// <copyright file="GameMap.cs" company="MUnique">
// Licensed under the MIT License. See LICENSE file in the project root for full license information.
// </copyright>

namespace MUnique.OpenMU.GameLogic;

using System.Collections.Concurrent;
using System.Threading;
using MUnique.OpenMU.GameLogic.NPC;
using MUnique.OpenMU.GameLogic.PlayerActions;
using MUnique.OpenMU.GameLogic.Views;
using MUnique.OpenMU.GameLogic.Views.World;
using MUnique.OpenMU.Pathfinding;
using MUnique.OpenMU.Persistence;
using MUnique.OpenMU.PlugIns;
using Nito.AsyncEx;

/// <summary>
/// The game map which contains instances of players, npcs, drops, and more.
/// </summary>
public class GameMap
{
    private readonly IDictionary<ushort, ILocateable> _objectsInMap = new ConcurrentDictionary<ushort, ILocateable>();

    private readonly IAreaOfInterestManager _areaOfInterestManager;

    private readonly IdGenerator _objectIdGenerator;

    private readonly IdGenerator _dropIdGenerator;

    private readonly ExitGate? _safezoneSpawnGate;

    private int _playerCount;

    /// <summary>
    /// Initializes a new instance of the <see cref="GameMap" /> class.
    /// </summary>
    /// <param name="mapDefinition">The map definition.</param>
    /// <param name="itemDropDuration">Duration of the item drop.</param>
    /// <param name="chunkSize">Size of the chunk.</param>
    public GameMap(GameMapDefinition mapDefinition, TimeSpan itemDropDuration, byte chunkSize)
    {
        this.Id = Guid.NewGuid();
        this.Definition = mapDefinition;
        this.ItemDropDuration = itemDropDuration;
        this.Terrain = new GameMapTerrain(this.Definition);

        this._areaOfInterestManager = new BucketAreaOfInterestManager(chunkSize);
        this._objectIdGenerator = new IdGenerator(ViewExtensions.ConstantPlayerId + 1, 0x7FFF);
        this._dropIdGenerator = new IdGenerator(0, ViewExtensions.ConstantPlayerId - 1);

        this._safezoneSpawnGate = this.Definition.GetSafezoneGate(this.Terrain);
    }

    /// <summary>
    /// Occurs when an object was added to the map.
    /// </summary>
    public event AsyncEventHandler<(GameMap Map, ILocateable Object)>? ObjectAdded;

    /// <summary>
    /// Occurs when an object was removed from the map.
    /// </summary>
    public event AsyncEventHandler<(GameMap Map, ILocateable Object)>? ObjectRemoved;

    /// <summary>
    /// Gets the map identifier.
    /// </summary>
    public ushort MapId => this.Definition.Number.ToUnsigned();

    /// <summary>
    /// Gets the terrain of the map.
    /// </summary>
    public GameMapTerrain Terrain { get; }

    /// <summary>
    /// Gets the safe zone spawn gate.
    /// </summary>
    public ExitGate? SafeZoneSpawnGate => this._safezoneSpawnGate;

    /// <summary>
    /// Gets the duration about how long drops are laying on the ground until they are disappearing.
    /// </summary>
    public TimeSpan ItemDropDuration { get; }

    /// <summary>
    /// Gets the definition of the map.
    /// </summary>
    public GameMapDefinition Definition { get; }

    /// <summary>
    /// Gets the unique identifier of this map instance.
    /// </summary>
    public Guid Id { get; }

    /// <summary>
    /// Gets the object with the specified identifier.
    /// </summary>
    /// <param name="id">The identifier.</param>
    /// <returns>The object with the specified identifier.</returns>
    public ILocateable? GetObject(ushort id)
    {
        this._objectsInMap.TryGetValue(id, out var result);
        return result;
    }

    // ADAMU-CUSTOM: remote NPC ("NPC list" mobile feature) — spawn olmuş NPC'yi definition number ile bul.
    /// <summary>
    /// Gets a spawned non-player-character on this map by its definition number.
    /// Used to open an NPC's window remotely (mobile "NPC list" feature), independent
    /// of the player's position.
    /// </summary>
    /// <param name="number">The <see cref="MUnique.OpenMU.DataModel.Configuration.MonsterDefinition.Number"/>.</param>
    /// <returns>The first matching non-player-character, or <c>null</c>.</returns>
    public NonPlayerCharacter? GetNpcByNumber(short number)
    {
        return this._objectsInMap.Values
            .OfType<NonPlayerCharacter>()
            .FirstOrDefault(npc => npc.Definition.Number == number);
    }

    // ADAMU-CUSTOM end

    /// <summary>
    /// Gets the attackables in range of the specified coordinates.
    /// </summary>
    /// <param name="point">The coordinates.</param>
    /// <param name="range">The range.</param>
    /// <returns>The attackables in range of the specified coordinate.</returns>
    public IList<IAttackable> GetAttackablesInRange(Point point, int range)
    {
        return this._areaOfInterestManager.GetInRange(point, range).OfType<IAttackable>().ToList();
    }

    /// <summary>
    /// Gets all non-player characters (e.g. merchants) within the specified range of a point.
    /// </summary>
    /// <param name="point">The coordinates.</param>
    /// <param name="range">The range.</param>
    /// <returns>The non-player characters in range of the specified coordinate.</returns>
    public IList<NonPlayerCharacter> GetNpcsInRange(Point point, int range)
    {
        return this._areaOfInterestManager.GetInRange(point, range).OfType<NonPlayerCharacter>().ToList();
    }

    /// <summary>
    /// Gets all dropped items and money within the specified range of a point.
    /// </summary>
    /// <param name="point">The coordinates.</param>
    /// <param name="range">The range.</param>
    /// <returns>Dropped items and money in range.</returns>
    public IList<ILocateable> GetDropsInRange(Point point, int range)
    {
        return this._areaOfInterestManager.GetInRange(point, range)
            .Where(l => l is DroppedItem or DroppedMoney)
            .ToList();
    }

    /// <summary>
    /// Gets the drop by id.
    /// </summary>
    /// <param name="dropId">The drop identifier.</param>
    /// <returns>The dropped item.</returns>
    public ILocateable? GetDrop(ushort dropId)
    {
        this._objectsInMap.TryGetValue(dropId, out var item);
        return item;
    }

    /// <summary>
    /// Removes the locateable from the map.
    /// </summary>
    /// <param name="locateable">The locateable.</param>
    public async ValueTask RemoveAsync(ILocateable locateable)
    {
        await this._areaOfInterestManager.RemoveObjectAsync(locateable).ConfigureAwait(false);
        if (this._objectsInMap.Remove(locateable.Id) && locateable.Id != 0)
        {
            if (locateable is DroppedItem
                || locateable is DroppedMoney)
            {
                this._dropIdGenerator.GiveBack(locateable.Id);
            }
            else
            {
                this._objectIdGenerator.GiveBack(locateable.Id);
            }

            if (locateable is Player player)
            {
                player.Id = 0;
                Interlocked.Decrement(ref this._playerCount);
            }

            if (this.ObjectRemoved is { } eventHandler)
            {
                await eventHandler((this, locateable)).ConfigureAwait(false);
            }
        }
    }

    /// <summary>
    /// Adds the locateable to the map.
    /// </summary>
    /// <param name="locateable">The locateable object.</param>
    public async ValueTask AddAsync(ILocateable locateable)
    {
        if (!this._objectsInMap.TryGetValue(locateable.Id, out var existing)
            || existing != locateable)
        {
            switch (locateable)
            {
                case DroppedItem droppedItem:
                    droppedItem.Id = (ushort)this._dropIdGenerator.GenerateId();
                    break;
                case DroppedMoney droppedMoney:
                    droppedMoney.Id = (ushort)this._dropIdGenerator.GenerateId();
                    break;
                case Player player:
                    player.Id = (ushort)this._objectIdGenerator.GenerateId();
                    Interlocked.Increment(ref this._playerCount);
                    break;
                case NonPlayerCharacter npc:
                    npc.Id = (ushort)this._objectIdGenerator.GenerateId();
                    break;
                case ISupportIdUpdate idUpdate:
                    idUpdate.Id = (ushort)this._objectIdGenerator.GenerateId();
                    break;
                default:
                    throw new ArgumentException($"Adding an object of type {locateable.GetType()} is not supported.");
            }

            this._objectsInMap.Add(locateable.Id, locateable);
        }

        await this._areaOfInterestManager.AddObjectAsync(locateable).ConfigureAwait(false);
        if (this.ObjectAdded is { } eventHandler)
        {
            await eventHandler((this, locateable)).ConfigureAwait(false);
        }
    }

    /// <summary>
    /// Moves the locatable on the map.
    /// </summary>
    /// <param name="locatable">The monster.</param>
    /// <param name="target">The new coordinates.</param>
    /// <param name="moveLock">The move lock.</param>
    /// <param name="moveType">Type of the move.</param>
    public ValueTask MoveAsync(ILocateable locatable, Point target, AsyncLock moveLock, MoveType moveType)
    {
        return this._areaOfInterestManager.MoveObjectAsync(locatable, target, moveLock, moveType);
    }

    /// <summary>
    /// Initializes a respawn for the specified locateable.
    /// </summary>
    /// <param name="locateable">The locateable.</param>
    public async ValueTask InitRespawnAsync(ILocateable locateable)
    {
        await this._areaOfInterestManager.RemoveObjectAsync(locateable).ConfigureAwait(false);
    }

    /// <summary>
    /// Respawns the specified locateable.
    /// </summary>
    /// <param name="locateable">The locateable.</param>
    public async ValueTask RespawnAsync(ILocateable locateable)
    {
        await this._areaOfInterestManager.RemoveObjectAsync(locateable).ConfigureAwait(false);
        await this._areaOfInterestManager.AddObjectAsync(locateable).ConfigureAwait(false);
    }

    /// <summary>
    /// Clears event NPCs.
    /// </summary>
    public async ValueTask ClearEventSpawnedNpcsAsync()
    {
        var eventMonsters = this._objectsInMap.Values
            .OfType<NonPlayerCharacter>()
            .Where(n => n.SpawnArea.SpawnTrigger is not SpawnTrigger.Automatic)
            .ToList();
        foreach (var monster in eventMonsters)
        {
            await monster.CurrentMap.RemoveAsync(monster).ConfigureAwait(false);
            monster.Dispose();
        }
    }

    /// <summary>
    /// Clears the drops on invalid terrain.
    /// </summary>
    public async ValueTask ClearDropsOnInvalidTerrainAsync()
    {
        var drops = this._objectsInMap.Values
            .OfType<DroppedItem>()
            .Where(d => !this.Terrain.WalkMap[d.Position.X, d.Position.Y])
            .ToList();

        foreach (var drop in drops)
        {
            await drop.DisposeAsync().ConfigureAwait(false);
        }
    }
}