feat(mail): add governed POP3 legacy import

src/govoplan_mail/backend/provider_state.py

@@ -16,6 +16,7 @@ from govoplan_mail.backend.db.models import (
     MailDeliveryCommand,
     MailMailboxFolderIndex,
     MailMailboxMessageIndex,
+    MailPop3Import,
     MailServerEndpoint,
     MailServerProfile,
 )
@@ -23,6 +24,7 @@ from govoplan_mail.backend.db.models import (
 
 SMTP_PROVIDER_ID = "mail.smtp_delivery"
 IMAP_PROVIDER_ID = "mail.imap_mailbox"
+POP3_PROVIDER_ID = "mail.pop3_legacy_import"
 _CURRENT_INDEX_WINDOW = timedelta(minutes=30)
 
 
@@ -38,6 +40,41 @@ def imap_provider_states(
     return _mail_provider_states(context, protocol="imap")
 
 
+def pop3_provider_states(
+    context: ExternalProviderStateContext,
+) -> tuple[ExternalProviderRuntimeState, ...]:
+    if not isinstance(context.session, Session):
+        raise RuntimeError("Mail provider state requires a database session.")
+    profiles = _profiles(context)
+    if not profiles:
+        return ()
+    profile_ids = tuple(item.id for item in profiles)
+    endpoints = _endpoints(
+        context.session,
+        profile_ids=profile_ids,
+        protocol="pop3",
+    )
+    endpoints_by_profile: dict[str, list[MailServerEndpoint]] = defaultdict(list)
+    for endpoint in endpoints:
+        endpoints_by_profile[endpoint.profile_id].append(endpoint)
+    metrics = _pop3_metrics(
+        context.session,
+        profile_ids=profile_ids,
+        tenant_id=context.tenant_id,
+    )
+    observed_at = datetime.now(UTC)
+    return tuple(
+        _pop3_state(
+            profile,
+            endpoints=endpoints_by_profile.get(profile.id, []),
+            metrics=metrics.get(profile.id, {}),
+            observed_at=observed_at,
+        )
+        for profile in profiles
+        if endpoints_by_profile.get(profile.id)
+    )
+
+
 def _mail_provider_states(
     context: ExternalProviderStateContext,
     *,
@@ -194,6 +231,37 @@ def _imap_metrics(
     return result
 
 
+def _pop3_metrics(
+    session: Session,
+    *,
+    profile_ids: tuple[str, ...],
+    tenant_id: str | None,
+) -> dict[str, dict[str, Any]]:
+    result: dict[str, dict[str, Any]] = defaultdict(dict)
+    statement = select(
+        MailPop3Import.profile_id,
+        MailPop3Import.deletion_status,
+        func.count(MailPop3Import.id),
+        func.max(MailPop3Import.imported_at),
+    ).where(MailPop3Import.profile_id.in_(profile_ids))
+    if tenant_id is not None:
+        statement = statement.where(MailPop3Import.tenant_id == tenant_id)
+    rows = session.execute(
+        statement.group_by(
+            MailPop3Import.profile_id,
+            MailPop3Import.deletion_status,
+        )
+    )
+    for profile_id, deletion_status, count, last_imported_at in rows:
+        item = result[str(profile_id)]
+        item[f"deletion_{deletion_status}"] = int(count)
+        current = _aware(item.get("last_imported_at"))
+        candidate = _aware(last_imported_at)
+        if candidate is not None and (current is None or candidate > current):
+            item["last_imported_at"] = candidate
+    return result
+
+
 def _smtp_state(
     profile: MailServerProfile,
     *,
@@ -321,6 +389,71 @@ def _imap_state(
     )
 
 
+def _pop3_state(
+    profile: MailServerProfile,
+    *,
+    endpoints: list[MailServerEndpoint],
+    metrics: dict[str, Any],
+    observed_at: datetime,
+) -> ExternalProviderRuntimeState:
+    enabled_endpoints = [
+        item
+        for item in endpoints
+        if item.is_active and bool((item.config or {}).get("legacy_import_enabled"))
+    ]
+    active = bool(profile.is_active) and bool(enabled_endpoints)
+    failed_deletions = int(metrics.get("deletion_failed", 0))
+    unknown_deletions = int(metrics.get("deletion_outcome_unknown", 0))
+    last_imported_at = _aware(metrics.get("last_imported_at"))
+    health = (
+        "inactive"
+        if not active
+        else "warning"
+        if failed_deletions or unknown_deletions
+        else "healthy"
+        if last_imported_at is not None
+        else "unknown"
+    )
+    return ExternalProviderRuntimeState(
+        provider_id=POP3_PROVIDER_ID,
+        binding_ref=f"mail:profile:{profile.id}:pop3",
+        authority_mode="governance_overlay",
+        observed_at=observed_at,
+        configured=True,
+        active=active,
+        health=health,
+        freshness="not_applicable",
+        conflict="pending" if unknown_deletions else "clear",
+        recovery=(
+            "not_applicable"
+            if not active
+            else "attention"
+            if failed_deletions or unknown_deletions
+            else "ready"
+        ),
+        last_success_at=last_imported_at,
+        detail=(
+            "POP3 legacy import is disabled."
+            if not active
+            else "POP3 source deletion evidence requires attention."
+            if failed_deletions or unknown_deletions
+            else "POP3 legacy import is enabled but has no retained import yet."
+            if last_imported_at is None
+            else "POP3 governed import evidence is available."
+        ),
+        metrics={
+            "active_endpoints": len(enabled_endpoints),
+            "imports": sum(
+                int(value)
+                for key, value in metrics.items()
+                if key.startswith("deletion_")
+            ),
+            "failed_deletions": failed_deletions,
+            "outcome_unknown_deletions": unknown_deletions,
+        },
+    )
+
+
 def _legacy_configured(profile: MailServerProfile, protocol: str) -> bool:
     value = profile.smtp_config if protocol == "smtp" else profile.imap_config
     return isinstance(value, dict) and bool(value)
@@ -336,7 +469,9 @@ def _aware(value: object | None) -> datetime | None:
 
 __all__ = [
     "IMAP_PROVIDER_ID",
+    "POP3_PROVIDER_ID",
     "SMTP_PROVIDER_ID",
     "imap_provider_states",
+    "pop3_provider_states",
     "smtp_provider_states",
 ]