using UnityEngine;
using System.Collections.Generic;

public interface ICardIdentifierListener {
    void OnTargetChange(Transform t);
    void OnTargetFound(Transform t);
    void OnTargetTracked(Transform t);
    void OnTargetLost(Transform t);
}

public static class CardIdentifierExt {
    // notify gameObject by sendMessage
    public static void listenCardIdentifier(this GameObject obj, string identifierName) {
        CardIdentifier.addObserver(obj, identifierName);
    }

    // notify monoBehaviour by Interface
    public static void listenCardIdentifier(this ICardIdentifierListener listener, string identifierName) {
        CardIdentifier.addObserver(listener, identifierName);
    }
}

/// <summary>
///     CardIdentifier[Observalbe]<br/>
///     notify the card transform
///     set a list of [GameObject/ICardIdentifierListener]
/// </summary>
public class CardIdentifier : HiARBaseObjectMonoBehaviour {

    public static readonly Dictionary<string, CardIdentifier> Identifiers = new Dictionary<string, CardIdentifier>();

    private readonly List<GameObject> _objects = new List<GameObject>();
    private readonly List<ICardIdentifierListener> _behaviours = new List<ICardIdentifierListener>();

    public bool IsFound { get; private set; }

    public void addObserver(GameObject obj) {
        if (_objects.Contains(obj)) return;
        _objects.Add(obj);
    }

    public void addObserver(ICardIdentifierListener behaviour) {
        if (_behaviours.Contains(behaviour)) return;
        _behaviours.Add(behaviour);
    }

    public static void addObserver(GameObject obj, string identifierName) {
        if (!Identifiers.ContainsKey(identifierName)) {
            Debug.LogWarning("no such CardIdentifier which named " + identifierName);
            return;
        }
        Identifiers[identifierName].addObserver(obj);
    }

    public static void addObserver(ICardIdentifierListener behaviour, string identifierName) {
        if (!Identifiers.ContainsKey(identifierName)) {
            Debug.LogWarning("no such CardIdentifier which named " + identifierName);
            return;
        }
        Identifiers[identifierName].addObserver(behaviour);
    }

    public void removeObserver(GameObject obj) {
        _objects.Remove(obj);
    }

    public void removeObserver(ICardIdentifierListener behaviour) {
        _behaviours.Remove(behaviour);
    }

    public static void removeObserver(GameObject obj, string identifierName) {
        if (!Identifiers.ContainsKey(identifierName)) {
            Debug.LogWarning("no such CardIdentifier which named " + identifierName);
            return;
        }
        Identifiers[identifierName].removeObserver(obj);
    }

    public static void removeObserver(ICardIdentifierListener behaviour, string identifierName) {
        if (!Identifiers.ContainsKey(identifierName)) {
            Debug.LogWarning("no such CardIdentifier which named " + identifierName);
            return;
        }
        Identifiers[identifierName].removeObserver(behaviour);
    }

    void Awake() {
        if (Identifiers.ContainsKey(name)) {
            Debug.LogError("CardIdentifier: you already have this CardIdentifier, which named " + name);
            Debug.Break();
        }
        Identifiers.Add(name, this);
    }

    /// <summary>
    ///     do not hide the children in this object
    /// </summary>
    void Start() {
        // to override the default
    }

    // change target to another
    public void OnTargetChange(anotherTransform) {
        foreach (var o in _objects) {
            o.SendMessage("OnTargetChange", anotherTransform);
        }
        foreach (var c in _behaviours) {
            c.OnTargetChange(anotherTransform);
        }
    }

    // *** the callback interface ***

    public void OnTargetFound(string targetId) {
        IsFound = true;
        foreach (var o in _objects) {
            o.SendMessage("OnTargetFound", transform);
        }
        foreach (var c in _behaviours) {
            c.OnTargetFound(transform);
        }
    }

    public void OnTargetTracked(string targetId) {
        foreach (var o in _objects) {
            o.SendMessage("OnTargetTracked", transform);
        }
        foreach (var c in _behaviours) {
            c.OnTargetTracked(transform);
        }
    }

    public void OnTargetLost(string targetId) {
        IsFound = false;
        foreach (var o in _objects) {
            o.SendMessage("OnTargetLost", transform);
        }
        foreach (var c in _behaviours) {
            c.OnTargetLost(transform);
        }
    }
}