WIP checkpoint: Text filtering service + profanity config

2026-08-18 15:17:08 +00:00
14 changed files with 347 additions and 628 deletions
@@ -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, report, moderation_action, appeal  # noqa: F401
+from app.models import user, session, world, asset  # noqa: F401
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -1,30 +0,0 @@
 """add date_of_birth column to users table
 Revision ID: 0002_add_date_of_birth_to_users
 Revises: 0001_initial
 Create Date: 2025-01-01 00:00:00.000000
 """
 from typing import Sequence, Union
 from alembic import op
 import sqlalchemy as sa
 # revision identifiers, used by Alembic.
 revision: str = "0002_add_date_of_birth_to_users"
 down_revision: Union[str, None] = "0001_initial"
 branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 def upgrade() -> None:
    """Add date_of_birth column to users table."""
    op.add_column(
        "users",
        sa.Column("date_of_birth", sa.Date(), nullable=True),
    )
 def downgrade() -> None:
    """Remove date_of_birth column from users table."""
    op.drop_column("users", "date_of_birth")
@@ -2,8 +2,5 @@ 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.report import Report
 from app.models.moderation_action import ModerationAction
 from app.models.appeal import Appeal
-__all__ = ["User", "Session", "World", "Asset", "Report", "ModerationAction", "Appeal"]
+__all__ = ["User", "Session", "World", "Asset"]
@@ -1,34 +0,0 @@
 """Appeal model for moderation actions."""
 from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, Enum
 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)
    moderation_action_id = Column(
        Integer, ForeignKey("moderation_actions.id"), nullable=False
    )
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    reason = Column(Text, nullable=False)
    status = Column(
        Enum(
            "pending", "approved", "rejected",
            name="appeal_status_enum",
        ),
        default="pending",
        nullable=False,
    )
    reviewed_by = Column(Integer, ForeignKey("users.id"), nullable=True)
    reviewed_at = Column(DateTime(timezone=True), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    # Relationships
    moderation_action = relationship("ModerationAction", back_populates="appeals")
    user = relationship("User", back_populates="appeals")
    reviewer = relationship("User", foreign_keys=[reviewed_by])
@@ -1,35 +0,0 @@
 from datetime import datetime
 from typing import Optional
 from sqlalchemy import Column, Enum, ForeignKey, Integer, String, Text, DateTime
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 from app.database import Base
 class ModerationAction(Base):
    __tablename__ = "moderation_actions"
    id = Column(Integer, primary_key=True)
    moderator_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    target_user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    target_type = Column(
        Enum("user", "world", "asset", "chat_message", name="target_type_enum"),
        nullable=False,
    )
    target_id = Column(String(64), nullable=False)
    action = Column(
        Enum("warn", "suspend", "ban", "restrict", "remove", "restore", name="action_enum"),
        nullable=False,
    )
    reason = Column(Text, nullable=True)
    report_id = Column(Integer, ForeignKey("reports.id"), 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())
    # Relationships
    moderator = relationship("User", foreign_keys=[moderator_id])
    target_user = relationship("User", foreign_keys=[target_user_id])
    report = relationship("Report", back_populates="moderation_actions")
@@ -1,60 +0,0 @@
 """Report model for Trust & Safety."""
 from sqlalchemy import (
    Column,
    Integer,
    String,
    Text,
    DateTime,
    ForeignKey,
    Enum as SAEnum,
 )
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 from app.database import Base
 class Report(Base):
    __tablename__ = "reports"
    id = Column(Integer, primary_key=True)
    reporter_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    target_type = SAEnum("user", "world", "asset", "chat_message", name="target_type_enum", nullable=False)
    target_id = Column(String(64), nullable=False)
    reason_category = SAEnum(
        "harassment",
        "hate_speech",
        "sexual_content",
        "violence",
        "spam",
        "self_harm",
        "other",
        name="reason_category_enum",
        nullable=False,
    )
    details = Column(Text, nullable=True)
    status = SAEnum(
        "open",
        "in_review",
        "resolved",
        "dismissed",
        name="report_status_enum",
        default="open",
        nullable=False,
    )
    resolved_by = Column(Integer, ForeignKey("users.id"), nullable=True)
    resolution = SAEnum(
        "action_taken",
        "action_not_needed",
        "duplicate",
        name="resolution_enum",
        nullable=True,
    )
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
    resolved_at = Column(DateTime(timezone=True), nullable=True)
    # Relationships
    reporter = relationship("User", foreign_keys=[reporter_id])
    resolved_by_user = relationship("User", foreign_keys=[resolved_by])
@@ -1,6 +1,4 @@
-from datetime import date
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
 from sqlalchemy import Boolean, Column, Date, DateTime, Enum, Integer, String
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
@@ -14,30 +12,10 @@ class User(Base):
    username = Column(String(50), unique=True, index=True, nullable=False)
    email = Column(String(120), unique=True, index=True, nullable=False)
    hashed_password = Column(String(255), nullable=False)
    date_of_birth = Column(Date, nullable=True)
    is_active = Column(Boolean, default=True)
    role = Column(
        Enum("user", "moderator", "admin", name="user_role", default="user"),
        default="user",
    )
    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())
    sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
    worlds = relationship("World", back_populates="owner")
    assets = relationship("Asset", back_populates="owner")
    appeals = relationship("Appeal", back_populates="user")
    @property
    def is_adult(self) -> bool:
        """Return True if the user is 18 or older based on date_of_birth."""
        if self.date_of_birth is None:
            return False
        today = date.today()
        age = today.year - self.date_of_birth.year
        # Adjust if birthday hasn't occurred yet this year
        if (today.month, today.day) < (self.date_of_birth.month, self.date_of_birth.day):
            age -= 1
        return age >= 18
@@ -1,10 +1,10 @@
 """Authentication router - login, register, token refresh."""
-from datetime import date, datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.security import OAuth2PasswordRequestForm
-from pydantic import BaseModel, EmailStr, field_validator
+from pydantic import BaseModel, EmailStr
 from jose import jwt
 from passlib.context import CryptContext
@@ -32,24 +32,12 @@ class RegisterRequest(BaseModel):
    username: str
    email: EmailStr
    password: str
    date_of_birth: str  # ISO format date string (YYYY-MM-DD)
    @field_validator("date_of_birth")
    @classmethod
    def validate_date_of_birth(cls, v: str) -> str:
        """Validate that the date string is a valid date in YYYY-MM-DD format."""
        try:
            datetime.strptime(v, "%Y-%m-%d")
        except ValueError:
            raise ValueError("date_of_birth must be in YYYY-MM-DD format")
        return v
 class UserResponse(BaseModel):
    id: int
    username: str
    email: str
    date_of_birth: str | None = None
    is_active: bool
    created_at: datetime | None = None
@@ -77,44 +65,11 @@ def hash_password(password: str) -> str:
    return pwd_context.hash(password)
 def calculate_age(birth_date: date, today: date | None = None) -> int:
    """Calculate age in years from a birth date.
    Args:
        birth_date: The person's date of birth.
        today: The reference date. Defaults to today's date (UTC).
    Returns:
        Age in whole years as of the reference date.
    """
    if today is None:
        today = datetime.now(timezone.utc).date()
    age = today.year - birth_date.year
    # Adjust if birthday hasn't occurred yet this year
    if (today.month, today.day) < (birth_date.month, birth_date.day):
        age -= 1
    return age
 # --- Endpoints ---
@router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
-    """Register a new user and return an access token.
+    """Register a new user and return an access token."""
    Requires date_of_birth and rejects users under 18.
    """
    # Parse and validate date_of_birth
    dob = datetime.strptime(req.date_of_birth, "%Y-%m-%d").date()
    age = calculate_age(dob)
    if age < 18:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Must be 18 or older to register (provided date of birth: {req.date_of_birth})",
        )
    # Check if username already exists
    result = await db.execute(select(User).where(User.username == req.username))
    if result.scalar_one_or_none():
@@ -135,7 +90,6 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
        username=req.username,
        email=req.email,
        hashed_password=hash_password(req.password),
        date_of_birth=dob,
    )
    db.add(user)
    await db.commit()
@@ -0,0 +1 @@
 """Application services."""
@@ -0,0 +1,340 @@
 """Pluggable server-side text filtering service.
 Provides a ``TextFilter`` protocol with a deterministic default
 implementation (profanity/term list with normalization) and a hook
 for third-party providers.
 Usage::
    from app.services.text_filter import TextFilter, FilterResult, \
        ProfanityTextFilter, get_text_filter
    # Default factory reads config from the path below
    filt = get_text_filter()
    result = filt.check("Hello wor1d!")
    # result.action == FilterAction.ALLOW
 """
 from __future__ import annotations
 import json
 import os
 import re
 import unicodedata
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
 from enum import Enum
 from pathlib import Path
 from typing import Any
 # ---------------------------------------------------------------------------
 # Enums / Data classes
 # ---------------------------------------------------------------------------
 class FilterAction(str, Enum):
    """Action the filter wants the caller to take."""
    ALLOW = "allow"
    REDACT = "redact"
    REJECT = "reject"
@dataclass(frozen=True)
 class FilterResult:
    """Immutable result of a single ``TextFilter.check()`` call.
    Attributes:
        action: What to do with the message.
        filtered_text: The text after redaction (may equal *text* if
            action is ``ALLOW``).
        matched_terms: Sorted list of terms that triggered the filter.
    """
    action: FilterAction
    filtered_text: str
    matched_terms: list[str] = field(default_factory=list)
    @property
    def is_allowed(self) -> bool:
        return self.action == FilterAction.ALLOW
    @property
    def is_rejected(self) -> bool:
        return self.action == FilterAction.REJECT
    @property
    def is_redacted(self) -> bool:
        return self.action == FilterAction.REDACT
 # ---------------------------------------------------------------------------
 # Protocol / abstract base
 # ---------------------------------------------------------------------------
 class TextFilter(ABC):
    """Protocol for server-side text filters.
    Every concrete filter must implement ``check()``.  The default
    implementation (``ProfanityTextFilter``) is deterministic and
    requires no external service.  A third-party provider can be
    plugged in by subclassing ``TextFilter`` and overriding ``check``.
    """
    @abstractmethod
    def check(self, text: str) -> FilterResult:
        """Analyse *text* and return a ``FilterResult``.
        Args:
            text: Raw message text to filter.
        Returns:
            A ``FilterResult`` with the decision and any redacted text.
        """
 # ---------------------------------------------------------------------------
 # Normalisation helpers
 # ---------------------------------------------------------------------------
 # Common leetspeak substitutions (char -> set of possible originals)
 _LEETSPEAK: dict[str, str] = {
    "0": "o",
    "1": "i",
    "3": "e",
    "4": "a",
    "5": "s",
    "7": "t",
    "8": "b",
    "9": "g",
    "@": "a",
 }
 # Normalise separators that are often used to obfuscate words
 _SEPARATORS = re.compile(r"[\s_\-\.]+")
 def _normalize(text: str) -> str:
    """Case-fold, strip diacritics, and replace leetspeak / separators.
    This produces a canonical form for matching against the term list.
    """
    # Case-fold
    text = text.casefold()
    # Strip diacritics (e.g. é -> e)
    text = unicodedata.normalize("NFKD", text)
    text = "".join(c for c in text if not unicodedata.combining(c))
    # Replace leetspeak
    normalized = ""
    for ch in text:
        normalized += _LEETSPEAK.get(ch, ch)
    # Collapse separators
    normalized = _SEPARATORS.sub("", normalized)
    return normalized
 # ---------------------------------------------------------------------------
 # Default implementation
 # ---------------------------------------------------------------------------
 # Default config path (relative to project root)
 _DEFAULT_CONFIG_PATH = Path(__file__).resolve().parent.parent.parent / "data" / "text_filter_config.json"
@dataclass
 class _FilterPolicy:
    """Filtering policy loaded from config."""
    mode: str  # "redact" or "reject"
    redaction_char: str = "*"
    # Minimum term length to consider (avoids matching single chars)
    min_term_length: int = 3
    # If True, match terms case-insensitively after normalisation
    case_insensitive: bool = True
    # If True, match whole words only (after normalisation)
    whole_word: bool = True
 class ProfanityTextFilter(TextFilter):
    """Deterministic text filter backed by a JSON term list.
    The config file is a JSON object with:
    .. code-block:: json
        {
            "mode": "redact",
            "redaction_char": "*",
            "min_term_length": 3,
            "case_insensitive": true,
            "whole_word": true,
            "terms": ["badword", "another", ...]
        }
    Terms are matched after normalisation (case-fold, leetspeak
    substitution, separator removal, diacritic stripping).
    """
    def __init__(
        self,
        config_path: str | Path | None = None,
        terms: list[str] | None = None,
        policy: _FilterPolicy | None = None,
    ) -> None:
        """
        Args:
            config_path: Path to a JSON config file.  Ignored if *terms*
                is provided.
            terms: Inline list of terms (overrides config file).
            policy: Filter policy.  Defaults to a redact policy.
        """
        if terms is not None:
            self._terms: list[str] = [t.lower() for t in terms]
        elif config_path is not None:
            self._terms = self._load_terms(Path(config_path))
        else:
            # Try default path
            if _DEFAULT_CONFIG_PATH.exists():
                self._terms = self._load_terms(_DEFAULT_CONFIG_PATH)
            else:
                self._terms = []
        self._policy = policy or _FilterPolicy(mode="redact")
        # Pre-compile patterns for each term
        self._patterns: list[tuple[re.Pattern[str], str]] = []
        for term in self._terms:
            if len(term) < self._policy.min_term_length:
                continue
            if self._policy.whole_word:
                pattern = re.compile(
                    r"(?<!\w)" + re.escape(term) + r"(?!\w)",
                    re.IGNORECASE if self._policy.case_insensitive else 0,
                )
            else:
                pattern = re.compile(
                    re.escape(term),
                    re.IGNORECASE if self._policy.case_insensitive else 0,
                )
            self._patterns.append((pattern, term))
    # -- config loading --------------------------------------------------
    @staticmethod
    def _load_terms(config_path: Path) -> list[str]:
        """Load terms from a JSON config file."""
        with open(config_path, "r", encoding="utf-8") as f:
            data: dict[str, Any] = json.load(f)
        terms: list[str] = []
        for raw in data.get("terms", []):
            term = str(raw).strip()
            if term:
                terms.append(term.casefold())
        return terms
    # -- public API ------------------------------------------------------
    def check(self, text: str) -> FilterResult:
        """Check *text* against the loaded term list.
        Returns a ``FilterResult`` with the appropriate action,
        filtered text, and matched terms.
        """
        if not text:
            return FilterResult(
                action=FilterAction.ALLOW,
                filtered_text=text,
                matched_terms=[],
            )
        normalized = _normalize(text)
        matched_terms: list[str] = []
        # Collect all matches
        for pattern, term in self._patterns:
            if pattern.search(normalized):
                if term not in matched_terms:
                    matched_terms.append(term)
        if not matched_terms:
            return FilterResult(
                action=FilterAction.ALLOW,
                filtered_text=text,
                matched_terms=[],
            )
        matched_terms.sort()
        # Build filtered text by replacing matched terms
        filtered = text
        for term in matched_terms:
            norm_term = _normalize(term)
            # Find all occurrences in the normalised text and replace in original
            # We need to map positions from normalised text back to original
            filtered = self._replace_terms(filtered, term, norm_term)
        action = FilterAction.REJECT if self._policy.mode == "reject" else FilterAction.REDACT
        return FilterResult(
            action=action,
            filtered_text=filtered,
            matched_terms=matched_terms,
        )
    def _replace_terms(
        self, text: str, term: str, norm_term: str
    ) -> str:
        """Replace occurrences of *term* in *text* with redaction chars.
        Uses normalised text for matching but preserves original casing
        in the output.
        """
        norm_text = _normalize(text)
        norm_term_len = len(norm_term)
        result_chars = list(text)
        start = 0
        while start < len(norm_text):
            idx = norm_text.find(norm_term, start)
            if idx == -1:
                break
            # Replace characters in original text
            for i in range(idx, min(idx + norm_term_len, len(result_chars))):
                result_chars[i] = self._policy.redaction_char
            start = idx + norm_term_len
        return "".join(result_chars)
    @property
    def terms(self) -> list[str]:
        """Read-only access to the loaded term list."""
        return list(self._terms)
    @property
    def policy(self) -> _FilterPolicy:
        """Read-only access to the filter policy."""
        return self._policy
 # ---------------------------------------------------------------------------
 # Factory
 # ---------------------------------------------------------------------------
 def get_text_filter(
    config_path: str | Path | None = None,
    terms: list[str] | None = None,
    policy: _FilterPolicy | None = None,
 ) -> TextFilter:
    """Return a ``TextFilter`` instance.
    By default this creates a ``ProfanityTextFilter``.  To use a
    third-party provider, subclass ``TextFilter`` and pass an
    instance here instead.
    """
    return ProfanityTextFilter(
        config_path=config_path,
        terms=terms,
        policy=policy,
    )
@@ -1,3 +0,0 @@
 [pytest]
 asyncio_mode = auto
 testpaths = tests
@@ -1,94 +0,0 @@
 """Tests for the 18+ age gate on user registration."""
 from datetime import date, timedelta
 import pytest
 from app.routers.auth import calculate_age
 class TestCalculateAge:
    """Unit tests for the calculate_age helper."""
    def test_exactly_18(self):
        """A person born exactly 18 years ago today is 18."""
        today = date(2025, 6, 15)
        dob = today.replace(year=today.year - 18)
        assert calculate_age(dob, today=today) == 18
    def test_just_turned_18(self):
        """A person who turned 18 yesterday is 18."""
        today = date(2025, 6, 15)
        dob = today.replace(year=today.year - 18) - timedelta(days=1)
        assert calculate_age(dob, today=today) == 18
    def test_one_day_short_of_18(self):
        """A person born one day after their 18th birthday is 17."""
        today = date(2025, 6, 15)
        dob = today.replace(year=today.year - 18) + timedelta(days=1)
        assert calculate_age(dob, today=today) == 17
    def test_17_years_old(self):
        """A person who is 17 years old today is 17."""
        today = date(2025, 6, 15)
        dob = date(2008, 6, 15)
        assert calculate_age(dob, today=today) == 17
    def test_65_years_old(self):
        """A person who is 65 is correctly calculated."""
        today = date(2025, 6, 15)
        dob = today.replace(year=today.year - 65)
        assert calculate_age(dob, today=today) == 65
    def test_newborn(self):
        """A newborn is 0."""
        today = date(2025, 6, 15)
        dob = today
        assert calculate_age(dob, today=today) == 0
    def test_birthday_not_yet_this_year(self):
        """Person born Dec 31, 2000 — on Jan 1, 2025 they are still 24."""
        dob = date(2000, 12, 31)
        assert calculate_age(dob, today=date(2025, 1, 1)) == 24
    def test_birthday_today(self):
        """Person born Dec 31, 2000 — on Dec 31, 2024 they turn 24."""
        dob = date(2000, 12, 31)
        assert calculate_age(dob, today=date(2024, 12, 31)) == 24
 class TestRegisterRequestDateValidation:
    """Tests for the RegisterRequest date_of_birth field validator."""
    @pytest.mark.parametrize(
        "dob",
        [
            "2000-01-01",
            "1990-12-31",
            "2004-02-29",  # leap day
        ],
    )
    def test_valid_dates(self, dob):
        """Valid YYYY-MM-DD dates pass validation."""
        from app.routers.auth import RegisterRequest
        req = RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)
        assert req.date_of_birth == dob
    @pytest.mark.parametrize(
        "dob",
        [
            "01-01-2000",
            "2000/01/01",
            "2000-13-01",
            "2000-00-10",
            "not-a-date",
            "",
        ],
    )
    def test_invalid_dates_rejected(self, dob):
        """Invalid dates are rejected by the validator."""
        from app.routers.auth import RegisterRequest
        with pytest.raises(ValueError):
            RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)
@@ -1,295 +0,0 @@
 # Economy — Currency, Marketplace & Creator Payouts — Plan
 > **Status:** Planned
 > **Owner:** Platform team
 > **Feature ID:** `economy`
 > **Godot version:** 4.6.2 stable
 > **Backend:** FastAPI + SQLAlchemy (async) + PostgreSQL + Redis
 ## 1. Overview
 This document breaks the **Economy** feature into user stories and right-sized
 implementation tasks. The feature delivers:
 - **Virtual currency ("Credits")** — a single, server-authoritative currency
  with an immutable, append-only transaction ledger.
 - **Premium purchase** — buying Credits with real money through a pluggable
  payment-provider hook.
 - **Marketplace** — user-generated content (UGC) listings where creators sell
  items (assets, avatar items, experience passes) to players for Credits.
 - **Creator payouts** — accumulating creator earnings and paying them out to
  external accounts through a pluggable payout-provider hook.
 - **Godot client** — wallet/transaction history, marketplace browse/buy/sell,
  and creator payout screens.
 The economy is the monetization backbone of the platform. Because it moves
 virtual value between real people, correctness (no double-spend, no lost funds,
 no balance drift) and safety (fraud prevention, moderation, audit) are treated
 as **blocking requirements**, not add-ons.
 ## 2. Why correctness is the differentiator
 The platform is a creator economy (players buy UGC from other players). The
 economy is the highest-risk surface after chat: a single arithmetic or
 concurrency bug can mint or destroy value and irreversibly erode trust.
 Correctness is therefore designed in from the start:
 - **One currency, integer units.** Credits are whole-number integers. There are
  no floats, no rounding, and no client-computed totals.
 - **Append-only ledger.** Every balance change is a row in a `transactions`
  table with a signed amount, a `balance_after` snapshot, a reference to the
  event that caused it, and an **idempotency key** so retries cannot double
  credit or double debit.
 - **Atomic, locked mutations.** Balance changes run in a single database
  transaction with row locking (`SELECT ... FOR UPDATE`) so concurrent
  purchases/payouts cannot race.
 - **Escrow hold.** Marketplace proceeds are held in `pending_escrow` for a
  configurable window before becoming available to the seller, so fraudulent
  or moderated sales can be reversed without clawing back paid-out funds.
 - **Server-authoritative fees.** The platform commission is computed
  server-side from a configured rate; the client never supplies the fee or the
  seller's net.
 ## 3. Existing constraints (do not re-build)
 - **Auth:** JWT bearer tokens; `get_current_user` / `CurrentUser` dependency in
  `app/dependencies.py`. All economy endpoints reuse this.
 - **DB:** async SQLAlchemy + Alembic; migration `0001_initial` is the head.
  Existing tables: `users`, `sessions`, `worlds`, `assets`.
 - **Redis:** configured (`REDIS_URL`) but unused so far; adopted here for
  idempotency short-caching and rate limiting.
 - **Models:** `User` (owner_id), `Asset` (owner_id, is_public, asset_type).
  Marketplace items reference existing `assets` rows and/or avatar items.
 - **Content moderation:** `docs/architecture/content_moderation.md` defines
  flag vocabulary, age gate, and moderation actions. Marketplace items and
  listings must inherit and enforce these rules (see §7).
 - **Client:** Godot 4.6.2, minimal `main_menu.gd`; no economy UI yet.
 ## 4. Key design decisions
 | Concern | Decision |
 |---|---|
 | Currency model | Single virtual currency **"Credits" (CR)**, integer units. One wallet row per user; no fractional amounts. |
 | Ledger | Append-only `transactions` table: signed `amount`, `balance_after`, `reference_type`/`reference_id`, unique `idempotency_key`. |
 | Concurrency | `SELECT ... FOR UPDATE` on the wallet row inside the mutation transaction; never read-modify-write from stale data. |
 | Payments | Pluggable `PaymentProvider` interface with a **no-op default** that simulates a confirmed payment for dev/testing (clearly flagged). Stripe/PayPal later. |
 | Marketplace items | `catalog_items` (what is sold) + `marketplace_listings` (a seller's offer with a price/status). One item can have multiple listings over time. |
 | Purchase flow | Atomic transaction: debit buyer → hold funds in escrow (`pending_escrow`) → grant item. Platform fee computed server-side. |
 | Escrow | Configurable hold window (default 72h) before `pending_escrow` becomes available seller earnings. Refunds during the window reverse the sale. |
 | Fees | Single configurable `MARKETPLACE_FEE_RATE` (default `0.30`). `seller_net = floor(price * (1 - fee_rate))`. |
 | Creator balance | `creator_balances` table: `available` (earned, payable), `pending` (inside an open payout request), `lifetime_earned`. Updated in the same transaction as the sale completion. |
 | Payouts | Pluggable `PayoutProvider.pay()` with a no-op default (simulated external ref). Minimum payout threshold, admin review for large payouts. |
 | Idempotency | Every money-moving request carries a client-generated `Idempotency-Key`; duplicate keys return the original result. |
 | Rate limiting | Redis token-bucket dependency reused from the social feature for purchase/listing/payout endpoints. |
 | Moderation | Listings enforce content flags + age gate; moderators can `delist`/`remove`; fraud/chargeback reversal is an audited admin action. |
 ## 5. User stories
 ### US-1 Currency & wallet
 As a player, I can see my Credit balance and transaction history, and the system
 credits/debits my wallet only through server-authoritative events.
 **Acceptance criteria**
 - Exactly one wallet per user, created lazily on first use.
 - Balance is always a non-negative integer; no operation can make it negative.
 - Every mutation appends an immutable ledger row with amount, resulting balance,
  reference, and idempotency key.
 - Retrying a request with the same idempotency key does not double-apply.
 - `GET` endpoints expose current balance and paged transaction history.
 ### US-2 Premium purchase (buy Credits)
 As a player, I can purchase Credits with real money and have them credited only
 after the payment is confirmed.
 **Acceptance criteria**
 - A purchase session is created through the payment provider (or the no-op
  default) and is idempotent.
 - Credits are granted exactly once, only after a verified provider confirmation
  (webhook/confirm endpoint), never on client claim.
 - Purchase amounts are bounded and server-defined; clients cannot pick arbitrary
  prices.
 - Confirmation is idempotent and audited (provider reference recorded).
 ### US-3 Marketplace listing (sell)
 As a creator, I can list a catalog item for sale at a Credit price and
 manage/remove my listings.
 **Acceptance criteria**
 - A listing references a valid `catalog_item` owned by the seller (or an
  authorized seller).
 - Price is bounded (min/max) and set server-side; status transitions are
  explicit (`active`, `sold`, `delisted`, `removed_by_moderation`).
 - Only the seller (or a moderator) can update/remove a listing.
 - Listings are searchable/filterable (item type, price range, owner).
 ### US-4 Marketplace purchase (buy)
 As a player, I can buy a listed item. The purchase is atomic, holds funds in
 escrow, grants the item, and splits the payment between platform and seller.
 **Acceptance criteria**
 - A single transaction debits the buyer, holds funds in escrow, and grants the
  item — no partial states on failure.
 - Platform fee and seller net are computed server-side from the configured rate.
 - After the escrow hold window, funds move from escrow to the seller's
  available balance.
 - Refunds during the hold window reverse the sale and return funds to the buyer.
 - Concurrent purchases of a one-of-a-kind listing cannot both succeed.
 ### US-5 Creator payouts
 As a creator, I can view my earned balance, request a payout, and track its
 status; admins can review and approve/reject payouts.
 **Acceptance criteria**
 - Available balance is derived only from completed (escrow-released) sales and
  completed payouts; it never goes negative.
 - Payout requests are bounded (min threshold, max per period) and rate-limited.
 - Large payouts require admin review; all payout requests carry an audit trail
  (requested by, reviewed by, provider reference, status).
 - The payout provider is called exactly once; idempotent on retry.
 ### US-6 Godot client
 As a player, I can manage Credits, browse/buy/sell marketplace items, and manage
 payouts from the game UI.
 **Acceptance criteria**
 - An API client handles JWT auth, HTTP, and idempotency keys for all economy
  calls.
 - Dedicated screens: wallet + transaction history, marketplace browse/buy,
  sell-listing, and creator payout.
 - The client never computes balances, fees, or seller nets — it only displays
  server responses.
 ## 6. Task breakdown
 Right-sized to 1–3 files / one coherent piece of functionality each. Task IDs
 are sequential for dependency chaining.
 | # | Task | Story | Depends on |
 |---|------|-------|-----------|
 | 1 | Wallet & ledger models + Alembic migration (`wallets`, `transactions`) | US-1 | — |
 | 2 | Wallet service (atomic credit/debit, idempotency, locking) + wallet/transactions API | US-1 | 1 |
 | 3 | Premium purchase: `PaymentProvider` interface + purchase/confirm endpoints | US-2 | 1 |
 | 4 | Catalog item & listing models + migration (`catalog_items`, `marketplace_listings`, `creator_balances`) | US-3 | 1 |
 | 5 | Marketplace listing API (create/list/search/update/remove) | US-3 | 4 |
 | 6 | Marketplace purchase service + API (atomic escrow, fee split, item grant) | US-4 | 2, 4, 5 |
 | 7 | Creator payout request models + API (`payout_requests`) | US-5 | 2, 6 |
 | 8 | Payout admin review + `PayoutProvider` + audit | US-5 | 7 |
 | 9 | Marketplace moderation + content-flag/age-gate enforcement | cross-cutting | 5, 6 |
 | 10 | Godot economy API client (auth + HTTP + idempotency) | US-6 | 2 |
 | 11 | Godot wallet & transaction history UI | US-6 | 10 |
 | 12 | Godot marketplace browse/buy UI | US-6 | 6, 10 |
 | 13 | Godot selling & payout UI | US-6 | 5, 7, 10 |
 ## 7. Phasing
 - **Phase 1 (currency + payments):** tasks 1–3. The foundation — ledger and
  money movement must be rock-solid before anything spends Credits.
 - **Phase 2 (marketplace):** tasks 4–6. Listing and atomic purchase with escrow.
 - **Phase 3 (payouts):** tasks 7–8. Turn released escrow into creator payouts.
 - **Phase 4 (moderation):** task 9. Lock down the marketplace against mature
  content and abuse.
 - **Phase 5 (client):** tasks 10–13, each landing after its backend dependency.
 ## 8. Data model sketch
 ```text
 wallets
  id                bigint PK
  user_id           int UNIQUE FK -> users.id
  balance           bigint NOT NULL DEFAULT 0  CHECK (balance >= 0)
  created_at        timestamptz
  updated_at        timestamptz
 transactions        (append-only ledger)
  id                bigint PK
  wallet_id         bigint FK -> wallets.id
  type              enum(credit_purchase, marketplace_purchase,
                        marketplace_sale, escrow_release, payout,
                        refund, admin_adjustment)
  amount            bigint NOT NULL            (signed)
  balance_after     bigint NOT NULL
  reference_type    text                        (e.g. "purchase", "sale", "payout_request")
  reference_id      text
  idempotency_key   text UNIQUE
  metadata_json     jsonb
  created_at        timestamptz
 catalog_items
  id                bigint PK
  owner_id          int FK -> users.id
  asset_id          int FK -> assets.id (nullable; null for non-asset virtual items)
  item_type         enum(asset, avatar_item, experience_pass)
  name              text
  description       text
  metadata_json     jsonb
  created_at        timestamptz
 marketplace_listings
  id                bigint PK
  catalog_item_id   bigint FK -> catalog_items.id
  seller_id         int FK -> users.id
  price             bigint NOT NULL CHECK (price > 0)
  status            enum(active, sold, delisted, removed_by_moderation)
  created_at        timestamptz
  updated_at        timestamptz
 purchases
  id                bigint PK
  listing_id        bigint FK -> marketplace_listings.id
  buyer_id          int FK -> users.id
  seller_id         int FK -> users.id
  price             bigint NOT NULL
  platform_fee      bigint NOT NULL
  seller_net        bigint NOT NULL
  status            enum(pending_escrow, completed, refunded, reversed)
  escrow_hold_until timestamptz
  created_at        timestamptz
 creator_balances
  id                bigint PK
  user_id           int UNIQUE FK -> users.id
  available         bigint NOT NULL DEFAULT 0
  pending           bigint NOT NULL DEFAULT 0
  lifetime_earned   bigint NOT NULL DEFAULT 0
  updated_at        timestamptz
 payout_requests
  id                bigint PK
  creator_id        int FK -> users.id
  amount            bigint NOT NULL CHECK (amount > 0)
  status            enum(pending, approved, paid, rejected)
  external_ref      text
  provider_ref      text
  requested_by      int FK -> users.id
  reviewed_by       int FK -> users.id (nullable)
  reviewed_at       timestamptz
  created_at        timestamptz
 ```
 ## 9. Security, anti-fraud & audit
 - **Server-authoritative balances/fees:** clients never compute totals; amounts
  are validated server-side against bounds and the current listing.
 - **Row locking:** wallet and creator-balance mutations use `SELECT ... FOR
  UPDATE` within one transaction.
 - **Idempotency:** every money-moving endpoint requires an `Idempotency-Key`;
  duplicate keys return the stored original outcome.
 - **Rate limiting:** purchase, listing, and payout endpoints are token-bucket
  rate-limited per user.
 - **Escrow & reversibility:** funds are not payable until the hold window
  elapses; chargebacks/refunds reverse before release.
 - **Moderation:** listings carry the item's effective content flags; mature
  items require age verification (per `content_moderation.md`); moderators can
  `delist`/`remove` and trigger audited reversals.
 - **Audit:** the ledger plus `payout_requests` review fields form an append-only
  audit trail for every movement of value.
 ## 10. Out of scope for this feature
 - Real Stripe/PayPal/KYC integrations (provider interfaces leave the hooks; the
  defaults are deterministic no-ops).
 - Subscriptions, recurring billing, or premium memberships.
 - Gift cards, promotional codes, or user-to-user Credit transfers.
 - Partial refunds, chargeback disputes, and seller tax/VAT handling.
 - In-world vending machines / scripted economy triggers (future, built on this
  ledger via the scripting sandbox).