import json
from pathlib import Path
from typing import Union

from .graph_models import FlowGraph, Node, Edge


def load_flow(path: Union[str, Path]) -> FlowGraph:
    path = Path(path)
    if not path.exists():
        raise FileNotFoundError(path)

    data = json.load(path.open("r", encoding="utf-8"))
    nodes = [Node(**n) for n in data.get("nodes", [])]
    edges = [Edge(**e) for e in data.get("edges", [])]
    return FlowGraph(nodes=nodes, edges=edges)


def save_flow(flow: FlowGraph, path: Union[str, Path]) -> None:
    path = Path(path)
    data = {
        "nodes": [n.__dict__ for n in flow.nodes],
        "edges": [e.__dict__ for e in flow.edges],
    }
    path.write_text(json.dumps(data, indent=2), encoding="utf-8")