using System.Collections.Generic;
using UnityEngine;

namespace NanoBrain {

    /// <summary>
    /// The Unity ScriptableObject to implement re-usable Cluster Prefabs
    /// </summary>
    [CreateAssetMenu(menuName = "Passer/Cluster")]
    public class ClusterPrefab : ScriptableObject {

        public Cluster cluster;
        /*
                /// The nuclei in this cluster
                [SerializeReference]
                // This list should not include any clusters...
                public List<Nucleus> nuclei = new();

                /// <summary>
                /// The output of this cluster
                /// </summary>
                /// <deprecated>This only returens the first(default) nucleus. Use outputs[0] instead</deprecated>
                public virtual Nucleus output => this.nuclei[0] as Nucleus;

                /// <summary>
                /// The nuclei in this cluster which are meant for receiving signals from outside the cluster
                /// </summary>
                /// <remark>This is currently the nuclei which do not have any incoming synapse</remark>
                public List<Nucleus> _inputs = null;
                public virtual List<Nucleus> inputs {
                    get {
                        if (this._inputs == null) {
                            this._inputs = new();
                            foreach (Nucleus receptor in this.nuclei) {
                                if (receptor is Nucleus nucleus) {
                                    // inputs have no incoming synapses yet.
                                    if (nucleus.synapses.Count == 0)
                                        this._inputs.Add(nucleus);
                                }
                            }
                        }
                        return this._inputs;
                    }
                }
                /// <summary>
                /// The nuclei in this cluster which are meant for sending signals onward
                /// </summary>
                private List<Nucleus> _outputs = null;
                public List<Nucleus> outputs {
                    get {
                        if (this._outputs == null)
                            RefreshOutputs();
                        return this._outputs;
                    }
                }
                /// <summary>
                /// Redetermine the outpus in the cluster
                /// </summary>
                public void RefreshOutputs() {
                    this._outputs = new();
                    foreach (Nucleus nucleus in this.nuclei) {
                        if (nucleus is Neuron neuron && neuron.receivers.Count == 0)
                            this._outputs.Add(nucleus);
                    }
                }
        */
        /// <summary>
        /// Retrieve a nucleus in this cluster
        /// </summary>
        /// <param name="nucleusName">The name of the nucleus</param>
        /// <returns>The Nucleus with the given name or null if no such Nucleus could be found</returns>
        public Nucleus GetNucleus(string nucleusName) {
            return cluster.GetNucleus(nucleusName);
            // foreach (Nucleus nucleus in this.nuclei) {
            //     if (nucleus.name == nucleusName)
            //         return nucleus;
            // }
            // return null;
        }

        // Call this function to ensure that there is at least one nucleus
        // This is an invariant and should be ensured before the nucleus is used
        // because output requires it.
        public void EnsureInitialization() {
            this.cluster.prefab = this;
            this.cluster.name = this.name;
            this.cluster.nuclei ??= new List<Nucleus>();
            if (this.cluster.nuclei.Count <= 0)
                new Neuron(this.cluster, "Output"); // Every cluster should have at least 1 neuron
            this.cluster.instanceCount = 1;
            // nuclei ??= new List<Nucleus>();
            // if (nuclei.Count == 0)
            //     new Neuron(this, "Output"); // Every cluster should have at least 1 neuron
        }

        public void GarbageCollection() {
            // HashSet<Nucleus> visitedNuclei = new();
            // foreach (Nucleus output in this.outputs)
            //     MarkNuclei(visitedNuclei, output);
            // //Debug.Log($"Garbage collection found {visitedNuclei.Count} Nuclei");
            // this.nuclei.RemoveAll(nucleus => visitedNuclei.Contains(nucleus) == false);
        }

        // public void MarkNuclei(HashSet<Nucleus> visitedNuclei, Nucleus nucleus) {
        //     if (nucleus is null)
        //         return;

        //     if (nucleus.parent != null && nucleus.parent.prefab != this)
        //         visitedNuclei.Add(nucleus.parent);
        //     else
        //         visitedNuclei.Add(nucleus);
        //     if (nucleus is Neuron neuron) {
        //         if (neuron.synapses != null) {
        //             HashSet<Synapse> visitedSynapses = new();
        //             foreach (Synapse synapse in neuron.synapses) {
        //                 if (synapse != null && synapse.neuron != null) {
        //                     visitedSynapses.Add(synapse);
        //                     if (synapse.neuron is Nucleus synapse_nucleus)
        //                         MarkNuclei(visitedNuclei, synapse_nucleus);
        //                 }
        //             }
        //             neuron.synapses.RemoveAll(synapse => visitedSynapses.Contains(synapse) == false);
        //         }
        //         if (neuron.receivers != null) {
        //             HashSet<Nucleus> visitedReceivers = new();
        //             foreach (Nucleus receiver in neuron.receivers) {
        //                 if (receiver != null && receiver != null) {
        //                     visitedReceivers.Add(receiver);
        //                     visitedNuclei.Add(receiver);
        //                 }
        //             }
        //             neuron.receivers.RemoveAll(receiver => visitedReceivers.Contains(receiver) == false);
        //         }
        //     }
        // }

        // public virtual void UpdateNuclei() {
        //     foreach (Nucleus nucleus in this.nuclei)
        //         nucleus.UpdateNuclei();
        // }

        // public int GetNucleusIndex(Nucleus receiver) {
        //     int ix = 0;
        //     foreach (Nucleus nucleus in this.nuclei) {
        //         if (receiver == nucleus)
        //             return ix;
        //         ix++;
        //     }
        //     return -1;
        // }
    }

}