"""Agent 热状态、频率控制和运行事件的 Redis 适配器。"""

import json
from typing import Protocol, cast

from redis import Redis

from zbt.core.config import Settings
from zbt.harness.events import RuntimeEvent
from zbt.infrastructure.redis.keys import RedisKeyBuilder


class AgentStateStore(Protocol):
    def allow_request(self, principal_id: str) -> bool: ...

    def touch_thread(
        self,
        thread_id: str,
        *,
        owner_type: str,
        owner_id: str,
        persona: str,
    ) -> None: ...

    def append_event(self, event: RuntimeEvent) -> None: ...

    def list_events(self, run_id: str) -> list[RuntimeEvent]: ...

    def close(self) -> None: ...


class InMemoryAgentStateStore:
    def __init__(self, rate_limit: int = 20) -> None:
        self._rate_limit = rate_limit
        self._request_counts: dict[str, int] = {}
        self._threads: dict[str, dict[str, str]] = {}
        self._events: dict[str, list[RuntimeEvent]] = {}

    def allow_request(self, principal_id: str) -> bool:
        count = self._request_counts.get(principal_id, 0) + 1
        self._request_counts[principal_id] = count
        return count <= self._rate_limit

    def touch_thread(
        self,
        thread_id: str,
        *,
        owner_type: str,
        owner_id: str,
        persona: str,
    ) -> None:
        self._threads[thread_id] = {
            "owner_type": owner_type,
            "owner_id": owner_id,
            "persona": persona,
        }

    def append_event(self, event: RuntimeEvent) -> None:
        self._events.setdefault(event.run_id, []).append(event)

    def list_events(self, run_id: str) -> list[RuntimeEvent]:
        return list(self._events.get(run_id, []))

    def close(self) -> None:
        return None


class RedisAgentStateStore:
    def __init__(self, settings: Settings) -> None:
        self._client: Redis = Redis.from_url(
            settings.redis_url,
            decode_responses=True,
        )
        self._keys = RedisKeyBuilder(settings.redis_prefix)
        self._rate_limit = settings.agent_rate_limit
        self._rate_window_seconds = settings.agent_rate_window_seconds
        self._hot_ttl_seconds = settings.agent_hot_state_ttl_seconds
        self._event_ttl_seconds = settings.agent_event_ttl_seconds

    def allow_request(self, principal_id: str) -> bool:
        key = self._keys.agent_rate(principal_id)
        count = cast(
            int,
            self._client.eval(
                """
                local current = redis.call('INCR', KEYS[1])
                if current == 1 then
                    redis.call('EXPIRE', KEYS[1], ARGV[1])
                end
                return current
                """,
                1,
                key,
                self._rate_window_seconds,
            ),
        )
        return count <= self._rate_limit

    def touch_thread(
        self,
        thread_id: str,
        *,
        owner_type: str,
        owner_id: str,
        persona: str,
    ) -> None:
        payload = json.dumps(
            {
                "owner_type": owner_type,
                "owner_id": owner_id,
                "persona": persona,
            },
            ensure_ascii=False,
            separators=(",", ":"),
        )
        self._client.set(
            self._keys.agent_thread_hot(thread_id),
            payload,
            ex=self._hot_ttl_seconds,
        )

    def append_event(self, event: RuntimeEvent) -> None:
        key = self._keys.agent_run_events(event.run_id)
        pipe = self._client.pipeline()
        pipe.rpush(key, event.model_dump_json())
        pipe.expire(key, self._event_ttl_seconds)
        pipe.execute()

    def list_events(self, run_id: str) -> list[RuntimeEvent]:
        raw_items = cast(
            list[str],
            self._client.lrange(self._keys.agent_run_events(run_id), 0, -1),
        )
        return [RuntimeEvent.model_validate_json(item) for item in raw_items]

    def close(self) -> None:
        self._client.close()