#!/usr/bin/env python
# -*- encoding: utf-8 -*-
'''
@File   :   elo.py
@Author :   liuyihui
@Email  :   liuyihui02@gmail.com
'''

# here put the import lib
import math
from typing_extensions import Self

class Person(object):
    '''personal information

    Attributes
    ----------
        rate : elo rate
        name : name
        sex  : male or female
        link : baike link

    Methods
    -------
        compute_K : compute the constant K
    '''
    def __init__(self, name: str, rate: float = 1400, *, sex: str = None, link: str = None) -> None:
        self.name = name
        self.rate = rate
        self.link = link

        if sex and sex not in ['male', 'female']:
            raise ValueError("Sex must be male or female")
        self.sex = sex

    def compute_wre(self, B: Self) -> float:
        '''compute win rate expectation (wre for short)

        Parameters
        ----------
            B : another person

        Returns
        -------
            wre : win rate expectation
        '''
        wre = 1 / (1 + math.pow(10, (B.rate-self.rate)/400))
        return wre

    def compute_K(self) -> float:
        if self.rate > 2400:
            return 12
        elif self.rate > 2000:
            return 24
        else:
            return 36

    def set_result(self, wre: float, res: float) -> None:
        '''set result of this game

        Parameters
        ----------
            wre : win rate expectation
            res : the result, 0 for lose, 1 for win and 0.5 for draw
        '''
        K = self.compute_K()
        self.rate += K * (res - wre)