feat: add dataset checkpoint sync for MCP

app/services/dataset_versions.py

@@ -0,0 +1,227 @@
+import hashlib
+import json
+from dataclasses import dataclass
+
+from sqlalchemy import desc, select
+from sqlalchemy.orm import Session
+
+from app.models import DatasetVersion, DatasetVersionItem, Employee
+
+
+@dataclass(frozen=True)
+class EmployeeMarker:
+    profile_key: str
+    employee_id: int | None
+    status: str
+    checksum: str
+
+
+def get_or_create_current_version(db: Session, *, crawl_run_id: int | None = None) -> DatasetVersion:
+    employees = db.scalars(select(Employee).order_by(Employee.profile_key)).all()
+    markers = [_employee_marker(employee) for employee in employees]
+    dataset_hash = _dataset_hash(markers)
+    latest = get_latest_version(db)
+    if latest and latest.hash == dataset_hash:
+        return latest
+
+    active_count = sum(1 for marker in markers if marker.status == "active")
+    dismissed_count = sum(1 for marker in markers if marker.status == "dismissed")
+    version = DatasetVersion(
+        hash=dataset_hash,
+        previous_hash=latest.hash if latest else None,
+        crawl_run_id=crawl_run_id,
+        employee_count=len(markers),
+        active_count=active_count,
+        dismissed_count=dismissed_count,
+    )
+    db.add(version)
+    db.flush()
+    for marker in markers:
+        db.add(
+            DatasetVersionItem(
+                dataset_version_id=version.id,
+                profile_key=marker.profile_key,
+                employee_id=marker.employee_id,
+                status=marker.status,
+                checksum=marker.checksum,
+            )
+        )
+    db.flush()
+    return version
+
+
+def get_latest_version(db: Session) -> DatasetVersion | None:
+    return db.scalar(select(DatasetVersion).order_by(desc(DatasetVersion.created_at), desc(DatasetVersion.id)).limit(1))
+
+
+def get_version_by_hash(db: Session, dataset_hash: str | None) -> DatasetVersion | None:
+    if not dataset_hash:
+        return None
+    return db.scalar(select(DatasetVersion).where(DatasetVersion.hash == dataset_hash).limit(1))
+
+
+def service_info_payload(db: Session, *, tools: list[dict], service_name: str, backend_version: str, protocol_version: str) -> dict:
+    version = get_or_create_current_version(db)
+    db.commit()
+    return {
+        "service_name": service_name,
+        "backend_version": backend_version,
+        "protocolVersion": protocol_version,
+        "tools": tools,
+        "dataset": _version_payload(version),
+    }
+
+
+def sync_employees_payload(db: Session, *, client_hash: str | None = None, include_data: bool = True) -> dict:
+    current = get_or_create_current_version(db)
+    db.commit()
+    if not client_hash:
+        return _full_sync_payload(db, current, include_data=include_data, reason=None)
+    if client_hash == current.hash:
+        return {
+            "mode": "delta",
+            "from_hash": client_hash,
+            "to_hash": current.hash,
+            "dataset": _version_payload(current),
+            "changes": {"added": [], "updated": [], "dismissed": [], "removed": []},
+        }
+
+    previous = get_version_by_hash(db, client_hash)
+    if not previous:
+        return _full_sync_payload(db, current, include_data=include_data, reason="unknown_client_hash", from_hash=client_hash)
+
+    return _delta_sync_payload(db, previous, current, include_data=include_data)
+
+
+def _full_sync_payload(
+    db: Session,
+    current: DatasetVersion,
+    *,
+    include_data: bool,
+    reason: str | None,
+    from_hash: str | None = None,
+) -> dict:
+    employees = db.scalars(select(Employee).order_by(Employee.profile_key)).all()
+    payload = {
+        "mode": "full",
+        "from_hash": from_hash,
+        "to_hash": current.hash,
+        "dataset": _version_payload(current),
+        "items": [_employee_payload(employee, include_data=include_data) for employee in employees],
+    }
+    if reason:
+        payload["reason"] = reason
+    return payload
+
+
+def _delta_sync_payload(db: Session, previous: DatasetVersion, current: DatasetVersion, *, include_data: bool) -> dict:
+    previous_items = _items_by_profile_key(previous)
+    current_items = _items_by_profile_key(current)
+    employees = {employee.profile_key: employee for employee in db.scalars(select(Employee)).all()}
+    added = []
+    updated = []
+    dismissed = []
+    removed = []
+
+    for profile_key, current_item in sorted(current_items.items()):
+        previous_item = previous_items.get(profile_key)
+        employee = employees.get(profile_key)
+        if not previous_item:
+            if employee:
+                added.append(_employee_payload(employee, include_data=include_data))
+            continue
+        if previous_item.checksum == current_item.checksum and previous_item.status == current_item.status:
+            continue
+        if current_item.status == "dismissed":
+            dismissed.append(_tombstone(profile_key, current_item.status, employee))
+        elif employee:
+            updated.append(_employee_payload(employee, include_data=include_data))
+
+    for profile_key, previous_item in sorted(previous_items.items()):
+        if profile_key not in current_items:
+            removed.append(_tombstone(profile_key, "removed", employees.get(profile_key), checksum=previous_item.checksum))
+
+    return {
+        "mode": "delta",
+        "from_hash": previous.hash,
+        "to_hash": current.hash,
+        "dataset": _version_payload(current),
+        "changes": {
+            "added": added,
+            "updated": updated,
+            "dismissed": dismissed,
+            "removed": removed,
+        },
+    }
+
+
+def _items_by_profile_key(version: DatasetVersion) -> dict[str, DatasetVersionItem]:
+    return {item.profile_key: item for item in version.items}
+
+
+def _version_payload(version: DatasetVersion) -> dict:
+    return {
+        "hash": version.hash,
+        "previous_hash": version.previous_hash,
+        "created_at": version.created_at.isoformat() if version.created_at else None,
+        "crawl_run_id": version.crawl_run_id,
+        "employee_count": version.employee_count,
+        "active_count": version.active_count,
+        "dismissed_count": version.dismissed_count,
+    }
+
+
+def _employee_marker(employee: Employee) -> EmployeeMarker:
+    return EmployeeMarker(
+        profile_key=employee.profile_key,
+        employee_id=employee.id,
+        status=employee.status,
+        checksum=employee.current_checksum or _payload_hash(employee.current_data or {}),
+    )
+
+
+def _dataset_hash(markers: list[EmployeeMarker]) -> str:
+    payload = [
+        {"profile_key": marker.profile_key, "status": marker.status, "checksum": marker.checksum}
+        for marker in sorted(markers, key=lambda item: item.profile_key)
+    ]
+    return _payload_hash(payload)
+
+
+def _payload_hash(value: object) -> str:
+    payload = json.dumps(value, ensure_ascii=False, sort_keys=True, separators=(",", ":"), default=str)
+    return hashlib.sha256(payload.encode("utf-8")).hexdigest()
+
+
+def _employee_payload(employee: Employee, *, include_data: bool) -> dict:
+    payload = {
+        "profile_key": employee.profile_key,
+        "profile_id": employee.profile_id,
+        "full_name": employee.full_name,
+        "status": employee.status,
+        "canonical_url": employee.canonical_url,
+        "last_seen_at": employee.last_seen_at.isoformat() if employee.last_seen_at else None,
+        "dismissed_at": employee.dismissed_at.isoformat() if employee.dismissed_at else None,
+        "checksum": employee.current_checksum or _payload_hash(employee.current_data or {}),
+    }
+    if include_data:
+        payload["data"] = employee.current_data
+    return payload
+
+
+def _tombstone(profile_key: str, status: str, employee: Employee | None, *, checksum: str | None = None) -> dict:
+    payload = {
+        "profile_key": profile_key,
+        "status": status,
+        "checksum": checksum or (employee.current_checksum if employee else None),
+    }
+    if employee:
+        payload.update(
+            {
+                "profile_id": employee.profile_id,
+                "full_name": employee.full_name,
+                "canonical_url": employee.canonical_url,
+                "dismissed_at": employee.dismissed_at.isoformat() if employee.dismissed_at else None,
+            }
+        )
+    return payload