import bitutils as bu

# this needs to be replaced at some point, because:
# - it uses old notation for align operation, which contradicts with
#   modern instruction sets, thus making it easily confusable with
#   the bu.al() operation which aligns bits to the left
def align_binary_to_right(value, size):
    if "b" in value:
        result = value.split("b")[1]
    else:
        result = str(value)

    return result.rjust(size, "0")

al = align_binary_to_right

def multiply(n, x, y, method):
    '''
    this method can be used to:
    - get step-by-step binary multiplication data using different methods;
    - get just the end result of binary multiplication;

    it takes 4 arguments:
    n - (int) base register bit length
    x - (int) value for X operand
    y - (int) value for Y operand
    method - (int) which method to use to perform multiplication

    it returns 2 items:
    - (list) table with step-by-step operations and descriptions (table format
             depends on the chosen method)
    - (str)  binary representation of the result (method-independant)

    Methods fully supported:
    - №2 (passed mult-test.py with 10 bits)
    - №4 (passed mult-test.py with 12 bits)
    '''

    if method == 2:
        # every table line has registers like so: RG1, RG3, RG2
        data_table = [[["0", "0"*(2*n), "0"*n + bu.ar(bin(y)[2:], n), bu.ar(bin(x)[2:], n), "-"]]*2]

        # iteration number
        i = 0

        while int('0b' + data_table[-1][-1][3], 2) != 0:
            data_table.append([])
            i += 1

            if data_table[-2][-1][3][-1] == "1":
                data_table[-1].append([
                    i,
                    #al(bin(int("0b"+data_table[-2][-1][1], 2) + int("0b"+data_table[-2][-1][2], 2))[-(2*n+1):], 2*n+1), # RG1 + RG3
                    bu.rsum(data_table[-2][-1][1], data_table[-2][-1][2], 2*n),
                    data_table[-2][-1][2],
                    data_table[-2][-1][3],
                    "RG1+RG3"
                ])

                data_table[-1].append([
                    i,
                    data_table[-1][-1][1],
                    bu.l(data_table[-1][-1][2]), # l(RG3).0
                    bu.r(data_table[-1][-1][3]), # 0.r(RG2)
                    "0.r(RG2), l(RG3).0"
                ])

            else:
                data_table[-1].append([
                    i,
                    data_table[-2][-1][1],
                    bu.l(data_table[-2][-1][2]), # l(RG3).0
                    bu.r(data_table[-2][-1][3]), # 0.r(RG2)
                    "0.r(RG2), l(RG3).0"
                ])

        return data_table, data_table[-1][-1][1]

    elif method == 4:
        # every table line has registers like so: RG1, RG3, RG2
        data_table = [[["0", "0"*(2*n+1), "0" + al(bin(y)[2:], n) + "0"*n, al(bin(x)[2:], n), "-"]]*2]

        # iteration number
        i = 0

        while int('0b' + data_table[-1][-1][3], 2) != 0:
            data_table.append([])
            i += 1

            if data_table[-2][-1][3][0] == "1":
                data_table[-1].append([
                    i,
                    al(bin(int("0b"+data_table[-2][-1][1], 2) + int("0b"+data_table[-2][-1][2], 2))[-(2*n+1):], 2*n+1), # RG1 + RG3
                    data_table[-2][-1][2],
                    data_table[-2][-1][3],
                    "RG1+RG3"
                ])

                data_table[-1].append([
                    i,
                    data_table[-1][-1][1],
                    '0' + data_table[-1][-1][2][:-1], # 0.r(RG3)
                    data_table[-1][-1][3][1:] + '0', # l(RG2).0
                    "0.r(RG3), l(RG2).0"
                ])

            else:
                data_table[-1].append([
                    i,
                    data_table[-2][-1][1],
                    '0' + data_table[-2][-1][2][:-1], # 0.r(RG3)
                    data_table[-2][-1][3][1:] + '0', # l(RG2).0
                    "0.r(RG3), l(RG2).0"
                ])

        return data_table, data_table[-1][-1][1][:-1]

def table_to_text(dt):
    from lib.prettytable import PrettyTable
    pt = PrettyTable()
    pt.field_names = ["Iteration", "RG1", "RG3", "RG2", "Operations"]

    for i in dt:
        for j in range(len(i)):
            if j+1 == len(i):
                pt.add_row(i[j], divider = True)
            else:
                pt.add_row(i[j])

    return pt.get_string()

if __name__ == "__main__":
    # a fully functional reference
    # implementation for this library
    # is provided below

    raw_x = input("X: ")
    raw_y = input("Y: ")

    if len(raw_x) == len(raw_y):
        n = len(raw_x)
    else:
        n = int(input("n: "))

    x = int("0b" + raw_x, 2)
    y = int("0b" + raw_y, 2)

    method = int(input("Method: "))

    dt, result = multiply(n, x, y, method)
    
    '''
    from lib.prettytable import PrettyTable
    pt = PrettyTable()
    pt.field_names = ["Iteration", "RG1", "RG3", "RG2", "Operations"]

    for i in dt:
        for j in range(len(i)):
            if j+1 == len(i):
                pt.add_row(i[j], divider = True)
            else:
                pt.add_row(i[j])

    print(pt)
    '''
    print(table_to_text(dt))
    print(f"Result: {result}")