// 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 System;
using System.Diagnostics;
using System.Linq;
using JetBrains.Annotations;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Input.Events;
using osu.Framework.Screens;
using osu.Game.Graphics.Containers;
using osu.Game.Graphics.UserInterface;
using osu.Game.Online.Rooms;
using osu.Game.Overlays;
using osu.Game.Screens.OnlinePlay.Lounge.Components;
using osu.Game.Screens.OnlinePlay.Match;
using osu.Game.Users;

namespace osu.Game.Screens.OnlinePlay.Lounge
{
    [Cached]
    public abstract class LoungeSubScreen : OnlinePlaySubScreen
    {
        public override string Title => "Lounge";

        protected override UserActivity InitialActivity => new UserActivity.SearchingForLobby();

        private readonly IBindable<bool> initialRoomsReceived = new Bindable<bool>();
        private readonly IBindable<bool> operationInProgress = new Bindable<bool>();

        private FilterControl filter;
        private Container content;
        private LoadingLayer loadingLayer;

        [Resolved]
        private Bindable<Room> selectedRoom { get; set; }

        [Resolved]
        private MusicController music { get; set; }

        [Resolved(CanBeNull = true)]
        private OngoingOperationTracker ongoingOperationTracker { get; set; }

        [CanBeNull]
        private IDisposable joiningRoomOperation { get; set; }

        [BackgroundDependencyLoader]
        private void load()
        {
            RoomsContainer roomsContainer;
            OsuScrollContainer scrollContainer;

            InternalChildren = new Drawable[]
            {
                content = new Container
                {
                    RelativeSizeAxes = Axes.Both,
                    Children = new Drawable[]
                    {
                        new Container
                        {
                            RelativeSizeAxes = Axes.Both,
                            Width = 0.55f,
                            Children = new Drawable[]
                            {
                                scrollContainer = new OsuScrollContainer
                                {
                                    RelativeSizeAxes = Axes.Both,
                                    ScrollbarOverlapsContent = false,
                                    Padding = new MarginPadding(10),
                                    Child = roomsContainer = new RoomsContainer { JoinRequested = joinRequested }
                                },
                                loadingLayer = new LoadingLayer(true),
                            }
                        },
                        new RoomInspector
                        {
                            Anchor = Anchor.TopRight,
                            Origin = Anchor.TopRight,
                            RelativeSizeAxes = Axes.Both,
                            Width = 0.45f,
                        },
                    },
                },
                filter = CreateFilterControl().With(d =>
                {
                    d.RelativeSizeAxes = Axes.X;
                    d.Height = 80;
                })
            };

            // scroll selected room into view on selection.
            selectedRoom.BindValueChanged(val =>
            {
                var drawable = roomsContainer.Rooms.FirstOrDefault(r => r.Room == val.NewValue);
                if (drawable != null)
                    scrollContainer.ScrollIntoView(drawable);
            });
        }

        protected override void LoadComplete()
        {
            base.LoadComplete();

            initialRoomsReceived.BindTo(RoomManager.InitialRoomsReceived);
            initialRoomsReceived.BindValueChanged(_ => updateLoadingLayer());

            if (ongoingOperationTracker != null)
            {
                operationInProgress.BindTo(ongoingOperationTracker.InProgress);
                operationInProgress.BindValueChanged(_ => updateLoadingLayer(), true);
            }
        }

        protected override void UpdateAfterChildren()
        {
            base.UpdateAfterChildren();

            content.Padding = new MarginPadding
            {
                Top = filter.DrawHeight,
                Left = WaveOverlayContainer.WIDTH_PADDING - DrawableRoom.SELECTION_BORDER_WIDTH + HORIZONTAL_OVERFLOW_PADDING,
                Right = WaveOverlayContainer.WIDTH_PADDING + HORIZONTAL_OVERFLOW_PADDING,
            };
        }

        protected override void OnFocus(FocusEvent e)
        {
            filter.TakeFocus();
        }

        public override void OnEntering(IScreen last)
        {
            base.OnEntering(last);

            onReturning();
        }

        public override void OnResuming(IScreen last)
        {
            base.OnResuming(last);

            if (selectedRoom.Value?.RoomID.Value == null)
                selectedRoom.Value = new Room();

            music?.EnsurePlayingSomething();

            onReturning();
        }

        private void onReturning()
        {
            filter.HoldFocus = true;
        }

        public override bool OnExiting(IScreen next)
        {
            filter.HoldFocus = false;
            return base.OnExiting(next);
        }

        public override void OnSuspending(IScreen next)
        {
            base.OnSuspending(next);
            filter.HoldFocus = false;
        }

        private void joinRequested(Room room)
        {
            Debug.Assert(joiningRoomOperation == null);
            joiningRoomOperation = ongoingOperationTracker?.BeginOperation();

            RoomManager?.JoinRoom(room, r =>
            {
                Open(room);
                joiningRoomOperation?.Dispose();
                joiningRoomOperation = null;
            }, _ =>
            {
                joiningRoomOperation?.Dispose();
                joiningRoomOperation = null;
            });
        }

        private void updateLoadingLayer()
        {
            if (operationInProgress.Value || !initialRoomsReceived.Value)
                loadingLayer.Show();
            else
                loadingLayer.Hide();
        }

        /// <summary>
        /// Push a room as a new subscreen.
        /// </summary>
        public virtual void Open(Room room)
        {
            // Handles the case where a room is clicked 3 times in quick succession
            if (!this.IsCurrentScreen())
                return;

            selectedRoom.Value = room;

            this.Push(CreateRoomSubScreen(room));
        }

        protected abstract FilterControl CreateFilterControl();

        protected abstract RoomSubScreen CreateRoomSubScreen(Room room);
    }
}