import Foundation
import CoreBluetooth

let SERVICE_UUID: CBUUID        = CBUUID(string: "76a3a3fa-b8d3-451a-9c78-bf5d7434d3cc")
let CHARACTERISTIC_UUID: CBUUID = CBUUID(string: "bffe9d64-0ee6-472b-849c-ab98182bd592")

final class ContentViewModel: NSObject, ObservableObject {
    @Published var isStateActive = false
    
    private var peripheralManager: CBPeripheralManager?
    
    override init() {
        super.init()
        
        if CBManager.authorization != .allowedAlways {
            print("Bluetooth Permission missing")
            return
        }
        
        peripheralManager = CBPeripheralManager(delegate: self, queue: nil)
    }
    
    private func setupServices() {
        let service = CBMutableService(type: SERVICE_UUID, primary: true)
        let characteristic = CBMutableCharacteristic(type: CHARACTERISTIC_UUID, properties: .write, value: nil, permissions: .writeable)
        
        service.characteristics = [characteristic]
        peripheralManager?.add(service)
        
        let data = [CBAdvertisementDataLocalNameKey: "Sample Service", CBAdvertisementDataServiceUUIDsKey: [SERVICE_UUID]] as [String : Any]
        peripheralManager?.startAdvertising(data)
    }
}

extension ContentViewModel: CBPeripheralManagerDelegate {
    func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) {
        switch peripheral.state {
        case .poweredOn:
            isStateActive = true
            setupServices()
            
        default:
            isStateActive = false
        }
    }
    
    func peripheralManager(_ peripheral: CBPeripheralManager, didReceiveWrite requests: [CBATTRequest]) {
        for request in requests {
            guard let value = request.value else { continue }
            let stringValue = String(decoding: value, as: UTF8.self)
            
            print("Write request: \(stringValue)")
        }
    }
}