from __future__ import annotations

import random
from functools import lru_cache
from typing import Any

import pandas as pd

from fleurs_cache import load_fleurs_table
from language import ALL_LANGS, LANG_ISO2_TO_ISO3
from sentence_sampling import sample_multi_group_bundle
from sib200_cache import load_sib200_table
from tatoeba import load_tatoeba_table


ADVERSE_FAMILY_LANGS: dict[str, tuple[str, ...]] = {
    "NordicLatin": ("sv", "no", "da", "is", "fi"),
    "BalticLatin": ("lv", "lt", "et"),
    "IberianRomance": ("es", "pt", "ca", "gl", "oc"),
    "ItaloRomance": ("it", "ro", "mt", "rm"),
    "FrenchLatin": ("fr", "oc"),
    "GermanicLatin": ("de", "nl", "af", "lb"),
    "PeripheralLatin": ("eu", "ku", "uz", "so", "su", "jv"),
    # Real confusion clusters from validation.
    "SouthSlavicLatin": ("bs", "hr", "sr"),
    "Malayic": ("id", "ms"),
    "Nguni": ("xh", "zu"),
    "CyrillicSlavic": ("ru", "uk", "be", "bg", "mk"),
    "CyrillicCentralAsian": ("kk", "mn", "tt", "ky", "tg", "ba", "ce"),
    "Arabic": ("ar", "fa", "ps", "sd", "ug", "ur", "ckb"),
    "IndicDevanagari": ("hi", "mr", "ne"),
    "IndicBengali": ("bn", "as"),
    "IndicSouth": ("ta", "te", "gu", "kn", "ml", "pa", "or"),
    "CJK": ("zh", "ja"),
    "Hebrew": ("he", "yi"),
    "English": ("en", "sco"),
}


def _normalize_text_key(text: str) -> str:
    return " ".join(str(text or "").split()).casefold().strip()


def _column_or_default(frame: pd.DataFrame, column: str, default: Any) -> pd.Series:
    if column in frame.columns:
        return frame[column]
    return pd.Series([default] * len(frame), index=frame.index)


def _standardize_frame(frame: pd.DataFrame, *, source: str) -> pd.DataFrame:
    if frame.empty:
        return pd.DataFrame()

    if source == "fleurs":
        standardized = frame.copy()
        standardized["source"] = source
        standardized["lang_iso2"] = _column_or_default(standardized, "model_lang", "").astype(str).str.strip()
        standardized["source_lang"] = _column_or_default(standardized, "source_lang", "").astype(str).str.strip()
        standardized["lang_iso3"] = _column_or_default(standardized, "lang_iso3", "").astype(str).str.strip()
        standardized["lang_iso3"] = standardized["lang_iso3"].where(standardized["lang_iso3"].ne(""), standardized["lang_iso2"].map(lambda lang: LANG_ISO2_TO_ISO3.get(lang, "")))
        standardized["split"] = _column_or_default(standardized, "split", "").astype(str).str.strip()
        standardized["example_id"] = pd.to_numeric(_column_or_default(standardized, "id", -1), errors="coerce").fillna(-1).astype(int)
        standardized["topic"] = ""
        standardized["label"] = -1
        return standardized.loc[:, ["source", "source_lang", "lang_iso2", "lang_iso3", "text", "split", "example_id", "topic", "label"]].copy()

    if source == "tatoeba":
        standardized = frame.copy()
        standardized["source"] = source
        standardized["source_lang"] = _column_or_default(standardized, "source_lang", "").astype(str).str.strip()
        standardized["lang_iso2"] = standardized["source_lang"]
        standardized["lang_iso3"] = _column_or_default(standardized, "lang_iso3", "").astype(str).str.strip()
        standardized["lang_iso3"] = standardized["lang_iso3"].where(standardized["lang_iso3"].ne(""), standardized["lang_iso2"].map(lambda lang: LANG_ISO2_TO_ISO3.get(lang, "")))
        standardized["split"] = ""
        standardized["example_id"] = pd.to_numeric(_column_or_default(standardized, "id", -1), errors="coerce").fillna(-1).astype(int)
        standardized["topic"] = ""
        standardized["label"] = -1
        return standardized.loc[:, ["source", "source_lang", "lang_iso2", "lang_iso3", "text", "split", "example_id", "topic", "label"]].copy()

    if source == "sib200":
        standardized = frame.copy()
        standardized["source"] = source
        standardized["source_lang"] = _column_or_default(standardized, "source_lang", "").astype(str).str.strip()
        standardized["lang_iso2"] = _column_or_default(standardized, "lang_iso2", "").astype(str).str.strip()
        standardized["lang_iso3"] = _column_or_default(standardized, "lang_iso3", "").astype(str).str.strip()
        standardized["lang_iso3"] = standardized["lang_iso3"].where(standardized["lang_iso3"].ne(""), standardized["lang_iso2"].map(lambda lang: LANG_ISO2_TO_ISO3.get(lang, "")))
        standardized["split"] = _column_or_default(standardized, "split", "").astype(str).str.strip()
        standardized["example_id"] = pd.to_numeric(_column_or_default(standardized, "index_id", -1), errors="coerce").fillna(-1).astype(int)
        standardized["topic"] = _column_or_default(standardized, "topic", "").astype(str).str.strip()
        standardized["label"] = pd.to_numeric(_column_or_default(standardized, "label", -1), errors="coerce").fillna(-1).astype(int)
        return standardized.loc[:, ["source", "source_lang", "lang_iso2", "lang_iso3", "text", "split", "example_id", "topic", "label"]].copy()

    raise RuntimeError(f"Unsupported source: {source}")


@lru_cache(maxsize=1)
def _load_adverse_pool() -> pd.DataFrame:
    frames: list[pd.DataFrame] = []
    source_loaders = (
        ("fleurs", load_fleurs_table),
        ("tatoeba", load_tatoeba_table),
        ("sib200", load_sib200_table),
    )
    for source, loader in source_loaders:
        try:
            source_frame = loader()
        except FileNotFoundError:
            continue
        standardized = _standardize_frame(source_frame, source=source)
        if not standardized.empty:
            frames.append(standardized)

    if not frames:
        raise RuntimeError("No cached sources were available for adverse mixes.")

    combined = pd.concat(frames, ignore_index=True)
    combined = combined[combined["text"].astype(str).str.strip().ne("")]
    combined = combined[combined["lang_iso2"].isin(ALL_LANGS)]
    combined["text_key"] = combined["text"].astype(str).map(_normalize_text_key)
    combined = combined[combined["text_key"].ne("")].drop_duplicates(subset=["lang_iso2", "text_key"], keep="first")
    return combined.reset_index(drop=True)


def _family_candidates(frame: pd.DataFrame) -> dict[str, tuple[str, ...]]:
    available_langs = set(frame["lang_iso2"].dropna().astype(str).tolist())
    families: dict[str, tuple[str, ...]] = {}
    for family, langs in ADVERSE_FAMILY_LANGS.items():
        candidates = tuple(lang for lang in langs if lang in available_langs)
        if len(candidates) >= 2:
            families[family] = candidates
    return families


def _bundle_row(row: pd.Series) -> dict[str, Any]:
    return {
        "text": str(row.get("text", "")).strip(),
        "raw_text": str(row.get("text", "")).strip(),
        "source": str(row.get("source", "adverse-mix")).strip(),
        "source_lang": str(row.get("source_lang", "")).strip(),
        "lang_iso2": str(row.get("lang_iso2", "")).strip(),
        "lang_iso3": str(row.get("lang_iso3", "")).strip(),
        "language": str(row.get("source_lang", row.get("lang_iso2", ""))).strip(),
        "split": str(row.get("split", "")).strip(),
        "example_id": int(row.get("example_id", -1)) if str(row.get("example_id", "-1")).strip().lstrip("-").isdigit() else -1,
        "topic": str(row.get("topic", "")).strip(),
        "label": int(row.get("label", -1)) if str(row.get("label", "-1")).strip().lstrip("-").isdigit() else -1,
    }


def fetch_random_adverse_mix() -> dict[str, Any]:
    frame = _load_adverse_pool()
    families = _family_candidates(frame)
    if not families:
        raise RuntimeError("No adverse language families had at least two available languages.")

    family, langs = random.choice(list(families.items()))
    bundle = sample_multi_group_bundle(
        frame,
        group_column="lang_iso2",
        row_to_sentence=_bundle_row,
        min_groups=2,
        max_groups=min(3, len(langs)),
        min_sentences_per_group=1,
        max_sentences_per_group=1,
        allowed_groups=set(langs),
    )
    return {
        **bundle,
        "source": "adverse-mix",
        "family": family,
        "family_langs": list(langs),
    }