"""
Client Redis partagé — pool de connexions async pour ARQ et Pub/Sub.
Inclut le parsing d'URL Redis centralisé pour éviter la duplication.
"""
from typing import Tuple, Optional

from redis.asyncio import ConnectionPool, Redis

from app.config import settings

_pool: ConnectionPool | None = None


def parse_redis_url(url: str | None = None) -> Tuple[str, int, Optional[str], int]:
    """
    Parse une URL Redis en (host, port, password, database).

    Format accepté : redis://[user:password@]host[:port][/db]
    Retourne ('localhost', 6379, None, 0) si l'URL est vide.
    """
    if url is None:
        url = settings.REDIS_URL

    if not url:
        return "localhost", 6379, None, 0

    if url.startswith("redis://"):
        url = url[8:]
    if url.startswith("rediss://"):
        url = url[9:]

    password: Optional[str] = None
    if "@" in url:
        auth_part, url = url.rsplit("@", 1)
        if ":" in auth_part:
            password = auth_part.split(":", 1)[1]
        else:
            password = auth_part

    database = 0
    if "/" in url:
        host_port, db_str = url.split("/", 1)
        if db_str:
            try:
                database = int(db_str)
            except ValueError:
                pass
    else:
        host_port = url

    host = "localhost"
    port = 6379
    if ":" in host_port:
        host, port_str = host_port.rsplit(":", 1)
        if port_str:
            try:
                port = int(port_str)
            except ValueError:
                port = 6379
    else:
        host = host_port or "localhost"

    return host, port, password, database


async def get_redis_pool() -> Redis:
    """Retourne un client Redis avec pool de connexions partagé."""
    global _pool
    if _pool is None:
        host, port, password, database = parse_redis_url()
        _pool = ConnectionPool.from_url(
            settings.REDIS_URL,
            max_connections=20,
            decode_responses=True,
        )
    return Redis(connection_pool=_pool)


async def close_redis_pool() -> None:
    """Ferme proprement le pool de connexions Redis."""
    global _pool
    if _pool is not None:
        await _pool.disconnect()
        _pool = None