//
//  AirDropState.swift
//  MioIsland AirDrop Plugin
//
//  Shared state + send coordinator. Single source of truth for what
//  the panel should render. Not strictly "ObservableObject" heavy —
//  we have only three phases, but using @Published keeps the door
//  open for future "sending progress" UI.
//

import AppKit
import Combine
import Foundation

@MainActor
final class AirDropState: ObservableObject {
    static let shared = AirDropState()

    enum Phase: Equatable {
        case idle
        case showingPicker
        case sent(count: Int)
        case error(message: String)
    }

    @Published var phase: Phase = .idle

    /// Last completed send — used to animate a brief "✓ 已发送" toast.
    @Published private(set) var lastSendAt: Date?

    /// Called by UI when user drops files or picks from NSOpenPanel.
    /// Kicks off NSSharingService (opens the AirDrop chooser window)
    /// and resets phase when the user dismisses the chooser.
    func send(files: [URL]) {
        let urls = files.filter { $0.isFileURL }
        guard !urls.isEmpty else { return }

        phase = .showingPicker

        AirDropService.perform(files: urls) { [weak self] result in
            guard let self else { return }
            Task { @MainActor in
                switch result {
                case .success:
                    self.phase = .sent(count: urls.count)
                    self.lastSendAt = Date()
                    // Drop back to idle after 2.5s so the drop zone is
                    // usable for the next file without a click.
                    DispatchQueue.main.asyncAfter(deadline: .now() + 2.5) { [weak self] in
                        guard let self else { return }
                        if case .sent = self.phase {
                            self.phase = .idle
                        }
                    }
                case .failure(let err):
                    self.phase = .error(message: err.localizedDescription)
                    DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in
                        guard let self else { return }
                        if case .error = self.phase {
                            self.phase = .idle
                        }
                    }
                }
            }
        }
    }

    /// Open NSOpenPanel to let the user pick files manually, then send.
    func chooseAndSend() {
        let panel = NSOpenPanel()
        panel.allowsMultipleSelection = true
        panel.canChooseDirectories = true
        panel.canChooseFiles = true
        panel.message = L10n.chooseFilesTitle
        panel.prompt = L10n.choose

        // Run modal on the main thread so it doesn't race the drop zone.
        panel.begin { [weak self] response in
            guard response == .OK else { return }
            self?.send(files: panel.urls)
        }
    }
}