// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using System.Linq;
using OpenTK;
using osu.Framework.Allocation;
using osu.Framework.Configuration;
using osu.Framework.Extensions.IEnumerableExtensions;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Input;
using osu.Game.Beatmaps;
using osu.Game.Beatmaps.ControlPoints;
using osu.Game.Beatmaps.Timing;
using osu.Game.Graphics;

namespace osu.Game.Screens.Edit.Components
{
    /// <summary>
    /// The timeline that sits at the bottom of the editor.
    /// </summary>
    public class SummaryTimeline : CompositeDrawable
    {
        private const float corner_radius = 5;
        private const float contents_padding = 15;
        private const float marker_bar_width = 2;

        private readonly Drawable background;

        private readonly Container markerContainer;

        private readonly Drawable timelineBar;
        private readonly Drawable marker;

        private readonly Bindable<WorkingBeatmap> beatmap = new Bindable<WorkingBeatmap>();

        public SummaryTimeline()
        {
            Masking = true;
            CornerRadius = 5;

            InternalChildren = new[]
            {
                    background = new Box { RelativeSizeAxes = Axes.Both },
                    new Container
                    {
                        RelativeSizeAxes = Axes.Both,
                        Padding = new MarginPadding { Left = contents_padding, Right = contents_padding },
                        Children = new[]
                        {
                            markerContainer = new Container
                            {
                                RelativeSizeAxes = Axes.Both,
                                Child = marker = new Container
                                {
                                    Anchor = Anchor.CentreLeft,
                                    Origin = Anchor.Centre,
                                    RelativePositionAxes = Axes.X,
                                    RelativeSizeAxes = Axes.Y,
                                    AutoSizeAxes = Axes.X,
                                    Children = new Drawable[]
                                    {
                                        new Triangle
                                        {
                                            Anchor = Anchor.TopCentre,
                                            Origin = Anchor.BottomCentre,
                                            Scale = new Vector2(1, -1),
                                            Size = new Vector2(10, 5),
                                        },
                                        new Triangle
                                        {
                                            Anchor = Anchor.BottomCentre,
                                            Origin = Anchor.BottomCentre,
                                            Size = new Vector2(10, 5)
                                        },
                                        new Box
                                        {
                                            Anchor = Anchor.Centre,
                                            Origin = Anchor.Centre,
                                            RelativeSizeAxes = Axes.Y,
                                            Width = 2,
                                            EdgeSmoothness = new Vector2(1, 0)
                                        }
                                    }
                                }
                            },
                            new ControlPointTimeline
                            {
                                Anchor = Anchor.Centre,
                                Origin = Anchor.BottomCentre,
                                RelativeSizeAxes = Axes.Both,
                                Height = 0.35f
                            },
                            new BookmarkTimeline
                            {
                                Anchor = Anchor.Centre,
                                RelativeSizeAxes = Axes.Both,
                                Height = 0.35f
                            },
                            timelineBar = new Container
                            {
                                RelativeSizeAxes = Axes.Both,
                                Children = new Drawable[]
                                {
                                    new Circle
                                    {
                                        Anchor = Anchor.CentreLeft,
                                        Origin = Anchor.CentreRight,
                                        Size = new Vector2(5)
                                    },
                                    new Box
                                    {
                                        Anchor = Anchor.CentreLeft,
                                        Origin = Anchor.CentreLeft,
                                        RelativeSizeAxes = Axes.X,
                                        Height = 1,
                                        EdgeSmoothness = new Vector2(0, 1),
                                    },
                                    new Circle
                                    {
                                        Anchor = Anchor.CentreRight,
                                        Origin = Anchor.CentreLeft,
                                        Size = new Vector2(5)
                                    },
                                }
                            },
                            new BreakTimeline
                            {
                                Anchor = Anchor.Centre,
                                Origin = Anchor.Centre,
                                RelativeSizeAxes = Axes.Both,
                                Height = 0.25f
                            }
                        }
                    }
                };
        }

        [BackgroundDependencyLoader]
        private void load(OsuGameBase osuGame, OsuColour colours)
        {
            background.Colour = colours.Gray1;
            marker.Colour = colours.Red;
            timelineBar.Colour = colours.Gray5;

            beatmap.BindTo(osuGame.Beatmap);

            markerContainer.RelativeChildSize = new Vector2((float)Math.Max(1, beatmap.Value.Track.Length), 1);
            beatmap.ValueChanged += b => markerContainer.RelativeChildSize = new Vector2((float)Math.Max(1, b.Track.Length), 1);
        }

        protected override bool OnDragStart(InputState state) => true;
        protected override bool OnDragEnd(InputState state) => true;
        protected override bool OnDrag(InputState state)
        {
            seekToPosition(state.Mouse.NativeState.Position);
            return true;
        }

        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
        {
            seekToPosition(state.Mouse.NativeState.Position);
            return true;
        }

        /// <summary>
        /// Seeks the <see cref="SummaryTimeline"/> to the time closest to a position on the screen relative to the <see cref="SummaryTimeline"/>.
        /// </summary>
        /// <param name="screenPosition">The position in screen coordinates.</param>
        private void seekToPosition(Vector2 screenPosition)
        {
            float markerPos = MathHelper.Clamp(markerContainer.ToLocalSpace(screenPosition).X, 0, markerContainer.DrawWidth);
            seekTo(markerPos / markerContainer.DrawWidth * beatmap.Value.Track.Length);
        }

        private void seekTo(double time) => beatmap.Value.Track.Seek(time);

        protected override void Update()
        {
            base.Update();
            marker.X = (float)beatmap.Value.Track.CurrentTime;
        }

        /// <summary>
        /// The part of the timeline that displays the control points.
        /// </summary>
        private class ControlPointTimeline : Timeline
        {
            protected override void LoadBeatmap(WorkingBeatmap beatmap)
            {
                ControlPointInfo cpi = beatmap.Beatmap.ControlPointInfo;

                cpi.TimingPoints.ForEach(addTimingPoint);

                // Consider all non-timing points as the same type
                cpi.SoundPoints.Select(c => (ControlPoint)c)
                    .Concat(cpi.EffectPoints)
                    .Concat(cpi.DifficultyPoints)
                    .Distinct()
                    // Non-timing points should not be added where there are timing points
                    .Where(c => cpi.TimingPointAt(c.Time).Time != c.Time)
                    .ForEach(addNonTimingPoint);
            }

            private void addTimingPoint(ControlPoint controlPoint) => Add(new TimingPointVisualisation(controlPoint));
            private void addNonTimingPoint(ControlPoint controlPoint) => Add(new NonTimingPointVisualisation(controlPoint));

            private class TimingPointVisualisation : ControlPointVisualisation
            {
                public TimingPointVisualisation(ControlPoint controlPoint)
                    : base(controlPoint)
                {
                }

                [BackgroundDependencyLoader]
                private void load(OsuColour colours) => Colour = colours.YellowDark;
            }

            private class NonTimingPointVisualisation : ControlPointVisualisation
            {
                public NonTimingPointVisualisation(ControlPoint controlPoint)
                    : base(controlPoint)
                {
                }

                [BackgroundDependencyLoader]
                private void load(OsuColour colours) => Colour = colours.Green;
            }

            private abstract class ControlPointVisualisation : PointVisualisation
            {
                protected ControlPointVisualisation(ControlPoint controlPoint)
                    : base(controlPoint.Time)
                {
                }
            }
        }

        /// <summary>
        /// The part of the timeline that displays bookmarks.
        /// </summary>
        private class BookmarkTimeline : Timeline
        {
            protected override void LoadBeatmap(WorkingBeatmap beatmap)
            {
                foreach (int bookmark in beatmap.BeatmapInfo.Bookmarks)
                    Add(new BookmarkVisualisation(bookmark));
            }

            private class BookmarkVisualisation : PointVisualisation
            {
                public BookmarkVisualisation(double startTime)
                    : base(startTime)
                {
                }

                [BackgroundDependencyLoader]
                private void load(OsuColour colours) => Colour = colours.Blue;
            }
        }

        /// <summary>
        /// The part of the timeline that displays breaks in the song.
        /// </summary>
        private class BreakTimeline : Timeline
        {
            protected override void LoadBeatmap(WorkingBeatmap beatmap)
            {
                foreach (var breakPeriod in beatmap.Beatmap.Breaks)
                    Add(new BreakVisualisation(breakPeriod));
            }

            private class BreakVisualisation : DurationVisualisation
            {
                public BreakVisualisation(BreakPeriod breakPeriod)
                    : base(breakPeriod.StartTime, breakPeriod.EndTime)
                {
                }

                [BackgroundDependencyLoader]
                private void load(OsuColour colours) => Colour = colours.Yellow;
            }
        }

        /// <summary>
        /// Represents a part of the editor timeline.
        /// </summary>
        private abstract class Timeline : CompositeDrawable
        {
            private readonly Container timeline;

            protected Timeline()
            {
                AddInternal(timeline = new Container { RelativeSizeAxes = Axes.Both });
            }

            [BackgroundDependencyLoader]
            private void load(OsuGameBase osuGame)
            {
                osuGame.Beatmap.ValueChanged += b =>
                {
                    timeline.Clear();
                    timeline.RelativeChildSize = new Vector2((float)Math.Max(1, b.Track.Length), 1);
                    LoadBeatmap(b);
                };

                timeline.RelativeChildSize = new Vector2((float)Math.Max(1, osuGame.Beatmap.Value.Track.Length), 1);
                LoadBeatmap(osuGame.Beatmap);
            }

            protected void Add(PointVisualisation visualisation) => timeline.Add(visualisation);
            protected void Add(DurationVisualisation visualisation) => timeline.Add(visualisation);

            protected abstract void LoadBeatmap(WorkingBeatmap beatmap);
        }

        /// <summary>
        /// Represents a singular point on a <see cref="Timeline"/>.
        /// </summary>
        private class PointVisualisation : Box
        {
            protected PointVisualisation(double startTime)
            {
                Origin = Anchor.TopCentre;

                RelativeSizeAxes = Axes.Y;
                Width = 1;
                EdgeSmoothness = new Vector2(1, 0);

                RelativePositionAxes = Axes.X;
                X = (float)startTime;
            }
        }

        /// <summary>
        /// Represents a spanning point on a <see cref="Timeline"/>.
        /// </summary>
        private class DurationVisualisation : Container
        {
            protected DurationVisualisation(double startTime, double endTime)
            {
                Masking = true;
                CornerRadius = corner_radius;

                RelativePositionAxes = Axes.X;
                RelativeSizeAxes = Axes.Both;
                X = (float)startTime;
                Width = (float)(endTime - startTime);

                AddInternal(new Box { RelativeSizeAxes = Axes.Both });
            }
        }
    }
}