"""Rover CLI wrapper for fetching subgraph SDL from Apollo GraphOS."""

import json
import subprocess


def list_subgraphs(graph_ref: str) -> list[str]:
    """List all subgraph names for a graph ref (e.g. 'my-graph@prod').

    Uses `rover subgraph list --format json` for reliable parsing.
    """
    result = subprocess.run(
        ['rover', 'subgraph', 'list', graph_ref, '--format', 'json'],
        capture_output=True,
        text=True,
    )
    if result.returncode != 0:
        raise RuntimeError(f'rover subgraph list failed:\n{result.stderr.strip()}')

    payload = json.loads(result.stdout)
    subgraphs = payload['data']['subgraphs']
    return sorted(s['name'] for s in subgraphs)


def fetch_subgraph_sdl(graph_ref: str, subgraph: str) -> str:
    """Fetch the deployed SDL for a single subgraph."""
    result = subprocess.run(
        ['rover', 'subgraph', 'fetch', graph_ref, '--name', subgraph],
        capture_output=True,
        text=True,
    )
    if result.returncode != 0:
        raise RuntimeError(f'rover subgraph fetch failed for {subgraph}:\n{result.stderr.strip()}')

    sdl = result.stdout
    if not sdl.strip():
        raise RuntimeError(f'rover returned empty SDL for {subgraph}')

    return sdl