import json
from functools import lru_cache
from pathlib import Path


CATALOG = Path(__file__).resolve().parent / "public/topics/methods.json"
FIELDS = {
    "credit_granularity": "credit_granularity",
    "required_supervision": "required_supervision",
    "learned_value_critic": "learned_value_critic",
    "evaluation_setting": "evaluation_settings",
}


@lru_cache(maxsize=1)
def method_catalog():
    return json.loads(CATALOG.read_text())


def values(method, facet):
    entries = method[FIELDS[facet]]
    if facet == "learned_value_critic":
        return {entries["value"]}
    return {entry["value"] for entry in entries}


def list_method_facets() -> dict:
    """List exact filter values for agent RL credit granularity, supervision, value critics and evaluation settings. Each value reports its source-supported method count."""
    catalog = method_catalog()
    return {
        "scope": catalog["scope"],
        "method_count": len(catalog["methods"]),
        "facets": {
            name: {
                **definition,
                "counts": {
                    value: sum(value in values(method, name) for method in catalog["methods"])
                    for value in definition["values"]
                },
            }
            for name, definition in catalog["facet_definitions"].items()
        },
        "matching": "Exact membership within each facet; AND across supplied facets. Empty filters are unrestricted. Unknown is distinct from yes and no.",
    }


def filter_methods(
    credit_granularity: str = "",
    required_supervision: str = "",
    learned_value_critic: str = "",
    evaluation_setting: str = "",
) -> dict:
    """Filter agent RL credit-assignment methods by research conditions and return original section evidence and BibTeX. Discover accepted values with list_method_facets. Filters combine with AND; empty strings leave a facet unrestricted. Unknown critic status never matches no. Results use publication order without a relevance or quality ranking."""
    catalog = method_catalog()
    filters = {
        "credit_granularity": credit_granularity,
        "required_supervision": required_supervision,
        "learned_value_critic": learned_value_critic,
        "evaluation_setting": evaluation_setting,
    }
    selected = {name: value for name, value in filters.items() if value}
    for name, value in selected.items():
        accepted = catalog["facet_definitions"][name]["values"]
        if value not in accepted:
            raise ValueError(f"Unsupported {name}: {value}. Accepted values: {accepted}")
    results = [
        method for method in catalog["methods"]
        if all(value in values(method, name) for name, value in selected.items())
    ]
    return {"scope": catalog["scope"], "filters": selected, "catalog_size": len(catalog["methods"]), "count": len(results), "results": results}