""" Functions for working with Makefiles
"""
from pathlib import Path

from qmk.errors import NoSuchKeyboardError


def parse_rules_mk_file(file, rules_mk=None):
    """Turn a rules.mk file into a dictionary.

    Args:
        file: path to the rules.mk file
        rules_mk: already parsed rules.mk the new file should be merged with

    Returns:
        a dictionary with the file's content
    """
    if not rules_mk:
        rules_mk = {}

    file = Path(file)
    if file.exists():
        rules_mk_lines = file.read_text().split("\n")

        for line in rules_mk_lines:
            # Filter out comments
            if line.strip().startswith("#"):
                continue

            # Strip in-line comments
            if '#' in line:
                line = line[:line.index('#')].strip()

            if '=' in line:
                # Append
                if '+=' in line:
                    key, value = line.split('+=', 1)
                    if key.strip() not in rules_mk:
                        rules_mk[key.strip()] = value.strip()
                    else:
                        rules_mk[key.strip()] += ' ' + value.strip()
                # Set if absent
                elif "?=" in line:
                    key, value = line.split('?=', 1)
                    if key.strip() not in rules_mk:
                        rules_mk[key.strip()] = value.strip()
                else:
                    if ":=" in line:
                        line.replace(":", "")
                    key, value = line.split('=', 1)
                    rules_mk[key.strip()] = value.strip()

    return rules_mk


def get_rules_mk(keyboard):
    """ Get a rules.mk for a keyboard

    Args:
        keyboard: name of the keyboard

    Raises:
        NoSuchKeyboardError: when the keyboard does not exists

    Returns:
        a dictionary with the content of the rules.mk file
    """
    # Start with qmk_firmware/keyboards
    kb_path = Path.cwd() / "keyboards"
    # walk down the directory tree
    # and collect all rules.mk files
    kb_dir = kb_path / keyboard
    if kb_dir.exists():
        rules_mk = dict()
        for directory in Path(keyboard).parts:
            kb_path = kb_path / directory
            rules_mk_path = kb_path / "rules.mk"
            if rules_mk_path.exists():
                rules_mk = parse_rules_mk_file(rules_mk_path, rules_mk)
    else:
        raise NoSuchKeyboardError("The requested keyboard and/or revision does not exist.")

    return rules_mk