from __future__ import annotations

import json
from typing import Any

from redis import Redis


class DeadLetterQueue:
    def __init__(self, redis_client: Redis, queue_name: str = "scenarist:dlq") -> None:
        self.redis = redis_client
        self.queue_name = queue_name

    def push(self, event: dict[str, Any], reason: str) -> None:
        payload = {"event": event, "reason": reason}
        self.redis.rpush(self.queue_name, json.dumps(payload))

    def list_items(self, limit: int = 100) -> list[dict[str, Any]]:
        raw = self.redis.lrange(self.queue_name, 0, max(0, limit - 1))
        return [json.loads(item) for item in raw]

    def replay_one(self) -> dict[str, Any] | None:
        raw = self.redis.lpop(self.queue_name)
        if raw is None:
            return None
        replay = json.loads(raw)
        event = replay.get("event", {})
        if isinstance(event, dict) and event.get("event_id"):
            # Reset retry bookkeeping before replaying into outbox hash.
            event["retries"] = 0
            event["available_at"] = 0
            self.redis.hset("scenarist:outbox", event["event_id"], json.dumps(event))
        return replay