from django.db import models
from django.utils import timezone
from django.core.validators import MinValueValidator, MaxValueValidator  

class Institute(models.Model):
    name = models.CharField(max_length=100)
    
    def __str__(self):
        return self.name

class Betriebskosten(models.Model):
    KOSTENTYP_CHOICES = [
        ('sach', 'Sachkostöen'),
        ('ln2', 'LN2'),
        ('helium', 'Helium'),
        ('inv', 'Inventar'),
    ]
    
    buchungsdatum = models.DateField('Buchungsdatum')
    rechnungsnummer = models.CharField('Rechnungsnummer', max_length=50)
    kostentyp = models.CharField('Kostentyp', max_length=10, choices=KOSTENTYP_CHOICES)
    gas_volume = models.DecimalField('Gasvolumen (Liter)', max_digits=10, decimal_places=2, null=True, blank=True)
    betrag = models.DecimalField('Betrag (€)', max_digits=10, decimal_places=2)
    beschreibung = models.TextField('Beschreibung', blank=True)
    
    @property
    def price_per_liter(self):
        if self.kostentyp == 'helium' and self.gas_volume:
            return self.betrag / self.gas_volume
        return None
    
    def __str__(self):
        return f"{self.buchungsdatum} - {self.get_kostentyp_display()} - {self.betrag}€"  # Fixed the missing quote

class Client(models.Model):
    name = models.CharField(max_length=100)
    address = models.TextField()
    institute = models.ForeignKey(Institute, on_delete=models.CASCADE)  # Remove null=True, blank=True
    
    def __str__(self):
        return f"{self.name} ({self.institute.name})"

class ExcelEntry(models.Model):
    client = models.ForeignKey(Client, on_delete=models.CASCADE)
    date = models.DateField(default=timezone.now)
    pressure = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        validators=[MinValueValidator(0)],
        default=0.00
    )
    purity = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        validators=[MinValueValidator(0), MaxValueValidator(100)],
        default=0.00
    )
    notes = models.TextField(blank=True, null=True)
    date_joined = models.DateField(auto_now_add=True)

    # Manual input
    lhe_zus = models.DecimalField(
        max_digits=10,
        decimal_places=3,
        validators=[MinValueValidator(0)],
        default=0.0
    )

    druckkorrektur = models.DecimalField(
        max_digits=10,
        decimal_places=3,
        validators=[MinValueValidator(0)],
        default=1.0
    )

    # Auto-calculated values (saved)
    constant_300 = models.DecimalField(
        max_digits=10,
        decimal_places=3,
        default=300.0
    )

    korrig_druck = models.DecimalField(
        max_digits=12,
        decimal_places=6,
        default=0.0
    )

    nm3 = models.DecimalField(
        max_digits=12,
        decimal_places=6,
        default=0.0
    )

    lhe = models.DecimalField(
        max_digits=12,
        decimal_places=6,
        default=0.0
    )

    lhe_ges = models.DecimalField(
        max_digits=12,
        decimal_places=6,
        default=0.0
    )
class SecondTableEntry(models.Model):
    client = models.ForeignKey(Client, on_delete=models.CASCADE)
    date = models.DateField(default=timezone.now)
    is_warm = models.BooleanField(default=False)
    lhe_delivery = models.CharField(max_length=100, blank=True, null=True)
    lhe_output = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        validators=[MinValueValidator(0)],
        blank=True,
        null=True
    )
    notes = models.TextField(blank=True, null=True)
    date_joined = models.DateField(auto_now_add=True)

    def __str__(self):
        return f"{self.client.name} - {self.date}"