fix: add support for negative timestamps (close #38) (#48)

* fix: negative timestamp in note_formatter_util (close #38)

* fix: convert negative timestamp

* fix: zeropad year for linux strftime

---------

Co-authored-by: vzhd1701 <vzhd1701@gmail.com>

evernote_backup/note_formatter_util.py

@@ -1,6 +1,6 @@
 import base64
 import sys
-from datetime import datetime
+from datetime import datetime, timedelta
 from typing import Optional
 
 
@@ -10,12 +10,15 @@ def fmt_time(timestamp: Optional[int]) -> Optional[str]:
 
     timestamp //= 1000
 
-    if timestamp < _get_max_timestamp():
-        date = datetime.utcfromtimestamp(timestamp)
-    else:
+    # https://dev.evernote.com/doc/reference/Types.html#Typedef_Timestamp
+    if timestamp < 0:
+        date = _date_from_past(timestamp)
+    elif timestamp >= _get_max_timestamp():
         date = _date_from_future(timestamp)
+    else:
+        date = datetime.utcfromtimestamp(timestamp)
 
-    return date.strftime("%Y%m%dT%H%M%SZ")
+    return date.strftime(f"{date.year:04}%m%dT%H%M%SZ")
 
 
 def fmt_binary(binary_data: bytes) -> str:
@@ -80,13 +83,23 @@ def _date_from_future(timestamp: int) -> datetime:  # noqa: WPS210
     m = mp + (3 if mp < 10 else -9)
     y += m <= 2
 
-    day_time = datetime.utcfromtimestamp(timestamp % 86400)
+    try:
+        day_time = datetime.utcfromtimestamp(timestamp % 86400)
+
+        return datetime(
+            year=y,
+            month=m,
+            day=d,
+            hour=day_time.hour,
+            minute=day_time.minute,
+            second=day_time.second,
+        )
+    except (OverflowError, ValueError, OSError):
+        return datetime.max
 
-    return datetime(
-        year=y,
-        month=m,
-        day=d,
-        hour=day_time.hour,
-        minute=day_time.minute,
-        second=day_time.second,
-    )
+
+def _date_from_past(timestamp: int) -> datetime:
+    try:
+        return datetime.utcfromtimestamp(0) - timedelta(seconds=abs(timestamp))
+    except (OverflowError, ValueError, OSError):
+        return datetime.min

tests/test_note_formatter.py

@@ -168,7 +168,8 @@ def test_note_from_future(mocker):
     formatter = NoteFormatter()
 
     # 9999-12-31 23:59:59
-    end_of_times = 253402300799999
+    end_of_times_bad = 999999999999999
+    end_of_times = 243402300799999
 
     # Emulate windows limit
     mock_timestamp = mocker.patch(
@@ -178,11 +179,29 @@ def test_note_from_future(mocker):
 
     note_from_future = Note(
         title="test",
-        created=end_of_times,
+        created=end_of_times_bad,
         updated=end_of_times,
     )
 
     formatted_note = formatter.format_note(note_from_future)
 
     assert "<created>99991231T235959Z</created>" in formatted_note
-    assert "<updated>99991231T235959Z</updated>" in formatted_note
+    assert "<updated>96830210T061319Z</updated>" in formatted_note
+
+
+def test_note_from_past(mocker):
+    formatter = NoteFormatter()
+
+    before_times_bad = -999999999999999
+    before_times = -50000000000000
+
+    note_from_future = Note(
+        title="test",
+        created=before_times_bad,
+        updated=before_times,
+    )
+
+    formatted_note = formatter.format_note(note_from_future)
+
+    assert "<created>00010101T000000Z</created>" in formatted_note
+    assert "<updated>03850725T070640Z</updated>" in formatted_note