using System;

namespace RoboidControl {

    /// <summary>
    /// A sensor which can detect touches
    /// </summary>
    public class DigitalSensor : Thing {
        /// <summary>
        /// Create a digital sensor without communication abilities
        /// </summary>
        /// <param name="invokeEvent">Invoke a OnNewThing event when the thing has been created</param>
        public DigitalSensor(bool invokeEvent = true) : base(Type.Switch, invokeEvent) { }
        /// <summary>
        /// Create a digital sensor for a participant
        /// </summary>
        /// <param name="owner">The owning participant</param>
        /// <param name="thingId">The ID of the thing, leave out or set to zero to generate an ID</param>
        /// <param name="invokeEvent">Invoke a OnNewThing event when the thing has been created</param>
        public DigitalSensor(Participant owner, byte thingId = 0, bool invokeEvent = true) : base(owner, Type.Switch, thingId, invokeEvent) { }
        /// <summary>
        /// Create a new child digital sensor
        /// </summary>
        /// <param name="parent">The parent thing</param>
        /// <param name="thingId">The ID of the thing, leave out or set to zero to generate an ID</param>
        /// <param name="invokeEvent">Invoke a OnNewThing event when the thing has been created</param>
        public DigitalSensor(Thing parent, byte thingId = 0, bool invokeEvent = true) : base(parent, Type.Switch, thingId, invokeEvent) { }

        /// <summary>
        /// Value which is true when the sensor is touching something, false otherwise
        /// </summary>
        private bool _state = false;
        public bool state {
            get { return _state; }
            set {
                if (_state != value) {
                    _state = value;
                }
                stateUpdated = true;
            }
        }
        private bool stateUpdated = false;

#if UNITY_5_3_OR_NEWER
        /// @copydoc Passer::RoboidControl::Thing::CreateComponent 
        public override void CreateComponent() {
            this.component = Unity.DigitalSensor.Create(this);
            this.component.core = this;
        }
#endif
        /// <summary>
        /// Function used to generate binary data for this digital sensor
        /// </summary>
        /// <returns>A byte array with the binary data</returns>
        /// <remark>The byte array will be empty when the digital status has not changed</remark>
        public override byte[] GenerateBinary() {
            if (!stateUpdated)
                return Array.Empty<byte>();

            byte[] bytes = new byte[1];
            bytes[0] = (byte)(state ? 1 : 0);
            stateUpdated = false;
            return bytes;
        }

        /// <summary>
        /// Function used to process binary data received for this digital sensor
        /// </summary>
        /// <param name="bytes">The binary data to process</param>
        public override void ProcessBinary(byte[] bytes) {
            this.state |= (bytes[0] == 1);
        }
    }
}