Added function template example

Author: RhetTbull

examples/date_delta.py

@@ -0,0 +1,92 @@
+""" Example showing how to use a custom template function for osxphotos {function} template
+    Example use:  osxphotos query --quiet --print "{function:date_delta.py::months_since(2021-01-01)}"
+"""
+
+import datetime
+import pathlib
+from typing import List, Optional, Union
+
+from osxphotos import PhotoInfo
+from osxphotos.datetime_utils import datetime_naive_to_local
+from osxphotos.phototemplate import RenderOptions
+
+
+def years_since(
+    photo: PhotoInfo, options: RenderOptions, args: Optional[str] = None, **kwargs
+) -> Union[List, str]:
+    """Return the number of years between the photo date and the date passed as an argument in format YYYY-MM-DD"""
+
+    if not args:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+    # if args doesn't match the expected format, raise an error
+    try:
+        date_arg = datetime_naive_to_local(datetime.datetime.strptime(args, "%Y-%m-%d"))
+    except ValueError:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+
+    return str(_years_since(photo.date, date_arg))
+
+
+def months_since(
+    photo: PhotoInfo, options: RenderOptions, args: Optional[str] = None, **kwargs
+) -> Union[List, str]:
+    """Return the number of months between the photo date and the date passed as an argument in format YYYY-MM-DD"""
+
+    if not args:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+    # if args doesn't match the expected format, raise an error
+    try:
+        date_arg = datetime_naive_to_local(datetime.datetime.strptime(args, "%Y-%m-%d"))
+    except ValueError:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+
+    return str(_months_since(photo.date, date_arg))
+
+
+def days_since(
+    photo: PhotoInfo, options: RenderOptions, args: Optional[str] = None, **kwargs
+) -> Union[List, str]:
+    """Return the number of days between the photo date and the date passed as an argument in format YYYY-MM-DD"""
+
+    if not args:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+    # if args doesn't match the expected format, raise an error
+    try:
+        date_arg = datetime_naive_to_local(datetime.datetime.strptime(args, "%Y-%m-%d"))
+    except ValueError:
+        raise ValueError(
+            "months_since function requires an argument in the form of a date string in the format YYYY-MM-DD"
+        )
+
+    return str(_days_since(photo.date, date_arg))
+
+
+def _months_since(start_date: datetime, end_date: datetime) -> int:
+    if start_date > end_date:
+        start_date, end_date = end_date, start_date
+    years_difference = end_date.year - start_date.year
+    months_difference = end_date.month - start_date.month
+    return years_difference * 12 + months_difference
+
+
+def _years_since(start_date: datetime, end_date: datetime) -> int:
+    if start_date > end_date:
+        start_date, end_date = end_date, start_date
+    years_difference = end_date.year - start_date.year
+    if (end_date.month, end_date.day) < (start_date.month, start_date.day):
+        years_difference -= 1
+    return years_difference
+
+
+def _days_since(start_date: datetime, end_date: datetime) -> int:
+    return abs((end_date - start_date).days)