from __future__ import annotations

import pandas as pd
import pytest

from macro_lactone_toolkit.validation.fragment_library_analysis import (
    build_position_diversity_table,
    count_non_dummy_atoms,
)


def test_count_non_dummy_atoms_excludes_dummy_atoms() -> None:
    assert count_non_dummy_atoms("*O") == 1
    assert count_non_dummy_atoms("*C") == 1
    assert count_non_dummy_atoms("*C(C)C") == 3


def test_build_position_diversity_table_combines_frequency_and_structure_metrics() -> None:
    dataframe = pd.DataFrame(
        [
            {"cleavage_position": 3, "fragment_smiles_plain": "*C"},
            {"cleavage_position": 3, "fragment_smiles_plain": "*CC"},
            {"cleavage_position": 3, "fragment_smiles_plain": "*CC"},
            {"cleavage_position": 3, "fragment_smiles_plain": "*O"},
            {"cleavage_position": 4, "fragment_smiles_plain": "*C"},
        ]
    )

    summary = build_position_diversity_table(dataframe).set_index("cleavage_position")

    assert summary.loc[3, "total_fragments"] == 4
    assert summary.loc[3, "unique_fragments"] == 3
    assert summary.loc[3, "normalized_unique_ratio"] == pytest.approx(0.75)
    assert summary.loc[3, "shannon_entropy"] > 0.0
    assert summary.loc[3, "normalized_shannon_entropy"] > 0.0
    assert summary.loc[3, "mean_pairwise_tanimoto_distance"] > 0.0

    assert summary.loc[4, "total_fragments"] == 1
    assert summary.loc[4, "unique_fragments"] == 1
    assert summary.loc[4, "mean_pairwise_tanimoto_distance"] == 0.0