Add reference data mappings and auto-download for PokeDB import tool

Add mappings module with pokemon form, location area, encounter method,
and version mappings. Auto-download PokeDB JSON exports from CDN on
first run, caching in .pokedb_cache/.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/import-pokedb/import_pokedb/loader.py

@@ -4,17 +4,20 @@ from __future__ import annotations
 
 import json
 import sys
+import urllib.request
 from pathlib import Path
 from typing import Any
 
-REQUIRED_FILES = [
-    "encounters.json",
-    "locations.json",
-    "location_areas.json",
-    "encounter_methods.json",
-    "versions.json",
-    "pokemon_forms.json",
-]
+_CDN_BASE = "https://cdn.pokedb.org"
+
+REQUIRED_FILES: dict[str, str] = {
+    "encounters.json": f"{_CDN_BASE}/data_export_encounters_json",
+    "locations.json": f"{_CDN_BASE}/data_export_locations_json",
+    "location_areas.json": f"{_CDN_BASE}/data_export_location_areas_json",
+    "encounter_methods.json": f"{_CDN_BASE}/data_export_encounter_methods_json",
+    "versions.json": f"{_CDN_BASE}/data_export_versions_json",
+    "pokemon_forms.json": f"{_CDN_BASE}/data_export_pokemon_forms_json",
+}
 
 
 class PokeDBData:
@@ -48,23 +51,38 @@ class PokeDBData:
         )
 
 
+def download_pokedb_data(data_dir: Path) -> None:
+    """Download missing PokeDB JSON export files into data_dir."""
+    data_dir.mkdir(parents=True, exist_ok=True)
+    missing = {f: url for f, url in REQUIRED_FILES.items() if not (data_dir / f).exists()}
+    if not missing:
+        return
+
+    print(f"Downloading {len(missing)} PokeDB file(s) to {data_dir}...")
+    for filename, url in missing.items():
+        dest = data_dir / filename
+        print(f"  {filename}...", end="", flush=True)
+        try:
+            urllib.request.urlretrieve(url, dest)
+            size_mb = dest.stat().st_size / (1024 * 1024)
+            print(f" {size_mb:.1f} MB")
+        except Exception as e:
+            print(f" FAILED", file=sys.stderr)
+            print(f"Error downloading {url}: {e}", file=sys.stderr)
+            sys.exit(1)
+    print()
+
+
 def load_pokedb_data(data_dir: Path) -> PokeDBData:
     """Load all PokeDB JSON export files from a directory.
 
-    Exits with an error message if any required files are missing or unparseable.
+    Downloads any missing files automatically, then validates and loads them.
     """
+    download_pokedb_data(data_dir)
+
     missing = [f for f in REQUIRED_FILES if not (data_dir / f).exists()]
     if missing:
-        print(
-            f"Error: Missing required PokeDB files in {data_dir}:",
-            file=sys.stderr,
-        )
-        for f in missing:
-            print(f"  - {f}", file=sys.stderr)
-        print(
-            "\nDownload the JSON export from https://pokedb.org/data-export",
-            file=sys.stderr,
-        )
+        print(f"Error: Still missing files after download: {missing}", file=sys.stderr)
         sys.exit(1)
 
     def _load(filename: str) -> list[dict[str, Any]]: