chat_backend/llm_be/finance/models.py

from django.conf import settings
from django.db import models
from django.utils import timezone

from chat_backend.models import Company, TimeInfoBase


class Invoice(TimeInfoBase):
    """Local ledger row for a billed period / Stripe invoice or checkout session."""

    class Provider(models.TextChoices):
        STRIPE = "stripe", "Stripe"

    class Status(models.TextChoices):
        DRAFT = "draft", "Draft"
        OPEN = "open", "Open"
        PAID = "paid", "Paid"
        VOID = "void", "Void"
        UNCOLLECTIBLE = "uncollectible", "Uncollectible"
        PAYMENT_FAILED = "payment_failed", "Payment failed"

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="invoices",
    )
    company = models.ForeignKey(
        Company,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="invoices",
    )
    provider = models.CharField(
        max_length=32,
        choices=Provider.choices,
        default=Provider.STRIPE,
    )
    status = models.CharField(
        max_length=32,
        choices=Status.choices,
        default=Status.OPEN,
        db_index=True,
    )
    currency = models.CharField(max_length=8, default="usd")
    amount_due = models.PositiveIntegerField(
        default=0,
        help_text="Amount due in the smallest currency unit (e.g. cents).",
    )
    amount_paid = models.PositiveIntegerField(
        default=0,
        help_text="Amount paid in the smallest currency unit (e.g. cents).",
    )
    period_start = models.DateTimeField(null=True, blank=True)
    period_end = models.DateTimeField(null=True, blank=True)
    stripe_invoice_id = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        unique=True,
        db_index=True,
    )
    stripe_checkout_session_id = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        unique=True,
        db_index=True,
    )
    stripe_subscription_id = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        db_index=True,
    )
    stripe_customer_id = models.CharField(max_length=255, blank=True, default="")
    hosted_invoice_url = models.URLField(blank=True, default="")
    description = models.CharField(max_length=512, blank=True, default="")

    class Meta:
        ordering = ["-created"]

    def __str__(self) -> str:
        return f"Invoice {self.pk} ({self.status}) user={self.user_id}"


class Payment(TimeInfoBase):
    """Local ledger row for a payment attempt / Stripe PaymentIntent or charge."""

    class Provider(models.TextChoices):
        STRIPE = "stripe", "Stripe"

    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        SUCCEEDED = "succeeded", "Succeeded"
        FAILED = "failed", "Failed"
        CANCELED = "canceled", "Canceled"
        REQUIRES_ACTION = "requires_action", "Requires action"

    invoice = models.ForeignKey(
        Invoice,
        on_delete=models.CASCADE,
        related_name="payments",
        null=True,
        blank=True,
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="payments",
    )
    company = models.ForeignKey(
        Company,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="payments",
    )
    provider = models.CharField(
        max_length=32,
        choices=Provider.choices,
        default=Provider.STRIPE,
    )
    status = models.CharField(
        max_length=32,
        choices=Status.choices,
        default=Status.PENDING,
        db_index=True,
    )
    currency = models.CharField(max_length=8, default="usd")
    amount = models.PositiveIntegerField(
        default=0,
        help_text="Amount in the smallest currency unit (e.g. cents).",
    )
    stripe_payment_intent_id = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        unique=True,
        db_index=True,
    )
    stripe_charge_id = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        unique=True,
        db_index=True,
    )
    paid_at = models.DateTimeField(null=True, blank=True)
    failure_message = models.CharField(max_length=512, blank=True, default="")

    class Meta:
        ordering = ["-created"]

    def __str__(self) -> str:
        return f"Payment {self.pk} ({self.status}) user={self.user_id}"

    def mark_succeeded(self, *, paid_at=None):
        self.status = self.Status.SUCCEEDED
        self.paid_at = paid_at or timezone.now()
        self.save(update_fields=["status", "paid_at", "last_modified"])