from __future__ import annotations

from django import forms

from .models import ScheduleConfig
from .scheduler import parse_cron_expr


class ScheduleConfigForm(forms.ModelForm):
    cron_expr = forms.CharField(
        label="Cron expression",
        help_text='Five-field cron expression, for example "15 2 * * *".',
    )
    prune_max_delete = forms.IntegerField(min_value=0)

    class Meta:
        model = ScheduleConfig
        fields = (
            "cron_expr",
            "user",
            "enabled",
            "prune",
            "prune_max_delete",
            "prune_protect_bases",
        )

    def clean_cron_expr(self) -> str:
        cron_expr = self.cleaned_data["cron_expr"].strip()
        try:
            parse_cron_expr(cron_expr)
        except ValueError as exc:
            raise forms.ValidationError(str(exc)) from exc
        return cron_expr