Commit inicial

state.py

@@ -0,0 +1,87 @@
+"""Persistencia del estado de migración (migration-state.json).
+
+El estado permite reanudar una migración interrumpida y evitar volver a
+copiar mensajes ya migrados. Nunca se almacenan contraseñas aquí.
+"""
+
+import json
+import os
+import tempfile
+import threading
+from datetime import datetime, timezone
+
+STATE_VERSION = 1
+
+
+class MigrationState:
+    def __init__(self, path: str, account: str):
+        self.path = path
+        self.account = account
+        self._lock = threading.Lock()
+        self._data = self._load()
+
+    def _load(self) -> dict:
+        if os.path.exists(self.path):
+            with open(self.path, "r", encoding="utf-8") as f:
+                data = json.load(f)
+            data.setdefault("folders", {})
+            return data
+        return {
+            "version": STATE_VERSION,
+            "account": self.account,
+            "created_at": datetime.now(timezone.utc).isoformat(),
+            "folders": {},
+        }
+
+    def save(self) -> None:
+        with self._lock:
+            self._data["updated_at"] = datetime.now(timezone.utc).isoformat()
+            target_dir = os.path.dirname(os.path.abspath(self.path)) or "."
+            os.makedirs(target_dir, exist_ok=True)
+            fd, tmp_path = tempfile.mkstemp(prefix=".migration-state-", dir=target_dir)
+            try:
+                with os.fdopen(fd, "w", encoding="utf-8") as f:
+                    json.dump(self._data, f, indent=2, ensure_ascii=False)
+                os.replace(tmp_path, self.path)
+            finally:
+                if os.path.exists(tmp_path):
+                    try:
+                        os.remove(tmp_path)
+                    except OSError:
+                        pass
+
+    def _folder(self, folder: str) -> dict:
+        return self._data["folders"].setdefault(
+            folder,
+            {"fingerprints": {}, "last_scanned_a_uid": 0, "a_uidvalidity": None},
+        )
+
+    def get_uidvalidity(self, folder: str):
+        return self._folder(folder).get("a_uidvalidity")
+
+    def set_uidvalidity(self, folder: str, value) -> None:
+        f = self._folder(folder)
+        if f.get("a_uidvalidity") != value:
+            f["a_uidvalidity"] = value
+            f["last_scanned_a_uid"] = 0
+
+    def get_last_scanned_uid(self, folder: str) -> int:
+        return self._folder(folder).get("last_scanned_a_uid", 0)
+
+    def set_last_scanned_uid(self, folder: str, uid: int) -> None:
+        f = self._folder(folder)
+        f["last_scanned_a_uid"] = max(f.get("last_scanned_a_uid", 0), uid)
+
+    def has_fingerprint(self, folder: str, fingerprint: str) -> bool:
+        return fingerprint in self._folder(folder)["fingerprints"]
+
+    def mark_migrated(self, folder: str, fingerprint: str, a_uid: int, b_uid, size: int) -> None:
+        self._folder(folder)["fingerprints"][fingerprint] = {
+            "a_uid": a_uid,
+            "b_uid": b_uid,
+            "size": size,
+            "migrated_at": datetime.now(timezone.utc).isoformat(),
+        }
+
+    def folders_seen(self) -> list[str]:
+        return list(self._data["folders"].keys())