"""Compile a role selection plan into a small dependency graph."""
from __future__ import annotations

from typing import Any


def build_task_graph(selection_plan: dict[str, Any]) -> dict[str, Any]:
    selected = selection_plan.get("selected") or {}
    producers = []
    for group in ("owner", "contributors"):
        value = selected.get(group)
        items = value if isinstance(value, list) else ([value] if value else [])
        for item in items:
            producers.append(item["role-id"] if isinstance(item, dict) else str(item))
    reviewers = [item["role-id"] if isinstance(item, dict) else str(item)
                 for item in selected.get("reviewers", []) or []]
    nodes = []
    for role_id in producers:
        nodes.append({"task-id": f"produce:{role_id}", "role-id": role_id, "depends-on": []})
    producer_nodes = [node["task-id"] for node in nodes]
    for role_id in reviewers:
        nodes.append({"task-id": f"review:{role_id}", "role-id": role_id,
                      "depends-on": producer_nodes, "independent": True})
    if len(nodes) > 1:
        nodes.append({"task-id": "synthesize", "role-id": selection_plan.get("synthesis-role") or "OPS-ORCH",
                      "depends-on": [node["task-id"] for node in nodes], "reads": "projection-first"})
    return {"workflow-id": selection_plan.get("workflow-id"), "nodes": nodes}