import click
from datetime import datetime
import pathlib
import sys
import shutil
import pandas as pd
import warnings
import re

from PyPDFForm import FormWrapper, PdfWrapper

warnings.filterwarnings("ignore")

Pathlike = pathlib.Path | str

WINHOME = pathlib.Path("/mnt/c/Users/Holgi/")
DESKTOP = WINHOME / "Desktop"

TODAY = datetime.now().strftime("%Y-%m-%d")


def _iso_date_to_german(date: str) -> str:
    return ".".join(reversed(date.split("-")))


def _search_files(
    folder: Pathlike, partial_name: str, suffix: str
) -> list[pathlib.Path]:
    parent = pathlib.Path(folder)
    if not suffix.startswith("."):
        suffix = f".{suffix}"
    files = (item for item in parent.iterdir() if item.is_file())
    non_hidden = (item for item in files if not item.stem.startswith("."))
    non_tempfile = (item for item in files if not item.stem.startswith("~"))
    types = (
        item for item in non_tempfile if item.suffix.lower() == suffix.lower()
    )
    return [item for item in types if partial_name.lower() in item.stem.lower()]


def _get_latest_file(
    folder: Pathlike, partial_name: str, suffix: str
) -> pathlib.Path | None:
    results = _search_files(folder, partial_name, suffix)
    if not results:
        return None
    creation_times = [item.stat().st_ctime for item in results]
    by_creation_time = sorted(zip(creation_times, results))
    newest_with_time = by_creation_time[-1]  # latest entry
    return newest_with_time[1]  # the path entry of the tuple


def _get_form_path(partial_name: str) -> pathlib.Path:
    own_parent = pathlib.Path(__file__).parent
    matches = _search_files(own_parent, partial_name, ".pdf")
    if len(matches) == 1:
        return matches[0]
    counts = len(matches)
    msg = f"Found {counts} matching pdf forms for '{partial_name}'"
    raise IOError(msg)


def _get_unique(data: pd.DataFrame, column: str) -> str | int | float:
    uniques = data[column].unique()
    if len(uniques) != 1:
        msg = f"Found multiple unique values for '{column}'"
        raise ValueError(msg)
    return uniques[0]


def _extract_travel_number(data: pd.DataFrame, column: str) -> str:
    belege = data[column]
    travel_nr = belege.apply(
        lambda x: re.search("(5\d{7,8})", x.replace(" ", ""))
    )
    match_result = travel_nr[travel_nr.first_valid_index()]
    return match_result[0]


@click.command()
@click.argument(
    "form", type=click.Path(exists=True, file_okay=True, dir_okay=False)
)
@click.option(
    "-o",
    "--output",
    default=None,
    help="Output file path, defaults to desktop folder",
)
def inspect(form, output):
    form = pathlib.Path(form)
    if not output:
        new_name = f"inspected {form.stem}{form.suffix}"
        output = DESKTOP / new_name
    preview_stream = PdfWrapper(str(form)).preview
    with output.open("wb+") as output_stream:
        output_stream.write(preview_stream)


def payments():
    downloads = WINHOME / "Downloads"
    forms = DESKTOP / "Formulare"

    latest_export = _get_latest_file(downloads, "Buchungen_SAP", ".xlsx")
    if not latest_export:
        sys.exit("Could not find an SuperX export file, aborting.")

    fields = ["BelegNr", "VorgängerBelegNr", "Kostenstelle", "Fonds", "Projekt"]
    converters = {field: str for field in fields}
    data = pd.read_excel(latest_export, skiprows=3, converters=converters)

    travel_nr = _extract_travel_number(data, "BelegNr")

    mask = data["Werttyp"] == "Zahlung"
    payments = data[mask].copy()

    summary = (
        payments.groupby("BelegNr")
        .agg({"Betrag": "sum", "BuDat": "first"})
        .reset_index()
        .sort_values("BelegNr")
    )

    try:
        cost_center = _get_unique(payments, "Kostenstelle")
        fonds = _get_unique(payments, "Fonds")
        project = _get_unique(payments, "Projekt")
        if not project or len(project) <= 4:
            project = ""
    except ValueError as e:
        sys.exit(str(e))

    form_data = {
        "Projekt": project,
        "Kostenstelle": cost_center,
        "Mittelbindung": travel_nr,
        "Fonds": fonds,
    }
    print(f"Projekt:       {project}")
    print(f"Kostenstelle:  {cost_center}")
    print(f"Mittelbindung: {travel_nr}")
    print(f"Fonds:         {fonds}")

    print("")
    print(f"    Datum          Betrag    SuperX")
    print("")

    for i, row in summary.iterrows():
        index = i + 1
        form_data.update(
            {
                f"Datum{index}": row["BuDat"],
                f"BelegNr aus SuberX{index}": row["BelegNr"],
                # no field "Euro{index}"
                # the automatic form calculation would not work.
            }
        )
        betrag = f"{row['Betrag']:0.2f}".replace(".", ",")
        print(f"    {row['BuDat']}    {betrag:>7}    {row['BelegNr']}")

    source_path = forms / "Vorlage UK-Abschlag, v2023-01.pdf"
    destination_path = DESKTOP / f"{TODAY} UK-Abschlag.pdf"
    form = FormWrapper(str(source_path))
    filled = form.fill(form_data, flatten=False)
    destination_path.write_bytes(filled.read())


@click.command()
@click.option("-l", "--search_last_name", prompt=True, required=True)
@click.option("-d", "--iso_date", prompt=True, required=True)
@click.option("-p", "--place", prompt=True, required=True)
def prepare_payments(search_last_name: str, iso_date: str, place: str):
    forms_path = DESKTOP / "Formulare"
    templates_path = forms_path / "vorbereitet UK-As"

    templates = _search_files(templates_path, f" {search_last_name}", ".pdf")
    if len(templates) == 0:
        sys.exit(
            f"Could not find a UK-A template for search '{search_last_name}'"
        )
    if len(templates) > 1:
        sys.exit(
            f"Found multiple UK-A templates for search '{search_last_name}'"
        )
    template = templates[0]

    rest, first_name = template.stem.rsplit(",", maxsplit=1)
    *_, last_name = rest.split()
    first_name = first_name.strip()
    last_name = last_name.strip()

    first_last = f"{first_name} {last_name}"
    last_first = f"{last_name}, {first_name}"
    travel_short = f"{last_first}, {place}"
    travel_name = f"{iso_date} {travel_short}"
    date = _iso_date_to_german(iso_date)

    folder = DESKTOP / f"{travel_name} (abgerechnet)"
    folder.mkdir()

    rk_path = folder / f" {travel_short}, Reisekostenabrechnung.txt"
    rk_path.write_text(rk_path.stem)

    uka_hint_path = (
        folder / f" UK-A {last_first}, Dienstreise {place}, Schlusszahlung.txt"
    )
    content = "\t".join(
        [
            _iso_date_to_german(TODAY),
            first_last,
            f"Schlusszahlung Dienstreise {place}, {date}",
        ]
    )
    uka_hint_path.write_text(content)

    source_path = forms_path / "Vorlage UK-Abschlag, v2023-01.pdf"
    destination_path = folder / f"{TODAY} {travel_short}, UK-Abschlag.pdf"
    shutil.copy(source_path, destination_path)

    form = FormWrapper(str(template))
    form_data = {
        "Verwendungszweck": f"Schlusszahlung Dienstreise nach {place}",
        "Begründung": f"Schlusszahlung Dienstreise {first_last} nach {place} am {date}",
        "Datum_Feststellung": _iso_date_to_german(TODAY),
        "Datum_Anordnung": _iso_date_to_german(TODAY),
    }
    filled = form.fill(form_data, flatten=False)

    uka_path = folder / f"{TODAY} {travel_short}, UK-A Schlusszahlung.pdf"
    uka_path.write_bytes(filled.read())