using Chessistics.Engine.Commands;
using Chessistics.Engine.Loading;
using Chessistics.Engine.Model;
using Chessistics.Engine.Simulation;
using Xunit;

namespace Chessistics.Tests.Loading;

/// <summary>
/// Validates campaign_01.json structural integrity:
/// no cell overlaps, unique building names, walls only on new cells.
/// </summary>
public class CampaignValidationTests
{
    private static CampaignDef LoadCampaign()
        => CampaignLoader.LoadFromFile("../../../../Data/campaigns/campaign_01.json");

    [Fact]
    public void Campaign01_NoBuildingOverlaps()
    {
        var campaign = LoadCampaign();
        var sim = new GameSim(campaign);
        sim.ProcessCommand(new LoadCampaignCommand());

        // Step through missions by manually applying patches and checking for conflicts
        var state = BoardState.FromCampaign(campaign);

        // Track all active buildings after each mission
        for (int i = 0; i < campaign.Missions.Count; i++)
        {
            var mission = campaign.Missions[i];
            state.ApplyTerrainPatch(mission.TerrainPatch, i);

            // After each mission, verify no cell has multiple building types
            foreach (var pos in state.Productions.Keys)
            {
                Assert.False(state.Demands.ContainsKey(pos),
                    $"Mission {i + 1}: Production and Demand overlap at {pos}");
                Assert.False(state.Transformers.ContainsKey(pos),
                    $"Mission {i + 1}: Production and Transformer overlap at {pos}");
                Assert.NotEqual(CellType.Wall, state.GetCell(pos));
            }

            foreach (var pos in state.Demands.Keys)
            {
                Assert.False(state.Transformers.ContainsKey(pos),
                    $"Mission {i + 1}: Demand and Transformer overlap at {pos}");
                Assert.NotEqual(CellType.Wall, state.GetCell(pos));
            }

            foreach (var pos in state.Transformers.Keys)
            {
                Assert.NotEqual(CellType.Wall, state.GetCell(pos));
            }
        }
    }

    [Fact]
    public void Campaign01_UniqueBuildingNames()
    {
        var campaign = LoadCampaign();
        var state = BoardState.FromCampaign(campaign);

        for (int i = 0; i < campaign.Missions.Count; i++)
        {
            state.ApplyTerrainPatch(campaign.Missions[i].TerrainPatch, i);
        }

        // Collect all building names
        var names = new List<string>();
        names.AddRange(state.Productions.Values.Select(p => p.Name));
        names.AddRange(state.Demands.Values.Select(d => d.Name));
        names.AddRange(state.Transformers.Values.Select(t => t.Name));

        var duplicates = names.GroupBy(n => n).Where(g => g.Count() > 1).Select(g => g.Key).ToList();
        Assert.Empty(duplicates);
    }

    [Fact]
    public void Campaign01_WallsOnlyOnNewOrEmptyCells()
    {
        var campaign = LoadCampaign();

        // Track which cells have buildings before each mission
        var buildingCells = new HashSet<Coords>();
        int prevWidth = campaign.InitialWidth;
        int prevHeight = campaign.InitialHeight;

        for (int i = 0; i < campaign.Missions.Count; i++)
        {
            var mission = campaign.Missions[i];

            // Check walls in this mission's patch
            foreach (var cell in mission.TerrainPatch.Cells)
            {
                if (cell.Type == CellType.Wall)
                {
                    // Wall should be on a cell that was either:
                    // - Outside the previous board dimensions (new cell)
                    // - Not a building cell
                    bool isNewCell = cell.Col >= prevWidth || cell.Row >= prevHeight;
                    bool isBuilding = buildingCells.Contains(new Coords(cell.Col, cell.Row));

                    Assert.True(isNewCell || !isBuilding,
                        $"Mission {i + 1}: Wall at ({cell.Col},{cell.Row}) overwrites an existing building");
                }
            }

            // Update building tracking
            foreach (var cell in mission.TerrainPatch.Cells)
            {
                var coords = new Coords(cell.Col, cell.Row);
                if (cell.Type is CellType.Production or CellType.Demand or CellType.Transformer)
                    buildingCells.Add(coords);
                else
                    buildingCells.Remove(coords);
            }

            prevWidth = mission.TerrainPatch.NewWidth;
            prevHeight = mission.TerrainPatch.NewHeight;
        }
    }

    [Fact]
    public void Campaign01_AllMissionsHaveFlavor()
    {
        var campaign = LoadCampaign();

        for (int i = 0; i < campaign.Missions.Count; i++)
        {
            Assert.False(string.IsNullOrWhiteSpace(campaign.Missions[i].Flavor),
                $"Mission {i + 1} ({campaign.Missions[i].Name}) has no flavor text");
        }
    }
}