#!/usr/bin/env python3
"""Use VERSION as the single source for frontend release metadata."""

import argparse
from pathlib import Path
import re


VERSION_FILE = Path("VERSION")
CHART_FILE = Path("deploy/helm/ai-spel-frontend/Chart.yaml")
SEMVER = re.compile(r"^(\d+)\.(\d+)\.(\d+)$")


def read_version() -> str:
    version = VERSION_FILE.read_text().strip()
    if not SEMVER.fullmatch(version):
        raise SystemExit(f"Invalid semantic version in {VERSION_FILE}: {version}")
    return version


def update_one(contents: str, pattern: str, replacement: str, description: str) -> str:
    updated, count = re.subn(pattern, replacement, contents, count=1, flags=re.MULTILINE)
    if count != 1:
        raise SystemExit(f"Expected one {description} in {CHART_FILE}, found {count}")
    return updated


def check(version: str) -> str:
    chart = CHART_FILE.read_text()
    chart_version = re.findall(r"(?m)^version:\s*(\S+)\s*$", chart)
    app_version = re.findall(r'(?m)^appVersion:\s*"(\S+)"\s*$', chart)
    if chart_version != [version] or app_version != [version]:
        raise SystemExit(
            f"Version drift: VERSION={version}, chart version={chart_version}, "
            f"appVersion={app_version}"
        )
    return version


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--check", action="store_true", help="verify metadata without editing")
    args = parser.parse_args()

    current = check(read_version())
    if args.check:
        print(current)
        return

    major, minor, patch = map(int, current.split("."))
    next_version = f"{major}.{minor}.{patch + 1}"
    chart = CHART_FILE.read_text()
    chart = update_one(
        chart,
        r"(?m)^version:\s*" + re.escape(current) + r"\s*$",
        f"version: {next_version}",
        "chart version",
    )
    chart = update_one(
        chart,
        r'(?m)^appVersion:\s*"' + re.escape(current) + r'"\s*$',
        f'appVersion: "{next_version}"',
        "chart appVersion",
    )
    VERSION_FILE.write_text(f"{next_version}\n")
    CHART_FILE.write_text(chart)
    print(next_version)


if __name__ == "__main__":
    main()