from __future__ import annotations

import argparse
import json
from dataclasses import asdict
from pathlib import Path

import pandas as pd

from .analyzer import MacroLactoneAnalyzer
from .errors import MacrolactoneError
from .fragmenter import MacrolactoneFragmenter


def main() -> None:
    parser = build_parser()
    args = parser.parse_args()
    if not hasattr(args, "func"):
        parser.print_help()
        raise SystemExit(1)
    args.func(args)


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(prog="macro-lactone-toolkit")
    subparsers = parser.add_subparsers(dest="command")

    analyze = subparsers.add_parser("analyze")
    _add_common_input_arguments(analyze)
    analyze.add_argument("--ring-size", type=int, default=None)
    analyze.set_defaults(func=run_analyze)

    number = subparsers.add_parser("number")
    number.add_argument("--smiles", required=True)
    number.add_argument("--ring-size", type=int, default=None)
    number.set_defaults(func=run_number)

    fragment = subparsers.add_parser("fragment")
    _add_common_input_arguments(fragment)
    fragment.add_argument("--ring-size", type=int, default=None)
    fragment.add_argument("--parent-id", default=None)
    fragment.add_argument("--errors-output", default=None)
    fragment.set_defaults(func=run_fragment)

    return parser


def run_analyze(args: argparse.Namespace) -> None:
    analyzer = MacroLactoneAnalyzer()
    if args.smiles:
        payload = analyzer.analyze_molecule(args.smiles)
        _write_output(payload, args.output)
        return

    rows = _read_csv_rows(args.input, args.smiles_column, args.id_column)
    payload = []
    for row in rows:
        analysis = analyzer.analyze_molecule(row["smiles"])
        analysis["parent_id"] = row["parent_id"]
        payload.append(analysis)
    _write_output(payload, args.output)


def run_number(args: argparse.Namespace) -> None:
    fragmenter = MacrolactoneFragmenter(ring_size=args.ring_size)
    payload = fragmenter.number_molecule(args.smiles).to_dict()
    _write_json(payload, None)


def run_fragment(args: argparse.Namespace) -> None:
    fragmenter = MacrolactoneFragmenter(ring_size=args.ring_size)

    if args.smiles:
        result = fragmenter.fragment_molecule(args.smiles, parent_id=args.parent_id)
        _write_output(result.to_dict(), args.output)
        return

    rows = _read_csv_rows(args.input, args.smiles_column, args.id_column)
    fragment_rows: list[dict] = []
    error_rows: list[dict] = []

    for row in rows:
        try:
            result = fragmenter.fragment_molecule(row["smiles"], parent_id=row["parent_id"])
        except MacrolactoneError as exc:
            error_rows.append(
                {
                    "parent_id": row["parent_id"],
                    "smiles": row["smiles"],
                    "error_type": type(exc).__name__,
                    "error_message": str(exc),
                }
            )
            continue

        for fragment in result.fragments:
            fragment_rows.append(
                {
                    "parent_id": result.parent_id,
                    "ring_size": result.ring_size,
                    **fragment.to_dict(),
                }
            )

    if args.output:
        _write_output(fragment_rows, args.output)
    else:
        _write_json({"fragments": fragment_rows, "errors": error_rows}, None)

    if args.errors_output:
        _write_output(error_rows, args.errors_output)


def _add_common_input_arguments(parser: argparse.ArgumentParser) -> None:
    group = parser.add_mutually_exclusive_group(required=True)
    group.add_argument("--smiles")
    group.add_argument("--input")
    parser.add_argument("--smiles-column", default="smiles")
    parser.add_argument("--id-column", default="id")
    parser.add_argument("--output", default=None)


def _read_csv_rows(input_path: str, smiles_column: str, id_column: str) -> list[dict]:
    dataframe = pd.read_csv(input_path)
    rows = []
    for index, row in dataframe.iterrows():
        parent_id = row[id_column] if id_column in dataframe.columns else f"row_{index}"
        rows.append(
            {
                "parent_id": str(parent_id),
                "smiles": row[smiles_column],
            }
        )
    return rows


def _write_output(payload: list[dict] | dict, output_path: str | None) -> None:
    if output_path is None:
        _write_json(payload, None)
        return

    path = Path(output_path)
    if path.suffix.lower() == ".csv":
        dataframe = pd.DataFrame(payload)
        dataframe.to_csv(path, index=False)
        return

    _write_json(payload, path)


def _write_json(payload: list[dict] | dict, output_path: Path | None) -> None:
    text = json.dumps(payload, indent=2, ensure_ascii=False)
    if output_path is None:
        print(text)
    else:
        output_path.write_text(text + "\n", encoding="utf-8")


if __name__ == "__main__":
    main()