from wtforms.validators import ValidationError
from datetime import date


def regular_costs_days_check(form, field):
    """
    Checks the input field to enter multiple days in the following format:
      `01-15,07-15` for Jan 15th and July 15
    """
    days = form.days.data
    for day in days.split(","):
        day = day.strip()
        if not day:
            raise ValidationError("Missing Date after ','")
        try:
            m, d = day.split("-")
            m_i = int(m)
            d_i = int(d)
        except Exception:
            raise ValidationError("Malformed Date, must be 'Month-Day'")
        try:
            d = date(2021, m_i, d_i)
        except Exception:
            raise ValidationError("{}-{} is not a valid date".format(m, d))


def odometer_date_check(form, field):
    """
    Checks that the entered date and odometer of the pit stop is conformant to
    the existing pit stops. That means, if a pitstops date is between two
    other pit stops, the odometer should be as well.

    :param form:
    :param field:
    :return:
    """
    odometer = form.odometer.data
    date = form.date.data
    pitstops = form.pitstops

    if len(pitstops) > 0:
        if date < pitstops[0].date and odometer >= pitstops[0].odometer:
            raise ValidationError(
                "The new odometer value must be less than %i km"
                % pitstops[0].odometer
            )

        if date >= pitstops[-1].date and odometer <= pitstops[-1].odometer:
            raise ValidationError(
                "The new odometer value must be greater than %i km"
                % pitstops[-1].odometer
            )

    if len(pitstops) > 1:
        for index in range(0, len(pitstops) - 1):
            if pitstops[index].date <= date < pitstops[index + 1].date:
                if (
                    odometer <= pitstops[index].odometer
                    or odometer >= pitstops[index + 1].odometer
                ):
                    raise ValidationError(
                        "The new odometer value must be greater than %i km and less than %i km"
                        % (
                            pitstops[index].odometer,
                            pitstops[index + 1].odometer,
                        )
                    )


def edit_odometer_date_check(form, field):
    """
    This makes exactly the same checks as 'odometer_date_check' but the
    odometers may be the same (to change only amount and price).

    :param form:
    :param field:
    :return:
    """
    odometer = form.odometer.data
    date = form.date.data
    pitstops = form.pitstops

    if len(pitstops) > 0:
        if date < pitstops[0].date and odometer > pitstops[0].odometer:
            raise ValidationError(
                "The new odometer value must be less than %i km"
                % pitstops[0].odometer
            )

        if date >= pitstops[-1].date and odometer < pitstops[-1].odometer:
            raise ValidationError(
                "The new odometer value must be greater than %i km"
                % pitstops[-1].odometer
            )

    if len(pitstops) > 1:
        for index in range(0, len(pitstops) - 1):
            if pitstops[index].date <= date < pitstops[index + 1].date:
                if (
                    odometer < pitstops[index].odometer
                    or odometer > pitstops[index + 1].odometer
                ):
                    raise ValidationError(
                        "The new odometer value must be greater than %i km and less than %i km"
                        % (
                            pitstops[index].odometer,
                            pitstops[index + 1].odometer,
                        )
                    )


def date_check(form, field):
    """
    Checks that the date of the pitstop is not before the date of the latest
    pitstop and not after today.

    :param form: the form where the field is in
    :param field: the field to check
    :return: Nothing or a ValidationError if the limits are not kept
    """
    if field.data < form.last_pitstop.date:
        raise ValidationError(
            "The new date must not be before %s" % form.last_pitstop.date
        )
    if field.data > date.today():
        raise ValidationError(
            "The new date must not be after %s" % date.today()
        )


def odometer_check(form, field):
    """

    :param form:
    :param field:
    :return:
    """
    if (
        not form.same_odometer_allowed
        and field.data <= form.last_pitstop.odometer
    ):
        raise ValidationError(
            "The new odometer value must be higher than %i km"
            % form.last_pitstop.odometer
        )
    if form.same_odometer_allowed and field.data < form.last_pitstop.odometer:
        raise ValidationError(
            "The new odometer value must be higher than %i km"
            % form.last_pitstop.odometer
        )


def litres_check(form, field):
    if field.data is not None and field.data <= 0:
        raise ValidationError("You must fuel at least 0.1 l")


def costs_check(form, field):
    if field.data is not None and field.data <= 0:
        raise ValidationError("Costs must be above 0.01 €.")


def edit_costs_check(form, field):
    """
    Costs must be given, if a default value was given to the form field.
    :param form:
    :param field:
    :return:
    """
    costs_check_required = (
        form.costs.default is not None and form.costs.default > 0
    )
    if costs_check_required and field.data is not None and field.data <= 0:
        raise ValidationError("Costs must be above 0.01 €.")