#!/usr/bin/env python3
# -*- coding: utf-8 -*-

__author__ = 'Windrivder'

import curses
from random import randrange, choice
from collections import defaultdict


# 用户行为
actions = ['Up', 'Left', 'Down', 'Right', 'Restart', 'Exit']
# 与用户行为对应的有效输入键的键值列表
letter_codes = [ord(ch) for ch in 'WASDRQwasdrq']
# 将输入与行为进行关联
actions_dict = dict(zip(letter_codes, actions * 2))


# 用户输入处理
def get_user_action(keyboard):
 char = "N"
 while char not in actions_dict:
 # keyboard 为 stdscr 对象,通过 getch() 获取用户输入的字符
 char = keyboard.getch()
 return actions_dict[char]


# 矩阵转置
def transpose(field):
 return [list(row) for row in zip(*field)]


# 矩阵逆转
def invert(field):
 return [row[::-1] for row in field]


# 创建棋盘
class GameField(object):

 def __init__(self, height=4, width=4, win=2048):
 self.height = height # 高
 self.width = width # 宽
 self.win_value = win # 过关分数
 self.score = 0 # 当前分数
 self.highscore = 0 # 最高分数
 self.reset() # 棋盘重置

 # 重置游戏棋盘
 def reset(self):
 if self.score > self.highscore:
 self.highscore = self.score
 self.score = 0
 # 生成 4 组 4 个 0 的列表
 self.field = [[0 for i in range(self.width)]
 for j in range(self.height)]
 # 调用封装好的函数,随机生成 2 或 4 放入 field 中
 self.spawn()
 self.spawn()

 def move(self, direction):
 # 一行向左合并, row 为 field 中的一个元素
 def move_row_left(row):
 def tighten(row): # 把零散的非零单位挤到一起
 new_row = [i for i in row if i != 0]
 new_row += [0 for i in range(len(row) - len(new_row))]
 return new_row

 # 对邻近的元素进行合并
 def merge(row):
 pair = False
 new_row = []
 for i in range(len(row)):
 if pair:
 new_row.append(2 * row[i])
 self.score += 2 * row[i]
 pair = False
 else:
 if i + 1 < len(row) and row[i] == row[i + 1]:
 pair = True
 new_row.append(0)
 else:
 new_row.append(row[i])
 assert len(new_row) == len(row)
 return new_row
 # 先挤到一起再合并再挤到一起
 return tighten(merge(tighten(row)))

 # 对矩阵进行转置与逆转,可以直接从左移得到其余三个方向的移动操作
 moves = {}
 moves['Left'] = lambda field: [move_row_left(row) for row in field]
 moves['Right'] = lambda field: invert(moves['Left'](invert(field)))
 moves['Up'] = lambda field: transpose(moves['Left'](transpose(field)))
 moves['Down'] = lambda field: transpose(
 moves['Right'](transpose(field)))

 if direction in moves:
 if self.move_is_possible(direction):
 self.field = moves[direction](self.field)
 self.spawn()
 return True
 else:
 return False

 # 判断输赢
 def is_win(self):
 return any(any(i >= self.win_value for i in row) for row in self.field)

 def is_gameover(self):
 return not any(self.move_is_possible(move) for move in actions)

 # 绘制游戏界面
 def draw(self, screen):
 help_string1 = '(W)Up (S)Down (A)Left (D)Right'
 help_string2 = ' (R)Restart (Q)Exit'
 gameover_string = ' GAME OVER'
 win_string = ' YOU WIN!'

 def cast(string):
 screen.addstr(string + '\n')

 # 绘制水平分割线
 def draw_hor_separator():
 line = '+' + ('+------' * self.width + '+')[1:]
 separator = defaultdict(lambda: line)
 if not hasattr(draw_hor_separator, 'counter'):
 draw_hor_separator.counter = 0
 cast(separator[draw_hor_separator.counter])
 draw_hor_separator.counter += 1

 def draw_row(row):
 cast(''.join('|{: ^5} '.format(num) if num >
 0 else '| ' for num in row) + '|')

 screen.clear()

 cast('SCORE: ' + str(self.score))
 if 0 != self.highscore:
 cast('HIGHSCORE: ' + str(self.highscore))

 for row in self.field:
 draw_hor_separator()
 draw_row(row)

 draw_hor_separator()

 if self.is_win():
 cast(win_string)
 else:
 if self.is_gameover():
 cast(gameover_string)
 else:
 cast(help_string1)
 cast(help_string2)

 # 随机生成一个 2 或 4
 def spawn(self):
 new_element = 4 if randrange(100) > 50 else 2
 (i, j) = choice([(i, j) for i in range(self.width)
 for j in range(self.height) if self.field[i][j] == 0])
 self.field[i][j] = new_element

 # 判断能否移动
 def move_is_possible(self, direction):
 def row_is_left_moveable(row):
 def change(i):
 # 可以移动
 if row[i] == 0 and row[i + 1] != 0:
 return True
 # 可以合并
 if row[i] != 0 and row[i + 1] == row[i]:
 return True
 return False
 return any(change(i) for i in range(len(row) - 1))

 check = {}
 check['Left'] = lambda field: any(
 row_is_left_moveable(row) for row in field)
 check['Right'] = lambda field: check['Left'](invert(field))
 check['Up'] = lambda field: check['Left'](transpose(field))
 check['Down'] = lambda field: check['Right'](transpose(field))

 if direction in check:
 return check[direction](self.field)
 else:
 return False


def main(stdscr):

 def init():
 # 重置游戏棋盘
 game_field.reset()
 return "Game"

 def not_game(state):
 # 绘制 Win 或 GameOver 的界面
 game_field.draw(stdscr)
 # 读取用户输入得到的 action,判断是重启游戏还是结束游戏
 action = get_user_action(stdscr)
 # 默认是当前状态,没有行为就会一直在当前界面循环
 responses = defaultdict(lambda: state)
 # 对应不同的行为转换到不同的状态
 responses['Restart'], responses['Exit'] = 'Init', 'Exit'
 return responses[action]

 def game():
 # 绘制当前棋盘状态
 game_field.draw(stdscr)
 # 读取用户输入得到的 action,绘制当前棋盘状态
 action = get_user_action(stdscr)

 if action == 'Restart':
 return 'Init'
 if action == 'Exit':
 return 'Exit'
 # move successful
 if game_field.move(action):
 if game_field.is_win():
 return 'Win'
 if game_field.is_gameover():
 return 'Gameover'
 return 'Game'

 state_actions = {
 'Init': init,
 'Win': lambda: not_game('Win'),
 'Gameover': lambda: not_game('Gameover'),
 'Game': game
 }

 curses.use_default_colors()
 game_field = GameField(win=64)

 state = 'Init'

 # 状态机开始循环
 while state != 'Exit':
 state = state_actions[state]()


if __name__ == '__main__':
 curses.wrapper(main)