using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.InputSystem;

/* 本文件用于控制手势的采集和比对
 * 也包含导出和导入手势的功能
*/
public class GestureManager
{
    // Start is called once before the first execution of Update after the MonoBehaviour is created
    public List<GesturePointOffset> gesturePointOffsetList { set; get; } = new List<GesturePointOffset>();
    public int sampleRate { set; get; } = 20;        // 采样率
    private Vector2 prePointLoc = new Vector2(0, 0); // 第一个点
    private Vector2 curPointLoc = new Vector2(0, 0); // 第二个点
    private float timer = 0f;       // 配合interval使用
    public bool isRecording;
    private float interval;     // 采样间隔，使用采样率计算
    private float lengthTorrence = 0.25f; // 允许的长度误差
    private DateTime startTime;
    private DateTime endTime;
    private float duration;
    private int screenWidth;
    private int screenHeight;

    public GestureManager()
    {
        interval = 1f / sampleRate;
        screenWidth = Screen.width;
        screenHeight = Screen.height;
    }

    public string ExportToJson()
    {
        string json = string.Empty;
        json = JsonConvert.SerializeObject(this);
        return json;
    }

    public void ImportFromJson(string json)
    {
        isRecording = false;
        var data = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
        sampleRate = int.Parse(data["sampleRate"].ToString());
        gesturePointOffsetList.Clear();
        GesturePointOffset[] pointOffsets = JsonConvert.DeserializeObject<GesturePointOffset[]>(data["gesturePointOffsetList"].ToString());
        foreach (var point in pointOffsets)
        {
            gesturePointOffsetList.Add(point);
        }
    }

    // 添加一个运动轨迹
    public void Record()
    {
        Vector2 pointLoc = Pointer.current.position.ReadValue();
        if (isRecording)
        {
            // if (!IsMouseOnScreen())
            // {
            //     StopRecording();
            //     Debug.Log("Mouse not on screen");
            //     return;
            // }

            if (gesturePointOffsetList.Count == 0)
            {
                prePointLoc = pointLoc;
                curPointLoc = pointLoc;
                GesturePointOffset gesturePointMovement = new GesturePointOffset(0, 0);
                gesturePointOffsetList.Add(gesturePointMovement);
                return;
            }
            else
            {
                //Debug.Log("interval:" + interval.ToString());
                timer += Time.deltaTime;
                if (timer >= interval)
                {
                    timer = 0f;
                    curPointLoc = pointLoc;

                    Vector2 normalizedCurPoint = NormalizePoint(curPointLoc);
                    Vector2 normalizedPrePoint = NormalizePoint(prePointLoc);
                    float distance = Vector2.Distance(normalizedCurPoint, normalizedPrePoint);

                    Vector2 direction = curPointLoc - prePointLoc;
                    float angle = Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg;
                    // float angle = Vector2.Angle(prePointLoc, curPointLoc);
                    GesturePointOffset gesturePointMovement = new GesturePointOffset(distance, angle);

                    if (distance * angle != 0)
                    {
                        gesturePointOffsetList.Add(gesturePointMovement);
                    }
                    prePointLoc = curPointLoc;
                }
            }
        }
    }

    public float CompareGesture(GestureManager anotherGesture)
    {
        float score = 0f;
        if (sampleRate != anotherGesture.sampleRate)
        {
            Debug.Log("Sample rate not match");
            return -1f;
        }

        if (gesturePointOffsetList.Count == 0 || anotherGesture.gesturePointOffsetList.Count == 0)
        {
            Debug.Log("Gesture point count is 0");
            return -1f;
        }

        int maxGesturePoints = Mathf.Max(gesturePointOffsetList.Count, anotherGesture.gesturePointOffsetList.Count);
        int minGesturePoints = Mathf.Min(gesturePointOffsetList.Count, anotherGesture.gesturePointOffsetList.Count);
        for (int i = 0; i < minGesturePoints; i++)
        {

            float distanceMin = Mathf.Min(gesturePointOffsetList[i].distance, anotherGesture.gesturePointOffsetList[i].distance);
            float distanceMax = Mathf.Max(gesturePointOffsetList[i].distance, anotherGesture.gesturePointOffsetList[i].distance);
            float angleMin = Mathf.Min(gesturePointOffsetList[i].angle, anotherGesture.gesturePointOffsetList[i].angle);
            float angleMax = Mathf.Max(gesturePointOffsetList[i].angle, anotherGesture.gesturePointOffsetList[i].angle);

            float distanceScore = 0f;
            if (distanceMin == 0)
            {
                distanceScore = 1f;
            }
            else
            {
                distanceScore = distanceMin / distanceMax;
            }

            float angleDitance1 = angleMax - angleMin;
            float angleDitance2 = 360 - angleDitance1;
            float angleScore = 1 - (Mathf.Min(angleDitance1, angleDitance2) / 180);

            score = score * (i / (i + 1f)) + (distanceScore + angleScore) / 2 * (1f / (i + 1));
        }

        // 如果长度超过公差范围，就要考虑调整score
        if ((maxGesturePoints / minGesturePoints) > (1f + lengthTorrence))
        {
            int deltaGesturePoints = Mathf.RoundToInt(maxGesturePoints - minGesturePoints * (1f + lengthTorrence));
            score = score * ((float)minGesturePoints / (minGesturePoints + deltaGesturePoints));
        }

        return score;
    }

    public void ResetGesture()
    {
        gesturePointOffsetList.Clear();
    }

    public void StartRecording()
    {
        isRecording = true;
        gesturePointOffsetList.Clear();
        timer = 0f;
        prePointLoc = Vector2.zero;
        curPointLoc = Vector2.zero;
        startTime = DateTime.Now;
    }
    public bool StopRecording()
    {
        isRecording = false;
        endTime = DateTime.Now;
        duration = (float)(endTime - startTime).TotalSeconds;
        Debug.Log("gesture duration:" + duration.ToString());
        Debug.Log("gesture point count:" + gesturePointOffsetList.Count.ToString());
        // 如果采样过少，就不记录这个手势
        if (gesturePointOffsetList.Count <= sampleRate/2)
        {
            Debug.Log("gesture duration too short");
            gesturePointOffsetList.Clear();
        }
        if (gesturePointOffsetList.Count > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    private bool IsMouseOnScreen()
    {
        Vector2 mousePos = Pointer.current.position.ReadValue();
        return mousePos.x >= 0 && mousePos.x < Screen.width &&
               mousePos.y >= 0 && mousePos.y < Screen.height;
    }

    private Vector2 NormalizePoint(Vector2 point)
    {
        float x = point.x / screenWidth;
        float y = point.y / screenHeight;
        return new Vector2(x, y);
    }
    private Vector2 DenormalizePoint(Vector2 point)
    {
        float x = point.x * screenWidth;
        float y = point.y * screenHeight;
        return new Vector2(x, y);
    }

    public void SetSampleRate(int rate)
    {
        sampleRate = rate;
        interval = 1f / sampleRate;
    }
}