using RealTimeGraphX.EventArguments;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace RealTimeGraphX
{
    /// <summary>
    /// Represents an <see cref="IGraphRenderer{XDataPoint, YDataPoint}"/> base class.
    /// </summary>
    /// <typeparam name="TDataSeries">The type of the graph data series.</typeparam>
    /// <typeparam name="XDataPoint">The type of the x-axis data point.</typeparam>
    /// <typeparam name="YDataPoint">The type of the y-axis data point.</typeparam>
    /// <seealso cref="RealTimeGraphX.GraphInputOutputComponentBase{RealTimeGraphX.IGraphController{XDataPoint, YDataPoint}, RealTimeGraphX.IGraphPainter}" />
    /// <seealso cref="RealTimeGraphX.IGraphRenderer{XDataPoint, YDataPoint}" />
    /// <seealso cref="RealTimeGraphX.IGraphRenderer" />
    public abstract class GraphRendererBase<TDataSeries, XDataPoint, YDataPoint> :
        GraphInputOutputComponentBase<IGraphController<TDataSeries, XDataPoint, YDataPoint>, IGraphPainter<TDataSeries>>,
        IGraphRenderer<TDataSeries, XDataPoint, YDataPoint>,
        IGraphRenderer<TDataSeries>
        where XDataPoint : GraphDataPointBase
        where YDataPoint : GraphDataPointBase
        where TDataSeries : IGraphDataSeries
    {
        private GraphDataQueue<PendingSeries> _pending_series_collection;
        private Dictionary<TDataSeries, PendingSeries> _to_render;
        private DateTime _last_render_time;
        private object _render_lock = new object();
        private Thread _render_thread;

        protected YDataPoint _current_min_y;
        protected YDataPoint _current_max_y;

        private PidController _pid_controller;
        private DateTime _last_pid_sample_time = DateTime.Now;

        #region Pending Series Class

        protected class PendingSeries
        {
            public TDataSeries Series { get; set; }
            public List<XDataPoint> XX { get; set; }
            public List<YDataPoint> YY { get; set; }

            public int NewItemsCount
            {
                get { return XX.Count - RenderedItems; }
            }

            public int RenderedItems { get; set; }
            public bool IsInvalidationSeries { get; set; }
        }

        #endregion

        #region Events

        /// <summary>
        /// Occurs when the current effective x-axis minimum/maximum has changed.
        /// </summary>
        public event EventHandler<RangeChangedEventArgs> EffectiveRangeXChanged;

        /// <summary>
        /// Occurs when the current effective y-axis minimum/maximum has changed.
        /// </summary>
        public event EventHandler<RangeChangedEventArgs> EffectiveRangeYChanged;

        /// <summary>
        /// Occurs when the connected input controller has changed.
        /// </summary>
        event EventHandler<InputChangedEventArgs<IGraphController<TDataSeries>>> IGraphInputComponent<IGraphController<TDataSeries>>.InputChanged
        {
            add
            {
                InputChanged += new EventHandler<InputChangedEventArgs<IGraphController<TDataSeries, XDataPoint, YDataPoint>>>((sender, e) => { value.Invoke(sender, new InputChangedEventArgs<IGraphController<TDataSeries>>(e.Input)); });
            }

            remove
            {
                InputChanged -= new EventHandler<InputChangedEventArgs<IGraphController<TDataSeries, XDataPoint, YDataPoint>>>((sender, e) => { value.Invoke(sender, new InputChangedEventArgs<IGraphController<TDataSeries>>(e.Input)); });
            }
        }

        #endregion

        #region Properties

        private TimeSpan _refreshRate;
        /// <summary>
        /// Gets or sets the renderer refresh rate.
        /// Higher rate requires more CPU time.
        /// </summary>
        public TimeSpan RefreshRate
        {
            get
            {
                return _refreshRate;
            }
            set
            {
                _refreshRate = value;
                RaisePropertyChangedAuto();
            }
        }

        private GraphDataPointBase _effectiveMinimumX;
        /// <summary>
        /// Gets the current effective x-axis minimum.
        /// </summary>
        public GraphDataPointBase EffectiveMinimumX
        {
            get
            {
                return _effectiveMinimumX;
            }
            private set
            {
                _effectiveMinimumX = value;
                RaisePropertyChangedAuto();
            }
        }

        private GraphDataPointBase _effectiveMaximumX;
        /// <summary>
        /// Gets the current effective x-axis maximum.
        /// </summary>
        public GraphDataPointBase EffectiveMaximumX
        {
            get
            {
                return _effectiveMaximumX;
            }
            private set
            {
                _effectiveMaximumX = value;
                RaisePropertyChangedAuto();
            }
        }

        private GraphDataPointBase _effectiveMinimumY;
        /// <summary>
        /// Gets the current effective y-axis minimum.
        /// </summary>
        public GraphDataPointBase EffectiveMinimumY
        {
            get
            {
                return _effectiveMinimumY;
            }
            private set
            {
                _effectiveMinimumY = value;
                RaisePropertyChangedAuto();
            }
        }

        private GraphDataPointBase _effectiveMaximumY;
        /// <summary>
        /// Gets the current effective y-axis maximum.
        /// </summary>
        public GraphDataPointBase EffectiveMaximumY
        {
            get
            {
                return _effectiveMaximumY;
            }
            private set
            {
                _effectiveMaximumY = value;
                RaisePropertyChangedAuto();
            }
        }

        /// <summary>
        /// Gets the current data point x position.
        /// </summary>
        public double CurrentXPosition { get; protected set; }

        private bool _isPaused;
        /// <summary>
        /// Gets or sets a value indicating whether to pause the graph movement.
        /// </summary>
        public bool IsPaused
        {
            get { return _isPaused; }
            set { _isPaused = value; RaisePropertyChangedAuto(); }
        }

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="GraphRendererBase{XDataPoint, YDataPoint}"/> class.
        /// </summary>
        public GraphRendererBase()
        {
            EffectiveMinimumX = GraphDataPointHelper.Init<XDataPoint>();
            EffectiveMinimumY = GraphDataPointHelper.Init<YDataPoint>();
            EffectiveMaximumX = GraphDataPointHelper.Init<XDataPoint>();
            EffectiveMaximumY = GraphDataPointHelper.Init<YDataPoint>();
            _last_render_time = DateTime.Now;
            _to_render = new Dictionary<TDataSeries, PendingSeries>();
            _pending_series_collection = new GraphDataQueue<PendingSeries>();
            RefreshRate = TimeSpan.FromMilliseconds(50);

            _pid_controller = new PidController(10, 10, -10);
        }

        #endregion

        #region Render Thread

        /// <summary>
        /// The rendering thread method.
        /// </summary>
        private void RenderThreadMethod()
        {
            while (Output != null)
            {
                if (!IsPaused)
                {
                    for (int i = 0; i < Input.DataSeriesCollection.Count; i++)
                    {
                        var series = _pending_series_collection.BlockDequeue();

                        if (!series.IsInvalidationSeries)
                        {
                            if (_to_render.ContainsKey(series.Series))
                            {
                                var s = _to_render[series.Series];
                                s.XX.AddRange(series.XX);
                                s.YY.AddRange(series.YY);
                            }
                            else
                            {
                                _to_render[series.Series] = series;
                            }

                            if (i == Input.DataSeriesCollection.Count - 1)
                            {
                                if (DateTime.Now > _last_render_time.AddMilliseconds(RefreshRate.TotalMilliseconds))
                                {
                                    if (Input.Range.AutoY)
                                    {
                                        _current_min_y = _to_render.Select(x => x.Value).SelectMany(x => x.YY).Min();
                                        _current_max_y = _to_render.Select(x => x.Value).SelectMany(x => x.YY).Max();
                                    }

                                    _last_render_time = DateTime.Now;
                                    RenderAndDraw(_to_render.ToList());
                                }
                            }
                        }
                        else
                        {
                            RenderAndDraw(_to_render.ToList());
                        }
                    }
                }
                else
                {
                    RenderAndDraw(_to_render.ToList());
                    Thread.Sleep(50);
                }
            }
        }

        #endregion

        #region Public Methods

        /// <summary>
        /// Renders the specified data points collection.
        /// • The number of data series of x and y must match.
        /// • The number of x and y collections must match.
        /// • The number of x and y data points must match.
        /// </summary>
        /// <param name="xxxx">The x-axis series collection.</param>
        /// <param name="yyyy">The y-axis series collection.</param>
        /// <exception cref="ArgumentOutOfRangeException">When pushing data to a multi series renderer, each series must contain the same amount of data.</exception>
        public void Render(IEnumerable<TDataSeries> seriesCollection, IEnumerable<IEnumerable<XDataPoint>> xxxx, IEnumerable<IEnumerable<YDataPoint>> yyyy)
        {
            List<List<XDataPoint>> xxxxList = xxxx.Select(x => x.ToList()).ToList();
            List<List<YDataPoint>> yyyyList = yyyy.Select(x => x.ToList()).ToList();

            int first_count_x = xxxxList[0].Count;
            int first_count_y = yyyyList[0].Count;


            bool is_data_valid = true;

            for (int i = 0; i < xxxxList.Count; i++)
            {
                if (xxxxList[0].Count != first_count_x)
                {
                    is_data_valid = false;
                    break;
                }

                if (xxxxList[0].Count != yyyyList[0].Count)
                {
                    is_data_valid = false;
                    break;
                }
            }

            if (!is_data_valid)
            {
                throw new ArgumentOutOfRangeException("When pushing data to a multi series renderer, each series must contain the same amount of data.");
            }

            var list = seriesCollection.ToList();

            for (int i = 0; i < list.Count; i++)
            {
                _pending_series_collection.BlockEnqueue(new PendingSeries()
                {
                    Series = list[i],
                    XX = xxxxList[i].ToList(),
                    YY = yyyyList[i].ToList(),
                });
            }
        }

        /// <summary>
        /// Invalidates the graph.
        /// </summary>
        public virtual void Invalidate()
        {
            _pending_series_collection.BlockEnqueue(new PendingSeries() { IsInvalidationSeries = true });
        }

        /// <summary>
        /// Connects this renderer to an <see cref="IGraphPainter"/>.
        /// </summary>
        /// <param name="painter">The graph painter.</param>
        /// <param name="fromOutput">Specifies whether this call was made from an <see cref="IGraphPainter"/> component.</param>
        public override void ConnectOutput(IGraphPainter<TDataSeries> painter, bool fromOutput = false)
        {
            painter.ThrowIfNull("Cannot connect a null painter.");

            DisconnectOutput();

            Output = painter;

            if (!fromOutput)
            {
                Output.ConnectInput(this, true);
            }

            _render_thread = new Thread(RenderThreadMethod);
            _render_thread.IsBackground = true;
            _render_thread.Name = "IGraphRenderer Render Thread";
            _render_thread.Start();

            OnEffectiveRangeYChanged(Input.Range.MinimumY, Input.Range.MaximumY);
        }

        /// <summary>
        /// Disconnects this renderer from the connected <see cref="IGraphPainter"/>.
        /// </summary>
        /// <param name="fromOutput">Specifies whether this call was made from an <see cref="IGraphPainter"/> component.</param>
        public override void DisconnectOutput(bool fromOutput = false)
        {
            if (Output != null)
            {
                if (!fromOutput)
                {
                    Output.DisconnectInput(true);
                }

                Output = null;
            }
        }

        /// <summary>
        /// Connects this renderer to the specified <see cref="IGraphController{XDataPoint, YDataPoint}"/>.
        /// </summary>
        /// <param name="controller">The controller.</param>
        /// <param name="fromInput">Specifies whether this call was made from an <see cref="IGraphController{XDataPoint, YDataPoint}"/> component.</param>
        public override void ConnectInput(IGraphController<TDataSeries, XDataPoint, YDataPoint> controller, bool fromInput = false)
        {
            controller.ThrowIfNull("Cannot connect a null controller.");

            DisconnectInput();

            if (!fromInput)
            {
                controller.ConnectOutput(this, true);
            }

            Input = controller;

            Input.RangeChanged += Input_RangeChanged;

            OnEffectiveRangeYChanged(Input.Range.MinimumY, Input.Range.MaximumY);
        }

        /// <summary>
        /// Disconnects this renderer from the current connected <see cref="IGraphController{XDataPoint, YDataPoint}"/>.
        /// </summary>
        /// <param name="fromInput">Specifies whether this call was made from an <see cref="IGraphController{XDataPoint, YDataPoint}"/> component.</param>
        public override void DisconnectInput(bool fromInput = false)
        {
            if (Input != null)
            {
                if (!fromInput)
                {
                    (Input as IGraphOutputComponent<IGraphRenderer<TDataSeries, XDataPoint, YDataPoint>>).DisconnectOutput(true);
                }

                Input.RangeChanged -= Input_RangeChanged;

                Input = null;
            }
        }

        /// <summary>
        /// Gets the connected input controller.
        /// </summary>
        IGraphController<TDataSeries> IGraphInputComponent<IGraphController<TDataSeries>>.Input
        {
            get
            {
                return Input;
            }
        }

        /// <summary>
        /// Connected this renderer to the specified graph controller.
        /// </summary>
        /// <param name="controller">The controller.</param>
        /// <param name="fromInput">Specifies whether this call was made from an <see cref="IGraphController"/> component.</param>
        void IGraphInputComponent<IGraphController<TDataSeries>>.ConnectInput(IGraphController<TDataSeries> controller, bool fromInput)
        {
            ConnectInput(controller as IGraphController<TDataSeries, XDataPoint, YDataPoint>, fromInput);
        }

        /// <summary>
        /// Clears the graph data.
        /// </summary>
        public void Clear()
        {
            while (_pending_series_collection.Count > 0)
            {
                _pending_series_collection.BlockDequeue();
            }

            _to_render.Clear();
        }

        #endregion

        #region Protected Methods

        /// <summary>
        /// Returns an array of absolute graph data points to render.
        /// This method is called per data series.
        /// </summary>
        /// <param name="seriesCollection">A collection of all data series that is currently in the rendering pass.</param>
        /// <param name="series">The current data series to render.</param>
        /// <param name="toRender">Pending data series object to render.</param>
        /// <returns></returns>
        protected abstract List<GraphPoint> OnRender(IEnumerable<PendingSeries> seriesCollection, TDataSeries series, PendingSeries toRender);

        /// <summary>
        /// Converts the specified relative x position to graph absolute position.
        /// </summary>
        /// <param name="x">The relative x position.</param>
        /// <returns></returns>
        protected virtual float ConvertXValueToRendererValue(double x)
        {
            return (float)(x * Output.SurfaceWidth / 100);
        }

        /// <summary>
        /// Converts the specified relative y position to graph absolute position.
        /// </summary>
        /// <param name="y">The relative y position.</param>
        /// <returns></returns>
        protected virtual float ConvertYValueToRendererValue(double y)
        {
            return (float)(Output.SurfaceHeight - (y * Output.SurfaceHeight / 100));
        }

        /// <summary>
        /// Raises the <see cref="EffectiveRangeXChanged"/> event.
        /// </summary>
        /// <param name="minimumX">The minimum x.</param>
        /// <param name="maximumX">The maximum x.</param>
        protected virtual void OnEffectiveRangeXChanged(GraphDataPointBase minimumX, GraphDataPointBase maximumX)
        {
            EffectiveMinimumX = minimumX;
            EffectiveMaximumX = maximumX;

            EffectiveRangeXChanged?.Invoke(this, new RangeChangedEventArgs()
            {
                Maximum = minimumX,
                Minimum = maximumX,
            });
        }

        /// <summary>
        /// Raises the <see cref="EffectiveRangeYChanged"/> event.
        /// </summary>
        /// <param name="minimumY">The minimum y.</param>
        /// <param name="maximumY">The maximum y.</param>
        protected virtual void OnEffectiveRangeYChanged(GraphDataPointBase minimumY, GraphDataPointBase maximumY)
        {
            EffectiveMinimumY = minimumY;
            EffectiveMaximumY = maximumY;

            EffectiveRangeYChanged?.Invoke(this, new RangeChangedEventArgs()
            {
                Maximum = minimumY,
                Minimum = maximumY,
            });
        }

        #endregion

        #region Private Methods

        /// <summary>
        /// Renders the and draws a complete set of data series and their data points.
        /// </summary>
        /// <param name="toRender">To render.</param>
        private void RenderAndDraw(List<KeyValuePair<TDataSeries, PendingSeries>> toRender)
        {
            lock (_render_lock)
            {
                var all_series = toRender.Select(x => x.Value);

                foreach (var series in toRender)
                {
                    var points = OnRender(all_series, series.Key, series.Value);

                    series.Value.RenderedItems = series.Value.XX.Count;

                    if (points.Count > 1)
                    {
                        Output.Draw(all_series.Select(x => x.Series), series.Value.Series, points);
                    }
                }
            }
        }

        #endregion

        #region Event Handlers

        /// <summary>
        /// Handles the controller range changed event.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The event arguments.</param>
        private void Input_RangeChanged(object sender, GraphRange<XDataPoint, YDataPoint> e)
        {
            OnEffectiveRangeYChanged(Input.Range.MinimumY, Input.Range.MaximumY);
            OnEffectiveRangeXChanged(EffectiveMinimumX, Input.Range.MaximumX);
        }

        #endregion
    }
}