WIP checkpoint: Trust & Safety: Moderation data model + Alembic migration

backend/alembic/versions/0001_initial.py

@@ -69,7 +69,7 @@ def upgrade() -> None:
         sa.Column(
             "visibility",
             postgresql.ENUM(
-                "public", "private", "friends_only", name="world_visibility"
+                "public", "private", "friends_only", name="world_visibility", create_type=False
             ),
             nullable=True,
         ),
@@ -89,7 +89,7 @@ def upgrade() -> None:
             "asset_type",
             postgresql.ENUM(
                 "image", "audio", "video", "document", "model_3d", "other",
-                name="asset_type",
+                name="asset_type", create_type=False,
             ),
             nullable=False,
         ),

backend/alembic/versions/0003_add_moderation_schema.py

@@ -1,310 +0,0 @@
-"""add moderation schema
-
-Revision ID: 0003_add_moderation_schema
-Revises: 0002_add_date_of_birth_to_users
-Create Date: 2025-01-01 00:00:00.000000
-
-"""
-from typing import Sequence, Union
-
-from alembic import op
-import sqlalchemy as sa
-from sqlalchemy.dialects import postgresql
-
-# revision identifiers, used by Alembic.
-revision: str = "0003_add_moderation_schema"
-down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
-
-
-def upgrade() -> None:
-    """Create moderation tables and extend users table."""
-    # ── ENUM types ──────────────────────────────────────────────
-
-    target_type_enum = postgresql.ENUM(
-        "user", "world", "asset", "chat_message",
-        name="target_type",
-    )
-    target_type_enum.create(op.get_bind(), checkfirst=True)
-
-    reason_category_enum = postgresql.ENUM(
-        "harassment", "hate_speech", "sexual_content", "violence",
-        "spam", "self_harm", "other",
-        name="reason_category",
-    )
-    reason_category_enum.create(op.get_bind(), checkfirst=True)
-
-    report_status_enum = postgresql.ENUM(
-        "open", "in_review", "resolved", "dismissed",
-        name="report_status",
-    )
-    report_status_enum.create(op.get_bind(), checkfirst=True)
-
-    resolution_enum = postgresql.ENUM(
-        "upheld", "modified", "dismissed",
-        name="resolution",
-    )
-    resolution_enum.create(op.get_bind(), checkfirst=True)
-
-    moderation_action_type_enum = postgresql.ENUM(
-        "warn", "suspend", "ban", "restrict", "remove", "restore",
-        name="moderation_action_type",
-    )
-    moderation_action_type_enum.create(op.get_bind(), checkfirst=True)
-
-    appeal_status_enum = postgresql.ENUM(
-        "pending", "approved", "rejected",
-        name="appeal_status",
-    )
-    appeal_status_enum.create(op.get_bind(), checkfirst=True)
-
-    user_role_enum = postgresql.ENUM(
-        "user", "moderator", "admin",
-        name="user_role",
-    )
-    user_role_enum.create(op.get_bind(), checkfirst=True)
-
-    # ── users table extensions ──────────────────────────────────
-
-    op.add_column(
-        "users",
-        sa.Column(
-            "role",
-            postgresql.ENUM(
-                "user", "moderator", "admin", name="user_role",
-                create_type=False,
-            ),
-            nullable=False,
-            server_default="user",
-        ),
-    )
-    op.add_column(
-        "users",
-        sa.Column("banned_until", sa.DateTime(timezone=True), nullable=True),
-    )
-    op.add_column(
-        "users",
-        sa.Column("suspended_until", sa.DateTime(timezone=True), nullable=True),
-    )
-
-    # ── reports table ───────────────────────────────────────────
-
-    op.create_table(
-        "reports",
-        sa.Column("id", sa.Integer(), primary_key=True),
-        sa.Column("reporter_id", sa.Integer(), nullable=False),
-        sa.Column(
-            "target_type",
-            postgresql.ENUM(
-                "user", "world", "asset", "chat_message",
-                name="target_type", create_type=False,
-            ),
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "reason_category",
-            postgresql.ENUM(
-                "harassment", "hate_speech", "sexual_content", "violence",
-                "spam", "self_harm", "other",
-                name="reason_category", create_type=False,
-            ),
-            nullable=False,
-        ),
-        sa.Column("details", sa.Text(), nullable=True),
-        sa.Column(
-            "status",
-            postgresql.ENUM(
-                "open", "in_review", "resolved", "dismissed",
-                name="report_status", create_type=False,
-            ),
-            nullable=False,
-            server_default="open",
-        ),
-        sa.Column("resolved_by", sa.Integer(), nullable=True),
-        sa.Column(
-            "resolution",
-            postgresql.ENUM(
-                "upheld", "modified", "dismissed",
-                name="resolution", create_type=False,
-            ),
-            nullable=True,
-        ),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.Column(
-            "updated_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
-        sa.ForeignKeyConstraint(
-            ["reporter_id"], ["users.id"], ondelete="CASCADE",
-        ),
-        sa.ForeignKeyConstraint(
-            ["resolved_by"], ["users.id"], ondelete="SET NULL",
-        ),
-    )
-    op.create_index(op.f("ix_reports_id"), "reports", ["id"], unique=False)
-    op.create_index(
-        op.f("ix_reports_reporter_id"), "reports", ["reporter_id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_reports_status"), "reports", ["status"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_reports_target"), "reports", ["target_type", "target_id"], unique=False,
-    )
-
-    # ── moderation_actions table ────────────────────────────────
-
-    op.create_table(
-        "moderation_actions",
-        sa.Column("id", sa.Integer(), primary_key=True),
-        sa.Column("moderator_id", sa.Integer(), nullable=False),
-        sa.Column("target_user_id", sa.Integer(), nullable=False),
-        sa.Column(
-            "target_type",
-            postgresql.ENUM(
-                "user", "world", "asset", "chat_message",
-                name="target_type", create_type=False,
-            ),
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "action",
-            postgresql.ENUM(
-                "warn", "suspend", "ban", "restrict", "remove", "restore",
-                name="moderation_action_type", create_type=False,
-            ),
-            nullable=False,
-        ),
-        sa.Column("reason", sa.Text(), nullable=True),
-        sa.Column("report_id", sa.Integer(), nullable=True),
-        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.ForeignKeyConstraint(
-            ["moderator_id"], ["users.id"], ondelete="SET NULL",
-        ),
-        sa.ForeignKeyConstraint(
-            ["target_user_id"], ["users.id"], ondelete="CASCADE",
-        ),
-        sa.ForeignKeyConstraint(
-            ["report_id"], ["reports.id"], ondelete="SET NULL",
-        ),
-    )
-    op.create_index(
-        op.f("ix_moderation_actions_id"),
-        "moderation_actions", ["id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_moderation_actions_moderator_id"),
-        "moderation_actions", ["moderator_id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_moderation_actions_target_user_id"),
-        "moderation_actions", ["target_user_id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_moderation_actions_target"),
-        "moderation_actions", ["target_type", "target_id"], unique=False,
-    )
-
-    # ── appeals table ───────────────────────────────────────────
-
-    op.create_table(
-        "appeals",
-        sa.Column("id", sa.Integer(), primary_key=True),
-        sa.Column(
-            "moderation_action_id", sa.Integer(), nullable=False,
-        ),
-        sa.Column("user_id", sa.Integer(), nullable=False),
-        sa.Column("reason", sa.Text(), nullable=False),
-        sa.Column(
-            "status",
-            postgresql.ENUM(
-                "pending", "approved", "rejected",
-                name="appeal_status", create_type=False,
-            ),
-            nullable=False,
-            server_default="pending",
-        ),
-        sa.Column("reviewed_by", sa.Integer(), nullable=True),
-        sa.Column("reviewed_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.ForeignKeyConstraint(
-            ["moderation_action_id"],
-            ["moderation_actions.id"], ondelete="CASCADE",
-        ),
-        sa.ForeignKeyConstraint(
-            ["user_id"], ["users.id"], ondelete="CASCADE",
-        ),
-        sa.ForeignKeyConstraint(
-            ["reviewed_by"], ["users.id"], ondelete="SET NULL",
-        ),
-    )
-    op.create_index(op.f("ix_appeals_id"), "appeals", ["id"], unique=False)
-    op.create_index(
-        op.f("ix_appeals_moderation_action_id"),
-        "appeals", ["moderation_action_id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_appeals_user_id"),
-        "appeals", ["user_id"], unique=False,
-    )
-    op.create_index(
-        op.f("ix_appeals_status"),
-        "appeals", ["status"], unique=False,
-    )
-
-
-def downgrade() -> None:
-    """Drop moderation tables and revert users table."""
-    op.drop_index(op.f("ix_appeals_status"), table_name="appeals")
-    op.drop_index(op.f("ix_appeals_user_id"), table_name="appeals")
-    op.drop_index(op.f("ix_appeals_moderation_action_id"), table_name="appeals")
-    op.drop_index(op.f("ix_appeals_id"), table_name="appeals")
-    op.drop_table("appeals")
-
-    op.drop_index(op.f("ix_moderation_actions_target"), table_name="moderation_actions")
-    op.drop_index(op.f("ix_moderation_actions_target_user_id"), table_name="moderation_actions")
-    op.drop_index(op.f("ix_moderation_actions_moderator_id"), table_name="moderation_actions")
-    op.drop_index(op.f("ix_moderation_actions_id"), table_name="moderation_actions")
-    op.drop_table("moderation_actions")
-
-    op.drop_index(op.f("ix_reports_target"), table_name="reports")
-    op.drop_index(op.f("ix_reports_status"), table_name="reports")
-    op.drop_index(op.f("ix_reports_reporter_id"), table_name="reports")
-    op.drop_index(op.f("ix_reports_id"), table_name="reports")
-    op.drop_table("reports")
-
-    op.drop_column("users", "suspended_until")
-    op.drop_column("users", "banned_until")
-    op.drop_column("users", "role")
-
-    # Drop ENUM types
-    postgresql.ENUM(name="appeal_status").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="moderation_action_type").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="resolution").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="report_status").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="reason_category").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="target_type").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="user_role").drop(op.get_bind(), checkfirst=True)

backend/alembic/versions/0003_moderation.py

@@ -0,0 +1,211 @@
+"""add moderation tables and extend users table
+
+Revision ID: 0003_moderation
+Revises: 0002_add_date_of_birth_to_users
+Create Date: 2025-01-01 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0003_moderation"
+down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def _create_enum_if_not_exists(enum_name: str, values: list[str]) -> None:
+    """Create a PostgreSQL ENUM type if it does not already exist."""
+    bind = op.get_bind()
+    # Check if the type already exists in pg_type
+    result = bind.execute(
+        sa.text(
+            "SELECT 1 FROM pg_type WHERE typname = :name"
+        ).bindparams(name=enum_name)
+    ).fetchone()
+    if result is None:
+        values_str = ", ".join(f"'{v}'" for v in values)
+        op.execute(f"CREATE TYPE {enum_name} AS ENUM ({values_str})")
+
+
+def upgrade() -> None:
+    """Add role, banned_until, suspended_until to users table
+    and create reports, moderation_actions, appeals tables."""
+
+    # --- Create ENUM types if they don't exist ---
+    _create_enum_if_not_exists("user_role", ["user", "moderator", "admin"])
+    _create_enum_if_not_exists("report_target_type", ["user", "world", "asset", "chat_message"])
+    _create_enum_if_not_exists("report_reason_category", [
+        "harassment", "hate_speech", "sexual_content",
+        "violence", "spam", "self_harm", "other"
+    ])
+    _create_enum_if_not_exists("report_status", ["open", "in_review", "resolved", "dismissed"])
+    _create_enum_if_not_exists("report_resolution", ["warn", "suspend", "ban", "restrict", "remove"])
+    _create_enum_if_not_exists("moderation_target_type", ["user", "world", "asset", "chat_message"])
+    _create_enum_if_not_exists("moderation_action_type", ["warn", "suspend", "ban", "restrict", "remove", "restore"])
+    _create_enum_if_not_exists("appeal_status", ["pending", "approved", "rejected"])
+
+    # --- Extend users table ---
+
+    # Add role column
+    op.add_column(
+        "users",
+        sa.Column(
+            "role",
+            postgresql.ENUM("user", "moderator", "admin", name="user_role", create_type=False),
+            nullable=False,
+            server_default="user",
+        ),
+    )
+
+    # Add banned_until column
+    op.add_column(
+        "users",
+        sa.Column("banned_until", sa.DateTime(timezone=True), nullable=True),
+    )
+
+    # Add suspended_until column
+    op.add_column(
+        "users",
+        sa.Column("suspended_until", sa.DateTime(timezone=True), nullable=True),
+    )
+
+    # --- Create reports table ---
+
+    op.create_table(
+        "reports",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("reporter_id", sa.Integer(), sa.ForeignKey("users.id"), nullable=False),
+        sa.Column(
+            "target_type",
+            postgresql.ENUM("user", "world", "asset", "chat_message", name="report_target_type", create_type=False),
+            nullable=False,
+        ),
+        sa.Column("target_id", sa.String(64), nullable=False),
+        sa.Column(
+            "reason_category",
+            postgresql.ENUM(
+                "harassment", "hate_speech", "sexual_content",
+                "violence", "spam", "self_harm", "other",
+                name="report_reason_category", create_type=False,
+            ),
+            nullable=False,
+        ),
+        sa.Column("details", sa.Text(), nullable=True),
+        sa.Column(
+            "status",
+            postgresql.ENUM("open", "in_review", "resolved", "dismissed", name="report_status", create_type=False),
+            nullable=False,
+            server_default="open",
+        ),
+        sa.Column("resolved_by", sa.Integer(), sa.ForeignKey("users.id"), nullable=True),
+        sa.Column(
+            "resolution",
+            postgresql.ENUM("warn", "suspend", "ban", "restrict", "remove", name="report_resolution", create_type=False),
+            nullable=True,
+        ),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
+    )
+
+    # Indexes for reports
+    op.create_index("ix_reports_reporter_id", "reports", ["reporter_id"])
+    op.create_index("ix_reports_target", "reports", ["target_type", "target_id"])
+    op.create_index("ix_reports_status", "reports", ["status"])
+
+    # --- Create moderation_actions table ---
+
+    op.create_table(
+        "moderation_actions",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("moderator_id", sa.Integer(), sa.ForeignKey("users.id"), nullable=False),
+        sa.Column("target_user_id", sa.Integer(), sa.ForeignKey("users.id"), nullable=True),
+        sa.Column(
+            "target_type",
+            postgresql.ENUM("user", "world", "asset", "chat_message", name="moderation_target_type", create_type=False),
+            nullable=False,
+        ),
+        sa.Column("target_id", sa.String(64), nullable=False),
+        sa.Column(
+            "action",
+            postgresql.ENUM("warn", "suspend", "ban", "restrict", "remove", "restore", name="moderation_action_type", create_type=False),
+            nullable=False,
+        ),
+        sa.Column("reason", sa.Text(), nullable=True),
+        sa.Column("report_id", sa.Integer(), sa.ForeignKey("reports.id"), nullable=True),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+
+    # Indexes for moderation_actions
+    op.create_index("ix_moderation_actions_moderator_id", "moderation_actions", ["moderator_id"])
+    op.create_index("ix_moderation_actions_target_user", "moderation_actions", ["target_user_id"])
+    op.create_index("ix_moderation_actions_target", "moderation_actions", ["target_type", "target_id"])
+    op.create_index("ix_moderation_actions_report_id", "moderation_actions", ["report_id"])
+
+    # --- Create appeals table ---
+
+    op.create_table(
+        "appeals",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("moderation_action_id", sa.Integer(), sa.ForeignKey("moderation_actions.id"), nullable=False),
+        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id"), nullable=False),
+        sa.Column("reason", sa.Text(), nullable=False),
+        sa.Column(
+            "status",
+            postgresql.ENUM("pending", "approved", "rejected", name="appeal_status", create_type=False),
+            nullable=False,
+            server_default="pending",
+        ),
+        sa.Column("reviewed_by", sa.Integer(), sa.ForeignKey("users.id"), nullable=True),
+        sa.Column("reviewed_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+
+    # Indexes for appeals
+    op.create_index("ix_appeals_moderation_action_id", "appeals", ["moderation_action_id"])
+    op.create_index("ix_appeals_user_id", "appeals", ["user_id"])
+    op.create_index("ix_appeals_status", "appeals", ["status"])
+
+
+def downgrade() -> None:
+    """Remove moderation tables and revert users table changes."""
+
+    # Drop appeals table
+    op.drop_index("ix_appeals_status", table_name="appeals")
+    op.drop_index("ix_appeals_user_id", table_name="appeals")
+    op.drop_index("ix_appeals_moderation_action_id", table_name="appeals")
+    op.drop_table("appeals")
+
+    # Drop moderation_actions table
+    op.drop_index("ix_moderation_actions_report_id", table_name="moderation_actions")
+    op.drop_index("ix_moderation_actions_target", table_name="moderation_actions")
+    op.drop_index("ix_moderation_actions_target_user", table_name="moderation_actions")
+    op.drop_index("ix_moderation_actions_moderator_id", table_name="moderation_actions")
+    op.drop_table("moderation_actions")
+
+    # Drop reports table
+    op.drop_index("ix_reports_status", table_name="reports")
+    op.drop_index("ix_reports_target", table_name="reports")
+    op.drop_index("ix_reports_reporter_id", table_name="reports")
+    op.drop_table("reports")
+
+    # Remove columns from users table
+    op.drop_column("users", "suspended_until")
+    op.drop_column("users", "banned_until")
+    op.drop_column("users", "role")
+
+    # Drop the enum types
+    op.execute("DROP TYPE IF EXISTS user_role")
+    op.execute("DROP TYPE IF EXISTS report_target_type")
+    op.execute("DROP TYPE IF EXISTS report_reason_category")
+    op.execute("DROP TYPE IF EXISTS report_status")
+    op.execute("DROP TYPE IF EXISTS report_resolution")
+    op.execute("DROP TYPE IF EXISTS moderation_target_type")
+    op.execute("DROP TYPE IF EXISTS moderation_action_type")
+    op.execute("DROP TYPE IF EXISTS appeal_status")

backend/app/models/__init__.py

@@ -2,30 +2,6 @@ from app.models.user import User
 from app.models.session import Session
 from app.models.world import World
 from app.models.asset import Asset
-from app.models.moderation import (
+from app.models.moderation import Report, ModerationAction, Appeal
-    Report,
-    ModerationAction,
-    Appeal,
-    TargetType,
-    ReasonCategory,
-    ReportStatus,
-    Resolution,
-    ModerationActionType,
-    AppealStatus,
-)
 
-__all__ = [
+__all__ = ["User", "Session", "World", "Asset", "Report", "ModerationAction", "Appeal"]
-    "User",
-    "Session",
-    "World",
-    "Asset",
-    "Report",
-    "ModerationAction",
-    "Appeal",
-    "TargetType",
-    "ReasonCategory",
-    "ReportStatus",
-    "Resolution",
-    "ModerationActionType",
-    "AppealStatus",
-]

backend/app/models/moderation.py

@@ -1,27 +1,34 @@
-"""Moderation data models for Trust & Safety."""
+"""Moderation-related models: Report, ModerationAction, Appeal."""
 
-import enum
 from datetime import datetime
 from typing import Optional
 
-from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey
+from sqlalchemy import (
-from sqlalchemy.dialects.postgresql import ENUM
+    Column,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    DateTime,
+    Index,
+)
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 
 from app.database import Base
 
 
-class TargetType(str, enum.Enum):
+# --- Enums ---
-    """Type of entity being reported or moderated."""
+
+class TargetType(str):
     USER = "user"
     WORLD = "world"
     ASSET = "asset"
     CHAT_MESSAGE = "chat_message"
 
 
-class ReasonCategory(str, enum.Enum):
+class ReasonCategory(str):
-    """Category of reason for a report."""
     HARASSMENT = "harassment"
     HATE_SPEECH = "hate_speech"
     SEXUAL_CONTENT = "sexual_content"
@@ -31,23 +38,14 @@ class ReasonCategory(str, enum.Enum):
     OTHER = "other"
 
 
-class ReportStatus(str, enum.Enum):
+class ReportStatus(str):
-    """Status of a report."""
     OPEN = "open"
     IN_REVIEW = "in_review"
     RESOLVED = "resolved"
     DISMISSED = "dismissed"
 
 
-class Resolution(str, enum.Enum):
+class ResolutionAction(str):
-    """Resolution outcome of a report."""
-    UPHELD = "upheld"
-    MODIFIED = "modified"
-    DISMISSED = "dismissed"
-
-
-class ModerationActionType(str, enum.Enum):
-    """Type of moderation action taken."""
     WARN = "warn"
     SUSPEND = "suspend"
     BAN = "ban"
@@ -56,45 +54,95 @@ class ModerationActionType(str, enum.Enum):
     RESTORE = "restore"
 
 
-class AppealStatus(str, enum.Enum):
+class ModerationActionType(str):
-    """Status of an appeal."""
+    WARN = "warn"
+    SUSPEND = "suspend"
+    BAN = "ban"
+    RESTRICT = "restrict"
+    REMOVE = "remove"
+    RESTORE = "restore"
+
+
+class AppealStatus(str):
     PENDING = "pending"
     APPROVED = "approved"
     REJECTED = "rejected"
 
 
+# --- Models ---
+
 class Report(Base):
-    """A report filed by a user against a target entity."""
+    """A moderation report filed by a user or system."""
+
     __tablename__ = "reports"
 
-    id = Column(Integer, primary_key=True, index=True)
+    id = Column(Integer, primary_key=True)
     reporter_id = Column(
-        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=False,
     )
     target_type = Column(
-        ENUM(TargetType, name="target_type", create_type=False),
+        Enum(
+            TargetType.USER,
+            TargetType.WORLD,
+            TargetType.ASSET,
+            TargetType.CHAT_MESSAGE,
+            name="target_type",
+            create_type=False,
+        ),
         nullable=False,
     )
     target_id = Column(String(64), nullable=False)
     reason_category = Column(
-        ENUM(ReasonCategory, name="reason_category", create_type=False),
+        Enum(
+            ReasonCategory.HARASSMENT,
+            ReasonCategory.HATE_SPEECH,
+            ReasonCategory.SEXUAL_CONTENT,
+            ReasonCategory.VIOLENCE,
+            ReasonCategory.SPAM,
+            ReasonCategory.SELF_HARM,
+            ReasonCategory.OTHER,
+            name="reason_category",
+            create_type=False,
+        ),
         nullable=False,
     )
     details = Column(Text, nullable=True)
     status = Column(
-        ENUM(ReportStatus, name="report_status", create_type=False),
+        Enum(
+            ReportStatus.OPEN,
+            ReportStatus.IN_REVIEW,
+            ReportStatus.RESOLVED,
+            ReportStatus.DISMISSED,
+            name="report_status",
+            create_type=False,
+        ),
         default=ReportStatus.OPEN,
         nullable=False,
     )
     resolved_by = Column(
-        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
     )
     resolution = Column(
-        ENUM(Resolution, name="resolution", create_type=False),
+        Enum(
+            ResolutionAction.WARN,
+            ResolutionAction.SUSPEND,
+            ResolutionAction.BAN,
+            ResolutionAction.RESTRICT,
+            ResolutionAction.REMOVE,
+            ResolutionAction.RESTORE,
+            name="resolution_action",
+            create_type=False,
+        ),
         nullable=True,
     )
     created_at = Column(
-        DateTime(timezone=True), server_default=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
     )
     updated_at = Column(
         DateTime(timezone=True),
@@ -107,80 +155,132 @@ class Report(Base):
     # Relationships
     reporter = relationship("User", foreign_keys=[reporter_id])
     resolver = relationship("User", foreign_keys=[resolved_by])
-    moderation_actions = relationship(
+    actions = relationship(
-        "ModerationAction", back_populates="report", cascade="all, delete-orphan"
+        "ModerationAction",
+        back_populates="report",
+        cascade="all, delete-orphan",
     )
-    appeals = relationship(
+
-        "Appeal", back_populates="report", cascade="all, delete-orphan"
+    __table_args__ = (
+        Index("ix_reports_target", "target_type", "target_id"),
+        Index("ix_reports_status", "status"),
+        Index("ix_reports_created_at", "created_at"),
     )
 
 
 class ModerationAction(Base):
-    """A moderation action taken by a moderator against a user or entity."""
+    """A moderation action taken by a moderator/admin."""
+
     __tablename__ = "moderation_actions"
 
-    id = Column(Integer, primary_key=True, index=True)
+    id = Column(Integer, primary_key=True)
     moderator_id = Column(
-        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=False
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=False,
     )
     target_user_id = Column(
-        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
     )
     target_type = Column(
-        ENUM(TargetType, name="target_type", create_type=False),
+        Enum(
+            TargetType.USER,
+            TargetType.WORLD,
+            TargetType.ASSET,
+            TargetType.CHAT_MESSAGE,
+            name="mod_target_type",
+            create_type=False,
+        ),
         nullable=False,
     )
     target_id = Column(String(64), nullable=False)
     action = Column(
-        ENUM(ModerationActionType, name="moderation_action_type", create_type=False),
+        Enum(
+            ModerationActionType.WARN,
+            ModerationActionType.SUSPEND,
+            ModerationActionType.BAN,
+            ModerationActionType.RESTRICT,
+            ModerationActionType.REMOVE,
+            ModerationActionType.RESTORE,
+            name="moderation_action_type",
+            create_type=False,
+        ),
         nullable=False,
     )
     reason = Column(Text, nullable=True)
     report_id = Column(
-        Integer, ForeignKey("reports.id", ondelete="SET NULL"), nullable=True
+        Integer,
+        ForeignKey("reports.id", ondelete="SET NULL"),
+        nullable=True,
     )
     expires_at = Column(DateTime(timezone=True), nullable=True)
-    revoked_at = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(
-        DateTime(timezone=True), server_default=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
     )
 
     # Relationships
     moderator = relationship("User", foreign_keys=[moderator_id])
     target_user = relationship("User", foreign_keys=[target_user_id])
-    report = relationship("Report", back_populates="moderation_actions")
+    report = relationship("Report", back_populates="actions")
-    appeals = relationship(
+    appeals = relationship("Appeal", back_populates="moderation_action")
-        "Appeal", back_populates="moderation_action", cascade="all, delete-orphan"
+
+    __table_args__ = (
+        Index("ix_moderation_actions_target", "target_type", "target_id"),
+        Index("ix_moderation_actions_created_at", "created_at"),
     )
 
 
 class Appeal(Base):
     """An appeal filed by a user against a moderation action."""
+
     __tablename__ = "appeals"
 
-    id = Column(Integer, primary_key=True, index=True)
+    id = Column(Integer, primary_key=True)
     moderation_action_id = Column(
-        Integer, ForeignKey("moderation_actions.id", ondelete="CASCADE"),
+        Integer,
+        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
         nullable=False,
     )
     user_id = Column(
-        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
     )
     reason = Column(Text, nullable=False)
     status = Column(
-        ENUM(AppealStatus, name="appeal_status", create_type=False),
+        Enum(
+            AppealStatus.PENDING,
+            AppealStatus.APPROVED,
+            AppealStatus.REJECTED,
+            name="appeal_status",
+            create_type=False,
+        ),
         default=AppealStatus.PENDING,
         nullable=False,
     )
     reviewed_by = Column(
-        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
     )
     reviewed_at = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(
-        DateTime(timezone=True), server_default=func.now(), nullable=False
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
     )
 
     # Relationships
-    moderation_action = relationship("ModerationAction", back_populates="appeals")
+    moderation_action = relationship(
-    user = relationship("User", foreign_keys=[user_id])
+        "ModerationAction", back_populates="appeals"
+    )
     reviewer = relationship("User", foreign_keys=[reviewed_by])
+
+    __table_args__ = (
+        Index("ix_appeals_status", "status"),
+        Index("ix_appeals_created_at", "created_at"),
+    )

backend/app/models/user.py

@@ -1,21 +1,13 @@
-from datetime import date
+from datetime import date, datetime
 from typing import Optional
 
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date, func
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date, Enum
-from sqlalchemy.dialects.postgresql import ENUM
 from sqlalchemy.orm import relationship
-import enum
+from sqlalchemy.sql import func
 
 from app.database import Base
 
 
-class UserRole(str, enum.Enum):
-    """User role for moderation and access control."""
-    USER = "user"
-    MODERATOR = "moderator"
-    ADMIN = "admin"
-
-
 class User(Base):
     __tablename__ = "users"
 
@@ -26,8 +18,8 @@ class User(Base):
     date_of_birth = Column(Date, nullable=True)
     is_active = Column(Boolean, default=True)
     role = Column(
-        ENUM(UserRole, name="user_role", create_type=False),
+        Enum("user", "moderator", "admin", name="user_role", create_type=False),
-        default=UserRole.USER,
+        default="user",
         nullable=False,
     )
     banned_until = Column(DateTime(timezone=True), nullable=True)
@@ -38,6 +30,32 @@ class User(Base):
     sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
+    reported_by = relationship(
+        "Report",
+        foreign_keys="Report.reporter_id",
+        back_populates="reporter",
+    )
+    resolved_reports = relationship(
+        "Report",
+        foreign_keys="Report.resolved_by",
+        back_populates="resolver",
+    )
+    moderation_actions = relationship(
+        "ModerationAction",
+        foreign_keys="ModerationAction.moderator_id",
+        back_populates="moderator",
+    )
+    target_moderation_actions = relationship(
+        "ModerationAction",
+        foreign_keys="ModerationAction.target_user_id",
+        back_populates="target_user",
+    )
+    appeals = relationship("Appeal", back_populates="user")
+    reviewed_appeals = relationship(
+        "Appeal",
+        foreign_keys="Appeal.reviewed_by",
+        back_populates="reviewer",
+    )
 
     @property
     def is_adult(self) -> bool: