Map events apart from the map: map_events/<map>/*.json of any mod merged by id (RpgMapEventResolver, RpgMapEventMerge); item Icon look for events; rpg_walk checks a pickup across leaving the map and loading a save

src/Data/RpgMapEventResolver.cs

@@ -0,0 +1,93 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using Cthangover.Core.Mods;
+using Cthangover.Core.Mods.Resolvers;
+using Cthangover.Core.Utils;
+
+namespace Cthangover.Mods.Rpg
+{
+    /// <summary>
+    /// Collects map events from <c>map_events/&lt;map id&gt;/**/*.json</c> of every
+    /// loaded mod in load order (files of one mod sorted by path), then from the
+    /// studio overlays, and merges them per map with <see cref="RpgMapEventMerge"/>.
+    /// <para/>
+    /// Events live apart from the map file (<c>maps/&lt;id&gt;.json</c> holds only
+    /// tiles, collision, spawn and encounters) so that any mod can put its own NPC,
+    /// chest or quest trigger on another mod's map without replacing the map, and
+    /// so that drawing and placing do not fight over one big file. Events of a map
+    /// no mod defines are kept and simply never shown.
+    /// </summary>
+    public class RpgMapEventResolver : ModAssetResolver
+    {
+        /// <summary>Group folder of event files.</summary>
+        public const string Directory = "map_events";
+
+        private Dictionary<string, List<RpgMapEvent>> cache;
+
+        /// <inheritdoc />
+        public override string Id => "rpg_map_events";
+
+        /// <summary>Events per map id, merged; cached until the next mod reload or <see cref="ClearCache"/>.</summary>
+        public Dictionary<string, List<RpgMapEvent>> Collect()
+        {
+            Context.Initialize();
+            if (cache != null)
+                return cache;
+
+            var merge = new RpgMapEventMerge();
+            foreach (var modId in Context.GetOrderedModIds())
+                CollectMod(Context.Mods[modId].FileProvider, modId, merge);
+            foreach (var overlay in ModOverlays.All)
+                CollectMod(overlay.Value, overlay.Key, merge);
+
+            cache = merge.Maps;
+            GameLogger.Log("RPG", $"map events: {cache.Values.Sum(l => l.Count)} event(s) on {cache.Count} map(s)");
+            return cache;
+        }
+
+        /// <inheritdoc />
+        public override void ClearCache() => cache = null;
+
+        private void CollectMod(IModFileProvider provider, string modId, RpgMapEventMerge merge)
+        {
+            foreach (var mapDir in provider.ListFiles(Directory).Where(e => e.EndsWith("/")).OrderBy(e => e, System.StringComparer.Ordinal))
+            {
+                var map = mapDir.TrimEnd('/');
+                map = map.Substring(map.LastIndexOf('/') + 1);
+                var files = new List<string>();
+                ListJson(provider, mapDir.TrimEnd('/'), files);
+                foreach (var file in files.OrderBy(f => f, System.StringComparer.Ordinal))
+                    ReadFile(provider, modId, map, file, merge);
+            }
+        }
+
+        private static void ListJson(IModFileProvider provider, string dir, List<string> files)
+        {
+            foreach (var entry in provider.ListFiles(dir))
+            {
+                if (entry.EndsWith("/"))
+                    ListJson(provider, entry.TrimEnd('/'), files);
+                else if (entry.EndsWith(".json", System.StringComparison.OrdinalIgnoreCase))
+                    files.Add(entry);
+            }
+        }
+
+        private void ReadFile(IModFileProvider provider, string modId, string map, string file, RpgMapEventMerge merge)
+        {
+            var text = Context.ReadResolvedText(modId, file, provider);
+            if (string.IsNullOrWhiteSpace(text))
+                return;
+            try
+            {
+                var data = JsonSerializer.Deserialize<RpgMapEventFile>(text, JsonOptionsProvider.ReadOptions);
+                foreach (var id in merge.Add(map, modId, file, data?.Events))
+                    GameLogger.Log("RPG", $"map '{map}': event '{id}' replaced by mod '{modId}' ({file})");
+            }
+            catch (JsonException ex)
+            {
+                GameLogger.Log("RPG", $"map events '{modId}/{file}': broken JSON: {ex.Message}", LogLevel.Error);
+            }
+        }
+    }
+}