add endpoint for requesting map data

tanks-backend/TanksServer/Endpoints.cs

@@ -24,14 +24,18 @@ internal sealed class Endpoints(
         app.Map("/controls", ConnectControlsAsync);
         app.MapGet("/map", () => mapService.MapNames);
         app.MapPost("/map", PostMap);
+        app.MapGet("/map/{name}", GetMapByName);
     }
 
     private Results<BadRequest<string>, NotFound<string>, Ok> PostMap([FromQuery] string name)
     {
         if (string.IsNullOrWhiteSpace(name))
             return TypedResults.BadRequest("invalid map name");
-        if (!mapService.TryGetMapByName(name, out var map))
+
+        name = name.Trim().ToUpperInvariant();
+        if (!mapService.TryGetPrototype(name, out var map))
             return TypedResults.NotFound("map with name not found");
+
         changeToRequestedMap.Request(map);
         return TypedResults.Ok();
     }
@@ -88,4 +92,19 @@ internal sealed class Endpoints(
         var player = playerService.GetOrAdd(name);
         return TypedResults.Ok(player.Name);
     }
+
+    private Results<Ok<MapInfo>, NotFound, BadRequest<string>> GetMapByName(string name)
+    {
+        name = name.Trim().ToUpperInvariant();
+        if (string.IsNullOrEmpty(name))
+            return TypedResults.BadRequest("map name cannot be empty");
+
+        if (!mapService.TryGetPrototype(name, out var prototype))
+            return TypedResults.NotFound();
+        if (!mapService.TryGetPreview(name, out var preview))
+            return TypedResults.NotFound();
+
+        var mapInfo = new MapInfo(prototype.Name, prototype.GetType().Name, preview.Data);
+        return TypedResults.Ok(mapInfo);
+    }
 }

tanks-backend/TanksServer/GameLogic/MapPrototype.cs

@@ -0,0 +1,8 @@
+namespace TanksServer.GameLogic;
+
+internal abstract class MapPrototype
+{
+    public abstract string Name { get; }
+
+    public abstract Map CreateInstance();
+}

tanks-backend/TanksServer/GameLogic/MapService.cs

@@ -1,14 +1,10 @@
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
+using DisplayCommands;
 using TanksServer.Graphics;
 
 namespace TanksServer.GameLogic;
 
-internal abstract class MapPrototype
-{
-    public abstract Map CreateInstance();
-}
-
 internal sealed class MapService
 {
     public const ushort TilesPerRow = 44;
@@ -17,9 +13,10 @@ internal sealed class MapService
     public const ushort PixelsPerRow = TilesPerRow * TileSize;
     public const ushort PixelsPerColumn = TilesPerColumn * TileSize;
 
-    private readonly Dictionary<string, MapPrototype> _maps = new();
+    private readonly Dictionary<string, MapPrototype> _mapPrototypes = new();
+    private readonly Dictionary<string, PixelGrid> _mapPreviews = new();
 
-    public IEnumerable<string> MapNames => _maps.Keys;
+    public IEnumerable<string> MapNames => _mapPrototypes.Keys;
 
     public Map Current { get; private set; }
 
@@ -29,29 +26,49 @@ internal sealed class MapService
             LoadMapString(file);
         foreach (var file in Directory.EnumerateFiles("./assets/maps/", "*.png"))
             LoadMapPng(file);
-
+        Current = GetRandomMap();
-        var chosenMapIndex = Random.Shared.Next(_maps.Count);
-        var chosenMapName = _maps.Keys.Skip(chosenMapIndex).First();
-        Current = _maps[chosenMapName].CreateInstance();
     }
 
-    public bool TryGetMapByName(string name, [MaybeNullWhen(false)] out MapPrototype map)
+    public bool TryGetPrototype(string name, [MaybeNullWhen(false)] out MapPrototype map)
-        => _maps.TryGetValue(name, out map);
+        => _mapPrototypes.TryGetValue(name, out map);
 
     public void SwitchTo(MapPrototype prototype) => Current = prototype.CreateInstance();
 
+    public bool TryGetPreview(string name, [MaybeNullWhen(false)] out PixelGrid pixelGrid)
+    {
+        if (_mapPreviews.TryGetValue(name, out pixelGrid))
+            return true; // already generated
+        if (!_mapPrototypes.TryGetValue(name, out var prototype))
+            return false; // name not found
+
+        pixelGrid = new PixelGrid(PixelsPerRow, PixelsPerColumn);
+        DrawMapStep.Draw(pixelGrid, prototype.CreateInstance());
+
+        _mapPreviews.TryAdd(name, pixelGrid); // another thread may have added the map already
+        return true; // new preview
+    }
+
     private void LoadMapPng(string file)
     {
-        var name = Path.GetFileName(file);
+        var name = MapNameFromFilePath(file);
         var prototype = new SpriteMapPrototype(name, Sprite.FromImageFile(file));
-        _maps.Add(Path.GetFileName(file), prototype);
+        _mapPrototypes.Add(name, prototype);
     }
 
     private void LoadMapString(string file)
     {
+        var name = MapNameFromFilePath(file);
         var map = File.ReadAllText(file).ReplaceLineEndings(string.Empty).Trim();
-        var name = Path.GetFileName(file);
         var prototype = new TextMapPrototype(name, map);
-        _maps.Add(name, prototype);
+        _mapPrototypes.Add(name, prototype);
+    }
+
+    private static string MapNameFromFilePath(string filePath) => Path.GetFileName(filePath).ToUpperInvariant();
+
+    private Map GetRandomMap()
+    {
+        var chosenMapIndex = Random.Shared.Next(_mapPrototypes.Count);
+        var chosenMapName = _mapPrototypes.Keys.Skip(chosenMapIndex).First();
+        return _mapPrototypes[chosenMapName].CreateInstance();
     }
 }

tanks-backend/TanksServer/GameLogic/SpriteMapPrototype.cs

@@ -5,17 +5,18 @@ namespace TanksServer.GameLogic;
 
 internal sealed class SpriteMapPrototype : MapPrototype
 {
-    private readonly string _name;
+    public override string Name { get; }
-    private readonly Sprite _sprite;
+
+    public Sprite Sprite { get; }
 
     public SpriteMapPrototype(string name, Sprite sprite)
     {
         if (sprite.Width != MapService.PixelsPerRow || sprite.Height != MapService.PixelsPerColumn)
-            throw new FileLoadException($"invalid image size in file {_name}");
+            throw new FileLoadException($"invalid image size in file {Name}");
 
-        _name = name;
+        Name = name;
-        _sprite = sprite;
+        Sprite = sprite;
     }
 
-    public override Map CreateInstance() => new(_name, _sprite.ToBoolArray());
+    public override Map CreateInstance() => new(Name, Sprite.ToBoolArray());
 }

tanks-backend/TanksServer/GameLogic/TextMapPrototype.cs

@@ -2,17 +2,19 @@ namespace TanksServer.GameLogic;
 
 internal sealed class TextMapPrototype : MapPrototype
 {
-    private readonly string _name;
+    public override string Name { get; }
-    private readonly string _text;
+
+    public string Text { get; }
 
     public TextMapPrototype(string name, string text)
     {
         if (text.Length != MapService.TilesPerColumn * MapService.TilesPerRow)
             throw new ArgumentException($"cannot load map {name}: invalid length");
-        _name = name;
+        Name = name;
-        _text = text;
+        Text = text;
     }
 
+
     public override Map CreateInstance()
     {
         var walls = new bool[MapService.PixelsPerRow, MapService.PixelsPerColumn];
@@ -21,7 +23,7 @@ internal sealed class TextMapPrototype : MapPrototype
         for (ushort tileY = 0; tileY < MapService.TilesPerColumn; tileY++)
         {
             var tile = new TilePosition(tileX, tileY);
-            if (_text[tileX + tileY * MapService.TilesPerRow] != '#')
+            if (Text[tileX + tileY * MapService.TilesPerRow] != '#')
                 continue;
 
             for (byte pixelInTileX = 0; pixelInTileX < MapService.TileSize; pixelInTileX++)
@@ -32,6 +34,6 @@ internal sealed class TextMapPrototype : MapPrototype
             }
         }
 
-        return new Map(_name, walls);
+        return new Map(Name, walls);
     }
 }

tanks-backend/TanksServer/Graphics/DrawMapStep.cs

@@ -1,18 +1,32 @@
+using DisplayCommands;
 using TanksServer.GameLogic;
 
 namespace TanksServer.Graphics;
 
 internal sealed class DrawMapStep(MapService map) : IDrawStep
 {
-    public void Draw(GamePixelGrid pixels)
+    public void Draw(GamePixelGrid pixels) => Draw(pixels, map.Current);
+
+    private static void Draw(GamePixelGrid pixels, Map map)
     {
         for (ushort y = 0; y < MapService.PixelsPerColumn; y++)
         for (ushort x = 0; x < MapService.PixelsPerRow; x++)
         {
-            if (!map.Current.IsWall(x, y))
+            if (!map.IsWall(x, y))
                 continue;
 
             pixels[x, y].EntityType = GamePixelEntityType.Wall;
         }
     }
+
+    public static void Draw(PixelGrid pixels, Map map)
+    {
+        for (ushort y = 0; y < MapService.PixelsPerColumn; y++)
+        for (ushort x = 0; x < MapService.PixelsPerRow; x++)
+        {
+            if (!map.IsWall(x, y))
+                continue;
+            pixels[x, y] = true;
+        }
+    }
 }

tanks-backend/TanksServer/Interactivity/AppSerializerContext.cs

@@ -7,5 +7,6 @@ namespace TanksServer.Interactivity;
 [JsonSerializable(typeof(IEnumerable<Player>))]
 [JsonSerializable(typeof(IEnumerable<string>))]
 [JsonSerializable(typeof(PlayerInfo))]
+[JsonSerializable(typeof(MapInfo))]
 [JsonSourceGenerationOptions(JsonSerializerDefaults.Web)]
 internal sealed partial class AppSerializerContext : JsonSerializerContext;

tanks-backend/TanksServer/Models/MapInfo.cs

@@ -0,0 +1,3 @@
+namespace TanksServer.Models;
+
+public record MapInfo(string Name, string TypeName, Memory<byte> Preview);