feat: add core modules (config, state, diff, apply, health)

diff.py

@@ -0,0 +1,65 @@
+import hashlib
+import logging
+from icalendar import Calendar
+
+logger = logging.getLogger(__name__)
+
+
+def parse_ics_events(ics_text: str) -> dict[str, str]:
+    cal = Calendar.from_ical(ics_text.encode() if isinstance(ics_text, str) else ics_text)
+    result = {}
+    for component in cal.walk():
+        if component.name != "VEVENT":
+            continue
+        uid = component.get("UID")
+        if uid is None:
+            logger.warning("Skipping event with no UID")
+            continue
+        uid_str = str(uid)
+        try:
+            event_bytes = component.to_ical()
+            file_hash = hashlib.sha256(event_bytes).hexdigest()
+            result[uid_str] = file_hash
+        except Exception as e:
+            logger.warning("Failed to process event %s: %s", uid_str, e)
+    return result
+
+
+def compute_diff(ics_uids: dict[str, str], known_uids: dict[str, str]) -> dict:
+    to_add = []
+    to_update = []
+    to_delete = []
+
+    for uid, file_hash in ics_uids.items():
+        if uid not in known_uids:
+            to_add.append((uid, file_hash))
+        elif known_uids[uid] != file_hash:
+            to_update.append((uid, file_hash))
+
+    for uid in known_uids:
+        if uid not in ics_uids:
+            to_delete.append(uid)
+
+    return {
+        "to_add": to_add,
+        "to_update": to_update,
+        "to_delete": to_delete,
+    }
+
+
+def parse_ics_events_with_data(ics_text: str) -> dict[str, bytes]:
+    cal = Calendar.from_ical(ics_text.encode() if isinstance(ics_text, str) else ics_text)
+    result = {}
+    for component in cal.walk():
+        if component.name != "VEVENT":
+            continue
+        uid = component.get("UID")
+        if uid is None:
+            logger.warning("Skipping event with no UID")
+            continue
+        uid_str = str(uid)
+        try:
+            result[uid_str] = component.to_ical()
+        except Exception as e:
+            logger.warning("Failed to process event %s: %s", uid_str, e)
+    return result