using System;
using System.Collections.Generic;
using Unity.MLAgents.Actuators;
using Unity.MLAgents.Sensors;

namespace Unity.MLAgents.Analytics
{
    internal struct InferenceEvent
    {
        /// <summary>
        /// Hash of the BehaviorName.
        /// </summary>
        public string BehaviorName;
        public string BarracudaModelSource;
        public string BarracudaModelVersion;
        public string BarracudaModelProducer;
        public string BarracudaPackageVersion;
        /// <summary>
        /// Whether inference is performed on CPU (0) or GPU (1).
        /// </summary>
        public int InferenceDevice;
        public List<EventObservationSpec> ObservationSpecs;
        public EventActionSpec ActionSpec;
        public List<EventActuatorInfo> ActuatorInfos;
        public int MemorySize;
        public long TotalWeightSizeBytes;
        public string ModelHash;
    }

    /// <summary>
    /// Simplified version of ActionSpec struct for use in analytics
    /// </summary>
    [Serializable]
    internal struct EventActionSpec
    {
        public int NumContinuousActions;
        public int NumDiscreteActions;
        public int[] BranchSizes;

        public static EventActionSpec FromActionSpec(ActionSpec actionSpec)
        {
            var branchSizes = actionSpec.BranchSizes ?? Array.Empty<int>();
            return new EventActionSpec
            {
                NumContinuousActions = actionSpec.NumContinuousActions,
                NumDiscreteActions = actionSpec.NumDiscreteActions,
                BranchSizes = branchSizes,
            };
        }
    }

    /// <summary>
    /// Information about an actuator.
    /// </summary>
    [Serializable]
    internal struct EventActuatorInfo
    {
        public int BuiltInActuatorType;
        public int NumContinuousActions;
        public int NumDiscreteActions;

        public static EventActuatorInfo FromActuator(IActuator actuator)
        {
            BuiltInActuatorType builtInActuatorType = Actuators.BuiltInActuatorType.Unknown;
            if (actuator is IBuiltInActuator builtInActuator)
            {
                builtInActuatorType = builtInActuator.GetBuiltInActuatorType();
            }

            var actionSpec = actuator.ActionSpec;

            return new EventActuatorInfo
            {
                BuiltInActuatorType = (int)builtInActuatorType,
                NumContinuousActions = actionSpec.NumContinuousActions,
                NumDiscreteActions = actionSpec.NumDiscreteActions
            };
        }
    }

    /// <summary>
    /// Information about one dimension of an observation.
    /// </summary>
    [Serializable]
    internal struct EventObservationDimensionInfo
    {
        public int Size;
        public int Flags;
    }

    /// <summary>
    /// Simplified summary of Agent observations for use in analytics
    /// </summary>
    [Serializable]
    internal struct EventObservationSpec
    {
        public string SensorName;
        public string CompressionType;
        public int BuiltInSensorType;
        public EventObservationDimensionInfo[] DimensionInfos;

        public static EventObservationSpec FromSensor(ISensor sensor)
        {
            var shape = sensor.GetObservationShape();
            var dimInfos = new EventObservationDimensionInfo[shape.Length];
            for (var i = 0; i < shape.Length; i++)
            {
                dimInfos[i].Size = shape[i];
                // TODO copy flags when we have them
            }

            var builtInSensorType =
                (sensor as IBuiltInSensor)?.GetBuiltInSensorType() ?? Sensors.BuiltInSensorType.Unknown;

            return new EventObservationSpec
            {
                SensorName = sensor.GetName(),
                CompressionType = sensor.GetCompressionType().ToString(),
                BuiltInSensorType = (int)builtInSensorType,
                DimensionInfos = dimInfos,
            };
        }
    }

    internal struct RemotePolicyInitializedEvent
    {
        public string TrainingSessionGuid;
        /// <summary>
        /// Hash of the BehaviorName.
        /// </summary>
        public string BehaviorName;
        public List<EventObservationSpec> ObservationSpecs;
        public EventActionSpec ActionSpec;
        public List<EventActuatorInfo> ActuatorInfos;

        /// <summary>
        /// This will be the same as TrainingEnvironmentInitializedEvent if available, but
        /// TrainingEnvironmentInitializedEvent maybe not always be available with older trainers.
        /// </summary>
        public string MLAgentsEnvsVersion;
        public string TrainerCommunicationVersion;
    }

    internal struct TrainingEnvironmentInitializedEvent
    {
        public string TrainingSessionGuid;

        public string TrainerPythonVersion;
        public string MLAgentsVersion;
        public string MLAgentsEnvsVersion;
        public string TorchVersion;
        public string TorchDeviceType;
        public int NumEnvironments;
        public int NumEnvironmentParameters;
    }

    [Flags]
    internal enum RewardSignals
    {
        Extrinsic = 1 << 0,
        Gail = 1 << 1,
        Curiosity = 1 << 2,
        Rnd = 1 << 3,
    }

    [Flags]
    internal enum TrainingFeatures
    {
        BehavioralCloning = 1 << 0,
        Recurrent = 1 << 1,
        Threaded = 1 << 2,
        SelfPlay = 1 << 3,
        Curriculum = 1 << 4,
    }

    internal struct TrainingBehaviorInitializedEvent
    {
        public string TrainingSessionGuid;

        public string BehaviorName;
        public string TrainerType;
        public RewardSignals RewardSignalFlags;
        public TrainingFeatures TrainingFeatureFlags;
        public string VisualEncoder;
        public int NumNetworkLayers;
        public int NumNetworkHiddenUnits;
    }
}