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

namespace MUnique.OpenMU.GameLogic.MiniGames;

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using MUnique.OpenMU.DataModel.Configuration;

/// <summary>
/// The context of the Heykel Savasi (statue war) event.
/// </summary>
/// <remarks>
/// This is the foundation class for the event: it tracks which team every participating player
/// belongs to, and enforces a team-balance rule when players attempt to join a team.
/// </remarks>
public class HeykelSavasiContext : MiniGameContext
{
    /// <summary>
    /// The maximum allowed difference between the red and blue team sizes after a join.
    /// </summary>
    private const int MaxTeamDifference = 2;

    /// <summary>
    /// The X1/Y1 anchor of the red team's base spawn gate.
    /// Must match Gates.cs targetGates 600 (RedBase).
    /// </summary>
    private const byte RedBaseAnchorX1 = 20;

    /// <summary>
    /// The X1/Y1 anchor of the red team's base spawn gate.
    /// Must match Gates.cs targetGates 600 (RedBase).
    /// </summary>
    private const byte RedBaseAnchorY1 = 20;

    /// <summary>
    /// The X1/Y1 anchor of the blue team's base spawn gate.
    /// Must match Gates.cs targetGates 601 (BlueBase).
    /// </summary>
    private const byte BlueBaseAnchorX1 = 220;

    /// <summary>
    /// The X1/Y1 anchor of the blue team's base spawn gate.
    /// Must match Gates.cs targetGates 601 (BlueBase).
    /// </summary>
    private const byte BlueBaseAnchorY1 = 220;

    private readonly ConcurrentDictionary<Player, HeykelSavasiTeam> _teams = new();

    /// <summary>
    /// Initializes a new instance of the <see cref="HeykelSavasiContext"/> class.
    /// </summary>
    /// <param name="key">The key of this context.</param>
    /// <param name="definition">The definition of the mini game.</param>
    /// <param name="gameContext">The game context, to which this game belongs.</param>
    /// <param name="mapInitializer">The map initializer, which is used when the event starts.</param>
    public HeykelSavasiContext(MiniGameMapKey key, MiniGameDefinition definition, IGameContext gameContext, IMapInitializer mapInitializer)
        : base(key, definition, gameContext, mapInitializer)
    {
    }

    /// <summary>
    /// Gets the current number of players assigned to the given team.
    /// </summary>
    /// <param name="team">The team.</param>
    /// <returns>The number of players currently assigned to <paramref name="team"/>.</returns>
    public int TeamCount(HeykelSavasiTeam team) => this._teams.Values.Count(t => t == team);

    /// <summary>
    /// Determines whether a player may currently join the given team, based on the team-balance rule.
    /// </summary>
    /// <param name="team">The team which a player wants to join.</param>
    /// <returns><c>true</c> if the join is allowed; otherwise, <c>false</c>.</returns>
    public bool CanJoin(HeykelSavasiTeam team) => IsJoinAllowed(this.TeamCount(HeykelSavasiTeam.Red), this.TeamCount(HeykelSavasiTeam.Blue), team);

    /// <summary>
    /// Assigns the given player to the given team.
    /// </summary>
    /// <param name="player">The player.</param>
    /// <param name="team">The team.</param>
    public void AssignTeam(Player player, HeykelSavasiTeam team) => this._teams[player] = team;

    /// <summary>
    /// Gets the team of the given player.
    /// </summary>
    /// <param name="player">The player.</param>
    /// <returns>The team of the player, or <see cref="HeykelSavasiTeam.None"/> if the player is not assigned to a team.</returns>
    public HeykelSavasiTeam GetTeam(Player player) => this._teams.TryGetValue(player, out var team) ? team : HeykelSavasiTeam.None;

    /// <summary>
    /// Gets the base spawn gate for the given team.
    /// </summary>
    /// <param name="team">The team.</param>
    /// <returns>The <see cref="ExitGate"/> which is the base spawn point of <paramref name="team"/>.</returns>
    /// <remarks>
    /// The gate is resolved by matching the X1/Y1 anchor of the gates created for this event's map
    /// (see Gates.cs targetGates 600/601, added in Task 0.3). Red anchors at (20, 20), Blue at (220, 220).
    /// </remarks>
    public ExitGate GetTeamSpawnGate(HeykelSavasiTeam team)
    {
        var (anchorX1, anchorY1) = team == HeykelSavasiTeam.Blue
            ? (BlueBaseAnchorX1, BlueBaseAnchorY1)
            : (RedBaseAnchorX1, RedBaseAnchorY1);

        return this.Definition.Entrance!.Map!.ExitGates.First(g => g.X1 == anchorX1 && g.Y1 == anchorY1);
    }

    /// <summary>
    /// Gets all players which are currently assigned to the given team.
    /// </summary>
    /// <param name="team">The team.</param>
    /// <returns>All players assigned to <paramref name="team"/>.</returns>
    public IEnumerable<Player> PlayersOf(HeykelSavasiTeam team) => this._teams.Where(kv => kv.Value == team).Select(kv => kv.Key);

    /// <summary>
    /// Determines, in a pure way, whether joining <paramref name="team"/> is allowed given the current
    /// team counts, according to the balance rule: the absolute difference between the red and blue
    /// team sizes must not exceed <see cref="MaxTeamDifference"/> after the prospective join.
    /// </summary>
    /// <param name="redCount">The current number of players in the red team.</param>
    /// <param name="blueCount">The current number of players in the blue team.</param>
    /// <param name="team">The team which a player wants to join.</param>
    /// <returns><c>true</c> if the join is allowed; otherwise, <c>false</c>.</returns>
    internal static bool IsJoinAllowed(int redCount, int blueCount, HeykelSavasiTeam team)
    {
        switch (team)
        {
            case HeykelSavasiTeam.Red:
                redCount++;
                break;
            case HeykelSavasiTeam.Blue:
                blueCount++;
                break;
            default:
                return false;
        }

        return Math.Abs(redCount - blueCount) <= MaxTeamDifference;
    }
}