feat: internal code for automatic exchange rate fetching

app/apps/currencies/models.py

@@ -1,8 +1,12 @@
+import logging
+
 from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator, MinValueValidator
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 
+logger = logging.getLogger(__name__)
+
 
 class Currency(models.Model):
     code = models.CharField(max_length=10, unique=True, verbose_name=_("Currency Code"))
@@ -78,3 +82,66 @@ class ExchangeRate(models.Model):
                 raise ValidationError(
                     {"to_currency": _("From and To currencies cannot be the same.")}
                 )
+
+
+class ExchangeRateService(models.Model):
+    """Configuration for exchange rate services"""
+
+    class ServiceType(models.TextChoices):
+        SYNTH_FINANCE = "synth_finance", "Synth Finance"
+        COINGECKO = "coingecko", "CoinGecko"
+
+    name = models.CharField(max_length=255, unique=True, verbose_name=_("Service Name"))
+    service_type = models.CharField(
+        max_length=255, choices=ServiceType.choices, verbose_name=_("Service Type")
+    )
+    is_active = models.BooleanField(default=True, verbose_name=_("Active"))
+    api_key = models.CharField(
+        max_length=255,
+        blank=True,
+        null=True,
+        verbose_name=_("API Key"),
+        help_text=_("API key for the service (if required)"),
+    )
+    fetch_interval_hours = models.PositiveIntegerField(
+        default=24,
+        validators=[MinValueValidator(1)],
+        verbose_name=_("Fetch Interval (hours)"),
+    )
+    last_fetch = models.DateTimeField(
+        null=True, blank=True, verbose_name=_("Last Successful Fetch")
+    )
+
+    target_currencies = models.ManyToManyField(
+        Currency,
+        verbose_name=_("Target Currencies"),
+        help_text=_(
+            "Select currencies to fetch exchange rates for. Rates will be fetched for each currency against their set exchange currency."
+        ),
+        related_name="exchange_services",
+        blank=True,
+    )
+
+    target_accounts = models.ManyToManyField(
+        "accounts.Account",
+        verbose_name=_("Target Accounts"),
+        help_text=_(
+            "Select accounts to fetch exchange rates for. Rates will be fetched for each account's currency against their set exchange currency."
+        ),
+        related_name="exchange_services",
+        blank=True,
+    )
+
+    class Meta:
+        verbose_name = _("Exchange Rate Service")
+        verbose_name_plural = _("Exchange Rate Services")
+        ordering = ["name"]
+
+    def __str__(self):
+        return self.name
+
+    def get_provider(self):
+        from apps.currencies.exchange_rates.fetcher import PROVIDER_MAPPING
+
+        provider_class = PROVIDER_MAPPING[self.service_type]
+        return provider_class(self.api_key)