import asyncio
import base64
import uuid
from concurrent.futures import ProcessPoolExecutor
from datetime import datetime, timedelta
from typing import Dict

import aioboto3
from arq.connections import RedisSettings
from fastapi import HTTPException, status, Query, Depends
from sqlalchemy.ext.asyncio import AsyncSession

from .models import Metadata, Document, Thread, Message

# Global executor for CPU tasks
cpu_pool = ProcessPoolExecutor(max_workers=4)

# Redis
redis_settings = RedisSettings.from_dsn("redis://localhost")

# S3
async def get_s3_client():
    return aioboto3.Session().client(
        's3',
        endpoint_url='http://localhost:9000',  # From env
        aws_access_key_id='minioadmin',
        aws_secret_access_key='minioadmin'
    )

# Routing Engine
def route_document(metadata: Metadata) -> str:
    rules = {
        "Finanzamt-München-I": "Steuerfestsetzung-Team-B",
        "Gericht-Berlin": "Zivilabteilung"
    }
    return rules.get(metadata.authority_id, "Fallback-Team")

# Rate Limiting
async def rate_limit(user_id: str, redis, limit: int = 10, window: int = 60):
    key = f"rate_limit:{user_id}"
    current = await redis.get(key)
    if current is None:
        await redis.setex(key, window, 1)
        return True
    count = int(current)
    if count >= limit:
        raise HTTPException(status_code=429, detail="Rate limit exceeded")
    await redis.incr(key)
    return True

# Validate Encrypted Payload (CPU-bound)
def validate_encrypted_payload(payload_b64: str) -> bool:
    payload_bytes = base64.b64decode(payload_b64)
    return payload_bytes.startswith(b'\x00\x01')  # Demo check

# GDPR Reaper
async def reaper(db: AsyncSession):
    stmt = delete(Document).where(Document.retention_date < datetime.now())
    await db.execute(stmt)
    await db.commit()