import argparse
import subprocess
from pathlib import Path

import pandas as pd
from jinja2 import Template


def construct_mails(
    data_file: Path,
    template_file: Path,
    sheet_name: str,
    full_area_name: str,
    from_addr: str,
    subject: str,
    name_idx: int,
    mail_idx: int,
    dry_run: bool = False,
) -> None:
    df = pd.read_excel(data_file, sheet_name=sheet_name)
    today = pd.to_datetime("today").normalize()
    for idx, row in df.iterrows():
        name = row[name_idx]
        mail = row[mail_idx]

        if pd.isna(mail):
            continue

        with template_file.open() as f:
            template = Template(f.read())

        msg = template.render(
            name=name,
            full_area_name=full_area_name,
        )

        payload = [
            "thunderbird",
            "-compose",
            f"to='{mail}',subject='{subject}',from='{from_addr}',body='{msg}'",
        ]
        if dry_run:
            print(payload)
        else:
            subprocess.run(payload)


def main():
    parser = argparse.ArgumentParser("TVStud Bonn Mail")
    parser.add_argument(
        "--data-file",
        type=Path,
        default=Path("Strukturaufbau.xlsx"),
        help="Path of the ods/Excel file containing the mapping data."
        "Defaults to 'Strukturaufbau.xlsx'",
    )
    parser.add_argument(
        "--template-file",
        type=Path,
        default=Path("template.txt"),
        help="Path of the text file containing the template for the mail body. "
        "Defaults to 'template.txt'.",
    )
    parser.add_argument(
        "--from-name",
        type=str,
        default="TVStud Bonn",
        help="Sender name to use. Defaults to 'TVStud Bonn'",
    )
    parser.add_argument(
        "--from-address",
        type=str,
        default="bonn@tvstud.de",
        help="Sender address to use. Defaults to 'bonn@tvstud.de'",
    )
    parser.add_argument(
        "--subject", type=str, default="TVStud Bonn TODO", help="Mail subject to use"
    )
    parser.add_argument(
        "--sheet",
        type=str,
        default=None,
        help="The name of the sheet to run on",
    )
    parser.add_argument(
        "--full-area-name",
        type=str,
        default=None,
        help="The name of the area to use in the mail (e.g. 'Psychologie' for the sheet 'Psycho'). "
        "If None, the sheet name is used instead. Defaults to None.",
    )

    parser.add_argument(
        "--print-sheets",
        action="store_true",
        help="Print available sheets and exit",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Do a dry run and only print the generated emails to stdout",
    )
    parser.add_argument(
        "--name-idx",
        type=int,
        default=0,
        help="Index of the column containing the names (0-based). Defaults to 0.",
    )
    parser.add_argument(
        "--mail-idx",
        type=int,
        default=6,
        help="Index of the column containing the mail addresses (0-based). Defaults to 6.",
    )

    args = parser.parse_args()

    if args.print_sheets or args.sheet is None:
        xl = pd.ExcelFile(args.data_file)
        print("Available sheets (specify via '--sheet'):")
        print(xl.sheet_names)
        return

    if args.full_area_name is None:
        args.full_area_name = args.sheet

    construct_mails(
        data_file=args.data_file,
        template_file=args.template_file,
        sheet_name=args.sheet,
        full_area_name=args.full_area_name,
        subject=args.subject,
        from_addr=args.from_address,
        name_idx=args.name_idx,
        mail_idx=args.mail_idx,
        dry_run=args.dry_run,
    )


if __name__ == "__main__":
    main()