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, moderation  # noqa: F401
+from app.models import user, session, world, asset, report, moderation_action, appeal  # noqa: F401
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.

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

backend/alembic/versions/0003_moderation.py

@@ -1,211 +0,0 @@
-"""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

@@ -2,6 +2,8 @@ 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.report import Report
+from app.models.moderation_action import ModerationAction
+from app.models.appeal import Appeal
 
 __all__ = ["User", "Session", "World", "Asset", "Report", "ModerationAction", "Appeal"]

backend/app/models/appeal.py

@@ -0,0 +1,67 @@
+"""Appeal model for moderation actions."""
+
+from datetime import datetime
+from typing import Optional
+
+from sqlalchemy import (
+    Column,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    DateTime,
+    CheckConstraint,
+)
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class Appeal(Base):
+    __tablename__ = "appeals"
+
+    id = Column(Integer, primary_key=True, index=True)
+    moderation_action_id = Column(
+        Integer,
+        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    reason = Column(Text, nullable=False)
+    status = Column(
+        Enum("pending", "approved", "rejected", name="appeal_status", create_type=False),
+        nullable=False,
+        default="pending",
+    )
+    reviewed_by = Column(
+        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,
+    )
+
+    # Relationships
+    moderation_action = relationship("ModerationAction", back_populates="appeals")
+    reviewer = relationship(
+        "User",
+        foreign_keys=[reviewed_by],
+        back_populates="reviewed_appeals",
+    )
+
+    __table_args__ = (
+        CheckConstraint(
+            "status IN ('pending', 'approved', 'rejected')",
+            name="check_appeal_status",
+        ),
+    )

backend/app/models/moderation.py

@@ -1,286 +0,0 @@
-"""Moderation-related models: Report, ModerationAction, Appeal."""
-
-from datetime import datetime
-from typing import Optional
-
-from sqlalchemy import (
-    Column,
-    Enum,
-    ForeignKey,
-    Integer,
-    String,
-    Text,
-    DateTime,
-    Index,
-)
-from sqlalchemy.orm import relationship
-from sqlalchemy.sql import func
-
-from app.database import Base
-
-
-# --- Enums ---
-
-class TargetType(str):
-    USER = "user"
-    WORLD = "world"
-    ASSET = "asset"
-    CHAT_MESSAGE = "chat_message"
-
-
-class ReasonCategory(str):
-    HARASSMENT = "harassment"
-    HATE_SPEECH = "hate_speech"
-    SEXUAL_CONTENT = "sexual_content"
-    VIOLENCE = "violence"
-    SPAM = "spam"
-    SELF_HARM = "self_harm"
-    OTHER = "other"
-
-
-class ReportStatus(str):
-    OPEN = "open"
-    IN_REVIEW = "in_review"
-    RESOLVED = "resolved"
-    DISMISSED = "dismissed"
-
-
-class ResolutionAction(str):
-    WARN = "warn"
-    SUSPEND = "suspend"
-    BAN = "ban"
-    RESTRICT = "restrict"
-    REMOVE = "remove"
-    RESTORE = "restore"
-
-
-class ModerationActionType(str):
-    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 moderation report filed by a user or system."""
-
-    __tablename__ = "reports"
-
-    id = Column(Integer, primary_key=True)
-    reporter_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=False,
-    )
-    target_type = Column(
-        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.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.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,
-    )
-    resolution = Column(
-        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,
-    )
-    updated_at = Column(
-        DateTime(timezone=True),
-        server_default=func.now(),
-        onupdate=func.now(),
-        nullable=False,
-    )
-    resolved_at = Column(DateTime(timezone=True), nullable=True)
-
-    # Relationships
-    reporter = relationship("User", foreign_keys=[reporter_id])
-    resolver = relationship("User", foreign_keys=[resolved_by])
-    actions = relationship(
-        "ModerationAction",
-        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/admin."""
-
-    __tablename__ = "moderation_actions"
-
-    id = Column(Integer, primary_key=True)
-    moderator_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=False,
-    )
-    target_user_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=True,
-    )
-    target_type = Column(
-        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.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,
-    )
-    expires_at = Column(DateTime(timezone=True), nullable=True)
-    created_at = Column(
-        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="actions")
-    appeals = relationship("Appeal", back_populates="moderation_action")
-
-    __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)
-    moderation_action_id = Column(
-        Integer,
-        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    user_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    reason = Column(Text, nullable=False)
-    status = Column(
-        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,
-    )
-    reviewed_at = Column(DateTime(timezone=True), nullable=True)
-    created_at = Column(
-        DateTime(timezone=True),
-        server_default=func.now(),
-        nullable=False,
-    )
-
-    # Relationships
-    moderation_action = relationship(
-        "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/moderation_action.py

@@ -0,0 +1,118 @@
+"""Moderation action model."""
+
+from datetime import datetime
+from enum import Enum as PyEnum
+from typing import Optional
+
+from sqlalchemy import (
+    Column,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    DateTime,
+    func,
+)
+from sqlalchemy.dialects.postgresql import TIMESTAMPTZ
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+class TargetType(str, PyEnum):
+    """Type of entity being reported or moderated."""
+    USER = "user"
+    WORLD = "world"
+    ASSET = "asset"
+    CHAT_MESSAGE = "chat_message"
+
+
+class ReasonCategory(str, PyEnum):
+    """Category of report reason."""
+    HARASSMENT = "harassment"
+    HATE_SPEECH = "hate_speech"
+    SEXUAL_CONTENT = "sexual_content"
+    VIOLENCE = "violence"
+    SPAM = "spam"
+    SELF_HARM = "self_harm"
+    OTHER = "other"
+
+
+class ReportStatus(str, PyEnum):
+    """Status of a report."""
+    OPEN = "open"
+    IN_REVIEW = "in_review"
+    RESOLVED = "resolved"
+    DISMISSED = "dismissed"
+
+
+class Resolution(str, PyEnum):
+    """Resolution outcome of a report."""
+    ACTION_TAKEN = "action_taken"
+    NO_ACTION = "no_action"
+
+
+class ModerationActionType(str, PyEnum):
+    """Type of moderation action."""
+    WARN = "warn"
+    SUSPEND = "suspend"
+    BAN = "ban"
+    RESTRICT = "restrict"
+    REMOVE = "remove"
+    RESTORE = "restore"
+
+
+class ModerationAction(Base):
+    __tablename__ = "moderation_actions"
+
+    id = Column(Integer, primary_key=True, index=True)
+    moderator_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    target_user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    target_type = Column(
+        Enum(TargetType, name="target_type_enum", create_type=False),
+        nullable=False,
+    )
+    target_id = Column(String(64), nullable=False)
+    action = Column(
+        Enum(ModerationActionType, name="moderation_action_type_enum", create_type=False),
+        nullable=False,
+    )
+    reason = Column(Text, nullable=True)
+    report_id = Column(
+        Integer,
+        ForeignKey("reports.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    expires_at = Column(TIMESTAMPTZ, nullable=True)
+    revoked_at = Column(TIMESTAMPTZ, nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+    )
+
+    # Relationships
+    moderator = relationship(
+        "User",
+        foreign_keys=[moderator_id],
+        back_populates="moderation_actions_given",
+    )
+    target_user = relationship(
+        "User",
+        foreign_keys=[target_user_id],
+        back_populates="moderation_actions_received",
+    )
+    report = relationship("Report", back_populates="moderation_actions")
+    appeals = relationship(
+        "Appeal",
+        back_populates="moderation_action",
+        cascade="all, delete-orphan",
+    )

backend/app/models/report.py

@@ -0,0 +1,146 @@
+"""Report model for user-generated moderation reports."""
+
+from datetime import datetime
+from typing import Optional
+
+import sqlalchemy as sa
+from sqlalchemy import (
+    Column,
+    DateTime,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+)
+from sqlalchemy.dialects.postgresql import TIMESTAMPTZ
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+class ReportStatus:
+    """Valid statuses for a Report."""
+
+    OPEN = "open"
+    IN_REVIEW = "in_review"
+    RESOLVED = "resolved"
+    DISMISSED = "dismissed"
+
+
+class Resolution:
+    """Possible resolution outcomes for a Report."""
+
+    ACTION_TAKEN = "action_taken"
+    NO_ACTION = "no_action"
+
+
+class TargetType:
+    """Types of entities that can be reported."""
+
+    USER = "user"
+    WORLD = "world"
+    ASSET = "asset"
+    CHAT_MESSAGE = "chat_message"
+
+
+class ReasonCategory:
+    """Categories for why something was reported."""
+
+    HARASSMENT = "harassment"
+    HATE_SPEECH = "hate_speech"
+    SEXUAL_CONTENT = "sexual_content"
+    VIOLENCE = "violence"
+    SPAM = "spam"
+    SELF_HARM = "self_harm"
+    OTHER = "other"
+
+
+class Report(Base):
+    __tablename__ = "reports"
+
+    id = Column(Integer, primary_key=True, index=True)
+    reporter_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    target_type = Column(
+        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.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.OPEN,
+            ReportStatus.IN_REVIEW,
+            ReportStatus.RESOLVED,
+            ReportStatus.DISMISSED,
+            name="report_status",
+            create_type=False,
+        ),
+        nullable=False,
+        default=ReportStatus.OPEN,
+    )
+    resolved_by = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    resolution = Column(
+        Enum(
+            Resolution.ACTION_TAKEN,
+            Resolution.NO_ACTION,
+            name="resolution",
+            create_type=False,
+        ),
+        nullable=True,
+    )
+    created_at = Column(
+        TIMESTAMPTZ,
+        nullable=False,
+        server_default=sa.func.now(),
+    )
+    updated_at = Column(
+        TIMESTAMPTZ,
+        nullable=False,
+        server_default=sa.func.now(),
+        onupdate=sa.func.now(),
+    )
+    resolved_at = Column(TIMESTAMPTZ, nullable=True)
+
+    # Relationships
+    reporter = relationship("User", foreign_keys=[reporter_id])
+    resolver = relationship("User", foreign_keys=[resolved_by])
+    moderation_actions = relationship(
+        "ModerationAction",
+        back_populates="report",
+        cascade="all, delete-orphan",
+    )
+    appeals = relationship(
+        "Appeal",
+        back_populates="report",
+        cascade="all, delete-orphan",
+    )

backend/app/models/user.py

@@ -1,4 +1,4 @@
-from datetime import date, datetime
+from datetime import date
 from typing import Optional
 
 from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date, Enum
@@ -8,6 +8,13 @@ from sqlalchemy.sql import func
 from app.database import Base
 
 
+class UserRole:
+    """Valid user roles."""
+    USER = "user"
+    MODERATOR = "moderator"
+    ADMIN = "admin"
+
+
 class User(Base):
     __tablename__ = "users"
 
@@ -18,9 +25,9 @@ class User(Base):
     date_of_birth = Column(Date, nullable=True)
     is_active = Column(Boolean, default=True)
     role = Column(
-        Enum("user", "moderator", "admin", name="user_role", create_type=False),
+        Enum(UserRole.USER, UserRole.MODERATOR, UserRole.ADMIN, name="user_role", create_type=False),
-        default="user",
         nullable=False,
+        default=UserRole.USER,
     )
     banned_until = Column(DateTime(timezone=True), nullable=True)
     suspended_until = Column(DateTime(timezone=True), nullable=True)
@@ -30,32 +37,16 @@ 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(
+    moderation_actions_given = 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(
+    moderation_actions_received = 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: