import uuid
from django.conf import settings
from django.db import models


class QCResult(models.Model):
    class VisualGrade(models.TextChoices):
        A = "A", "A"
        B = "B", "B"
        C = "C", "C"
        FAIL = "Fail", "Fail"

    class VerificationStatus(models.TextChoices):
        DRAFT = "draft", "Draft"
        VALIDATED = "validated", "Validated"
        APPROVED = "approved", "Approved"
        REJECTED = "rejected", "Rejected"

    class ResultStatus(models.TextChoices):
        WITHIN_SPEC = "within_spec", "Within Specification"
        OUTSIDE_SPEC = "outside_spec", "Outside Specification"
        MISSING = "missing", "Missing"
        UNIT_MISMATCH = "unit_mismatch", "Unit Mismatch"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    batch = models.ForeignKey("batches.ProcessingBatch", on_delete=models.CASCADE, related_name="qc_results")
    ffa_percentage = models.DecimalField(max_digits=5, decimal_places=2)
    moisture_percentage = models.DecimalField(max_digits=5, decimal_places=2)
    peroxide_value = models.DecimalField(max_digits=5, decimal_places=2)
    visual_grade = models.CharField(max_length=5, choices=VisualGrade.choices)
    overall_pass = models.BooleanField()
    tested_by = models.CharField(max_length=255, blank=True)
    tested_at = models.DateTimeField(auto_now_add=True)
    lab_reference = models.CharField(max_length=255, blank=True)

    spec_version = models.CharField(max_length=20, blank=True)
    entered_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True, related_name="qc_entered"
    )
    verified_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True, related_name="qc_verified"
    )
    verification_status = models.CharField(
        max_length=20, choices=VerificationStatus.choices, default=VerificationStatus.DRAFT
    )
    approved_at = models.DateTimeField(null=True, blank=True)
    method_ffa = models.CharField(max_length=255, blank=True)
    method_moisture = models.CharField(max_length=255, blank=True)
    method_peroxide = models.CharField(max_length=255, blank=True)
    result_status = models.CharField(
        max_length=20, choices=ResultStatus.choices, default=ResultStatus.WITHIN_SPEC
    )
    superseded_by = models.ForeignKey(
        "self", on_delete=models.SET_NULL, null=True, blank=True, related_name="supersedes"
    )
    is_quarantine = models.BooleanField(default=False)

    class Meta:
        db_table = "qc_results"
        ordering = ["-tested_at"]

    def __str__(self):
        status = "PASS" if self.overall_pass else "FAIL"
        return f"QC for {self.batch.batch_reference}: {status}"