PyRIGS/assets/models.py

import re

from django.core.exceptions import ValidationError
from django.db import models, connection
from django.urls import reverse
from reversion import revisions as reversion
from reversion.models import Version

from RIGS.models import RevisionMixin, Profile


class AssetCategory(models.Model):
    class Meta:
        verbose_name = 'Asset Category'
        verbose_name_plural = 'Asset Categories'
        ordering = ['name']

    name = models.CharField(max_length=80)

    def __str__(self):
        return self.name


class AssetStatus(models.Model):
    class Meta:
        verbose_name = 'Asset Status'
        verbose_name_plural = 'Asset Statuses'
        ordering = ['name']

    name = models.CharField(max_length=80)
    should_show = models.BooleanField(
        default=True, help_text="Should this be shown by default in the asset list.")
    display_class = models.CharField(max_length=80, blank=True, null=True, help_text="HTML class to be appended to alter display of assets with this status, such as in the list.")

    def __str__(self):
        return self.name


@reversion.register
class Supplier(models.Model, RevisionMixin):
    class Meta:
        ordering = ['name']

    name = models.CharField(max_length=80)
    phone = models.CharField(max_length=15, blank=True, null=True)
    email = models.EmailField(blank=True, null=True)
    address = models.TextField(blank=True, null=True)

    notes = models.TextField(blank=True, null=True)

    def get_absolute_url(self):
        return reverse('supplier_list')

    def __str__(self):
        return self.name


class Connector(models.Model):
    description = models.CharField(max_length=80)
    current_rating = models.DecimalField(decimal_places=2, max_digits=10, help_text='Amps')
    voltage_rating = models.IntegerField(help_text='Volts')
    num_pins = models.IntegerField(blank=True, null=True)

    def __str__(self):
        return self.description


# Things are nullable that shouldn't be because I didn't properly fix the data structure when moving this to its own model...
class CableType(models.Model):
    class Meta:
        ordering = ['plug', 'socket', '-circuits']

    circuits = models.IntegerField(default=1)
    cores = models.IntegerField(default=3)
    plug = models.ForeignKey(Connector, on_delete=models.CASCADE,
                             related_name='plug', null=True)
    socket = models.ForeignKey(Connector, on_delete=models.CASCADE,
                               related_name='socket', null=True)

    def __str__(self):
        if self.plug and self.socket:
            return "%s → %s" % (self.plug.description, self.socket.description)
        else:
            return "Unknown"


def get_available_asset_id(wanted_prefix=""):
    sql = """
    SELECT a.asset_id_number+1
    FROM assets_asset a
    LEFT OUTER JOIN assets_asset b ON
        (a.asset_id_number + 1 = b.asset_id_number AND
        a.asset_id_prefix = b.asset_id_prefix)
    WHERE b.asset_id IS NULL AND a.asset_id_number >= %s AND a.asset_id_prefix = %s;
    """
    with connection.cursor() as cursor:
        cursor.execute(sql, [9000, wanted_prefix])
        row = cursor.fetchone()
        if row is None or row[0] is None:
            return 9000
        else:
            return row[0]


@reversion.register
class Asset(models.Model, RevisionMixin):
    class Meta:
        ordering = ['asset_id_prefix', 'asset_id_number']
        permissions = [
            ('asset_finance', 'Can see financial data for assets')
        ]

    parent = models.ForeignKey(to='self', related_name='asset_parent',
                               blank=True, null=True, on_delete=models.SET_NULL)
    asset_id = models.CharField(max_length=15, unique=True)
    description = models.CharField(max_length=120)
    category = models.ForeignKey(to=AssetCategory, on_delete=models.CASCADE)
    status = models.ForeignKey(to=AssetStatus, on_delete=models.CASCADE)
    serial_number = models.CharField(max_length=150, blank=True)
    purchased_from = models.ForeignKey(to=Supplier, on_delete=models.CASCADE, blank=True, null=True, related_name="assets")
    date_acquired = models.DateField()
    date_sold = models.DateField(blank=True, null=True)
    purchase_price = models.DecimalField(blank=True, null=True, decimal_places=2, max_digits=10)
    salvage_value = models.DecimalField(blank=True, null=True, decimal_places=2, max_digits=10)
    comments = models.TextField(blank=True)

    # Audit
    last_audited_at = models.DateTimeField(blank=True, null=True)
    last_audited_by = models.ForeignKey(Profile, on_delete=models.SET_NULL, related_name='audited_by', blank=True, null=True)

    # Cable assets
    is_cable = models.BooleanField(default=False)
    cable_type = models.ForeignKey(to=CableType, blank=True, null=True, on_delete=models.SET_NULL)
    length = models.DecimalField(decimal_places=1, max_digits=10,
                                 blank=True, null=True, help_text='m')
    csa = models.DecimalField(decimal_places=2, max_digits=10,
                              blank=True, null=True, help_text='mm²')

    # Hidden asset_id components
    # For example, if asset_id was "C1001" then asset_id_prefix would be "C" and number "1001"
    asset_id_prefix = models.CharField(max_length=8, default="")
    asset_id_number = models.IntegerField(default=1)

    reversion_perm = 'assets.asset_finance'

    def get_absolute_url(self):
        return reverse('asset_detail', kwargs={'pk': self.asset_id})

    def __str__(self):
        return "{} | {}".format(self.asset_id, self.description)

    def clean(self):
        errdict = {}
        if self.date_sold and self.date_acquired > self.date_sold:
            errdict["date_sold"] = ["Cannot sell an item before it is acquired"]

        self.asset_id = self.asset_id.upper()
        asset_search = re.search("^([a-zA-Z0-9]*?[a-zA-Z]?)([0-9]+)$", self.asset_id)
        if asset_search is None:
            errdict["asset_id"] = [
                "An Asset ID can only consist of letters and numbers, with a final number"]

        if self.purchase_price and self.purchase_price < 0:
            errdict["purchase_price"] = ["A price cannot be negative"]

        if self.salvage_value and self.salvage_value < 0:
            errdict["salvage_value"] = ["A price cannot be negative"]

        if self.is_cable:
            if not self.length or self.length <= 0:
                errdict["length"] = ["The length of a cable must be more than 0"]
            if not self.csa or self.csa <= 0:
                errdict["csa"] = ["The CSA of a cable must be more than 0"]
            if not self.cable_type:
                errdict["cable_type"] = ["A cable must have a type"]

        if errdict != {}:  # If there was an error when validation
            raise ValidationError(errdict)

    @property
    def activity_feed_string(self):
        return str(self)

    @property
    def display_id(self):
        return str(self.asset_id)