import uuid
from abc import ABC, abstractmethod
from threading import current_thread

from django_redis import get_redis_connection

import logging

logger = logging.getLogger('apps')


class ILock(ABC):

    @abstractmethod
    def try_lock(self, timeout: int) -> bool:
        pass

    @abstractmethod
    def unlock(self) -> None:
        pass


class SimpleLock(ILock):
    KEY_PREFIX = "lock:"
    # ID_PREFIX = str(uuid.uuid4()).replace("-", '') + "-"
    ID_PREFIX = '-'

    def __init__(self, name: str, alias: str = "default") -> None:
        self.name = name
        self.redis_con = get_redis_connection(alias)
        self.key = f"{self.KEY_PREFIX}{name}{self.ID_PREFIX}"

    def try_lock(self, timeout: int) -> bool:
        current_thread_id, value = self.get_value()
        logger.info(f"线程:{current_thread_id}开始获取锁")
        is_locked = self.set_if_absent(self.key, value, timeout)
        logger.info(f"线程:{current_thread_id}获取锁是否成功: {bool(is_locked)}")
        return bool(is_locked)

    def get_value(self) -> tuple:
        current_thread_id = current_thread().ident
        value = f"{self.ID_PREFIX}{current_thread_id}"
        return current_thread_id, value

    def unlock(self) -> None:
        current_thread_id, value = self.get_value()
        logger.info(f"线程:{current_thread_id}开始删除锁")
        lua_script = """if (redis.call('get', KEYS[1]) == ARGV[1]) then
                            -- 释放锁 del key
                            return redis.call('del', KEYS[1])
                        end
                        return 0
                    """
        deleted = self.redis_con.eval(lua_script, 1, self.key, value)
        logger.info(f"线程:{current_thread_id}删除锁是否成功: {bool(deleted)}")

    def set_if_absent(self, key: str, value: str, timeout: int) -> bool:
        return bool(self.redis_con.set(key, value, ex=timeout, nx=True))