from argparse import ArgumentParser
from .memory import translate_memory
from .arith_logic import translate_arith_logic
from .compare import translate_compare
from .utils import *


def vm_translate(input_path):
    # program name, for static variable labels
    input_fn = input_path.split("/")[-1]
    prog = input_fn[:-3] if input_fn.endswith(".vm") else input_fn

    try:
        input_file = open(input_path)
    except:
        exit_on_error(f"Cannot open input file: {input_fn}", EXIT_CODE_FILE_ERROR)

    # load all vm commands from file
    vm_cmds = []
    line = input_file.readline()
    while line:
        cmd = line.rstrip("\n").split("//", maxsplit=1)[0].strip()
        if cmd:
            vm_cmds.append(cmd)
        line = input_file.readline()

    input_file.close()

    asm = ""
    for cmd in vm_cmds:
        # tokenize vm_line, hand to sub-translators based on first token
        match cmd.split():
            case []:
                continue
            case [("push" | "pop") as action, segment, index]:
                asm += translate_memory(action, segment, index, prog)
            case [("add" | "sub" | "neg" | "and" | "or" | "not") as command]:
                asm += translate_arith_logic(command)
            case [("lt" | "eq" | "gt") as command]:
                asm += translate_compare(command)
            case _:
                exit_on_error(
                    f"Syntax error: invalid command: {cmd}", EXIT_CODE_SYNTAX_ERROR
                )

    output_path = (
        input_path[:-3] + ".asm" if input_path.endswith(".vm") else input_path + ".asm"
    )
    try:
        output_file = open(output_path, "w")
    except:
        exit_on_error(f"Cannot open output file: {output_fn}", EXIT_CODE_FILE_ERROR)

    output_file.write(asm)
    output_file.close()
    print(f"Assembly written to {output_path}")


if __name__ == "__main__":
    parser = ArgumentParser("hack-vm")
    parser.add_argument("input_path", help="input file in HACK VM")
    args = parser.parse_args()
    vm_translate(args.input_path)