From f03a58a802261c82d40475d62c021601c3d31344 Mon Sep 17 00:00:00 2001
From: Ben Kurtovic <ben@benkurtovic.com>
Date: Fri, 1 May 2026 22:46:10 -0500
Subject: [PATCH] Improve background URL generation

---
 src/copyvios/background.py | 96 ++++++++++++++++++++++------------------------
 1 file changed, 45 insertions(+), 51 deletions(-)

diff --git a/src/copyvios/background.py b/src/copyvios/background.py
index dffac8c..ead211d 100644
--- a/src/copyvios/background.py
+++ b/src/copyvios/background.py
@@ -1,11 +1,10 @@
 __all__ = ["get_background"]
 
-import bisect
+import functools
 import json
 import logging
 import random
 import re
-import urllib.parse
 from dataclasses import dataclass
 from datetime import UTC, date, datetime, timedelta
 from typing import Self
@@ -18,16 +17,16 @@ from .cookies import get_cookies
 
 logger = logging.getLogger(__name__)
 
-THUMB_SIZES = [20, 40, 60, 120, 250, 330, 500, 960, 1280, 1920, 3840]
-
 
 @dataclass(frozen=True)
 class BackgroundInfo:
     filename: str
+
+
+@dataclass(frozen=True)
+class BackgroundURLs:
     url: str
     descurl: str
-    width: int
-    height: int
 
 
 @dataclass(frozen=True)
@@ -54,27 +53,6 @@ def _get_commons_site() -> Site:
         return cache.bot.wiki.add_site(project="wikimedia", lang="commons")
 
 
-def _load_file(site: Site, filename: str) -> BackgroundInfo | None:
-    prefix = "File:"
-    try:
-        data = site.api_query(
-            action="query",
-            prop="imageinfo",
-            iiprop="url|size|canonicaltitle",
-            titles=prefix + filename,
-        )
-        res = list(data["query"]["pages"].values())[0]["imageinfo"][0]
-        name = res["canonicaltitle"]
-        assert isinstance(name, str), name
-    except Exception:
-        logger.exception(f"Failed to get info for file {prefix + filename!r}")
-        return None
-    name = name.removeprefix(prefix).replace(" ", "_")
-    return BackgroundInfo(
-        name, res["url"], res["descriptionurl"], res["width"], res["height"]
-    )
-
-
 def _get_fresh_from_potd() -> BackgroundInfo | None:
     site = _get_commons_site()
     date = datetime.now(UTC).strftime("%Y-%m-%d")
@@ -93,7 +71,7 @@ def _get_fresh_from_potd() -> BackgroundInfo | None:
     if not filename:
         logger.exception(f"Failed to extract POTD from {page.title!r}")
         return None
-    return _load_file(site, filename)
+    return BackgroundInfo(filename)
 
 
 def _get_fresh_from_list() -> BackgroundInfo | None:
@@ -114,19 +92,7 @@ def _get_fresh_from_list() -> BackgroundInfo | None:
     except IndexError:
         logger.exception(f"Failed to find any images on {page.title!r}")
         return None
-    return _load_file(site, filename)
-
-
-def _build_url(screen: ScreenInfo, background: BackgroundInfo) -> str:
-    width = screen.width
-    if background.width / background.height > screen.width / screen.height:
-        width = int(background.width / background.height * screen.height)
-    i = bisect.bisect_right(THUMB_SIZES, width)
-    width = THUMB_SIZES[i] if i < len(THUMB_SIZES) else background.width
-    if width >= background.width:
-        return background.url
-    url = background.url.replace("/commons/", "/commons/thumb/")
-    return f"{url}/{width}px-{urllib.parse.quote(background.filename)}"
+    return BackgroundInfo(filename)
 
 
 _BACKGROUNDS = {
@@ -134,20 +100,48 @@ _BACKGROUNDS = {
     "list": _get_fresh_from_list,
 }
 
-_BACKGROUND_CACHE: dict[str, BackgroundInfo | None] = {}
+_BACKGROUND_INFO_CACHE: dict[str, BackgroundInfo | None] = {}
 _LAST_BACKGROUND_UPDATES: dict[str, date] = {
     key: datetime.min.date() for key in _BACKGROUNDS
 }
 
 
-def _get_background(selected: str) -> BackgroundInfo | None:
+def _get_background_info(selected: str) -> BackgroundInfo | None:
     next_day = _LAST_BACKGROUND_UPDATES[selected] + timedelta(days=1)
     max_age = datetime(next_day.year, next_day.month, next_day.day, tzinfo=UTC)
     if datetime.now(UTC) > max_age:
         update_func = _BACKGROUNDS.get(selected, _get_fresh_from_list)
-        _BACKGROUND_CACHE[selected] = update_func()
+        _BACKGROUND_INFO_CACHE[selected] = update_func()
         _LAST_BACKGROUND_UPDATES[selected] = datetime.now(UTC).date()
-    return _BACKGROUND_CACHE[selected]
+    return _BACKGROUND_INFO_CACHE[selected]
+
+
+@functools.lru_cache(maxsize=256)
+def _get_background_urls(
+    background: BackgroundInfo, screen_width: int
+) -> BackgroundURLs | None:
+    site = _get_commons_site()
+    prefix = "File:"
+    try:
+        data = site.api_query(
+            action="query",
+            prop="imageinfo",
+            iiprop="url|canonicaltitle",
+            iiurlwidth=screen_width,
+            titles=prefix + background.filename,
+        )
+        res = list(data["query"]["pages"].values())[0]["imageinfo"][0]
+        name = res["canonicaltitle"]
+        assert isinstance(name, str), name
+        url = res["thumburl"]
+        descurl = res["descriptionurl"]
+    except Exception:
+        logger.exception(
+            f"Failed to get info for file {prefix + background.filename!r}"
+        )
+        return None
+    name = name.removeprefix(prefix).replace(" ", "_")
+    return BackgroundURLs(url=url, descurl=descurl)
 
 
 def get_background(selected: str) -> tuple[str | None, str | None]:
@@ -161,9 +155,9 @@ def get_background(selected: str) -> tuple[str | None, str | None]:
     else:
         screen = ScreenInfo()
 
-    background = _get_background(selected)
-    if background:
-        bg_url = _build_url(screen, background)
-        return bg_url, background.descurl
-    else:
-        return None, None
+    bg_info = _get_background_info(selected)
+    if bg_info is not None:
+        bg_urls = _get_background_urls(bg_info, screen.width)
+        if bg_urls is not None:
+            return bg_urls.url, bg_urls.descurl
+    return None, None