#!/usr/bin/env python3
from argparse import ArgumentParser
from dataclasses import dataclass
from pathlib import Path

@dataclass
class Version:
    major: int = 1
    minor: int = 0
    patch: int = 0

    def __str__(self):
        return f"{self.major}.{self.minor}.{self.patch}"

    def __init__(self, version_str: str):
        try:
            match list(map(int, version_str.split("."))):
                case [major, minor, patch]:
                    self.major, self.minor, self.patch = major, minor, patch
                    return
                case _:
                    raise ValueError("Version file must contain 3 parts (SemVer)!")
        except ValueError as e:
            raise ValueError(f"Version must contain numbers only!") from e

def parse_args():
    parser = ArgumentParser("build.py", description="Docker multi-arch build helper.")
    version_group = parser.add_mutually_exclusive_group()
    version_group.add_argument("--major", "-m", action="store_true", help="Increase the major version before building.")
    version_group.add_argument("--minor", "-n", action="store_true", help="Increase the minor version before building.")
    version_group.add_argument("--patch", "-p", action="store_true", help="Increase the patch version before building.")
    parser.add_argument("--file", "-f", type=str, default="version.txt", help="File to store the current version in.")
    return parser.parse_args()

def save_version(version_file: Path, version: Version):
    with version_file.open("w", encoding="utf-8") as f:
        f.write(str(version))

def load_version(version_file: Path):
    try:
        with version_file.open("r", encoding="utf-8") as f:
            return Version(f.read().strip())
    except FileNotFoundError:
        return Version()

def main():
    args = parse_args()
    version_file = Path(args.file)
    version = load_version(version_file)
    save_version(version_file, version)

if __name__ == '__main__':
    main()