from __future__ import annotations

import json
from functools import lru_cache
from pathlib import Path
from typing import Iterable

from news_mcp.config import ENTITY_ALIASES_FILE

# Small, explicit canonical alias map.
# Keep this conservative and grow it only when a shorthand is clearly useful.
@lru_cache(maxsize=1)
def _alias_map() -> dict[str, str]:
    path = Path(ENTITY_ALIASES_FILE)
    if not path.exists():
        return {}
    try:
        raw = json.loads(path.read_text(encoding="utf-8"))
    except Exception:
        return {}
    out: dict[str, str] = {}
    if isinstance(raw, dict):
        for k, v in raw.items():
            if k and v:
                out[str(k).strip().lower()] = str(v).strip()
    return out


def _lookup_alias(key: str) -> str | None:
    return _alias_map().get(key)


def normalize_entity(value: str) -> str:
    key = str(value).strip().lower()
    if not key:
        return ""
    return _lookup_alias(key) or str(value).strip()


def normalize_query(value: str) -> str:
    return normalize_entity(value)


def normalize_entities(values: Iterable[str]) -> list[str]:
    out: list[str] = []
    seen: set[str] = set()
    for value in values or []:
        norm = normalize_entity(value)
        key = norm.lower()
        if not norm or key in seen:
            continue
        seen.add(key)
        out.append(norm)
    return out