"""
Redis Queue Helper — Push/pop jobs, track status, rate limiting
"""

import json
import time
import os
import redis

# Default connection settings
REDIS_HOST = os.getenv('REDIS_HOST', 'localhost')
REDIS_PORT = int(os.getenv('REDIS_PORT', 6379))
QUEUE_NAME = 'pdf:queue'
STATUS_PREFIX = 'pdf:status:'
RATE_PREFIX = 'pdf:rate:'


def get_redis():
    """Get a Redis connection."""
    return redis.Redis(
        host=REDIS_HOST,
        port=REDIS_PORT,
        decode_responses=True
    )


def push_job(job_id: str, pdf_path: str, options: dict = None):
    """Push a job to the processing queue."""
    r = get_redis()
    payload = json.dumps({
        'job_id': job_id,
        'pdf_path': pdf_path,
        'options': options or {},
        'queued_at': time.time()
    })
    r.lpush(QUEUE_NAME, payload)
    set_job_status(job_id, 'queued', 0, 'Waiting in queue')


def pop_job(timeout: int = 0):
    """Pop a job from the queue (blocking)."""
    r = get_redis()
    result = r.brpop(QUEUE_NAME, timeout=timeout)
    if result:
        _, payload = result
        return json.loads(payload)
    return None


def set_job_status(job_id: str, status: str, progress: int = 0, message: str = ''):
    """Set job status in Redis."""
    r = get_redis()
    data = {
        'status': status,
        'progress': progress,
        'message': message,
        'updated_at': time.time()
    }
    r.set(STATUS_PREFIX + job_id, json.dumps(data), ex=86400)  # 24h TTL


def get_job_status(job_id: str) -> dict:
    """Get job status from Redis."""
    r = get_redis()
    data = r.get(STATUS_PREFIX + job_id)
    if data:
        return json.loads(data)
    return None


def check_rate_limit(ip: str, action: str, limit: int, window: int) -> bool:
    """
    Check rate limit. Returns True if within limit, False if exceeded.

    Args:
        ip: Client IP address
        action: Action name (e.g., 'upload', 'check')
        limit: Max requests allowed
        window: Time window in seconds
    """
    r = get_redis()
    key = f"{RATE_PREFIX}{ip}:{action}"
    current = r.incr(key)
    if current == 1:
        r.expire(key, window)
    return current <= limit


def get_queue_length() -> int:
    """Get the number of jobs waiting in queue."""
    r = get_redis()
    return r.llen(QUEUE_NAME)