using System.Collections.Immutable;

namespace SideScrollerGame.Sim.Runtime;

public sealed class SimulationState
{
    public SimulationState(int tick, int seed, ulong randomState, ulong lastRandomValue, ImmutableArray<PlayerState> players, ImmutableHashSet<string> activatedTriggerIds)
    {
        Tick = tick;
        Seed = seed;
        RandomState = randomState;
        LastRandomValue = lastRandomValue;
        Players = players.IsDefault ? ImmutableArray<PlayerState>.Empty : players;
        ActivatedTriggerIds = activatedTriggerIds == default ? ImmutableHashSet<string>.Empty : activatedTriggerIds;
    }

    public SimulationState Clone()
    {
        var builder = ImmutableArray.CreateBuilder<PlayerState>(Players.Length);
        foreach (var player in Players)
            builder.Add(player.Clone());

        return new(Tick, Seed, RandomState, LastRandomValue, builder.MoveToImmutable(), ActivatedTriggerIds);
    }

    public PlayerState GetRequiredPlayer(PlayerId playerId)
    {
        foreach (var player in Players)
        {
            if (player.PlayerId == playerId)
                return player;
        }

        throw new InvalidOperationException($"Unknown player id {playerId.Value}.");
    }

    public void AdvanceTick(int tick, ulong randomState, ulong lastRandomValue)
    {
        Tick = tick;
        RandomState = randomState;
        LastRandomValue = lastRandomValue;
    }

    public bool ActivateTrigger(string triggerId)
    {
        if (ActivatedTriggerIds.Contains(triggerId))
            return false;

        ActivatedTriggerIds = ActivatedTriggerIds.Add(triggerId);
        return true;
    }

    public int Tick { get; private set; }

    public int Seed { get; }

    public ulong RandomState { get; private set; }

    public ulong LastRandomValue { get; private set; }

    public ImmutableArray<PlayerState> Players { get; }

    public ImmutableHashSet<string> ActivatedTriggerIds { get; private set; }
}