"""Tätigkeitsnachweis-Generator – Konfigurations-Loader."""

import configparser
import json
import fnmatch
from pathlib import Path
from typing import Optional

from .models import AppConfig, FieldSchema, OutputMapping


def load_settings(config_dir: Path, project_root: Path) -> AppConfig:
    """Lädt settings.ini und gibt ein AppConfig-Objekt zurück."""
    ini_path = config_dir / "settings.ini"
    if not ini_path.exists():
        raise FileNotFoundError(f"settings.ini nicht gefunden: {ini_path}")

    parser = configparser.ConfigParser()
    parser.read(ini_path, encoding="utf-8")

    paths = parser["paths"] if "paths" in parser else {}
    output = parser["output"] if "output" in parser else {}
    parsing = parser["parsing"] if "parsing" in parser else {}

    return AppConfig(
        input_dir=str(project_root / paths.get("input_dir", "input")),
        template_dir=str(project_root / paths.get("template_dir", "template")),
        output_dir=str(project_root / paths.get("output_dir", "output")),
        filename_pattern=output.get("filename_pattern", "{last_name}_{first_name}_Tätigkeitsnachweis.xlsx"),
        month_sheet_pattern=parsing.get("month_sheet_pattern", "* 20??"),
        skip_empty_name=parsing.getboolean("skip_empty_name", True),
        skip_empty_antragsnummer=parsing.getboolean("skip_empty_antragsnummer", True),
    )


def load_input_schema(config_dir: Path) -> list[FieldSchema]:
    """Lädt input-fields.json."""
    schema_path = config_dir / "input-fields.json"
    if not schema_path.exists():
        raise FileNotFoundError(f"input-fields.json nicht gefunden: {schema_path}")

    with open(schema_path, "r", encoding="utf-8") as f:
        data = json.load(f)

    return [FieldSchema(**item) for item in data]


def load_output_mapping(config_dir: Path) -> list[OutputMapping]:
    """Lädt output-fields.json."""
    mapping_path = config_dir / "output-fields.json"
    if not mapping_path.exists():
        raise FileNotFoundError(f"output-fields.json nicht gefunden: {mapping_path}")

    with open(mapping_path, "r", encoding="utf-8") as f:
        data = json.load(f)

    return [OutputMapping(**item) for item in data]


def get_available_files(directory: Path, extension: str = ".xlsx") -> list[str]:
    """Listet alle Dateien mit der angegebenen Erweiterung im Verzeichnis auf."""
    if not directory.exists():
        return []
    files = sorted(
        f.name for f in directory.iterdir()
        if f.is_file() and f.suffix.lower() == extension and not f.name.startswith("~")
    )
    return files


def get_available_input_files(config: AppConfig) -> list[str]:
    """Listet alle .xlsx-Dateien im input-Ordner."""
    return get_available_files(Path(config.input_dir))


def get_available_templates(config: AppConfig) -> list[str]:
    """Listet alle .xlsx-Dateien im template-Ordner."""
    return get_available_files(Path(config.template_dir))


def is_month_sheet(sheet_name: str, pattern: str) -> bool:
    """Prüft, ob ein Sheet-Name dem Monatsmuster entspricht."""
    return fnmatch.fnmatch(sheet_name.strip(), pattern)