import AppKit

@MainActor
public final class GlobalShortcuts {
    public enum Destination: Hashable, Sendable {
        case launcher
        case command(Application.Command)

        public var title: String {
            switch self {
            case .launcher: "Applications"
            case .command(let command): Application.commands.first { $0.command == command }!.name
            }
        }

        var storageKey: String {
            switch self {
            case .launcher: "globalActivationShortcut"
            case .command(let command): "globalCommandShortcut.\(command.rawValue)"
            }
        }
    }

    public private(set) static var destinations: [Destination] =
        [.launcher] + Application.Command.allCases.map { .command($0) }

    public let bindings: [GlobalShortcut]
    private let defaults: UserDefaults
    private var isSuspended = false
    public var isRecording: Bool { isSuspended }

    init(defaults: UserDefaults, bindings: [GlobalShortcut]) {
        precondition(bindings.count == Self.destinations.count)
        self.defaults = defaults
        self.bindings = bindings
    }

    public init(
        defaults: UserDefaults = .standard,
        action: @escaping @MainActor (Destination) -> Void
    ) {
        self.defaults = defaults
        bindings = Self.destinations.map { destination in
            GlobalShortcut(defaults: defaults, storageKey: destination.storageKey) {
                action(destination)
            }
        }
    }

    public func start() -> [String] {
        isSuspended = false
        var errors: [String] = []
        for (index, binding) in bindings.enumerated() {
            do {
                if let saved = defaults.object(forKey: Self.destinations[index].storageKey) {
                    guard let candidate = KeyboardShortcut(storedValue: saved) else {
                        throw ShortcutError.invalidSavedShortcut
                    }
                    try validate(candidate, at: index)
                }
                try binding.start()
            } catch {
                binding.suspend()
                errors.append("\(Self.destinations[index].title): \(error.localizedDescription)")
            }
        }
        return errors
    }

    public func beginRecording() {
        isSuspended = true
        bindings.forEach { $0.suspend() }
    }

    public func cancelRecording() -> [String] {
        guard isRecording else { return [] }
        return start()
    }

    public func finishRecording(_ candidate: KeyboardShortcut?, at index: Int) -> [String] {
        var errors: [String] = []
        do { try setShortcut(candidate, at: index) }
        catch { errors.append(error.localizedDescription) }
        return errors + cancelRecording()
    }

    public func stop() {
        isSuspended = false
        bindings.forEach { $0.stop() }
    }

    public func setShortcut(_ candidate: KeyboardShortcut?, at index: Int) throws {
        if let candidate { try validate(candidate, at: index) }
        let binding = bindings[index]
        try binding.setShortcut(candidate)
        if isSuspended { binding.suspend() }
    }

    func validate(_ candidate: KeyboardShortcut, at index: Int) throws {
        if let action = Self.localAction(for: candidate, keyName: candidate.keyName) {
            throw ShortcutError.inAppConflict(shortcut: candidate.displayName, action: action)
        }
        for (otherIndex, destination) in Self.destinations.enumerated() where otherIndex != index {
            if KeyboardShortcut(storedValue: defaults.object(forKey: destination.storageKey)) == candidate {
                throw ShortcutError.duplicate(shortcut: candidate.displayName, destination: destination.title)
            }
        }
    }

    // Match Conjure's menu equivalents, action buttons, and launcher/emoji panel handling.
    static func localAction(for candidate: KeyboardShortcut, keyName: String) -> String? {
        let key = keyName.lowercased()
        if candidate.modifiers == .command {
            switch key {
            case ",": return "Settings"
            case "h": return "Hide Conjure"
            case "q": return "Quit Conjure"
            case "w": return "Close Window"
            case "x": return "Cut"
            case "c": return "Copy"
            case "v": return "Paste"
            case "a": return "Select All"
            case "n": return "New Note"
            case "z": return "Undo"
            case "m": return "Minimize"
            case "k": return "entry actions"
            case "return", "enter": return "Open, Copy, Translate, or confirm uninstall"
            case "1"..."9" where key.utf8.count == 1: return "numbered application launching"
            default: break
            }
        } else if candidate.modifiers == [.command, .option], key == "h" {
            return "Hide Others"
        } else if candidate.modifiers == [.command, .shift], key == "z" {
            return "Redo"
        } else if candidate.modifiers == .control {
            switch key {
            case "h", "j", "k", "l": return "launcher and emoji navigation"
            default: break
            }
        }
        return nil
    }
}