WIP checkpoint: T1: Moderation data model + Alembic migration

backend/alembic/env.py

@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import create_async_engine
 
 from app.config import settings
 from app.database import Base
-from app.models import user, session, world, asset  # noqa: F401
+from app.models import user, session, world, asset, moderation  # noqa: F401
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.

backend/alembic/versions/0003_add_moderation_schema.py

@@ -0,0 +1,310 @@
+"""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_trust_safety.py

@@ -1,268 +0,0 @@
-"""add trust & safety columns and tables
-
-Revision ID: 0003_trust_safety
-Revises: 0002_add_date_of_birth_to_users
-Create Date: 2025-07-10 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_trust_safety"
-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:
-    """Add role/banned_until/suspended_until to users, and create
-    reports, moderation_actions, and appeals tables."""
-
-    # ── ENUM types ──────────────────────────────────────────────
-
-    role_enum = postgresql.ENUM("user", "moderator", "admin", name="role")
-    role_enum.create(op.get_bind(), checkfirst=True)
-
-    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(
-        "action_taken",
-        "action_not_needed",
-        "duplicate",
-        "escalated",
-        name="resolution",
-    )
-    resolution_enum.create(op.get_bind(), checkfirst=True)
-
-    moderation_action_enum = postgresql.ENUM(
-        "warn", "suspend", "ban", "restrict", "remove", "restore",
-        name="moderation_action",
-    )
-    moderation_action_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)
-
-    # ── users table changes ─────────────────────────────────────
-
-    op.add_column(
-        "users",
-        sa.Column(
-            "role",
-            role_enum,
-            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.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "reporter_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False
-        ),
-        sa.Column(
-            "target_type",
-            target_type_enum,
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "reason_category",
-            reason_category_enum,
-            nullable=False,
-        ),
-        sa.Column("details", sa.Text(), nullable=True),
-        sa.Column(
-            "status",
-            report_status_enum,
-            nullable=False,
-            server_default="open",
-        ),
-        sa.Column(
-            "resolved_by",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column(
-            "resolution",
-            resolution_enum,
-            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),
-            onupdate=sa.func.now(),
-            nullable=False,
-        ),
-        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
-        sa.UniqueConstraint("reporter_id", "target_type", "target_id"),
-    )
-    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)
-
-    # ── moderation_actions table ────────────────────────────────
-
-    op.create_table(
-        "moderation_actions",
-        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "moderator_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column(
-            "target_user_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column(
-            "target_type",
-            target_type_enum,
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "action",
-            moderation_action_enum,
-            nullable=False,
-        ),
-        sa.Column("reason", sa.Text(), nullable=False),
-        sa.Column(
-            "report_id",
-            sa.Integer(),
-            sa.ForeignKey("reports.id", ondelete="SET NULL"),
-            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,
-        ),
-    )
-    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,
-    )
-
-    # ── appeals table ───────────────────────────────────────────
-
-    op.create_table(
-        "appeals",
-        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "moderation_action_id",
-            sa.Integer(),
-            sa.ForeignKey("moderation_actions.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column(
-            "user_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column("reason", sa.Text(), nullable=False),
-        sa.Column(
-            "status",
-            appeal_status_enum,
-            nullable=False,
-            server_default="pending",
-        ),
-        sa.Column(
-            "reviewed_by",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            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.UniqueConstraint("moderation_action_id", "user_id"),
-    )
-    op.create_index(op.f("ix_appeals_id"), "appeals", ["id"], unique=False)
-    op.create_index(op.f("ix_appeals_user_id"), "appeals", ["user_id"], unique=False)
-
-
-def downgrade() -> None:
-    """Remove trust & safety tables and columns."""
-
-    op.drop_index(op.f("ix_appeals_user_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_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_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").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="role").drop(op.get_bind(), checkfirst=True)

backend/app/models/__init__.py

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

backend/app/models/moderation.py

@@ -1,225 +1,186 @@
-"""Trust & Safety models: reports, moderation actions, and appeals."""
+"""Moderation data models for Trust & Safety."""
 
+import enum
 from datetime import datetime
 from typing import Optional
 
-from sqlalchemy import (
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey
-    CheckConstraint,
+from sqlalchemy.dialects.postgresql import ENUM
-    Column,
-    DateTime,
-    Enum,
-    ForeignKey,
-    Integer,
-    String,
-    Text,
-    UniqueConstraint,
-    func,
-)
-from sqlalchemy.dialects.postgresql import ENUM as PG_ENUM
 from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
 
 from app.database import Base
 
 
-# ---------------------------------------------------------------------------
+class TargetType(str, enum.Enum):
-# ENUM helpers — created explicitly in Alembic, not via SQLAlchemy create_type
+    """Type of entity being reported or moderated."""
-# ---------------------------------------------------------------------------
+    USER = "user"
+    WORLD = "world"
+    ASSET = "asset"
+    CHAT_MESSAGE = "chat_message"
 
-_role_enum = PG_ENUM(
-    "user", "moderator", "admin",
-    name="user_role",
-    create_type=False,
-)
 
-_target_type_enum = PG_ENUM(
+class ReasonCategory(str, enum.Enum):
-    "user", "world", "asset", "chat_message",
+    """Category of reason for a report."""
-    name="target_type",
+    HARASSMENT = "harassment"
-    create_type=False,
+    HATE_SPEECH = "hate_speech"
-)
+    SEXUAL_CONTENT = "sexual_content"
+    VIOLENCE = "violence"
+    SPAM = "spam"
+    SELF_HARM = "self_harm"
+    OTHER = "other"
 
-_reason_category_enum = PG_ENUM(
-    "harassment", "hate_speech", "sexual_content", "violence",
-    "spam", "self_harm", "other",
-    name="reason_category",
-    create_type=False,
-)
 
-_report_status_enum = PG_ENUM(
+class ReportStatus(str, enum.Enum):
-    "open", "in_review", "resolved", "dismissed",
+    """Status of a report."""
-    name="report_status",
+    OPEN = "open"
-    create_type=False,
+    IN_REVIEW = "in_review"
-)
+    RESOLVED = "resolved"
+    DISMISSED = "dismissed"
 
-_resolution_enum = PG_ENUM(
-    "action_taken", "action_not_needed", "duplicate", "escalated",
-    name="resolution",
-    create_type=False,
-)
 
-_moderation_action_enum = PG_ENUM(
+class Resolution(str, enum.Enum):
-    "warn", "suspend", "ban", "restrict", "remove", "restore",
+    """Resolution outcome of a report."""
-    name="moderation_action",
+    UPHELD = "upheld"
-    create_type=False,
+    MODIFIED = "modified"
-)
+    DISMISSED = "dismissed"
 
-_appeal_status_enum = PG_ENUM(
+
-    "pending", "approved", "rejected",
+class ModerationActionType(str, enum.Enum):
-    name="appeal_status",
+    """Type of moderation action taken."""
-    create_type=False,
+    WARN = "warn"
-)
+    SUSPEND = "suspend"
+    BAN = "ban"
+    RESTRICT = "restrict"
+    REMOVE = "remove"
+    RESTORE = "restore"
+
+
+class AppealStatus(str, enum.Enum):
+    """Status of an appeal."""
+    PENDING = "pending"
+    APPROVED = "approved"
+    REJECTED = "rejected"
 
 
 class Report(Base):
-    """A user-submitted report about another entity."""
+    """A report filed by a user against a target entity."""
-
     __tablename__ = "reports"
 
-    id = Column(Integer, primary_key=True, autoincrement=True)
+    id = Column(Integer, primary_key=True, index=True)
     reporter_id = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
-        ForeignKey("users.id", ondelete="CASCADE"),
+    )
+    target_type = Column(
+        ENUM(TargetType, name="target_type", create_type=False),
         nullable=False,
     )
-    target_type = Column(_target_type_enum, nullable=False)
     target_id = Column(String(64), nullable=False)
-    reason_category = Column(_reason_category_enum, nullable=False)
+    reason_category = Column(
+        ENUM(ReasonCategory, name="reason_category", create_type=False),
+        nullable=False,
+    )
     details = Column(Text, nullable=True)
     status = Column(
-        _report_status_enum,
+        ENUM(ReportStatus, name="report_status", create_type=False),
+        default=ReportStatus.OPEN,
         nullable=False,
-        server_default="open",
     )
     resolved_by = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
-        ForeignKey("users.id", ondelete="SET NULL"),
+    )
+    resolution = Column(
+        ENUM(Resolution, name="resolution", create_type=False),
         nullable=True,
     )
-    resolution = Column(_resolution_enum, nullable=True)
     created_at = Column(
-        DateTime(timezone=True),
+        DateTime(timezone=True), server_default=func.now(), nullable=False
-        server_default=func.now(),
     )
     updated_at = Column(
         DateTime(timezone=True),
+        server_default=func.now(),
         onupdate=func.now(),
+        nullable=False,
     )
     resolved_at = Column(DateTime(timezone=True), nullable=True)
 
-    # Coalesce duplicate reports from the same reporter about the same target
-    __table_args__ = (
-        UniqueConstraint("reporter_id", "target_type", "target_id",
-                         name="uq_reporter_target"),
-    )
-
     # Relationships
-    reporter = relationship("User", back_populates="reports",
+    reporter = relationship("User", foreign_keys=[reporter_id])
-                            foreign_keys=[reporter_id])
+    resolver = relationship("User", foreign_keys=[resolved_by])
-    resolved_by_user = relationship("User", back_populates="resolved_reports",
-                                    foreign_keys=[resolved_by])
     moderation_actions = relationship(
-        "ModerationAction",
+        "ModerationAction", back_populates="report", cascade="all, delete-orphan"
-        back_populates="report",
-        cascade="all, delete-orphan",
     )
     appeals = relationship(
-        "Appeal",
+        "Appeal", back_populates="report", cascade="all, delete-orphan"
-        back_populates="report",
-        cascade="all, delete-orphan",
     )
 
 
 class ModerationAction(Base):
-    """A moderation action taken against a target."""
+    """A moderation action taken by a moderator against a user or entity."""
-
     __tablename__ = "moderation_actions"
 
-    id = Column(Integer, primary_key=True, autoincrement=True)
+    id = Column(Integer, primary_key=True, index=True)
     moderator_id = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=False
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
     )
     target_user_id = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
-        ForeignKey("users.id", ondelete="SET NULL"),
+    )
-        nullable=True,
+    target_type = Column(
+        ENUM(TargetType, name="target_type", create_type=False),
+        nullable=False,
     )
-    target_type = Column(_target_type_enum, nullable=False)
     target_id = Column(String(64), nullable=False)
-    action = Column(_moderation_action_enum, nullable=False)
+    action = Column(
-    reason = Column(Text, nullable=False)
+        ENUM(ModerationActionType, name="moderation_action_type", create_type=False),
+        nullable=False,
+    )
+    reason = Column(Text, nullable=True)
     report_id = Column(
-        Integer,
+        Integer, ForeignKey("reports.id", ondelete="SET NULL"), nullable=True
-        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),
+        DateTime(timezone=True), server_default=func.now(), nullable=False
-        server_default=func.now(),
     )
 
     # Relationships
-    moderator = relationship("User", back_populates="moderation_actions",
+    moderator = relationship("User", foreign_keys=[moderator_id])
-                             foreign_keys=[moderator_id])
+    target_user = relationship("User", foreign_keys=[target_user_id])
-    target_user = relationship("User", back_populates="moderation_actions_target",
+    report = relationship("Report", back_populates="moderation_actions")
-                               foreign_keys=[target_user_id])
-    report = relationship(
-        "Report",
-        back_populates="moderation_actions",
-    )
     appeals = relationship(
-        "Appeal",
+        "Appeal", back_populates="moderation_action", cascade="all, delete-orphan"
-        back_populates="moderation_action",
-        cascade="all, delete-orphan",
     )
 
 
 class Appeal(Base):
-    """An appeal against a moderation action."""
+    """An appeal filed by a user against a moderation action."""
-
     __tablename__ = "appeals"
 
-    id = Column(Integer, primary_key=True, autoincrement=True)
+    id = Column(Integer, primary_key=True, index=True)
     moderation_action_id = Column(
-        Integer,
+        Integer, ForeignKey("moderation_actions.id", ondelete="CASCADE"),
-        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
         nullable=False,
     )
     user_id = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
     )
     reason = Column(Text, nullable=False)
     status = Column(
-        _appeal_status_enum,
+        ENUM(AppealStatus, name="appeal_status", create_type=False),
+        default=AppealStatus.PENDING,
         nullable=False,
-        server_default="pending",
     )
     reviewed_by = Column(
-        Integer,
+        Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=True,
     )
     reviewed_at = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(
-        DateTime(timezone=True),
+        DateTime(timezone=True), server_default=func.now(), nullable=False
-        server_default=func.now(),
-    )
-
-    # Prevent duplicate open appeals per sanction
-    __table_args__ = (
-        UniqueConstraint("moderation_action_id", "user_id",
-                         name="uq_action_user_appeal"),
     )
 
     # Relationships
-    moderation_action = relationship(
+    moderation_action = relationship("ModerationAction", back_populates="appeals")
-        "ModerationAction",
+    user = relationship("User", foreign_keys=[user_id])
-        back_populates="appeals",
+    reviewer = relationship("User", foreign_keys=[reviewed_by])
-    )
-    user = relationship("User", back_populates="appeals")
-    reviewed_by_user = relationship("User", back_populates="reviewed_appeals",
-                                    foreign_keys=[reviewed_by])

backend/app/models/user.py

@@ -1,13 +1,21 @@
 from datetime import date
 from typing import Optional
 
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date, func
+from sqlalchemy.dialects.postgresql import ENUM
 from sqlalchemy.orm import relationship
-from sqlalchemy.sql import func
+import enum
 
 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"
 
@@ -17,6 +25,13 @@ class User(Base):
     hashed_password = Column(String(255), nullable=False)
     date_of_birth = Column(Date, nullable=True)
     is_active = Column(Boolean, default=True)
+    role = Column(
+        ENUM(UserRole, name="user_role", create_type=False),
+        default=UserRole.USER,
+        nullable=False,
+    )
+    banned_until = Column(DateTime(timezone=True), nullable=True)
+    suspended_until = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())