feat(datev): add personio to datev converter and tests

sepacetamol/templates/base.html

@@ -30,6 +30,8 @@
 
 <main role="main" class="container">
 
+    <h1>SEPAcetamol</h1>
+
     {% block content %}
     {% endblock %}
 

sepacetamol/templates/datev.html

@@ -0,0 +1,43 @@
+{% extends "base.html" %}
+
+{% load static %}
+
+
+{% block content %}
+    <h2>Personio accounting</h2>
+
+    {% for message in messages %}
+        <div class="alert alert-{{ message.level_tag }}" role="alert">{{ message }}</div>
+    {% endfor %}
+
+    <form class="mb-3" method="post" enctype="multipart/form-data">
+
+        {% csrf_token %}
+
+        <div class="row mb-3">
+            <label for="consultant-number" class="col-sm-2 col-form-label">Consultant number</label>
+            <div class="col-sm-8">
+                <input type="text" class="form-control" id="consultant-number" name="consultant-number"
+                       value="{{ datev_settings.consultant_number }}" placeholder="843719" required>
+            </div>
+        </div>
+
+        <div class="row mb-3">
+            <label for="client-number" class="col-sm-2 col-form-label">Client number</label>
+            <div class="col-sm-8">
+                <input type="text" class="form-control" id="client-number" name="client-number"
+                       value="{{ datev_settings.client_number }}" placeholder="10487" required>
+            </div>
+        </div>
+
+        <div class="col-auto mb-3">
+            <input type="file" class="form-control" id="personio-file" name="personio-file"
+                   accept=".xlsx,application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" required>
+        </div>
+
+        <div class="col-auto">
+            <button type="submit" class="btn btn-primary">Convert file</button>
+        </div>
+
+    </form>
+{% endblock %}

sepacetamol/templates/index.html

@@ -3,7 +3,9 @@
 {% load static %}
 
 {% block content %}
-    <h1>SEPAcetamol</h1>
+    <div class="alert alert-info" role="alert">
+        For Personio → DATEV converter, <a href="{% url "personio-datev" %}">follow along</a>.
+    </div>
 
     <p>
         Download the <a href="{% static "sepa-xml-template.xlsx" %}">wire table template</a>,

sepacetamol/urls.py

@@ -1,8 +1,9 @@
 from django.urls import path
 
-from .views import sepa
+from .views import datev, sepa
 
 urlpatterns = [
     path("", sepa.index, name="index"),
     path("generate/", sepa.generate, name="generate"),
+    path("personio-datev/", datev.index, name="personio-datev"),
 ]

sepacetamol/views/datev.py

@@ -0,0 +1,287 @@
+import calendar
+import csv
+import re
+from datetime import date, datetime
+from io import StringIO
+from typing import Annotated, Literal, Optional
+
+from django.contrib import messages as message
+from django.http import HttpResponse, HttpResponseBadRequest
+from django.shortcuts import render
+from django.utils.encoding import smart_str
+from openpyxl.reader.excel import load_workbook
+from pydantic import BaseModel, Field, field_validator
+
+
+def float_to_german(value: float) -> str:
+    return f"{value:.2f}".replace(".", ",")
+
+
+def unquote_empty_csv_strings(value: str) -> str:
+    while ';"";' in value:
+        value = value.replace(';"";', ";;")
+    result = value.removesuffix(';""')
+    return result if result == value else result + ";"
+
+
+def date_to_datev(d: date) -> str:
+    return d.strftime("%Y%m%d")
+
+
+PositiveInt = Annotated[int, Field(gt=0)]
+
+
+class DatevSettings(BaseModel):
+    consultant_number: PositiveInt
+    client_numer: PositiveInt
+
+    class Config:
+        populate_by_name = True
+        validate_default = True
+        validate_assignment = True
+        frozen = True
+
+
+class DatevModel(BaseModel):
+    def model_dump_csv(self) -> str:
+        output = StringIO()
+        datev_writer = csv.writer(output, quoting=csv.QUOTE_NONNUMERIC, delimiter=";")
+        datev_writer.writerow(self.model_dump().values())
+        return "\n".join(unquote_empty_csv_strings(line) for line in output.getvalue().splitlines())
+
+    class Config:
+        populate_by_name = True
+        validate_default = True
+        validate_assignment = True
+        frozen = True
+
+
+class DatevHeader(DatevModel):
+    flag: Literal["EXTF", "DTVF"]
+    version_numer: Literal[700] = 700
+    format_category: Literal[16, 20, 21, 46, 48, 65]
+    format_name: Literal[
+        "Buchungsstapel",
+        "Wiederkehrende Buchungen",
+        "Debitoren/Kreditoren",
+        "Sachkontenbeschriftungen",
+        "Zahlungsbedingungen",
+        "Diverse Adressen",
+    ]
+    format_version: Literal[2, 4, 5, 9, 12]
+    created_on: Optional[str] = Field(
+        default=None,
+        pattern=(
+            r"^20[0-9]{2}(0[1-9]|1[0-2])(0[1-9]|[1-2][0-9]|3[0-1])"
+            r"(2[0-3]|[01][0-9])[0-5][0-9][0-5][0-9][0-9][0-9][0-9]$"
+        ),
+    )
+    reserved_07: str = Field(default="", max_length=0)
+    reserved_08: Optional[str] = Field(default=None, pattern=r"^\w{1,2}$")
+    reserved_09: Optional[str] = Field(default=None, pattern=r"^\w{1,25}$")
+    reserved_10: Optional[str] = Field(default=None, pattern=r"^\w{1,25}$")
+    consultant_number: int = Field(ge=1001, le=9999999)
+    client_numer: int = Field(ge=1, le=99999)
+    business_year_start: int
+    gl_account_length: int = Field(ge=4, le=8)
+    date_from: int
+    date_till: int
+    designation: str = Field(pattern=r"^[\w.\-/ ]{0,30}$")
+    initials: Optional[str] = Field(default=None, pattern=r"^([A-Z]{2}){1,2}$")
+    record_type: Optional[Literal[1, 2]] = None
+    accounting_reason: Optional[Literal[0, 30, 40, 50, 64]] = None
+    locking: Literal[0, 1]
+    currency_code: str = Field(default="EUR", pattern=r"^[A-Z]{3}$")
+    reserved_23: str = Field(default="", max_length=0)
+    derivatives_flag: str = Field(default="", max_length=0)
+    reserved_25: str = Field(default="", max_length=0)
+    reserved_26: str = Field(default="", max_length=0)
+    gl_chart_of_accounts: str = Field(pattern=r"^(\d{2}){0,2}$")
+    industry_solution_id: Optional[int] = Field(default=None, ge=0, le=9999)
+    reserved_29: str = Field(default="", max_length=0)
+    reserved_30: str = Field(default="", max_length=0)
+    application_information: str = Field(default="", max_length=16)
+
+    @field_validator("business_year_start", "date_from", "date_till")
+    def date_pattern(cls, v):
+        if re.match(r"^20[0-9]{2}(0[1-9]|1[0-2])(0[1-9]|[1-2][0-9]|3[0-1])$", str(v)) is None:
+            raise ValueError("must match date pattern")
+        return v
+
+
+class DatevBooking(DatevModel):
+    umsatz: str = Field(
+        alias="Umsatz",
+        pattern=r"^\d{1,10}[,]\d{2}$",
+        description="Umsatz/Betrag für den Datensatz, z.B.: 1234567890,12 .Betrag muss positiv sein.",
+    )
+    soll_haben_kz: Literal["S", "H"] = Field(
+        alias="Soll-/Haben-Kennzeichen",
+        description="Soll-/Haben-Kennzeichnung bezieht sich auf das Feld #7 Konto",
+    )
+    wkz_umsatz: Optional[str] = Field(
+        alias="WKZ Umsatz",
+        default=None,
+        pattern=r"^[A-Z]{3}$",
+        description="ISO-Code der Währung",
+    )
+    kurs: Optional[str] = Field(
+        alias="Kurs",
+        default=None,
+        pattern=r"^[1-9]\d{0,3}[,]\d{2,6}$",
+        description="Wenn Umsatz in Fremdwährung bei #1 angegeben wird #4, #5 und #6 sind zu übergeben, z.B.: 12,34",
+    )
+    basisumsatz: Optional[str] = Field(
+        alias="Basisumsatz",
+        default=None,
+        pattern=r"^\d{1,10}[,]\d{2}$",
+        description="Siehe #4, z.B.: 1234567890,12",
+    )
+    wkz_basisumsatz: Optional[str] = Field(
+        alias="WKZ Basisumsatz",
+        default=None,
+        pattern=r"^[A-Z]{3}$",
+        description="Siehe #4",
+    )
+    konto: int = Field(alias="Konto", description="Sach- oder Personenkonto, z.B. 8400")
+    gegenkonto: int = Field(alias="Gegenkonto (ohne BU-Schlüssel)", description="Sach- oder Personenkonto, z.B. 70000")
+    bu_schluessel: Optional[int] = Field(
+        alias="BU-Schlüssel",
+        default=None,
+        ge=1000,
+        le=9999,
+        description="Steuerungskennzeichen zur Abbildung verschiedener Funktionen/Sachverhalte",
+    )
+    belegdatum: str = Field(
+        alias="Belegdatum",
+        pattern=r"^\d{4}$",
+        description="Format: TTMM, z.B. 0105, Das Jahr wird immer aus dem Feld 13 des Headers ermittelt",
+    )
+    belegfeld_1: Optional[str] = Field(
+        alias="Belegfeld 1",
+        default=None,
+        pattern=r"^[\w$%\-/]{0,36}$",
+        description="Rechnungs-/Belegnummer, wird als 'Schlüssel' für den Ausgleich offener Rechnungen genutzt",
+    )
+    belegfeld_2: Optional[str] = Field(
+        alias="Belegfeld 2",
+        default=None,
+        pattern=r"^[\w$%\-/]{0,12}$",
+        description="Mehrere Funktionen",
+    )
+    skonto: Optional[str] = Field(
+        alias="Skonto",
+        default=None,
+        pattern=r"^([1-9]\d{0,7}[,]\d{2})$",
+        description="Skontobetrag, z.B. 3,71 - nur bei Zahlungsbuchungen zulässig",
+    )
+    buchungstext: str = Field(
+        alias="Buchungstext",
+        max_length=60,
+        description="0-60 Zeichen",
+    )
+    postensperre: Optional[Literal[0, 1]] = Field(
+        alias="Postensperre",
+        default=None,
+        description="Mahn- oder Zahlsperre, 0 = keine Sperre (default), 1 = Sperre",
+    )
+
+    def model_dump_csv_header(self) -> str:
+        output = StringIO()
+        datev_writer = csv.DictWriter(
+            output,
+            fieldnames=self.model_dump(by_alias=True).keys(),
+            quoting=csv.QUOTE_NONNUMERIC,
+            delimiter=";",
+        )
+        datev_writer.writeheader()
+        return output.getvalue().strip()
+
+
+def convert_personio_to_datev(request) -> HttpResponse:
+    datev_settings = DatevSettings(
+        consultant_number=request.POST["consultant-number"],
+        client_numer=request.POST["client-number"],
+    )
+
+    try:
+        worksheet = load_workbook(request.FILES["personio-file"]).active
+    except Exception as e:
+        raise ValueError("Personio file could not be loaded, please check the format") from e
+
+    def get_booking(row) -> tuple[date, DatevBooking]:
+        (datum, _, _, umsatz, sh, _, _, gegenkonto, konto, belegfeld_1, buchungstext, *_) = row
+
+        datum = datetime.strptime(datum, "%d.%m.%Y").date()
+
+        soll_haben = "S" if not sh else sh
+
+        if umsatz < 0:
+            soll_haben = "H" if soll_haben == "S" else "S"
+
+        return (
+            datum,
+            DatevBooking(
+                umsatz=float_to_german(abs(umsatz)),
+                soll_haben_kz=soll_haben,
+                konto=konto,
+                gegenkonto=gegenkonto,
+                belegdatum=datum.strftime("%d%m"),
+                belegfeld_1=belegfeld_1,
+                buchungstext=buchungstext,
+            ),
+        )
+
+    bookings = [
+        get_booking([value.strip() if isinstance(value, str) else value for value in row])
+        for row in worksheet.iter_rows(min_row=3, values_only=True)
+        if any(row)
+    ]
+
+    (datum, first_booking), *_ = bookings
+
+    header = DatevHeader(
+        flag="EXTF",
+        format_category=21,
+        format_name="Buchungsstapel",
+        format_version=9,
+        consultant_number=datev_settings.consultant_number,
+        client_numer=datev_settings.client_numer,
+        business_year_start=date_to_datev(datum.replace(month=1, day=1)),
+        gl_account_length=4,
+        date_from=date_to_datev(datum.replace(day=1)),
+        date_till=date_to_datev(datum.replace(day=calendar.monthrange(datum.year, datum.month)[1])),
+        designation=f"Lohnbuchungen {datum.strftime('%Y-%m')}",
+        currency_code="EUR",
+        locking=0,
+        gl_chart_of_accounts="03",
+    )
+
+    target_filename = f"EXTF_Personio-{datum.strftime('%Y-%m')}.csv"
+
+    contents = "\r\n".join(
+        [header.model_dump_csv()]
+        + [first_booking.model_dump_csv_header()]
+        + [booking.model_dump_csv() for _, booking in bookings],
+    ).encode("cp1252")
+
+    response = HttpResponse(content_type="text/csv")
+    response["Content-Disposition"] = "attachment; filename=%s" % smart_str(target_filename)
+    response.write(contents)
+
+    return response
+
+
+def index(request):
+    if request.method == "GET":
+        return render(request, "datev.html")
+    elif request.method == "POST":
+        try:
+            response = convert_personio_to_datev(request)
+        except Exception as e:
+            message.error(request, e)
+            return render(request, "datev.html")
+        else:
+            return response
+    else:
+        return HttpResponseBadRequest