from io import BytesIO
from typing import Optional

import structlog
from django.utils.translation import gettext_lazy as _
from openpyxl import Workbook

from vbv_lernwelt.course.models import CourseSessionUser
from vbv_lernwelt.course_session.services.export_attendance import (
    add_user_headers,
    make_export_filename,
)
from vbv_lernwelt.dashboard.utils import create_csu_dict

PERSONS_EXPORT_FILENAME = _("export_personen")

logger = structlog.get_logger(__name__)


def export_persons(
    course_session_users: list[CourseSessionUser],
    save_as_file: bool = False,
) -> Optional[bytes]:
    if not course_session_users:
        return

    wb = Workbook()
    # remove the first sheet is just easier than keeping track of the active sheet
    wb.remove(wb.active)
    csu_data = [
        create_csu_dict(csu, include_private_data=True) for csu in course_session_users
    ]
    csu_data.sort(key=lambda x: x["last_name"])
    _create_sheet(
        wb,
        csu_data,
    )

    if save_as_file:
        wb.save(make_export_filename(PERSONS_EXPORT_FILENAME))
    else:
        output = BytesIO()
        wb.save(output)

        output.seek(0)
        return output.getvalue()


def _create_sheet(
    wb: Workbook,
    course_session_user_data: list[dict],
):
    sheet = wb.create_sheet()

    if len(course_session_user_data) == 0:
        return sheet

    # headers
    # common user headers, Circle <title> <learningcontenttitle> bestanden,  Circle <title> <learningcontenttitle> Resultat, ...
    col_idx = add_user_headers(sheet)
    sheet.cell(row=1, column=col_idx, value=str(_("Telefon")))
    sheet.cell(row=1, column=col_idx + 1, value=str(_("Rolle")))

    _add_rows(sheet, course_session_user_data)

    return sheet


def _add_rows(
    sheet,
    users,
):
    idx_offset = 0

    for row_idx, user in enumerate(users, start=2):
        user_role = _role_as_string(user.get("role"))
        idx = row_idx - idx_offset

        sheet.cell(row=idx, column=1, value=user["first_name"])
        sheet.cell(row=idx, column=2, value=user["last_name"])
        sheet.cell(row=idx, column=3, value=user["email"])
        sheet.cell(row=idx, column=4, value=user.get("Lehrvertragsnummer", ""))
        sheet.cell(
            row=idx,
            column=5,
            value=user.get("phone_number", ""),
        )
        sheet.cell(row=idx, column=6, value=user_role)


def _role_as_string(role):
    if role == "MEMBER":
        return str(_("Teilnehmer"))
    elif role == "EXPERT":
        return str(_("Trainer"))
    elif role == "SUPERVISOR":
        return str(_("Regionenleiter"))
    else:
        return role