Gets the scrambler steps for a Rubiks cube, for the given solution

rubik_scrambler_for_a_solution.py

"""
For the given Rubik's cube solution, generates the scramble

For getting solution:
https://ruwix.com/widget/3d/?label=Sample%20Solve&alg=F%20R%20F%20R%20U%20U%20L%20R%20L%20R%20U%27&flags=showalg&colors=WCA

for this specific solution
    F R F R U U L R L R U'

the scramble step is:
    U R' L' R' L' U' U' R' F' R' F'

IFRAME CODE for above ex solution/scramble:
<iframe width="250" height="380" style="width: 250px; height: 380px; overflow: hidden;" src="https://ruwix.com/widget/3d/?label=Sample%20Solve&alg=F%20R%20F%20R%20U%20U%20L%20R%20L%20R%20U'&flags=showalg&colors=WCA" scrolling="no"></iframe>

using roofpig code: https://github.com/larspetrus/Roofpig

    <script src="http://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
    <script src="roofpig_and_three.min.js"></script>

    <div class="roofpig" data-config="alg=F R F R U U L R L R U'|flags=showalg|colors=WCA">Sample Solve</div>

Creating the cube dynamically:
    CubeAnimation.create_in_dom('#show-alg', "alg=F R F R U U L R L R U'", "class='my-roofpig'");
"""
import re


class Solution:

    def __init__(self, solution_steps):
        # self.steps_v1 = [x.strip() for x in solution_steps.strip(' ') if x.strip()]
        self.steps = [x for x in re.split("\s", solution_steps) if x]

    # def not_reduced(self):
    #   return ("'" in self.steps) or ('2' in self.steps)

    # def reduce_v1(self):
    #   def reduce_char(ch):
    #       if ch in self.steps:
    #           x = self.steps.index(ch)
    #           self.steps = self.steps[:x] + self.steps[x+1:]
    #           self.steps[x-1] += ch
    #           return True
    #       return False

    #   while self.not_reduced():
    #       if reduce_char("'"):
    #           continue
    #       if reduce_char("2"):
    #           continue

    #   return " ".join(self.steps)

    def reduce(self):
        return " ".join(self.steps)

    def get_scramble_steps(self):
        """Gets the steps for scrambling of the solution! Should be reduced first!
        needed for v1 approach, not needed now!
        """
        scramble_steps = []
        for step in self.steps:
            if len(step) == 2:
                if step[-1] == "'":
                    scramble_steps.append(step[0])
                elif step[-1] == "2":
                    scramble_steps.append(step)
                else:
                    raise Exception(f"INVALID l2 step: {step}")
            elif len(step) == 1:
                scramble_steps.append(step + "'")
            else:
                raise Exception(f"INVALID step: {step}")
        return " ".join(scramble_steps[::-1])


def test_reducer():
    tests_data = [ 
    {
    "input_solution": """
       F    R  F  R  U     U  L  
       R L
       R   
       U'
    """,
    "expected_reduced": "F R F R U U L R L R U'",
    "expected_scramble_steps": 
            # "F' R' F' R' U' U' L' R' L' R' U"  # step1
            "U R' L' R' L' U' U' R' F' R' F'"    # reversed for step1
    },
    {
    "input_solution": """
       F2    R  F'  R  U     U  L  
       R L
       R2   
       U'
    """,
    "expected_reduced": "F2 R F' R U U L R L R2 U'",
    "expected_scramble_steps": 
        # "F2 R' F R' U' U' L' R' L' R2 U"
          "U R2 L' R' L' U' U' R' F R' F2"
    },
    ]

    for td in tests_data:
        x = Solution(td['input_solution'])
        final_solution = x.reduce()
        print(f"{final_solution=}")
        assert final_solution == td['expected_reduced']
        print(" ... PASS 1")
        scramble_steps = x.get_scramble_steps()
        print(f"{scramble_steps=}")
        assert scramble_steps == td['expected_scramble_steps']
        print(" ... PASS 2")


if __name__ == "__main__":
    import sys

    if len(sys.argv) == 1:
        test_reducer()
    else:
        "F R F R U U L R L R U'"
        r = Solution(sys.argv[1])
        solution = r.reduce()
        steps = r.get_scramble_steps()
        print(f"steps   =\"{steps!s}\"")
        print(f"solution=\"{solution!s}\"")