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


class AvailabilitySlot(models.Model):
    equipment_item = models.ForeignKey(
        "equipment.EquipmentItem",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="availability_slots",
    )
    adventure_offering = models.ForeignKey(
        "adventrues.AdventureOffering",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="availability_slots",
    )
    starts_at = models.DateTimeField()
    ends_at = models.DateTimeField()
    is_available = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        constraints = [
            models.CheckConstraint(
                condition=Q(equipment_item__isnull=False, adventure_offering__isnull=True)
                | Q(equipment_item__isnull=True, adventure_offering__isnull=False),
                name="availability_slot_exactly_one_target",
            ),
            models.CheckConstraint(condition=Q(ends_at__gt=models.F("starts_at")), name="availability_slot_valid_range"),
        ]
        ordering = ("starts_at",)

    def __str__(self) -> str:
        target = self.equipment_item or self.adventure_offering
        return f"{target} | {self.starts_at} - {self.ends_at}"


class Booking(models.Model):
    class Status(models.TextChoices):
        REQUESTED = "requested", "Requested"
        APPROVED = "approved", "Approved"
        DECLINED = "declined", "Declined"
        CANCELLED = "cancelled", "Cancelled"
        CONFIRMED = "confirmed", "Confirmed"

    customer = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="bookings", limit_choices_to={"is_customer": True}
    )
    vendor = models.ForeignKey("accounts.VendorProfile", on_delete=models.CASCADE, related_name="bookings")
    equipment_item = models.ForeignKey(
        "equipment.EquipmentItem", on_delete=models.SET_NULL, null=True, blank=True, related_name="bookings"
    )
    adventure_offering = models.ForeignKey(
        "adventrues.AdventureOffering", on_delete=models.SET_NULL, null=True, blank=True, related_name="bookings"
    )
    starts_at = models.DateTimeField()
    ends_at = models.DateTimeField()
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.REQUESTED)
    total_price = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    customer_notes = models.TextField(blank=True)
    vendor_notes = models.TextField(blank=True)
    listing_click = models.ForeignKey(
        "marketing.ListingClick",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="bookings",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        constraints = [
            models.CheckConstraint(
                condition=Q(equipment_item__isnull=False, adventure_offering__isnull=True)
                | Q(equipment_item__isnull=True, adventure_offering__isnull=False),
                name="booking_exactly_one_target",
            ),
            models.CheckConstraint(condition=Q(ends_at__gt=models.F("starts_at")), name="booking_valid_range"),
        ]
        ordering = ("-created_at",)

    def __str__(self) -> str:
        return f"Booking #{self.id} ({self.status})"


class BookingEventLog(models.Model):
    booking = models.ForeignKey(Booking, on_delete=models.CASCADE, related_name="events")
    from_status = models.CharField(max_length=16, choices=Booking.Status.choices, blank=True)
    to_status = models.CharField(max_length=16, choices=Booking.Status.choices)
    note = models.TextField(blank=True)
    actor = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ("-created_at",)

    def __str__(self) -> str:
        return f"Booking {self.booking_id}: {self.from_status} -> {self.to_status}"