import Carbon
import AppKit

final class HotkeyManager {
    static let shared = HotkeyManager()

    /// ⌘⇧S — live capture (ScreenCaptureKit at capture time).
    var onTrigger: (() -> Void)?
    /// ⌃⇧⌘S — frozen capture (snapshot at hotkey press).
    var onFrozenTrigger: (() -> Void)?
    /// ⌃⇧⌘R — screen recording (region or window); toggles stop.
    var onRecordTrigger: (() -> Void)?

    private var hotKeyRefs: [EventHotKeyRef?] = []
    private var eventHandlerRef: EventHandlerRef?
    private let signature: OSType = 0x4B505452

    private init() {}

    func register() {
        var eventType = EventTypeSpec(
            eventClass: OSType(kEventClassKeyboard),
            eventKind: UInt32(kEventHotKeyPressed)
        )
        InstallEventHandler(GetApplicationEventTarget(), { _, event, _ in
            var hotKeyID = EventHotKeyID()
            let status = GetEventParameter(
                event,
                EventParamName(kEventParamDirectObject),
                EventParamType(typeEventHotKeyID),
                nil,
                MemoryLayout<EventHotKeyID>.size,
                nil,
                &hotKeyID
            )
            guard status == noErr else { return noErr }
            DispatchQueue.main.async {
                switch hotKeyID.id {
                case 1: HotkeyManager.shared.onTrigger?()
                case 2: HotkeyManager.shared.onFrozenTrigger?()
                case 3: HotkeyManager.shared.onRecordTrigger?()
                default: break
                }
            }
            return noErr
        }, 1, &eventType, nil, &eventHandlerRef)

        registerHotkey(id: 1, keyCode: UInt32(kVK_ANSI_S), modifiers: UInt32(cmdKey | shiftKey))
        registerHotkey(id: 2, keyCode: UInt32(kVK_ANSI_S), modifiers: UInt32(cmdKey | shiftKey | controlKey))
        registerHotkey(id: 3, keyCode: UInt32(kVK_ANSI_R), modifiers: UInt32(cmdKey | shiftKey | controlKey))
    }

    private func registerHotkey(id: UInt32, keyCode: UInt32, modifiers: UInt32) {
        var ref: EventHotKeyRef?
        let hotKeyID = EventHotKeyID(signature: signature, id: id)
        RegisterEventHotKey(keyCode, modifiers, hotKeyID, GetApplicationEventTarget(), 0, &ref)
        hotKeyRefs.append(ref)
    }
}