Handle exit elevators and secret levels

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_data/lib/src/wl_parser.dart

@@ -83,7 +83,7 @@ abstract class WLParser {
       walls: parseWalls(vswap),
       sprites: parseSprites(vswap),
       sounds: parseSounds(vswap).map((bytes) => PcmSound(bytes)).toList(),
-      levels: parseMaps(mapHead, gameMaps, isShareware: isShareware),
+      episodes: parseEpisodes(mapHead, gameMaps, isShareware: isShareware),
       vgaImages: parseVgaImages(vgaDict, vgaHead, vgaGraph),
       adLibSounds: audio.adLib,
       music: audio.music,
@@ -236,22 +236,39 @@ abstract class WLParser {
     return images;
   }
 
+  // --- Episode Names (From the original C Executable) ---
+  static const List<String> _sharewareEpisodeNames = [
+    "Episode 1\nEscape from Wolfenstein",
+  ];
+
+  static const List<String> _retailEpisodeNames = [
+    "Episode 1\nEscape from Wolfenstein",
+    "Episode 2\nOperation: Eisenfaust",
+    "Episode 3\nDie, Fuhrer, Die!",
+    "Episode 4\nA Dark Secret",
+    "Episode 5\nTrail of the Madman",
+    "Episode 6\nConfrontation",
+  ];
+
   /// Parses MAPHEAD and GAMEMAPS to extract the raw level data.
-  static List<WolfLevel> parseMaps(
+  static List<Episode> parseEpisodes(
     ByteData mapHead,
     ByteData gameMaps, {
     bool isShareware = true,
   }) {
-    List<WolfLevel> levels = [];
-
-    // 1. Select the correct map based on the version
-    final activeMusicMap = isShareware ? _sharewareMusicMap : _retailMusicMap;
-
+    List<WolfLevel> allLevels = [];
     int rlewTag = mapHead.getUint16(0, Endian.little);
 
+    // Select the correct music map based on the version
+    final activeMusicMap = isShareware ? _sharewareMusicMap : _retailMusicMap;
+    final episodeNames = isShareware
+        ? _sharewareEpisodeNames
+        : _retailEpisodeNames;
+
+    // The game allows for up to 100 maps per file
     for (int i = 0; i < 100; i++) {
       int mapOffset = mapHead.getUint32(2 + (i * 4), Endian.little);
-      if (mapOffset == 0) continue;
+      if (mapOffset == 0) continue; // Empty map slot
 
       int plane0Offset = gameMaps.getUint32(mapOffset + 0, Endian.little);
       int plane1Offset = gameMaps.getUint32(mapOffset + 4, Endian.little);
@@ -259,13 +276,15 @@ abstract class WLParser {
       int plane0Length = gameMaps.getUint16(mapOffset + 12, Endian.little);
       int plane1Length = gameMaps.getUint16(mapOffset + 14, Endian.little);
 
+      // --- EXTRACT ACTUAL GAME DATA NAME ---
+      // The name is exactly 16 bytes long, starting at offset 22
       List<int> nameBytes = [];
       for (int n = 0; n < 16; n++) {
         int charCode = gameMaps.getUint8(mapOffset + 22 + n);
-        if (charCode == 0) break;
+        if (charCode == 0) break; // Stop at the null-terminator
         nameBytes.add(charCode);
       }
-      String name = ascii.decode(nameBytes);
+      String parsedName = ascii.decode(nameBytes);
 
       // --- DECOMPRESS PLANES ---
       final compressedWallData = gameMaps.buffer.asUint8List(
@@ -282,7 +301,7 @@ abstract class WLParser {
       Uint16List carmackExpandedObjects = _expandCarmack(compressedObjectData);
       List<int> flatObjectGrid = _expandRlew(carmackExpandedObjects, rlewTag);
 
-      // --- BUILD GRIDS ---
+      // --- BUILD 64x64 GRIDS ---
       List<List<int>> wallGrid = [];
       List<List<int>> objectGrid = [];
 
@@ -297,17 +316,14 @@ abstract class WLParser {
         objectGrid.add(objectRow);
       }
 
-      // Determine music track index.
-      // We use 'i' because it represents the absolute map slot (e.g. Map 12).
-      // If a map exists past the bounds of our lookup table (custom maps),
-      // we wrap around safely.
+      // --- ASSIGN MUSIC ---
       int trackIndex = (i < activeMusicMap.length)
           ? activeMusicMap[i]
           : activeMusicMap[i % activeMusicMap.length];
 
-      levels.add(
+      allLevels.add(
         WolfLevel(
-          name: name,
+          name: parsedName,
           wallGrid: wallGrid,
           objectGrid: objectGrid,
           musicIndex: trackIndex,
@@ -315,7 +331,35 @@ abstract class WLParser {
       );
     }
 
-    return levels;
+    // 2. Group the parsed levels into Episodes!
+    List<Episode> episodes = [];
+
+    // Calculate how many episodes we need (10 levels per episode)
+    int totalEpisodes = (allLevels.length / 10).ceil();
+
+    for (int i = 0; i < totalEpisodes; i++) {
+      int startIndex = i * 10;
+      int endIndex = startIndex + 10;
+
+      // Safety clamp for incomplete episodes at the end of the file
+      if (endIndex > allLevels.length) {
+        endIndex = allLevels.length;
+      }
+
+      // If we run out of hardcoded id Software names, generate a custom one!
+      String epName = (i < episodeNames.length)
+          ? episodeNames[i]
+          : "Episode ${i + 1}\nCustom Maps";
+
+      episodes.add(
+        Episode(
+          name: epName,
+          levels: allLevels.sublist(startIndex, endIndex),
+        ),
+      );
+    }
+
+    return episodes;
   }
 
   /// Extracts AdLib sounds and IMF music tracks from the audio files.