import random

from nonebot import on_message, require
from nonebot.adapters.onebot.v11 import GroupMessageEvent
from nonebot.log import logger

require("nonebot_plugin_alconna")
from nonebot_plugin_alconna import UniMessage

PROB_A = 1.4
# group_id: (last_msg, is_repeated, p)
group_stat: dict[int, tuple[str, bool, float]] = {}

"""
不复读率 随 复读次数 指数级衰减
从第2条复读，即第3条重复消息开始有几率触发复读

a 设为一个略大于1的小数，最好不要超过2，建议1.6
复读概率计算式：p_n = 1 - 1/a^n
递推式：p_n+1 = 1 - (1 - p_n) / a
"""

repeater = on_message(block=False)


@repeater.handle()
async def repeater_handle(ev: GroupMessageEvent):
    group_id = ev.group_id
    msg = str(ev.message)

    if group_id not in group_stat:
        group_stat[group_id] = (msg, False, 0.0)
        return

    last_msg, is_repeated, p = group_stat[group_id]
    if last_msg == msg:  # 群友正在复读
        if not is_repeated:  # 机器人尚未复读过，开始测试复读
            if random.random() < p:  # 概率测试通过，复读并设 flag
                try:
                    group_stat[group_id] = (msg, True, 0.0)
                    await UniMessage.text(ev.message.extract_plain_text()).send()
                except Exception as e:
                    logger.error(f"复读失败: {type(e)}")
                    logger.exception(e)
            else:  # 概率测试失败，蓄力
                p = 1 - (1 - p) / PROB_A
                group_stat[group_id] = (msg, False, p)
    else:  # 不是复读，重置
        group_stat[group_id] = (msg, False, 0.0)