[aws-lambda] Improve script (#259)

- make the script more resilient to changes in the page by using column names,
- use the product release releaseDate as the date, else the date the version was first found, else the current date (previously the date the version was first found was not used),
- move some code to the Product class.

src/common/endoflife.py

@@ -40,10 +40,9 @@ class AutoConfig:
 
 
 class Product:
-    """Model an endoflife.date product.
-    """
+    """Model an endoflife.date product."""
 
-    def __init__(self, name: str, load_product_data: bool = False):
+    def __init__(self, name: str, load_product_data: bool = False, load_versions_data: bool = False):
         self.name: str = name
         self.versions = {}
         self.versions_path: str = f"{VERSIONS_PATH}/{name}.json"
@@ -58,6 +57,15 @@ class Product:
                 logging.warning(f"no product data found for {self.name} at {self.product_path}")
                 self.product_data = None
 
+        if load_versions_data:
+            if os.path.isfile(self.versions_path):
+                with open(self.versions_path) as f:
+                    logging.info(f"loaded versions data for {self.name} from {self.versions_path}")
+                    self.old_versions = json.load(f)
+            else:
+                logging.warning(f"no versions data found for {self.name} at {self.versions_path}")
+                self.old_versions = None
+
     def get_auto_configs(self, method: str) -> list[AutoConfig]:
         configs = []
 
@@ -76,6 +84,17 @@ class Product:
     def get_version_date(self, version: str) -> datetime:
         return self.versions[version] if version in self.versions else None
 
+    def get_old_version_date(self, version: str) -> datetime:
+        return datetime.strptime(self.old_versions[version], "%Y-%m-%d") if (
+            self.old_versions
+            and version in self.old_versions
+        ) else None
+
+    def get_release_date(self, release_cycle: str) -> datetime:
+        for release in self.product_data["releases"]:
+            if release["releaseCycle"] == release_cycle:
+                return release["releaseDate"]
+
     def declare_version(self, version: str, date: datetime) -> None:
         if version in self.versions:
             if self.versions[version] != date: