from django.db import models
from django.core.validators import EmailValidator
from django.utils import timezone


class ContactUs(models.Model):
    """
    Contact Us model for handling contact form submissions.
    """
    CATEGORY_CHOICES = [
        ('همکاری', 'همکاری'),
        ('فروش', 'فروش'),
        ('پشتیبانی', 'پشتیبانی'),
        ('درخواست مشاور', 'درخواست مشاور'),
        ('سایر', 'سایر'),
    ]
    
    name = models.CharField(max_length=200, verbose_name='نام و نام خانوادگی')
    email_or_phone = models.CharField(
        max_length=200, 
        verbose_name='ایمیل / شماره تماس',
        help_text='Can be either email or phone number'
    )
    description = models.TextField(verbose_name='توضیحات')
    category = models.CharField(
        max_length=50, 
        choices=CATEGORY_CHOICES,
        verbose_name='دسته‌بندی'
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='تاریخ ایجاد')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='تاریخ بروزرسانی')
    
    class Meta:
        verbose_name = 'تماس با ما'
        verbose_name_plural = 'تماس‌های با ما'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['-created_at']),
            models.Index(fields=['category']),
        ]
    
    def __str__(self):
        return f"{self.name} - {self.category}"


class Composition(models.Model):
    """
    Composition model for storing composition information.
    """
    name = models.CharField(max_length=200, verbose_name='نام')
    description = models.TextField(verbose_name='توضیحات')
    # Legacy single-image field, kept for backward compatibility.
    # New uploads use the related CompositionImage model below.
    image = models.ImageField(
        upload_to='compositions/',
        verbose_name='تصویر',
        null=True,
        blank=True
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='تاریخ ایجاد')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='تاریخ بروزرسانی')
    
    class Meta:
        verbose_name = 'ترکیب'
        verbose_name_plural = 'ترکیبات'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['-created_at']),
        ]
    
    def __str__(self):
        return self.name
    
    @property
    def main_image(self):
        """Return the image flagged as main, falling back to the first image."""
        return self.images.filter(is_main=True).first() or self.images.first()


class CompositionImage(models.Model):
    """
    Image belonging to a Composition. A composition can have many images,
    and at most one of them can be flagged as the main image.
    """
    composition = models.ForeignKey(
        Composition,
        on_delete=models.CASCADE,
        related_name='images',
        verbose_name='ترکیب'
    )
    image = models.ImageField(
        upload_to='compositions/',
        verbose_name='تصویر'
    )
    is_main = models.BooleanField(default=False, verbose_name='تصویر اصلی')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='تاریخ ایجاد')
    
    class Meta:
        verbose_name = 'تصویر ترکیب'
        verbose_name_plural = 'تصاویر ترکیب'
        # Main image first, then newest.
        ordering = ['-is_main', '-created_at']
        constraints = [
            # At most one main image per composition.
            models.UniqueConstraint(
                fields=['composition'],
                condition=models.Q(is_main=True),
                name='unique_main_image_per_composition'
            )
        ]
    
    def __str__(self):
        return f"{self.composition.name} - {'main' if self.is_main else 'image'} #{self.pk}"
    
    def save(self, *args, **kwargs):
        # Ensure only one main image per composition: if this one is being
        # set as main, unset the flag on the others.
        if self.is_main:
            CompositionImage.objects.filter(
                composition=self.composition, is_main=True
            ).exclude(pk=self.pk).update(is_main=False)
        super().save(*args, **kwargs)


class Campaign(models.Model):
    """
    Campaign model for storing campaign information.
    """
    name = models.CharField(max_length=200, verbose_name='نام')
    description = models.TextField(verbose_name='توضیحات')
    start_time = models.DateTimeField(verbose_name='زمان شروع')
    end_time = models.DateTimeField(verbose_name='زمان پایان')
    image = models.ImageField(
        upload_to='campaigns/',
        verbose_name='تصویر',
        null=True,
        blank=True
    )
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='تاریخ ایجاد')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='تاریخ بروزرسانی')
    
    class Meta:
        verbose_name = 'کمپین'
        verbose_name_plural = 'کمپین‌ها'
        ordering = ['-start_time']
        indexes = [
            models.Index(fields=['-start_time']),
            models.Index(fields=['end_time']),
        ]
    
    def __str__(self):
        return self.name
    
    def is_active(self):
        """Check if campaign is currently active."""
        now = timezone.now()
        return self.start_time <= now <= self.end_time
    
    def is_upcoming(self):
        """Check if campaign is upcoming."""
        return timezone.now() < self.start_time
    
    def is_ended(self):
        """Check if campaign has ended."""
        return timezone.now() > self.end_time