUserInfoKey] as? NSRunningApplication,
              app.executableURL?.path == ClaudeControl.binaryPath
        else { return }
        reconcile()
    }

    func markActive(_ name: String) {
        lastActiveName = name
    }

    // Public so callers (menu open, right after a command completes) can
    // force an immediate reconcile as a correctness backstop, without that
    // being the primary update mechanism.
    func reconcile() {
        let profiles = ProfileStore.loadAll()
        let collisions = ProfileStore.findCollisions(among: profiles)
        guard collisions.isEmpty else {
            delegate?.liveStateFoundCollisions(collisions)
            return
        }

        let running = ClaudeControl.runningInstances()
        let infos = profiles.map { profile -> ProfileInfo in
            let dir = profile.name == "default" ? nil : profile.appDir
            let match = running.first { $0.userDataDir == dir }
            return ProfileInfo(profile: profile, running: match != nil, pid: match?.pid)
        }
        delegate?.liveStateDidChange(infos)
    }
}