// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics;
using osu.Game.Graphics;
using osu.Framework.Graphics.Sprites;
using osuTK;
using osu.Game.Online.API.Requests.Responses;
using osu.Game.Users.Drawables;
using osu.Game.Graphics.Containers;
using osu.Game.Utils;
using osu.Framework.Graphics.Cursor;
using osu.Framework.Bindables;
using System.Linq;
using osu.Game.Graphics.Sprites;
using osu.Game.Online.Chat;
using osu.Framework.Allocation;
using System.Collections.Generic;
using System;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Extensions.IEnumerableExtensions;
using System.Collections.Specialized;
using osu.Game.Overlays.Comments.Buttons;

namespace osu.Game.Overlays.Comments
{
    public class DrawableComment : CompositeDrawable
    {
        private const int avatar_size = 40;

        public Action<DrawableComment, int> RepliesRequested;

        public readonly Comment Comment;

        public readonly BindableBool ShowDeleted = new BindableBool();
        public readonly Bindable<CommentsSortCriteria> Sort = new Bindable<CommentsSortCriteria>();
        private readonly Dictionary<long, Comment> loadedReplies = new Dictionary<long, Comment>();

        public readonly BindableList<DrawableComment> Replies = new BindableList<DrawableComment>();

        private readonly BindableBool childrenExpanded = new BindableBool(true);

        private int currentPage;

        private FillFlowContainer childCommentsVisibilityContainer;
        private FillFlowContainer childCommentsContainer;
        private LoadRepliesButton loadRepliesButton;
        private ShowMoreButton showMoreButton;
        private ShowRepliesButton showRepliesButton;
        private ChevronButton chevronButton;
        private DeletedCommentsCounter deletedCommentsCounter;

        public DrawableComment(Comment comment)
        {
            Comment = comment;
        }

        [BackgroundDependencyLoader]
        private void load(OverlayColourProvider colourProvider)
        {
            LinkFlowContainer username;
            FillFlowContainer info;
            LinkFlowContainer message;
            GridContainer content;
            VotePill votePill;

            RelativeSizeAxes = Axes.X;
            AutoSizeAxes = Axes.Y;
            InternalChildren = new Drawable[]
            {
                new Container
                {
                    RelativeSizeAxes = Axes.X,
                    AutoSizeAxes = Axes.Y,
                    Padding = getPadding(Comment.IsTopLevel),
                    Child = new FillFlowContainer
                    {
                        RelativeSizeAxes = Axes.X,
                        AutoSizeAxes = Axes.Y,
                        Direction = FillDirection.Vertical,
                        Children = new Drawable[]
                        {
                            content = new GridContainer
                            {
                                RelativeSizeAxes = Axes.X,
                                AutoSizeAxes = Axes.Y,
                                ColumnDimensions = new[]
                                {
                                    new Dimension(GridSizeMode.Absolute, size: avatar_size + 10),
                                    new Dimension(),
                                },
                                RowDimensions = new[]
                                {
                                    new Dimension(GridSizeMode.AutoSize)
                                },
                                Content = new[]
                                {
                                    new Drawable[]
                                    {
                                        new Container
                                        {
                                            Size = new Vector2(avatar_size),
                                            Children = new Drawable[]
                                            {
                                                new UpdateableAvatar(Comment.User)
                                                {
                                                    Size = new Vector2(avatar_size),
                                                    Masking = true,
                                                    CornerRadius = avatar_size / 2f,
                                                    CornerExponent = 2,
                                                },
                                                votePill = new VotePill(Comment)
                                                {
                                                    Anchor = Anchor.CentreLeft,
                                                    Origin = Anchor.CentreRight,
                                                    Margin = new MarginPadding
                                                    {
                                                        Right = 5
                                                    }
                                                }
                                            }
                                        },
                                        new FillFlowContainer
                                        {
                                            RelativeSizeAxes = Axes.X,
                                            AutoSizeAxes = Axes.Y,
                                            Direction = FillDirection.Vertical,
                                            Spacing = new Vector2(0, 4),
                                            Margin = new MarginPadding
                                            {
                                                Vertical = 2
                                            },
                                            Children = new Drawable[]
                                            {
                                                new FillFlowContainer
                                                {
                                                    AutoSizeAxes = Axes.Both,
                                                    Direction = FillDirection.Horizontal,
                                                    Spacing = new Vector2(10, 0),
                                                    Children = new Drawable[]
                                                    {
                                                        username = new LinkFlowContainer(s => s.Font = OsuFont.GetFont(size: 14, weight: FontWeight.Bold))
                                                        {
                                                            AutoSizeAxes = Axes.Both
                                                        },
                                                        new ParentUsername(Comment),
                                                        new OsuSpriteText
                                                        {
                                                            Alpha = Comment.IsDeleted ? 1 : 0,
                                                            Font = OsuFont.GetFont(size: 14, weight: FontWeight.Bold),
                                                            Text = "deleted"
                                                        }
                                                    }
                                                },
                                                message = new LinkFlowContainer(s => s.Font = OsuFont.GetFont(size: 14))
                                                {
                                                    RelativeSizeAxes = Axes.X,
                                                    AutoSizeAxes = Axes.Y
                                                },
                                                info = new FillFlowContainer
                                                {
                                                    AutoSizeAxes = Axes.Both,
                                                    Direction = FillDirection.Horizontal,
                                                    Spacing = new Vector2(10, 0),
                                                    Children = new Drawable[]
                                                    {
                                                        new DrawableDate(Comment.CreatedAt, 12, false)
                                                        {
                                                            Colour = colourProvider.Foreground1
                                                        }
                                                    }
                                                },
                                                new Container
                                                {
                                                    AutoSizeAxes = Axes.Both,
                                                    Children = new Drawable[]
                                                    {
                                                        showRepliesButton = new ShowRepliesButton(Comment.RepliesCount)
                                                        {
                                                            Expanded = { BindTarget = childrenExpanded }
                                                        },
                                                        loadRepliesButton = new LoadRepliesButton
                                                        {
                                                            Action = () => RepliesRequested(this, ++currentPage)
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            },
                            childCommentsVisibilityContainer = new FillFlowContainer
                            {
                                RelativeSizeAxes = Axes.X,
                                AutoSizeAxes = Axes.Y,
                                Direction = FillDirection.Vertical,
                                Padding = new MarginPadding { Left = 20 },
                                Children = new Drawable[]
                                {
                                    childCommentsContainer = new FillFlowContainer
                                    {
                                        RelativeSizeAxes = Axes.X,
                                        AutoSizeAxes = Axes.Y,
                                        Direction = FillDirection.Vertical
                                    },
                                    deletedCommentsCounter = new DeletedCommentsCounter
                                    {
                                        ShowDeleted = { BindTarget = ShowDeleted },
                                        Margin = new MarginPadding
                                        {
                                            Top = 10
                                        }
                                    },
                                    showMoreButton = new ShowMoreButton
                                    {
                                        Action = () => RepliesRequested(this, ++currentPage)
                                    }
                                }
                            },
                        }
                    }
                },
                new Container
                {
                    Size = new Vector2(70, 40),
                    Anchor = Anchor.TopRight,
                    Origin = Anchor.TopRight,
                    Margin = new MarginPadding { Horizontal = 5 },
                    Child = chevronButton = new ChevronButton
                    {
                        Anchor = Anchor.CentreLeft,
                        Origin = Anchor.CentreLeft,
                        Expanded = { BindTarget = childrenExpanded },
                        Alpha = 0
                    }
                }
            };

            if (Comment.UserId.HasValue)
                username.AddUserLink(Comment.User);
            else
                username.AddText(Comment.LegacyName);

            if (Comment.EditedAt.HasValue)
            {
                info.Add(new OsuSpriteText
                {
                    Font = OsuFont.GetFont(size: 12, weight: FontWeight.Regular),
                    Text = $@"edited {HumanizerUtils.Humanize(Comment.EditedAt.Value)} by {Comment.EditedUser.Username}",
                    Colour = colourProvider.Foreground1
                });
            }

            if (Comment.HasMessage)
            {
                var formattedSource = MessageFormatter.FormatText(Comment.Message);
                message.AddLinks(formattedSource.Text, formattedSource.Links);
            }

            if (Comment.IsDeleted)
            {
                content.FadeColour(OsuColour.Gray(0.5f));
                votePill.Hide();
            }

            if (Comment.IsTopLevel)
            {
                AddInternal(new Box
                {
                    Anchor = Anchor.BottomCentre,
                    Origin = Anchor.BottomCentre,
                    RelativeSizeAxes = Axes.X,
                    Height = 1.5f,
                    Colour = OsuColour.Gray(0.1f)
                });
            }

            if (Replies.Any())
                onRepliesAdded(Replies);

            Replies.CollectionChanged += (_, args) =>
            {
                switch (args.Action)
                {
                    case NotifyCollectionChangedAction.Add:
                        onRepliesAdded(args.NewItems.Cast<DrawableComment>());
                        break;

                    default:
                        throw new NotSupportedException(@"You can only add replies to this list. Other actions are not supported.");
                }
            };
        }

        protected override void LoadComplete()
        {
            ShowDeleted.BindValueChanged(show =>
            {
                if (Comment.IsDeleted)
                    this.FadeTo(show.NewValue ? 1 : 0);
            }, true);
            childrenExpanded.BindValueChanged(expanded => childCommentsVisibilityContainer.FadeTo(expanded.NewValue ? 1 : 0), true);

            updateButtonsState();

            base.LoadComplete();
        }

        public bool ContainsReply(long replyId) => loadedReplies.ContainsKey(replyId);

        private void onRepliesAdded(IEnumerable<DrawableComment> replies)
        {
            var page = createRepliesPage(replies);

            if (LoadState == LoadState.Loading)
            {
                addRepliesPage(page, replies);
                return;
            }

            LoadComponentAsync(page, loaded => addRepliesPage(loaded, replies));
        }

        private void addRepliesPage(FillFlowContainer<DrawableComment> page, IEnumerable<DrawableComment> replies)
        {
            childCommentsContainer.Add(page);

            var newReplies = replies.Select(reply => reply.Comment);
            newReplies.ForEach(reply => loadedReplies.Add(reply.Id, reply));
            deletedCommentsCounter.Count.Value += newReplies.Count(reply => reply.IsDeleted);
            updateButtonsState();
        }

        private FillFlowContainer<DrawableComment> createRepliesPage(IEnumerable<DrawableComment> replies) => new FillFlowContainer<DrawableComment>
        {
            RelativeSizeAxes = Axes.X,
            AutoSizeAxes = Axes.Y,
            Direction = FillDirection.Vertical,
            Children = replies.ToList()
        };

        private void updateButtonsState()
        {
            var loadedReplesCount = loadedReplies.Count;
            var hasUnloadedReplies = loadedReplesCount != Comment.RepliesCount;

            loadRepliesButton.FadeTo(hasUnloadedReplies && loadedReplesCount == 0 ? 1 : 0);
            showMoreButton.FadeTo(hasUnloadedReplies && loadedReplesCount > 0 ? 1 : 0);
            showRepliesButton.FadeTo(loadedReplesCount != 0 ? 1 : 0);

            if (Comment.IsTopLevel)
                chevronButton.FadeTo(loadedReplesCount != 0 ? 1 : 0);

            showMoreButton.IsLoading = loadRepliesButton.IsLoading = false;
        }

        private MarginPadding getPadding(bool isTopLevel)
        {
            if (isTopLevel)
            {
                return new MarginPadding
                {
                    Horizontal = 70,
                    Vertical = 15
                };
            }

            return new MarginPadding
            {
                Top = 10
            };
        }

        private class ParentUsername : FillFlowContainer, IHasTooltip
        {
            public string TooltipText => getParentMessage();

            private readonly Comment parentComment;

            public ParentUsername(Comment comment)
            {
                parentComment = comment.ParentComment;

                AutoSizeAxes = Axes.Both;
                Direction = FillDirection.Horizontal;
                Spacing = new Vector2(3, 0);
                Alpha = comment.ParentId == null ? 0 : 1;
                Children = new Drawable[]
                {
                    new SpriteIcon
                    {
                        Icon = FontAwesome.Solid.Reply,
                        Size = new Vector2(14),
                    },
                    new OsuSpriteText
                    {
                        Font = OsuFont.GetFont(size: 14, weight: FontWeight.Bold, italics: true),
                        Text = parentComment?.User?.Username ?? parentComment?.LegacyName
                    }
                };
            }

            private string getParentMessage()
            {
                if (parentComment == null)
                    return string.Empty;

                return parentComment.HasMessage ? parentComment.Message : parentComment.IsDeleted ? @"deleted" : string.Empty;
            }
        }
    }
}