using Chessistics.Engine.Commands;
using Chessistics.Engine.Events;
using Chessistics.Engine.Model;
using Chessistics.Tests.Helpers;
using Xunit;

namespace Chessistics.Tests.Simulation;

public class GameSimTests
{
    private SimHelper CreateLevel1Sim()
    {
        var level = new BoardBuilder(4, 4)
            .WithProduction(0, 0, "Scierie", CargoType.Wood)
            .WithDemand(3, 0, "Depot Royal", CargoType.Wood, 3, 30)
            .WithStock(PieceKind.Rook, 3)
            .Build();
        return SimHelper.FromLevel(level);
    }

    [Fact]
    public void PlacePiece_Succeeds()
    {
        var sim = CreateLevel1Sim();
        var events = sim.Place(PieceKind.Rook, (0, 0), (1, 0));

        Assert.Single(events);
        Assert.IsType<PiecePlacedEvent>(events[0]);
        var placed = (PiecePlacedEvent)events[0];
        Assert.Equal(PieceKind.Rook, placed.Kind);
    }

    [Fact]
    public void PlacePiece_StockExhausted_Rejected()
    {
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
        sim.Place(PieceKind.Rook, (0, 1), (1, 1));
        sim.Place(PieceKind.Rook, (0, 2), (1, 2));

        // 4th rook — only 3 in stock
        var events = sim.Place(PieceKind.Rook, (0, 3), (1, 3));
        Assert.IsType<PlacementRejectedEvent>(events[0]);
    }

    [Fact]
    public void PlaceDuringRunning_Succeeds()
    {
        // In the new system, placement works in any phase
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
        sim.Resume(); // Paused → Running

        var events = sim.Place(PieceKind.Rook, (0, 1), (1, 1));
        Assert.IsType<PiecePlacedEvent>(events[0]);
    }

    [Fact]
    public void RemoveDuringRunning_Succeeds()
    {
        // In the new system, removal works in any phase
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
        sim.Resume(); // Paused → Running

        var events = sim.Remove(1);
        Assert.IsType<PieceRemovedEvent>(events[0]);
    }

    [Fact]
    public void SinglePiece_Oscillates()
    {
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (2, 0));

        // Step 1: piece moves from (0,0) to (2,0)
        var events1 = sim.Step();
        Assert.Contains(events1, e => e is PieceMovedEvent m && m.From == new Coords(0, 0) && m.To == new Coords(2, 0));

        // Step 2: piece moves back from (2,0) to (0,0)
        var events2 = sim.Step();
        Assert.Contains(events2, e => e is PieceMovedEvent m && m.From == new Coords(2, 0) && m.To == new Coords(0, 0));

        // Step 3: piece moves forward again
        var events3 = sim.Step();
        Assert.Contains(events3, e => e is PieceMovedEvent m && m.From == new Coords(0, 0) && m.To == new Coords(2, 0));
    }

    [Fact]
    public void ChainedPieces_TransferCargo()
    {
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (1, 0));
        sim.Place(PieceKind.Rook, (2, 0), (3, 0));

        var allEvents = sim.StepN(20);

        Assert.Contains(allEvents, e => e is CargoProducedEvent);
        Assert.Contains(allEvents, e => e is CargoTransferredEvent);
    }

    [Fact]
    public void Production_GeneratesEveryTurn()
    {
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (0, 0), (1, 0));

        var allEvents = sim.StepN(6);

        var prodEvents = allEvents.OfType<CargoProducedEvent>().ToList();
        Assert.Equal(6, prodEvents.Count);
    }

    [Fact]
    public void MissionComplete_WhenAllDemandsMet()
    {
        var level = new BoardBuilder(3, 1)
            .WithProduction(0, 0, "P", CargoType.Wood)
            .WithDemand(2, 0, "D", CargoType.Wood, 1, 30)
            .WithStock(PieceKind.Rook, 2)
            .Build();
        var sim = SimHelper.FromLevel(level);

        sim.Place(PieceKind.Rook, (1, 0), (2, 0));

        var allEvents = sim.StepN(10);

        Assert.Contains(allEvents, e => e is MissionCompleteEvent);
    }

    [Fact]
    public void InitialPhase_IsPaused()
    {
        var sim = CreateLevel1Sim();
        var snap = sim.Snapshot;
        Assert.Equal(SimPhase.Paused, snap.Phase);
    }

    [Fact]
    public void StepFromPaused_Works()
    {
        var sim = CreateLevel1Sim();
        sim.Place(PieceKind.Rook, (1, 0), (2, 0));

        // Step directly from Paused
        var events = sim.Step();
        Assert.Contains(events, e => e is TurnStartedEvent);
    }
}