Adiciona suporte para datas de preprint em FulltextDates (#1052)

* feat(dates): add preprint_date support to FulltextDates

- Add cached_property preprint_date to extract preprint date from history
- Include preprint dates in get_peer_reviewed_stats method
- Calculate days_from_preprint_to_received and days_from_preprint_to_published
- Add estimation flags for preprint-related intervals
- Support serialization of preprint_date when serialize_dates=True

* test(dates): add comprehensive tests for preprint_date functionality

- Add TestPreprintDate class with tests for:
  - Preprint date extraction when present
  - Behavior when preprint date is absent
  - Partial preprint dates (year and month only)
  - Multiple preprint dates (first one is selected)

- Add TestGetPeerReviewedStatsWithPreprint class with tests for:
  - Complete peer review cycle including preprint
  - Preprint with estimated dates
  - Only preprint and published dates scenario
  - Custom default values for partial preprint dates
  - Date serialization with preprint
  - Negative intervals for out-of-order dates

- Fix leap year calculations (2024 has 366 days)
- Correct day count from Dec 15, 2023 to Mar 1, 2024 (77 days)

Author: robertatakenaka

packtools/sps/models/dates.py

@@ -415,6 +415,19 @@ def date_types_ordered_by_date(self):
         # obtem uma lista com os nomes dos eventos ordenados
         return [event[0] for event in self.ordered_events]
 
+    @cached_property
+    def preprint_date(self):
+        """Get preprint date as a Date instance.
+
+        Returns:
+            Date: Date instance for the preprint date, or None if not available
+        """
+        try:
+            node = self.front.xpath(".//history//date[@date-type='preprint']")[0]
+            return Date(node)
+        except (IndexError, AttributeError):
+            return None
+
     @cached_property
     def received_date(self):
         """Get received date as a Date instance.
@@ -444,6 +457,11 @@ def accepted_date(self):
     def get_peer_reviewed_stats(
         self, default_month=6, default_day=15, serialize_dates=False
     ):
+        preprint = {}
+        if self.preprint_date:
+            preprint = self.preprint_date.get_date(
+                default_month=default_month, default_day=default_day
+            )
         received = {}
         if self.received_date:
             received = self.received_date.get_date(
@@ -460,11 +478,17 @@ def get_peer_reviewed_stats(
                 default_month=default_month, default_day=default_day
             )
 
+        preprint_date = preprint.get("date")
         received_date = received.get("date")
         accepted_date = accepted.get("date")
         published_date = published.get("date")
 
         stats = {}
+        stats["preprint_date"] = (
+            preprint_date.isoformat()
+            if serialize_dates and preprint_date
+            else preprint_date
+        )
         stats["received_date"] = (
             received_date.isoformat()
             if serialize_dates and received_date
@@ -480,6 +504,10 @@ def get_peer_reviewed_stats(
             if serialize_dates and published_date
             else published_date
         )
+        stats["days_from_preprint_to_received"] = get_days(preprint_date, received_date)
+        stats["estimated_days_from_preprint_to_received"] = preprint.get(
+            "estimated"
+        ) or received.get("estimated")
         stats["days_from_received_to_accepted"] = get_days(received_date, accepted_date)
         stats["estimated_days_from_received_to_accepted"] = received.get(
             "estimated"
@@ -490,6 +518,13 @@ def get_peer_reviewed_stats(
         stats["estimated_days_from_accepted_to_published"] = accepted.get(
             "estimated"
         ) or published.get("estimated")
+
+        stats["days_from_preprint_to_published"] = get_days(
+            preprint_date, published_date
+        )
+        stats["estimated_days_from_preprint_to_published"] = preprint.get(
+            "estimated"
+        ) or published.get("estimated")
         stats["days_from_received_to_published"] = get_days(
             received_date, published_date
         )