# -*- coding: utf-8 -*-
# vim:fenc=utf-8
# $File: game.py
# $Date: Tue Nov 28 14:4726 2017 +0800
# $Author: renyong15 © <mails.tsinghua.edu.cn>
#

import utils
import copy


'''
(1, 1) is considered as the upper left corner of the board,
(size, 1) is the lower left
'''

DELTA = [[1,0], [-1,0], [0, -1], [0, 1]]

class Executor:
    def __init__(self, **kwargs):
        self.game = kwargs['game']


    def _bfs(self, vertex, color, block, status, alive_break):
        block.append(vertex)
        status[self.game._flatten(vertex)] = True
        nei = self._neighbor(vertex)
        for n in nei:
            if not status[self.game._flatten(n)]:
                if self.game.board[self.game._flatten(n)] == color:
                    self._bfs(n, color, block, status, alive_break)

    def _find_block(self, vertex, alive_break = False):
        block = []
        status = [False] * (self.game.size * self.game.size)
        color = self.game.board[self.game._flatten(vertex)]
        self._bfs(vertex, color, block, status, alive_break)

        for b in block:
            for n in self._neighbor(b):
                if self.game.board[self.game._flatten(n)] == utils.EMPTY:
                    return False,block
        return True,block


    def _is_qi(self, color, vertex):
        nei = self._neighbor(vertex)
        for n in nei:
            if self.game.board[self.game._flatten(n)] == utils.EMPTY:
                return True
         
        self.game.board[self.game._flatten(vertex)] = color
        for n in nei:
            if self.game.board[self.game._flatten(n)] == utils.another_color(color):
                can_kill,block = self._find_block(n)
                if can_kill: 
                    self.game.board[self.game._flatten(vertex)] = utils.EMPTY
                    return True

        ### can not suicide
        can_kill,block = self._find_block(vertex)
        if can_kill: 
            self.game.board[self.game._flatten(vertex)] = utils.EMPTY
            return False

        self.game.board[self.game._flatten(vertex)] = utils.EMPTY
        return True


    def _check_global_isomorphous(self, color, vertex):
        ##backup
        _board = copy.copy(self.game.board)
        self.game.board[self.game._flatten(vertex)] = color
        self._process_board(color, vertex)
        if self.game.board in self.game.history:
            res = True
        else:
            res = False

        self.game.board = _board
        return res


    def _in_board(self, vertex):
        x, y =  vertex
        if x < 1 or x > self.game.size: return False
        if y < 1 or y > self.game.size: return False
        return True


    def _neighbor(self, vertex):
        x,y = vertex
        nei = []
        for d in DELTA:
            _x = x + d[0]
            _y = y + d[1]
            if self._in_board((_x, _y)):
                nei.append((_x, _y))
        return nei

    def _process_board(self, color, vertex):
        nei = self._neighbor(vertex)
        for n in nei:
            if self.game.board[self.game._flatten(n)] == utils.another_color(color):
                can_kill, block = self._find_block(n, alive_break = True)
                if can_kill:
                    for b in block:
                        self.game.board[self.game._flatten(b)] = utils.EMPTY
                        

    def is_valid(self, color, vertex):
        ### in board
        if not self._in_board(vertex):
            return False

        ### already have stone
        if not self.game.board[self.game._flatten(vertex)] == utils.EMPTY:
            return False

        ### check if it is qi
        if not self._is_qi(color, vertex):
            return False


        if self._check_global_isomorphous(color, vertex):
            return False

        return True

    def do_move(self, color, vertex):
        if not self.is_valid(color, vertex):
            return False
        self.game.board[self.game._flatten(vertex)] = color
        self._process_board(color,vertex)
        self.game.history.append(copy.copy(self.game.board))
        return True


class Game:
    def __init__(self, size=19, komi=6.5):
        self.size = size
        self.komi = 6.5
        self.board = [utils.EMPTY] * (self.size * self.size)
        self.strategy = None
        self.executor = Executor(game = self)
        self.history = []

    def _flatten(self, vertex):
        x,y = vertex
        return (y - 1) * self.size + (x-1)
        

    def clear(self):
        self.board = [utils.EMPTY] * (self.size * self.size)

    def set_size(self, n):
        self.size = n
        self.clear()

    def set_komi(self, k):
        self.komi = k


    def check_valid(self, vertex):
        return True

    def do_move(self, color, vertex):
        if vertex == utils.PASS:
            return True
        res = self.executor.do_move(color, vertex)
        return res
        

    def gen_move(self, color):
        #move = self.strategy.gen_move(color)
        #return move
        return utils.PASS


    def status2symbol(self, s):
        pool = { utils.WHITE:'#', utils.EMPTY:'.', utils.BLACK:'*', utils.FILL:'F', utils.UNKNOWN:'?'}
        return pool[s]
    

    def show_board(self):
        row = [i for i in range(1, 20)]
        col = ' abcdefghijklmnopqrstuvwxyz'

        for i in range(self.size):
            print(row[i], end = '    ')
            if row[i] < 10:
                print(' ', end = '')
            for j in range(self.size):
                print(self.status2symbol(self.board[self._flatten((j+1,i+1))]), end='    ')
            print('\n')
        print(' ', end = '')
        for j in range(self.size + 1):
            print(col[j], end = '    ')
        print('\n')