#!/usr/bin/env python3
"""Cut a release for Moon Household Budget.

Usage:
    python release.py <version> "<change 1>" "<change 2>" ... \\
        [--title "Short title"] [--date YYYY-MM-DD]

Prepends a new entry to changelog.json (the single source of truth that drives
__version__, the footer version chip, and the /changelog page) and regenerates
CHANGELOG.md to match.

Versioning: semver-ish — bump the patch (0.1.0 -> 0.1.1) for fixes, the minor
(0.1.0 -> 0.2.0) for new features. Run this for EVERY deploy (see CLAUDE.md).
"""
import json
import os
import sys
from datetime import date

HERE = os.path.dirname(os.path.abspath(__file__))
CHANGELOG_JSON = os.path.join(HERE, "changelog.json")
CHANGELOG_MD = os.path.join(HERE, "CHANGELOG.md")


def load():
    try:
        with open(CHANGELOG_JSON) as f:
            return json.load(f)
    except (OSError, json.JSONDecodeError):
        return []


def render_md(data):
    lines = [
        "# Changelog",
        "",
        "All notable changes to Moon Household Budget. Newest first.",
        "Generated from changelog.json by release.py — do not edit by hand.",
        "",
    ]
    for rel in data:
        head = f"## {rel['version']} — {rel.get('date', '')}"
        if rel.get("title"):
            head += f" — {rel['title']}"
        lines += [head, ""]
        lines += [f"- {c}" for c in rel.get("changes", [])]
        lines.append("")
    return "\n".join(lines)


def main(argv):
    if len(argv) < 2:
        print(__doc__)
        return 1

    version = argv[1]
    title, rel_date, changes = "", date.today().isoformat(), []
    i = 2
    while i < len(argv):
        if argv[i] == "--title" and i + 1 < len(argv):
            title = argv[i + 1]; i += 2
        elif argv[i] == "--date" and i + 1 < len(argv):
            rel_date = argv[i + 1]; i += 2
        else:
            changes.append(argv[i]); i += 1

    if not changes:
        print("error: provide at least one change bullet")
        return 1

    data = load()
    if data and data[0].get("version") == version:
        print(f"error: version {version} is already the latest entry")
        return 1

    entry = {"version": version, "date": rel_date}
    if title:
        entry["title"] = title
    entry["changes"] = changes
    data.insert(0, entry)

    with open(CHANGELOG_JSON, "w") as f:
        json.dump(data, f, indent=2)
        f.write("\n")
    with open(CHANGELOG_MD, "w") as f:
        f.write(render_md(data))

    print(f"released v{version} ({rel_date}) with {len(changes)} change(s)")
    print("  -> changelog.json + CHANGELOG.md updated. Now commit + deploy.")
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))