"""
@author: Mateusz779
"""
pointer = 0
cell = []
code = ""


def main():
    """
    Main function
    """

    global code, cell, pointer
    code = input("Enter the code: ")
    print("\n\n")
    if code != "":
        for i in range(len(code)):
            interpreter(code[i], i)
    print("\n\n")

def interpreter(znak, i):
    """
    Brainfuck interpreter
    
    > increment the data pointer (to point to the next cell to the right).
    < decrement the data pointer (to point to the next cell to the left).
    + increment (increase by one) the byte at the data pointer.
    - decrement (decrease by one) the byte at the data pointer.
    . output the byte at the data pointer.
    , accept one byte of input, storing its value in the byte at the data pointer.
    [ if the byte at the data pointer is zero, then instead of
        moving the instruction pointer forward to the next command,
        jump it forward to the command after the matching ]
    ] if the byte at the data pointer is nonzero, then instead of moving
        the instruction pointer forward to the next command,
        jump it back to the command after the matching [.
    """

    global code, cell, pointer
    match znak:
        case ">":
            pointer += 1
            if(pointer > len(cell) - 1):
                cell.append(0)
        case "<":
            pointer -= 1
            if pointer < 0:
                pointer = 0
                cell.insert(0, 0)
        case "+":
            try:
                cell[pointer] += 1
            except:
                cell.append(0)
                cell[pointer] += 1
        case "-":
            try:
                cell[pointer] -= 1
                if cell[pointer] < 0:
                    cell[pointer] = 0
            except:
                cell.append(0)
        case ".":
            try:
                if cell[pointer] == 10 or cell[pointer] == 13:
                    print("\n")
                else:
                    print(chr(cell[pointer]), end="")
            except:
                cell.append(0)
                print(chr(cell[pointer]), end="")
        case ",":
            try:
                cell[pointer] = ord(input("Enter a character: "))
            except:
                cell.append(0)
                cell[pointer] = ord(input("Enter a character: "))
        case "[":
            try:
                loop_begin = i
                if cell[pointer] != 0:
                    loop_end = code.find("]", i)
                    for a in range(0, cell[pointer]-1):
                        for j in range(1, loop_end-loop_begin):
                            interpreter(code[loop_begin + j], loop_begin + j)
            except:
                cell.append(0)

if __name__ == '__main__':
    main()