using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using JD.Collections;
using JD.Collections.Interfaces;
using JD.Kernel.Classes;
using JD.Kernel.Structs;
using JD.Timeline.Model.Curves;
using TeaBox;
using TeaBox.Editors.Curves;
using JD.Serialization;
using BezierCurve = TeaBox.Editors.Curves.BezierCurve;
using FrameConverter = JD.Core.FrameConverter;

namespace JD.Timeline.View.CurveEditor
{
    /// <summary>
    /// Visual representation of the model curve.
    /// </summary>
    internal class ClipCurve : BezierCurve
    {
        private readonly BezierCurveFloat _model;
        private readonly Scope _isUpdatingView = new Scope();
        private readonly Scope _isUpdatingModel;
        private float _minBoundsWidth;

        public ClipCurve(BezierCurveFloat model, Scope isUpdatingModel)
        {
            _isUpdatingModel = isUpdatingModel;
            _model = model;
            ColorChannel = model.Type.Infos().ColorChannel;
        }

        public BezierCurveFloat Model
        {
            get { return _model; }
        }

        protected override void Points_CollectionChanged(object sender, CollectionChangedEventArgs<CurvePoint> e)
        {
            base.Points_CollectionChanged(sender, e);

            // When updating the view, a lot of events are trigger
            // but those values should not affect the model.
            if (!_isUpdatingView.InScope && !Points.IsUpdating)
            {
                UpdateModel();

                // Restore the end bound so that when a point outside the curve bound is moved, user cannot move it back outside the bounds.
                _minBoundsWidth = Math.Min(_minBoundsWidth, CurveTimeFromFrame(_model.Keys.Select(point => point.Frame).DefaultIfEmpty().Max()));
            }
        }

        /// <summary>
        /// Fills the model with the new view values.
        /// </summary>
        private void UpdateModel()
        {
            using (_isUpdatingModel.Begin())
            using (_model.BeginScopedUpdate())
            {
                _model.Keys.Clear();
                foreach (var point in BezierPoints)
                {
                    var pointModel = _model.AddBezierPoint(ToModelTime(point.Position), ToModelTime(point.In.Position), ToModelTime(point.Out.Position));
                    point.Tag = pointModel;
                }
            }
        }

        /// <summary>
        /// Fills the view with the current model values.
        /// </summary>
        public void UpdateView()
        {
            using (_isUpdatingView.Begin())
            using (Points.BeginScopedUpdate())
            {
                // Keep the existing points so the selection is persisted.
                Dictionary<KeyFloat, BezierCurvePoint> existingPoints = Points.OfType<BezierCurvePoint>().ToDictionary(point => (KeyFloat)point.Tag);

                Points.Clear();
                UpdateBounds();

                foreach (var point in _model.Keys.OrderBy(model => model.Frame))
                {
                    BezierCurvePoint bezierPoint;
                    if (!existingPoints.TryGetValue(point, out bezierPoint))
                    {
                        bezierPoint = new BezierCurvePoint();
                    }

                    bezierPoint.Tag = point;
                    bezierPoint.Position = ToViewTime(point.Position);
                    bezierPoint.In.Position = ToViewTime(point.In);
                    bezierPoint.Out.Position = ToViewTime(point.Out);

                    Points.Add(bezierPoint);
                }
            }
        }

        /// <summary>
        /// When a clip has keys outside the bounds of the clip, we allow the user to manipulate those key outside the bounds
        /// but when resized with valid bounds, we restore the clip limit.
        /// </summary>
        protected override void Clamp(CurvePoint point, RectangleF region)
        {
            region.Width = Math.Max(region.Width, _minBoundsWidth);
            base.Clamp(point, region);
        }

        private void UpdateBounds()
        {
            Bounds = ToCurveBounds(_model.Type.Infos().ValueRange);
            _minBoundsWidth = CurveTimeFromFrame(_model.Keys.Select(point => point.Frame).DefaultIfEmpty().Max());
        }

        private RectangleF ToCurveBounds(Range<float> valueRange)
        {
            var bounds = Bounds;
            bounds.Y = valueRange.Min;
            bounds.Height = valueRange.Max - valueRange.Min;
            bounds.X = CurveTimeFromFrame(_model.Clip.StartFrame);
            bounds.Width = CurveTimeFromFrame(_model.Clip.Duration);
            return bounds;
        }

        public PointF ToModelTime(PointF point)
        {
            var x = FrameFromCurveTime(point.X) - _model.Clip.StartFrame;
            var y = point.Y / _model.Type.Infos().EditionUnitConversion;
            return new PointF(x, y);
        }

        private PointF ToViewTime(PointF point)
        {
            var x = CurveTimeFromFrame(point.X + _model.Clip.StartFrame);
            var y = point.Y * _model.Type.Infos().EditionUnitConversion;
            return new PointF(x, y);
        }

        private static float CurveTimeFromFrame(float frame)
        {
            return FrameConverter.TimeFromFrame(frame);
        }

        public static float FrameFromCurveTime(float frame)
        {
            return FrameConverter.FrameFromTime(frame);
        }

        public override string ToString()
        {
            return "View of " + Model;
        }
    }
}