#!/usr/bin/env python3
"""Fail-closed validation for a multiplayer promotion evidence report."""

import json
import sys
from typing import Any


STAGES = ("development", "internal", "casual-canary", "casual", "provisional-ranked", "ranked")


def _required_true(report: dict[str, Any], key: str) -> None:
    value: Any = report
    for part in key.split("."):
        if not isinstance(value, dict) or part not in value:
            raise ValueError(f"missing gate: {key}")
        value = value[part]
    if value is not True:
        raise ValueError(f"gate did not pass: {key}")


def validate_release_report(report: dict[str, Any]) -> tuple[str, str]:
    if not isinstance(report, dict):
        raise ValueError("release report must be an object")
    source = report.get("from_stage")
    target = report.get("to_stage")
    if source not in STAGES or target not in STAGES:
        raise ValueError("from_stage and to_stage must be known release stages")
    if STAGES.index(target) != STAGES.index(source) + 1:
        raise ValueError(f"promotion must advance exactly one stage: {source!r} -> {target!r}")
    if not isinstance(report.get("release_id"), str) or not report["release_id"].strip():
        raise ValueError("release_id is required")
    for gate in (
        "slo_passed", "security_passed", "cost_passed", "rollback_rehearsed",
        "playtests.eu_passed", "playtests.na_passed", "legacy.phase6_passed",
        "legacy.enet_passed",
    ):
        _required_true(report, gate)
    return source, target


def main() -> int:
    if len(sys.argv) != 2:
        print(f"usage: {sys.argv[0]} report.json", file=sys.stderr)
        return 2
    try:
        with open(sys.argv[1], encoding="utf-8") as handle:
            source, target = validate_release_report(json.load(handle))
    except (OSError, ValueError, json.JSONDecodeError) as error:
        print(f"release gate failed: {error}", file=sys.stderr)
        return 1
    print(f"release gate passed: {source} -> {target}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())