#!/usr/bin/env python3
"""Decide whether a rebuild is needed.

The build bundles its own R plus every non-system library it links against, so
Arch moving `r`, `icu`, `jsoncpp` and friends cannot affect an installed JASP and
must not trigger a rebuild — republishing costs every user a ~1.7 GB download.

What is left is Qt6, which stays a system dependency. Qt guarantees binary
compatibility across Qt 6 minor releases, so only a *major* Qt transition
warrants a rebuild.

Writes GITHUB_OUTPUT-style key=value pairs to stdout (and to $GITHUB_OUTPUT).
"""

import json
import os
import sys
import urllib.request

STATE_FILE = "state.json"
GH_LATEST = "https://api.github.com/repos/jasp-stats/jasp-desktop/releases/latest"
# No repo filter: icu lives in core while qt6-base lives in extra, and pinning
# the wrong repo silently returns zero results and disables the trigger.
ARCH_PKG = "https://archlinux.org/packages/search/json/?name={}"


def fetch_json(url: str) -> dict:
    req = urllib.request.Request(url, headers={"User-Agent": "jasp-desktop-bin-ci"})
    with urllib.request.urlopen(req, timeout=30) as r:
        return json.load(r)


def arch_version(pkg: str) -> str:
    results = fetch_json(ARCH_PKG.format(pkg)).get("results", [])
    # Ignore staging/testing/kde-unstable: users are on the stable repos.
    stable = [r for r in results if r["repo"] in ("core", "extra")]
    if not stable:
        raise RuntimeError(f"package {pkg} not found in Arch core/extra")
    return stable[0]["pkgver"]


def minor(version: str) -> str:
    return ".".join(version.split(".")[:2])


def main() -> int:
    forced = os.environ.get("FORCE_BUILD", "").lower() == "true"
    pinned_tag = os.environ.get("JASP_TAG", "").strip()

    jasp_tag = pinned_tag or fetch_json(GH_LATEST)["tag_name"]
    qt_version = arch_version("qt6-base")
    qt_major = qt_version.split(".")[0]
    qt_minor = minor(qt_version)

    try:
        state = json.loads(open(STATE_FILE).read())
    except FileNotFoundError:
        state = {}

    reasons = []
    if forced:
        reasons.append("manually forced")
    if state.get("jasp_tag") != jasp_tag:
        reasons.append(f"JASP {state.get('jasp_tag', 'none')} -> {jasp_tag}")
    if state.get("qt6_major") != qt_major:
        reasons.append(f"Qt major {state.get('qt6_major', 'none')} -> {qt_major}")

    needs_build = bool(reasons)

    print(f"jasp_tag  = {jasp_tag}")
    print(f"qt        = {qt_version} (major {qt_major})")
    print(f"decision  = {'BUILD' if needs_build else 'up to date'}")
    for reason in reasons:
        print(f"  reason: {reason}")
    if not needs_build:
        print("  (Qt minor bumps are binary-compatible and everything else is bundled)")

    out = os.environ.get("GITHUB_OUTPUT")
    if out:
        with open(out, "a") as fh:
            fh.write(f"needs_build={'true' if needs_build else 'false'}\n")
            fh.write(f"jasp_tag={jasp_tag}\n")
            fh.write(f"qt6_major={qt_major}\n")
            fh.write(f"qt6_minor={qt_minor}\n")
            fh.write(f"reasons={'; '.join(reasons)}\n")
    return 0


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