Add {series_sort} to the download template

It gives the series with a leading article at the end, as Calibre's default does for {series}.

README.md

@@ -459,8 +459,9 @@ gives `The Saga - 02 - The Book - Ann Writer.epub`.
 
 In Calibre, `{title}` and `{series}` give the title sort in a file name, for example `Book, The`.
 In Bindery, they keep the article. This is the same as Calibre with the tweak
-`save_template_title_series_sorting` set to `strictly_alphabetic`. Use `{title_sort}` for the title
-with the article at the end.
+`save_template_title_series_sorting` set to `strictly_alphabetic`. Use `{title_sort}` and
+`{series_sort}` for the title and the series with the article at the end. `{series_sort}` is a
+Bindery field. Calibre does not have it, and gives empty text for it.
 
 | Field | Value |
 | --- | --- |
@@ -469,6 +470,7 @@ with the article at the end.
 | `{authors}`, `{author}` | The authors, with ` & ` between them. |
 | `{author_sort}` | The authors with the last name first: `Writer, Ann`. |
 | `{series}` | The series. |
+| `{series_sort}` | The series with a leading article at the end: `Saga, The`. |
 | `{series_index}` | The series number: `2`, or `2.5`. |
 | `{tags}` | The tags in sorted order, with `, ` between them. |
 | `{languages}` | The language, as Bindery stores it. |

bindery/filename_template.py

@@ -5,6 +5,8 @@ the order of titles and series as an argument. Dates take a strftime format, wit
 default. Bindery takes {field}, {field[0]}, {field:format|prefix|suffix} and {{ }}. It refuses template
 functions and the program modes. It never runs template text as code.
 
+{series_sort} is a Bindery field. It is to {series} what {title_sort} is to {title}. Calibre has no such field.
+
 The tags sort close to Calibre's ICU rules, but their order can differ for characters outside ASCII.
 """
 
@@ -34,6 +36,8 @@ FIELDS = {
     "author": "The authors",
     "author_sort": "The author sort string. To use only the first letter of the name, use {author_sort[0]}",
     "series": "The series",
+    "series_sort": 'The series with a leading "The", "A" or "An" at the end, such as "Saga, The". '
+    "Calibre does not have this field",
     "series_index": "The series number. To get leading zeros, use {series_index:0>3s}",
     "tags": "The tags",
     "languages": "The language",
@@ -207,7 +211,8 @@ def prepare(
         values["authors"] = values["author"] = " & ".join(a.replace("&", "&&") for a in authors)
         values["author_sort"] = " & ".join(author_sort(a) for a in authors)
     if series:
-        values["series"] = title_sort(series) if library else series.strip()
+        values["series_sort"] = title_sort(series)
+        values["series"] = values["series_sort"] if library else series.strip()
         if meta.get("series_index") is not None:
             values["series_index"] = series_index(meta["series_index"])
     values["tags"] = ", ".join(sorted(meta.get("tags") or [], key=_tag_key)).removeprefix("/")

bindery/static/js/settings.js

@@ -208,7 +208,8 @@ export function settingsPage(main, _params, config) {
           h(
             'li',
             {},
-            '{title} and {series} keep a leading "The", "A" or "An". {title_sort} moves it to the end, so ' +
+            '{title} and {series} keep a leading "The", "A" or "An". {title_sort} and {series_sort} move it to the ' +
+              'end, so ' +
               '"The Book" becomes "Book, The". Calibre puts the title sort in {title} as well, unless you set its ' +
               'tweak save_template_title_series_sorting to strictly_alphabetic.',
           ),

tests/test_api_flows.py

@@ -164,6 +164,8 @@ def test_download_template_names_the_file(client, story):
     # The default moves the article to the end, as Calibre's default does.
     client.put("/api/settings", json={"download_template": ""}, headers=H)
     assert 'filename="Book, The - Ann Writer.epub"' in download_name(client, sid)
+    client.put("/api/settings", json={"download_template": "{series_sort} - {title} - {id}"}, headers=H)
+    assert f'filename="Saga, The - The Book - {sid}.epub"' in download_name(client, sid)
     # The ID is that of the CWA book, when the story has one.
     o.store.update_story(sid, calibre_id=77, pinned={"title": "Caf\u00e9", "series": ["", None]})
     client.put("/api/settings", json={"download_template": "{series:|| - }{title} - {id}"}, headers=H)

tests/test_filename_template.py

@@ -55,6 +55,11 @@ def test_reference_cases_for_a_missing_series_and_for_alphabetic_order():
     assert expand("{series}", "strictly_alphabetic") == "The Saga"
 
 
+def test_series_sort_is_a_bindery_field():
+    assert expand("{series_sort}") == expand("{series_sort}", "strictly_alphabetic") == "Saga, The"
+    assert ft.expand("x{series_sort}x", ft.prepare(NO_SERIES, 42)) == "xx"
+
+
 @pytest.mark.parametrize(
     "template,expected",
     [