using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;

public class ExpressionRecognition : MonoBehaviour
{
    public FaceInfo.Expression currentExpression
    {
        get
        {
            return _currentExpression;
        }
        private set
        {
            if(_currentExpression != value)
            {
                _currentExpression = value;
                if(!expressionDuration.ContainsKey(value))
                {
                    expressionDuration.Add(value, new ExpressionDuration());
                }
            }
        }
    }
    FaceInfo.Expression _currentExpression;
    Dictionary<FaceInfo.Expression, ExpressionDuration> expressionDuration = new Dictionary<FaceInfo.Expression, ExpressionDuration>();
    /// <summary>
    /// 当检测到一个表情持续一定时间后，触发事件
    /// </summary>
    public float triggerEventDuration = 2;
    /// <summary>
    /// 当一个表情长时间未检测到，就重置它的状态
    /// </summary>
    public float resetExpDurationInterval = 5;
    /// <summary>
    /// 触发表情事件后的冷却时间
    /// </summary>
    public float triggerEventCD = 20;
    public event UnityAction<FaceInfo.Expression> onRecognizingExpression;
    IFaceRecognizer recognizer;
    float triggerCDTimer = 0;
    class ExpressionDuration
    {
        /// <summary>
        /// 检测到的时长
        /// </summary>
        public float duration
        {
            get
            {
                return _duration;
            }
            set
            {
                _duration = value;
                unrecognizedInterval = 0;
            }
        }
        float _duration;
        /// <summary>
        /// 未检测到的时间间隔
        /// </summary>
        public float unrecognizedInterval;
    }
    private void Awake()
    {
        recognizer = GetComponentInChildren<IFaceRecognizer>(false);
        recognizer.BindListener(OnRecognizedFaces);
        triggerCDTimer = triggerEventCD;
    }

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        triggerCDTimer += Time.deltaTime;
        foreach (var item in expressionDuration)
        {
            if(item.Key == currentExpression)
            {
                item.Value.duration += Time.deltaTime;
                //当前表情持续时间大于一定值后，触发表情识别事件
                if (item.Key != FaceInfo.Expression.Neutral && item.Value.duration > triggerEventDuration && triggerCDTimer > triggerEventCD)
                {
                    Debug.Log("触发表情：" + currentExpression);
                    triggerCDTimer = 0;
                    if (onRecognizingExpression != null)
                        onRecognizingExpression(item.Key);
                }
            }
            else
            {
                item.Value.unrecognizedInterval += Time.deltaTime;
                if (item.Value.unrecognizedInterval > resetExpDurationInterval)
                {
                    item.Value.duration = 0;
                }
            }
        }
    }

    void OnRecognizedFaces(FaceInfo[] infos)
    {
        if(infos!= null && infos.Length > 0)
        {
            FaceInfo largestFace = infos[0];
            for (int i = 1; i < infos.Length; i++)
            {
                var info = infos[i];
                //取面积最大的一个
                if (info.box.height * info.box.width > largestFace.box.height * largestFace.box.width)
                {
                    largestFace = info;
                }
            }
            currentExpression = largestFace.expression;
            return;
        }
        else
        {
            currentExpression = FaceInfo.Expression.Neutral;
            return;
        }
    }
}