Improves dateutil parsing

Closes #133
Fixes #183, #185, #228

jrnl/time.py

@@ -0,0 +1,49 @@
+from datetime import datetime
+from dateutil.parser import parse as dateparse
+try: import parsedatetime.parsedatetime_consts as pdt
+except ImportError: import parsedatetime as pdt
+
+DEFAULT_FUTURE = datetime(datetime.now().year, 12, 31, 23, 59, 59)
+DEFAULT_PAST = datetime(datetime.now().year, 1, 1, 0, 0)
+
+consts = pdt.Constants(usePyICU=False)
+consts.DOWParseStyle = -1  # "Monday" will be either today or the last Monday
+CALENDAR = pdt.Calendar(consts)
+
+
+def parse(date_str, inclusive=False, default_hour=None, default_minute=None):
+    """Parses a string containing a fuzzy date and returns a datetime.datetime object"""
+    if not date_str:
+        return None
+    elif isinstance(date_str, datetime):
+        return date_str
+
+    try:
+        date = dateparse(date_str, default=DEFAULT_FUTURE if inclusive else DEFAULT_PAST)
+        flag = 1 if date.hour == date.minute == 0 else 2
+        date = date.timetuple()
+    except ValueError:
+        date, flag = CALENDAR.parse(date_str)
+
+    if not flag:  # Oops, unparsable.
+        try:  # Try and parse this as a single year
+            year = int(date_str)
+            return datetime(year, 1, 1)
+        except ValueError:
+            return None
+        except TypeError:
+            return None
+
+    if flag is 1:  # Date found, but no time. Use the default time.
+        date = datetime(*date[:3], hour=default_hour or 0, minute=default_minute or 0)
+    else:
+        date = datetime(*date[:6])
+
+    # Ugly heuristic: if the date is more than 4 weeks in the future, we got the year wrong.
+    # Rather then this, we would like to see parsedatetime patched so we can tell it to prefer
+    # past dates
+    dt = datetime.now() - date
+    if dt.days < -28:
+        date = date.replace(date.year - 1)
+
+    return date