using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UnityEngine;

namespace Assets.AR
{
    public class ARVideoPlayerControl
    {
        private const float MinVideoPlaybackSpeedChangeInterval = 0.2f;
        private const float MaxPlaybackSpeed = 1.5f;
        private const float MaxCameraDistanceError = 200f;
        private DateTime lastPlaybackSpeedChange = DateTime.MinValue;
        private float fixedTimeFrame;
        private DateTime fixedTimeSeekFinished = DateTime.MinValue;
        private int lapCount = 1;
        private double lapLength;

        public float FixedVideoFrame => this.fixedTimeFrame;

        //public IDistanceSource RiderDistance { get; set; 

        public AVProVideoPlayer VideoPlayer { get; private set; }

        //public ISpeedSource RiderSpeed { get; set; }

        public VideoPointsSync VideoSyncSource { get; set; }

        public ARRoute Route { get; set; }

        public int VideoFrameOffset { get; set; }

        public float CameraFollowDistance { get; set; }

        public bool AllowUpdate { get; set; } = true;

        public float CameraDistanceError { get; private set; }

        public bool IsTimeFixed { get; private set; }

        public float FrameIndexDistanceCorrection { get; private set; }

        public bool IsMultilap => this.lapCount > 1;

        public void SetVideoPlayer(AVProVideoPlayer player) => this.VideoPlayer = player;

        public void SetMultiLap(int lapCount, double lapLength)
        {
            this.lapCount = lapCount;
            this.lapLength = lapLength;
        }

        public void FixTimeByDistance(float distance) => this.FixTimeByFrame(this.VideoSyncSource.GetVideoFrameAtDistance(distance));

        public void FixTimeByFrame(float frame)
        {
            this.IsTimeFixed = true;
            this.fixedTimeFrame = frame;
            this.fixedTimeSeekFinished = DateTime.MinValue;
            if (this.VideoPlayer.IsPaused)
                this.VideoPlayer.Resume();
            this.VideoPlayer.SetPlaybackSpeed(0.25f);
            this.VideoPlayer.Seek((long)frame, true);
        }

        public void UnFixTime()
        {
            //this.IsTimeFixed = false;
            //float videoFrameAtDistance = this.VideoSyncSource.GetVideoFrameAtDistance(this.RiderDistance.LapDistance);
            //float num = this.VideoSyncSource.AverageVideoSpeed(videoFrameAtDistance, videoFrameAtDistance);
            //float playbackSpeed = (double)num != 0.0 ? this.RiderSpeed.Speed / num : 0.0f;
            //if (this.VideoPlayer.IsPaused)
            //    this.VideoPlayer.Resume();
            //this.VideoPlayer.SetPlaybackSpeed(playbackSpeed);
            //this.lastPlaybackSpeedChange = DateTime.UtcNow;
            //this.VideoPlayer.Seek((long)videoFrameAtDistance, true);
        }

        private void SkipVideoToDistance(float distance) => this.SkipVideoToFrame((long)this.VideoSyncSource.GetVideoFrameAtDistance(distance));

        private void SkipVideoToFrame(long frame) => this.VideoPlayer.Seek(frame);

        private const float TimerInterval = 0.2f;
        
        /// <summary>
        /// update video play rate
        /// </summary>
        /// <param name="speed">播放速度</param>
        /// <param name="routeDistance">骑行距离</param>
        public void UpdateVideoPlayRate(float speed, float routeDistance)
        {
            if (!this.AllowUpdate)
                return;
            if (this.IsTimeFixed)
            {
                if (this.VideoPlayer.IsSeeking)
                    return;
                if (this.fixedTimeSeekFinished == DateTime.MinValue)
                    this.fixedTimeSeekFinished = DateTime.UtcNow;
                if (DateTime.UtcNow.Subtract(this.fixedTimeSeekFinished).TotalSeconds < 0.25)
                    return;
                if (this.VideoPlayer.CurrentFrame > this.fixedTimeFrame)
                    this.VideoPlayer.Pause();
               
                this.VideoPlayer.UpdateCurrentFrame();
                this.FrameIndexDistanceCorrection = 0.0f;
            }
            else
            {
                var videoFrameAtDistance1 = this.VideoSyncSource.GetVideoFrameAtDistance(routeDistance);
                var val2 = routeDistance - this.CameraFollowDistance;
            
                var distance = Math.Max(0.0f, val2);
                var frame = this.VideoSyncSource.GetVideoFrameAtDistance(distance) + this.VideoFrameOffset;
                if (this.Route != null && this.Route.GetVisibility(frame) > 10.0)
                    frame = (float)this.Route.GetFrameAtDistance(Math.Max(0.0, this.Route.GetDistanceForFrame(videoFrameAtDistance1) - this.CameraFollowDistance)) + this.VideoFrameOffset;
           
                this.VideoPlayer.UpdateCurrentFrame();
                var distanceForVideoFrame = this.VideoSyncSource.GetDistanceForVideoFrame(this.VideoPlayer.CurrentFrame - (float)this.VideoFrameOffset);
                float frameOffset;
                if (this.Route != null)
                {
                    var frameAtDistance = this.Route.GetFrameAtDistance(this.Route.GetDistanceForFrame(this.VideoPlayer.CurrentFrame - this.VideoFrameOffset) + Mathf.Min(routeDistance, this.CameraFollowDistance));
                    frameOffset = videoFrameAtDistance1 - (float)frameAtDistance;
                }
                else
                    frameOffset = frame - (this.VideoPlayer.CurrentFrame - this.VideoFrameOffset);
                var num1 = Mathf.Clamp01(PFMath.Lerp(0.0f, 1f, 100f, 0.0f, Mathf.Abs(frameOffset)));
                this.FrameIndexDistanceCorrection = frameOffset * num1;
                this.CameraDistanceError = distance - distanceForVideoFrame;
                if (this.IsMultilap)
                {
                    var num2 = distance - (distanceForVideoFrame + (float)this.lapLength);
                    if (Math.Abs(num2) < Math.Abs(this.CameraDistanceError) && Math.Abs(num2) < 200.0)
                        return;
                }
                if (Math.Abs(this.CameraDistanceError) > 200.0)
                {
                    this.SkipVideoToDistance(distance);
                }
                else
                {
                    var totalSeconds = DateTime.UtcNow.Subtract(this.lastPlaybackSpeedChange).TotalSeconds;
                    if (totalSeconds >= 0.0 && totalSeconds < TimerInterval)
                        return;
                    var num3 = (float)totalSeconds;
                    var num4 = num3 * speed;
                    var offset = this.VideoSyncSource.GetDistanceForVideoFrame((this.VideoPlayer.CurrentFrame - this.VideoFrameOffset + num3 * this.VideoPlayer.PlaybackSpeed * this.VideoPlayer.FrameRate));
                    var left = (double)Math.Abs(distance + num4 - offset);
                    var right = (double)Math.Abs(this.CameraDistanceError);

                    if (left <= right)
                        return;
                    var videoFrameAtDistance2 = this.VideoSyncSource.GetVideoFrameAtDistance(routeDistance + num4);
                    var num5 = this.VideoSyncSource.AverageVideoSpeed(videoFrameAtDistance1, videoFrameAtDistance2);
                    var ratio = (num5 != 0.0 ? speed / num5 : 0.0f);
                    var deltaRatio = (float)((frame - (this.VideoPlayer.CurrentFrame - this.VideoFrameOffset)) / 2.0) / this.VideoPlayer.FrameRate;
                    var playbackSpeed = Mathf.Clamp(ratio + deltaRatio, 0.0f, 1.5f);
                    
                    if (playbackSpeed == this.VideoPlayer.PlaybackSpeed || !this.VideoPlayer.SetPlaybackSpeed(playbackSpeed))
                        return;
                    this.lastPlaybackSpeedChange = DateTime.UtcNow;
                }
            }
        }
    }
}