from django.core.validators import RegexValidator
from django.db import models
from django.db.models import Q

from .base import IdentifiedModel


class SourceRecord(IdentifiedModel):
    class Format(models.TextChoices):
        BANK_CSV = "BANK_CSV", "Bank CSV"
        OUROCARD_TXT = "OUROCARD_TXT", "Ourocard TXT"

    transaction = models.ForeignKey("finance.Transaction", on_delete=models.PROTECT, related_name="source_records")
    document_hash = models.CharField(max_length=64, validators=[
        RegexValidator(r"\A[0-9a-f]{64}\Z", "Use a lowercase SHA-256 hexadecimal digest.")])
    source_format = models.CharField(max_length=16, choices=Format.choices)
    parser_version = models.CharField(max_length=128)
    item_locator = models.CharField(max_length=255)

    class Meta:
        constraints = [
            models.CheckConstraint(condition=Q(source_format__in=["BANK_CSV", "OUROCARD_TXT"]), name="source_valid_format"),
            models.CheckConstraint(condition=Q(document_hash__regex=r"^[0-9a-f]{64}$"), name="source_valid_hash"),
            models.CheckConstraint(condition=Q(parser_version__regex=r"\S"), name="source_nonblank_parser"),
            models.CheckConstraint(condition=Q(item_locator__regex=r"\S"), name="source_nonblank_locator"),
            models.UniqueConstraint(fields=["document_hash", "item_locator"], name="source_document_item_unique"),
        ]


class AuditEvent(IdentifiedModel):
    class ActorKind(models.TextChoices):
        HUMAN = "HUMAN", "Human"
        APPLICATION = "APPLICATION", "Application"
        AGENT = "AGENT", "Agent"

    class Outcome(models.TextChoices):
        SUCCESS = "SUCCESS", "Success"
        FAILURE = "FAILURE", "Failure"

    actor_kind = models.CharField(max_length=16, choices=ActorKind.choices)
    actor_identifier = models.CharField(max_length=255)
    operation = models.CharField(max_length=128)
    target_id = models.UUIDField(null=True, blank=True)
    outcome = models.CharField(max_length=16, choices=Outcome.choices)
    changed_fields = models.JSONField(default=list, blank=True)
    error_code = models.CharField(max_length=128, blank=True)

    class Meta:
        constraints = [
            models.CheckConstraint(condition=Q(actor_kind__in=["HUMAN", "APPLICATION", "AGENT"]), name="audit_valid_actor"),
            models.CheckConstraint(condition=Q(outcome__in=["SUCCESS", "FAILURE"]), name="audit_valid_outcome"),
            models.CheckConstraint(condition=Q(actor_identifier__regex=r"\S"), name="audit_nonblank_actor"),
            models.CheckConstraint(condition=Q(operation__regex=r"\S"), name="audit_nonblank_operation"),
        ]