From 642b5e368168bb31f928d9935512ed3339edd9bb Mon Sep 17 00:00:00 2001
From: Veronica Berglyd Olsen <1619840+vkbo@users.noreply.github.com>
Date: Sun, 11 Feb 2024 20:57:27 +0100
Subject: [PATCH] Add a formatting function for file extension filters for file
 dialogs

---
 novelwriter/common.py               | 15 ++++++++++++++-
 novelwriter/constants.py            |  6 ++++++
 tests/test_base/test_base_common.py | 22 +++++++++++++++++-----
 3 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/novelwriter/common.py b/novelwriter/common.py
index b658cf6d..0c160fe9 100644
--- a/novelwriter/common.py
+++ b/novelwriter/common.py
@@ -41,7 +41,7 @@ from PyQt5.QtCore import QCoreApplication, QUrl
 
 from novelwriter.enum import nwItemClass, nwItemType, nwItemLayout
 from novelwriter.error import logException
-from novelwriter.constants import nwConst, nwUnicode
+from novelwriter.constants import nwConst, nwLabels, nwUnicode, trConst
 
 if TYPE_CHECKING:  # pragma: no cover
     from typing import TypeGuard  # Requires Python 3.10
@@ -248,6 +248,19 @@ def formatVersion(value: str) -> str:
     return value.lower().replace("a", " Alpha ").replace("b", " Beta ").replace("rc", " RC ")
 
 
+def formatFileFilter(extensions: list[str | tuple[str, str]]) -> str:
+    """Format a list of extensions, or extension + label pairs into a
+    QFileDialog extensions filter.
+    """
+    result = []
+    for ext in extensions:
+        if isinstance(ext, str):
+            result.append(f"{trConst(nwLabels.FILE_FILTERS.get(ext))} ({ext})")
+        elif isinstance(ext, tuple) and len(ext) == 2:
+            result.append(f"{ext[0]} ({ext[1]})")
+    return ";;".join(result)
+
+
 ##
 #  String Functions
 ##
diff --git a/novelwriter/constants.py b/novelwriter/constants.py
index e2599512..bd8d366d 100644
--- a/novelwriter/constants.py
+++ b/novelwriter/constants.py
@@ -270,6 +270,12 @@ class nwLabels:
         nwBuildFmt.J_HTML: ".json",
         nwBuildFmt.J_NWD:  ".json",
     }
+    FILE_FILTERS = {
+        "*.txt": QT_TRANSLATE_NOOP("Constant", "Text files"),
+        "*.md":  QT_TRANSLATE_NOOP("Constant", "Markdown files"),
+        "*.nwd": QT_TRANSLATE_NOOP("Constant", "novelWriter files"),
+        "*":     QT_TRANSLATE_NOOP("Constant", "All files"),
+    }
     UNIT_NAME = {
         "mm": QT_TRANSLATE_NOOP("Constant", "Millimetres"),
         "cm": QT_TRANSLATE_NOOP("Constant", "Centimetres"),
diff --git a/tests/test_base/test_base_common.py b/tests/test_base/test_base_common.py
index 0aa96456..7cadfe9e 100644
--- a/tests/test_base/test_base_common.py
+++ b/tests/test_base/test_base_common.py
@@ -34,11 +34,11 @@ from PyQt5.QtCore import QUrl
 
 from novelwriter.common import (
     checkBool, checkFloat, checkInt, checkIntTuple, checkPath, checkString,
-    checkStringNone, checkUuid, formatInt, formatTime, formatTimeStamp,
-    formatVersion, fuzzyTime, getFileSize, hexToInt, isHandle, isItemClass,
-    isItemLayout, isItemType, isTitleTag, jsonEncode, makeFileNameSafe, minmax,
-    numberToRoman, NWConfigParser, openExternalPath, readTextFile, simplified,
-    transferCase, xmlIndent, yesNo
+    checkStringNone, checkUuid, formatFileFilter, formatInt, formatTime,
+    formatTimeStamp, formatVersion, fuzzyTime, getFileSize, hexToInt, isHandle,
+    isItemClass, isItemLayout, isItemType, isTitleTag, jsonEncode,
+    makeFileNameSafe, minmax, numberToRoman, NWConfigParser, openExternalPath,
+    readTextFile, simplified, transferCase, xmlIndent, yesNo
 )
 
 
@@ -346,6 +346,18 @@ def testBaseCommon_formatVersion():
 # END Test testBaseCommon_formatVersion
 
 
+@pytest.mark.base
+def testBaseCommon_formatFileFilter():
+    """Test the formatFileFilter function."""
+    assert formatFileFilter(["*.txt"]) == "Text files (*.txt)"
+    assert formatFileFilter(["*.txt", "*"]) == "Text files (*.txt);;All files (*)"
+    assert formatFileFilter([("Stuff", "*.stuff"), "*.txt", "*"]) == (
+        "Stuff (*.stuff);;Text files (*.txt);;All files (*)"
+    )
+
+# END Test testBaseCommon_formatFileFilter
+
+
 @pytest.mark.base
 def testBaseCommon_simplified():
     """Test the simplified function."""