# common/utils/cache/regions.py
import time

from dogpile.cache import make_region
from urllib.parse import urlparse


def get_redis_config(app):
    """
    Create Redis configuration dict based on app config.
    Handles both authenticated and non-authenticated setups.
    """
    # Parse the REDIS_BASE_URI to get all components
    redis_uri = urlparse(app.config['REDIS_BASE_URI'])

    config = {
        'host': redis_uri.hostname,
        'port': int(redis_uri.port or 6379),
        'db': 0,
        'redis_expiration_time': 3600,
        'distributed_lock': True,
        'thread_local_lock': False,
        # Built-in connection pooling parameters
        'connection_pool_class': 'redis.BlockingConnectionPool',
        'connection_pool_class_kwargs': {
            'max_connections': 20,
            'timeout': 20,
            'retry_on_timeout': True,
            'socket_connect_timeout': 5,
            'socket_timeout': 5,
        },

        # Key prefix for namespace isolation
        'key_mangler': lambda key: f"cache:workers:{key}"
    }

    # Add authentication if provided
    if redis_uri.username and redis_uri.password:
        config.update({
            'username': redis_uri.username,
            'password': redis_uri.password
        })

    # SSL support using centralised config
    cert_path = app.config.get('REDIS_CA_CERT_PATH')
    if cert_path and redis_uri.scheme == 'rediss':
        import ssl
        # Create SSL context
        ssl_context = ssl.create_default_context()
        ssl_context.load_verify_locations(cert_path)
        ssl_context.verify_mode = ssl.CERT_REQUIRED
        ssl_context.check_hostname = app.config.get('REDIS_SSL_CHECK_HOSTNAME', True)

        # Add SSL to connection pool kwargs (correct for redis-py)
        config['connection_pool_class_kwargs']['ssl'] = True
        config['connection_pool_class_kwargs']['ssl_cert_reqs'] = ssl.CERT_REQUIRED
        config['connection_pool_class_kwargs']['ssl_ca_certs'] = cert_path
        config['connection_pool_class_kwargs']['ssl_check_hostname'] = app.config.get('REDIS_SSL_CHECK_HOSTNAME', True)
        # Also pass explicit context (preferred when available)
        config['connection_pool_class_kwargs']['ssl_context'] = ssl_context

    return config


def create_cache_regions(app):
    """Initialise all cache regions with app config"""
    redis_config = get_redis_config(app)
    regions = {}
    startup_time = int(time.time())

    # Region for model-related caching (ModelVariables etc)
    model_region = make_region(name='eveai_model').configure(
        'dogpile.cache.redis',
        arguments=redis_config,
        replace_existing_backend=True
    )
    regions['eveai_model'] = model_region

    # Region for eveai_chat_workers components (Specialists, Retrievers, ...)
    eveai_chat_workers_region = make_region(name='eveai_chat_workers').configure(
        'dogpile.cache.redis',
        arguments=redis_config,
        replace_existing_backend=True
    )
    regions['eveai_chat_workers'] = eveai_chat_workers_region

    # Region for eveai_workers components (Processors, ...)
    eveai_workers_region = make_region(name='eveai_workers').configure(
        'dogpile.cache.redis',
        arguments=redis_config,  # Same config for now
        replace_existing_backend=True
    )
    regions['eveai_workers'] = eveai_workers_region

    eveai_config_region = make_region(name='eveai_config').configure(
        'dogpile.cache.redis',
        arguments=redis_config,
        replace_existing_backend=True
    )
    regions['eveai_config'] = eveai_config_region

    return regions