#!/usr/bin/env python

from elements import *
import random


class Computer:
	''' The Computer module represents the computer scrabble player 
		in the User vs Computer mode.
	'''
	def __init__(self, letters):
		''' Initialize the Computer class.
			
			@param letters: List of the Letters to use.
		'''
		self.__letters = bag.remove_letters()
				
	
	def get_letters(self):
		''' Return the list of Letters.
			
			@return: the list of elements.
		'''		
		return self.__letters
		
	def letters_length(self):
		''' Return the length of the list of Letters.
			
			@return: the number of elements.
		'''
		return len(self.__letters)
	
	def get_letter_at(self, index):
		''' Get the letter at the specified index of the list.
			
			@param index: the index
			@return: the Letter
		'''		
		return self.__letter[index]
	
	def add_letter(self, letter):
		''' Add a new Letter to the list of Letters.
			
			@param letter: the new Letter.
		'''
		self.__letters.append(letter)
	
		
	def swap_letters(self, bag, amount=0):
		''' Return the given amount of Letters to the bag, and take
			the same amount from the bag.
			
			@param bag: the bag
			@param amount: the amount.
			@return: True if it is possible otherwise False.
		'''
		from_bag = bag.remove_letters(amount)
		if from_bag == -1:
			return False
		
		to_bag = [] 
		i = 0
		amount = len(from_bag) 
		while i < amount:
			for j in range(0, self.letters_length()):
				if random.randint(0, 1) and i < amount:
					l = self.get_letter_at(j)
					to_bag.append(l)
					self.get_letters().remove(l)
					i += 1
		
		bag.add_letters(to_bag)
		for l in from_bag:
			self.add_letter(l)
		return True			
			
			
								
	def make_move(self, board, dict, moves):
		''' Function which calculates the move that the computer
			will make.
			
			@param board: the current gameboard
			@param dict: the dictionary
			@param moves: the list of Moves that were made along the game.
			@return: the Move made.
		'''
		move = Move()
		for i in range(0, board.get_size()):
			for j in range(0, board.get_size()):
				if not board.is_tile_empty(i, j):
					letter = board.get_value_at(i, j)
					criterion, type = utility.can_form_a_word(board, 
														      self.get_letters(),
														      letter, i, j)
					words = utility.search_words_that_match(criterion, 
															dict)
					for w in words:
						possible = move.try_move(board, w, type, i, j)
						if possible:
							move.calculate_score()
							return move
		# probar intercambiar letras.
		# else pasar turno.
		# to be continued..