#!/usr/bin/env python3
"""Check reef binding files against authoritative sibling declarations."""

from __future__ import annotations

import argparse
import json
from pathlib import Path

import yaml


def load_yaml(path: Path) -> dict:
    value = yaml.safe_load(path.read_text(encoding="utf-8"))
    if not isinstance(value, dict):
        raise ValueError(f"{path}: expected a YAML mapping")
    return value


def ids(items: object, key: str) -> set[str]:
    if not isinstance(items, list):
        return set()
    return {
        item[key]
        for item in items
        if isinstance(item, dict) and isinstance(item.get(key), str)
    }


def expected_rapps(parent: Path, reef_id: str) -> set[str]:
    result: set[str] = set()
    for declaration_path in sorted(parent.glob("rapp-*/declarations/rapp.yaml")):
        declaration = load_yaml(declaration_path)
        if reef_id in declaration.get("bound_reefs", []):
            result.add(str(declaration["rapp_id"]))
    return result


def expected_rails(parent: Path, declared: list[str]) -> set[str]:
    result: set[str] = set()
    for rail_id in declared:
        declaration_path = parent / rail_id / "declarations" / "rail.yaml"
        declaration = load_yaml(declaration_path)
        result.add(str(declaration["rail_id"]))
    return result


def assess(repo: Path, parent: Path) -> list[str]:
    reef = load_yaml(repo / "declarations" / "reef.yaml")
    reef_id = str(reef["reef_id"])
    rapp_bindings = load_yaml(repo / "bindings" / "rapps.yaml")
    rail_bindings = load_yaml(repo / "bindings" / "rails.yaml")

    actual_rapps = ids(rapp_bindings.get("bound_rapps"), "rapp_id")
    derived_rapps = expected_rapps(parent, reef_id)
    actual_rails = ids(rail_bindings.get("hosted_rails"), "rail_id")
    derived_rails = expected_rails(parent, list(reef.get("hosted_rails", [])))

    failures: list[str] = []
    if actual_rapps != derived_rapps:
        failures.append(
            f"rapp projection differs: binding={sorted(actual_rapps)}, "
            f"derived={sorted(derived_rapps)}"
        )
    if actual_rails != derived_rails:
        failures.append(
            f"rail projection differs: binding={sorted(actual_rails)}, "
            f"declared={sorted(derived_rails)}"
        )
    return failures


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--repo", type=Path, default=Path(__file__).parents[1])
    parser.add_argument("--parent", type=Path)
    args = parser.parse_args()
    repo = args.repo.resolve()
    parent = (args.parent or repo.parent).resolve()
    failures = assess(repo, parent)
    print(json.dumps({"pass": not failures, "failures": failures}))
    return bool(failures)


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