import Foundation
import NIOCore


struct DeviceResponse {

    static var deviceTimedOut: DeviceResponse {
        .init(event: .deviceTimedOut)
    }

    static var deviceNotConnected: DeviceResponse {
        .init(event: .deviceNotConnected)
    }

    static var unexpectedSocketEvent: DeviceResponse {
        .init(event: .unexpectedSocketEvent)
    }

    static var invalidMessageData: DeviceResponse {
        .init(event: .invalidMessageData)
    }

    static var noBodyData: DeviceResponse {
        .init(event: .noBodyData)
    }

    static var operationInProgress: DeviceResponse {
        .init(event: .operationInProgress)
    }

    /// The response to a key from the server
    let event: MessageResult

    /// The index of the next key to use
    let response: Message?

    init?(_ buffer: ByteBuffer) {
        guard let byte = buffer.getBytes(at: 0, length: 1) else {
            print("No bytes received from device")
            return nil
        }
        guard let event = MessageResult(rawValue: byte[0]) else {
            print("Unknown response \(byte[0]) received from device")
            return nil
        }
        self.event = event
        guard let data = buffer.getSlice(at: 1, length: Message.length) else {
            self.response = nil
            return
        }
        self.response = Message(decodeFrom: data)
    }

    init(event: MessageResult) {
        self.event = event
        self.response = nil
    }

    var encoded: Data {
        guard let message = response else {
            return Data([event.rawValue])
        }
        return Data([event.rawValue]) + message.encoded
    }
}