app/usage/usage_tracker.py

import threading
from enum import Enum
from collections import defaultdict


class UsageFeature(str, Enum):
    TEXT = "text"
    IMAGE = "image"
    VIDEO = "video"
    EMR = "emr"
    SPEECH = "speech"


class UsageTracker:
    """
    Simple in-memory usage tracker.
    - Not durable: resets on process restart.
    - Thread-safe for single-process deployments.
    """

    TEXT_FREE_LIMIT = 10

    def __init__(self) -> None:
        self._lock = threading.Lock()
        self._counts: dict[str, dict[UsageFeature, int]] = defaultdict(
            lambda: defaultdict(int)
        )

    def record(self, user_id: str, feature: UsageFeature) -> int:
        with self._lock:
            self._counts[user_id][feature] += 1
            return self._counts[user_id][feature]

    def get_count(self, user_id: str, feature: UsageFeature) -> int:
        with self._lock:
            return self._counts[user_id][feature]


# Singleton instance shared across dependencies
usage_tracker = UsageTracker()