"""Contracts for curated external mappings and released baseline outputs."""

from __future__ import annotations

from pathlib import Path

import numpy as np
import pandas as pd
import torch

from .data import require_columns


GOLD_COLUMNS = (
    "bgc_id",
    "product_group_id",
    "product_id",
    "mibig_reference_id",
    "genus",
    "source",
)


def validate_gold_mapping(mapping: pd.DataFrame) -> None:
    require_columns(mapping, GOLD_COLUMNS, "external gold mapping")
    if mapping["bgc_id"].duplicated().any():
        raise ValueError("External BGC IDs must be unique")
    if mapping[list(GOLD_COLUMNS)].isna().any().any():
        raise ValueError("Primary gold mapping fields may not be null")
    if (mapping["product_group_id"].astype(str).str.len() == 0).any():
        raise ValueError("Product group IDs may not be empty")


def quarantine_external_reference_overlap(
    training_assignments: pd.DataFrame,
    external_mapping: pd.DataFrame,
) -> tuple[pd.DataFrame, pd.DataFrame]:
    """Exclude training pseudo-labels linked to external MIBiG references."""
    validate_gold_mapping(external_mapping)
    require_columns(training_assignments, ["mibig_reference_id", "split"], "training assignments")
    external_references = set(external_mapping["mibig_reference_id"].astype(str))
    overlap = training_assignments["mibig_reference_id"].astype(str).isin(external_references)
    quarantined = training_assignments[overlap].copy()
    filtered = training_assignments[~overlap].copy()
    if set(filtered.loc[filtered["split"] == "train", "mibig_reference_id"]).intersection(
        external_references
    ):
        raise AssertionError("External reference leakage remains after quarantine")
    return filtered, quarantined


def cross_genus_subset(mapping: pd.DataFrame, training_genera: set[str]) -> pd.DataFrame:
    validate_gold_mapping(mapping)
    normalized = {value.strip().lower() for value in training_genera}
    return mapping[~mapping["genus"].astype(str).str.strip().str.lower().isin(normalized)].copy()


def load_released_embeddings(path: str | Path) -> dict[str, torch.Tensor]:
    """Load BGC-MLM or other released embeddings from an ID-keyed NPZ file."""
    archive = np.load(path, allow_pickle=False)
    if "bgc_ids" not in archive or "embeddings" not in archive:
        raise ValueError("Released embedding NPZ requires 'bgc_ids' and 'embeddings' arrays")
    identifiers = archive["bgc_ids"].astype(str)
    embeddings = archive["embeddings"]
    if embeddings.ndim != 2 or len(identifiers) != len(embeddings):
        raise ValueError("Released embedding arrays have inconsistent shapes")
    return {
        identifier: torch.tensor(vector, dtype=torch.float32)
        for identifier, vector in zip(identifiers, embeddings)
    }


def load_bigscape_edges(path: str | Path) -> pd.DataFrame:
    """Load a normalized BiG-SCAPE edge export without calling it Pfam Jaccard."""
    edges = pd.read_csv(path)
    require_columns(edges, ["record_a", "record_b", "similarity"], "BiG-SCAPE edges")
    if ((edges["similarity"] < 0) | (edges["similarity"] > 1)).any():
        raise ValueError("BiG-SCAPE similarities must be in [0, 1]")
    return edges