from die import Die

class Yahtzee:
    """A command-line Yahtzee game.
    This version of Yahtzee is initialized with a list of goals.
    """
    def __init__(self, goals):
        "starts a Yahtzee game."
        self.score = 0
        self.goals = goals
        self.dice = [Die() for num in range(5)]

    def play(self):
        "Run the main game loop until all goals are reached."
        print("Welcome to Yahtzee!")
        self.score = 0
        for goal in self.goals:
            goal.used = False
        while self.count_unused_goals() > 0:
            self.play_round()
        print(f"Your final score was {self.score}")

    def play_round(self):
        "Play a single round: roll, allow rerolls, choose a goal, and score."
        print("=" * 80)
        self.rolls_left = 3
        for die in self.dice:
            die.roll()
        self.show_status()
        goal = self.choose_goal()
        goal.used = True
        self.score += goal.score(self.dice)

    def show_status(self):
        "Display the current game status to the player"
        dice = ', '.join([str(die) for die in self.dice])
        print(f"Score: {self.score}. Rolls left: {self.rolls_left}. Dice: {dice}.")

    def choose_goal(self):
        "Prompt the player to pick a scoring goal or re-roll"
        options = []
        unused_goals = self.get_unused_goals()
        for goal in unused_goals:
            option = goal.prompt(self.dice)
            options.append(option)
        if self.rolls_left > 0:
            options.append("Re-roll")
        choice = self.get_choice(options)
        if options[choice] == "Re-roll":
            self.reroll()
            self.show_status()
            return self.choose_goal()
        else:
            return unused_goals[choice]

    def get_choice(self, options):
        "Prompt the user to select one option from a list of options."
        print("What would you like to do?")
        for i, option in enumerate(options):
            print(f"{i}. {option}")
        choice = input("> ")
        while not self.option_choice_is_valid(choice, options):
            print("Sorry, that's not a valid choice.")
            choice = input("> ")
        return int(choice)

    def option_choice_is_valid(self, choice, options):
        "Validate that a user's option choice string is an allowed index."
        if not choice.isdigit():
            return False
        if int(choice) < 0:
            return False
        if int(choice) >= len(options):
            return False
        return True

    def count_unused_goals(self):
        "Return the number of goals that haven't been used yet."
        return len(self.get_unused_goals())

    def get_unused_goals(self):
        "Return a list of goal objects that are not yet used."
        unused_goals = []
        for goal in self.goals:
            if not goal.used:
                unused_goals.append(goal)
        return unused_goals

    def reroll(self):
        "Perform a reroll of selected dice and decrement available rerolls."
        self.rolls_left -= 1
        choices = self.get_reroll_choices()
        dice_to_reroll = self.get_dice_to_reroll(choices)
        for die in dice_to_reroll:
            die.roll()

    def get_dice_to_reroll(self, choice_ints):
        "Map a list of face-value integers to Die objects to reroll."
        dice_to_reroll = []
        for die in self.dice:
            if die.face in choice_ints:
                choice_ints.remove(die.face)
                dice_to_reroll.append(die)
        return dice_to_reroll

    def get_reroll_choices(self):
        "Ask the user which dice (by face value digits) to reroll."
        print("Which dice do you want to re-roll?")
        choices = input("> ")
        while not self.reroll_choices_are_valid(choices):
            print("Please enter the numbers on dice you want to re-roll.")
            choices = input("> ")
        choice_ints = [int(digit) for digit in choices]
        return choice_ints
        
    def reroll_choices_are_valid(self, choices_str):
        "Validate that the reroll choice string corresponds to existing dice."
        if not choices_str.isdigit():
            return False
        choice_ints = [int(digit) for digit in choices_str]
        for die in self.dice:
            if die.face in choice_ints:
                choice_ints.remove(die.face)
        return len(choice_ints) == 0