from django.db import models
from django.db.models import Sum

from datetime import date

DISCOUNT_UNIT_CHOICE = [
    (0, "%"),
    (1, "€"),
]


class Client(models.Model):
    class Meta:
        verbose_name = 'Client'
        verbose_name_plural = 'Clients'

    name = models.CharField(max_length=255, verbose_name="Nom")
    address = models.CharField(max_length=255, verbose_name="Adresse")
    postal_code = models.IntegerField(verbose_name="Code postal")
    city = models.CharField(max_length=255, verbose_name="Ville")
    contact = models.CharField(max_length=255, verbose_name="Personne de contact")
    email = models.EmailField(max_length=254)
    phone_number = models.CharField(max_length=20, verbose_name="Téléphone")
    company_number = models.CharField(
        max_length=50,
        verbose_name="N° d'entreprise",
        blank=True,
        null=True
    )

    def __str__(self):
        return "%s" % (self.name)
    

class DiscountClient(models.Model):
    class Meta:
        verbose_name = 'Réduction client'
        verbose_name_plural = 'Réductions clients'

    label = models.CharField(max_length=255, verbose_name='Libellé')
    client = models.ManyToManyField(Client, verbose_name="discounts" )
    quantity = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        verbose_name="Quantité",
        default=1
    )
    unit = models.PositiveSmallIntegerField(
        choices=DISCOUNT_UNIT_CHOICE, verbose_name="Unité"
    )

    def __str__(self):
        return f"{self.label} - {self.quantity} {self.unit}"

    # def amount_htva(self):
    #     if self.unit: 
    #         return - self.quantity
    #     return (self.contract.get_contract_sum("total_amount_htva") * self.quantity / 100)

    # def amount_tvac(self):
    #     if self.unit:
    #         return self.quantity * 0.21
    #     return (self.contract.get_contract_sum("total_amount_tvac") * self.quantity / 100)


class Estimate(models.Model):
    class Meta:
        verbose_name = 'Devis'
        verbose_name_plural = 'Devis'

    name = models.CharField(max_length=255, verbose_name="Nom")
    client = models.ForeignKey(Client, on_delete=models.CASCADE, related_name="estimates")
    date = models.DateField(auto_now_add=True)
    details = models.TextField()

    def __str__(self):
        return "%s" % (self.name)


class Contract(models.Model):
    class Meta:
        verbose_name = 'Contrat'
        verbose_name_plural = 'Contrats'

    name = models.CharField(max_length=255, verbose_name="Nom")
    client = models.ForeignKey(Client, on_delete=models.CASCADE, related_name="contracts")
    advance = models.DecimalField(
        max_digits=6,
        decimal_places=2,
        blank=True,
        verbose_name="Acompte",
        default=0
    )
    reference = models.CharField(max_length=255, verbose_name="Référence", blank=True, null=True)
    is_finished = models.BooleanField(default=True, blank=True)
    date = models.DateField(auto_now_add=True)
    invoiced_date = models.DateField(default=None, blank=True, null=True)

    def __str__(self):
        return "%s" % (self.name)   

    def get_contract_sum(self, key):
        return  self.get_prestation.aggregate(Sum(key))[key + '__sum']

    # def __generate_reference(self):
    #     """
    #     Génère automatiquement la référence du contract
    #     """
    #     if self.id is None:
    #         object_id = "XX"
    #     elif self.id < 10:
    #         object_id = "0" + str(self.id)
    #     else:
    #         object_id = self.id
    #     self.reference = str(self.date.year) + "-" + object_id

    # def save(self, *args, **kwargs):
    #     """
    #     Enregistre l'objet en DB après avoir calculé le montant total.
    #     """
    #     super().save(*args, **kwargs)
    #     self.__generate_reference()
    #     super().save(*args, **kwargs)

class PrestationType(models.Model):
    class Meta:
        verbose_name = 'Type de prestations'
        verbose_name_plural = 'Types de prestations'

    label = models.CharField(max_length=255, verbose_name='Libellé')

    def __str__(self):
        return f"{self.label}"

class Prestation(models.Model):
    class Meta:
        verbose_name = 'Prestations'
        verbose_name_plural = 'Prestations'
        ordering = ['date']

    contract = models.ForeignKey(
        Contract,
        on_delete=models.CASCADE,
        related_name="get_prestation",
        blank=True,
        null=True
    )
    prestation_type = models.ForeignKey(PrestationType, blank=True, null=True, on_delete=models.SET_NULL)
    date = models.DateField()
    label = models.CharField(max_length=255, verbose_name='Libellé')
    unit = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        verbose_name="Unité",
        default=1
    )
    unit_price = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        verbose_name="Prix unitaire",
        default="12,5"
    )
    total_amount_htva = models.DecimalField(
        max_digits=6,
        decimal_places=2,
        blank=True,
        verbose_name="Prix (htva)",
        default=0
    )
    tva_value = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        blank=True,
        verbose_name="TVA",
        default=21
    )
    total_amount_tvac = models.DecimalField(
        max_digits=6,
        decimal_places=2,
        blank=True,
        verbose_name="Prix (tvac)",
        default=0
    )
    duration = models.PositiveIntegerField(null=True, blank=True)
    time_estimated = models.PositiveIntegerField(null=True, blank=True)
    time_tracked = models.PositiveIntegerField(null=True, blank=True)

    def __compute_total_amount(self):
        """
        Calcule le montant total de la prestation.
        """
        self.total_amount_htva = self.unit * self.unit_price
        self.total_amount_tvac = self.unit * self.unit_price * self.tva_value

    def save(self, *args, **kwargs):
        """
        Enregistre l'objet en DB après avoir calculé le montant total.
        """
        self.__compute_total_amount()
        super().save(*args, **kwargs)


class DiscountContract(models.Model):
    class Meta:
        verbose_name = 'Réduction contrat'
        verbose_name_plural = 'Réductions contrat'

    contract = models.ForeignKey(
        Contract,   
        on_delete=models.CASCADE,
        related_name="discounts",
        blank=True,
        null=True
    )
    label = models.CharField(max_length=255, verbose_name='Libellé')
    quantity = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        verbose_name="Quantité",
        default=1
    )
    unit = models.PositiveSmallIntegerField(
        choices=DISCOUNT_UNIT_CHOICE, verbose_name="Unité"
    )

    def __str__(self):
        return f"{self.label} ({self.contract}) - {self.quantity} {self.unit}"

    def amount_htva(self):
        if self.unit: 
            return - self.quantity
        return (self.contract.get_contract_sum("total_amount_htva") * self.quantity / 100)

    def amount_tvac(self):
        if self.unit:
            return self.quantity * 0.21
        return (self.contract.get_contract_sum("total_amount_tvac") * self.quantity / 100)