import uuid

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


class Invoice(models.Model):
    class Status(models.TextChoices):
        DRAFT = "draft", "Draft"
        SENT = "sent", "Sent"
        PAID = "paid", "Paid"
        OVERDUE = "overdue", "Overdue"
        CANCELLED = "cancelled", "Cancelled"
        REFUNDED = "refunded", "Refunded"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    member = models.ForeignKey(
        "members.MemberProfile",
        on_delete=models.CASCADE,
        related_name="invoices",
    )
    invoice_number = models.CharField(max_length=50, unique=True)
    issue_date = models.DateField()
    due_date = models.DateField()
    subtotal = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    tax_amount = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    discount_amount = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    total_amount = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.DRAFT,
    )
    notes = models.TextField(blank=True, default="")
    paid_at = models.DateTimeField(null=True, blank=True)
    location = models.ForeignKey(
        "core.Location",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="invoices",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Invoice"
        verbose_name_plural = "Invoices"

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


class InvoiceItem(models.Model):
    class ItemType(models.TextChoices):
        MEMBERSHIP = "membership", "Membership"
        PT_SESSION = "pt_session", "PT Session"
        CLASS_DROP_IN = "class_drop_in", "Class Drop-in"
        PRODUCT = "product", "Product"
        SERVICE = "service", "Service"
        OTHER = "other", "Other"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    invoice = models.ForeignKey(
        Invoice,
        on_delete=models.CASCADE,
        related_name="items",
    )
    description = models.CharField(max_length=255)
    quantity = models.PositiveIntegerField(default=1)
    unit_price = models.DecimalField(max_digits=10, decimal_places=2)
    total_price = models.DecimalField(max_digits=10, decimal_places=2)
    item_type = models.CharField(
        max_length=20,
        choices=ItemType.choices,
        default=ItemType.OTHER,
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["created_at"]
        verbose_name = "Invoice Item"
        verbose_name_plural = "Invoice Items"

    def __str__(self):
        return f"{self.description} (x{self.quantity})"


class Payment(models.Model):
    class PaymentMethod(models.TextChoices):
        CARD = "card", "Card"
        MPESA = "mpesa", "M-Pesa"
        CASH = "cash", "Cash"
        BANK_TRANSFER = "bank_transfer", "Bank Transfer"
        PAYSTACK = "paystack", "Paystack"
        STRIPE = "stripe", "Stripe"
        OTHER = "other", "Other"

    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        COMPLETED = "completed", "Completed"
        FAILED = "failed", "Failed"
        REFUNDED = "refunded", "Refunded"
        CANCELLED = "cancelled", "Cancelled"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    invoice = models.ForeignKey(
        Invoice,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="payments",
    )
    member = models.ForeignKey(
        "members.MemberProfile",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="payments",
    )
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    currency = models.CharField(max_length=3, default="KES")
    payment_method = models.CharField(
        max_length=20,
        choices=PaymentMethod.choices,
    )
    gateway_transaction_id = models.CharField(
        max_length=255, blank=True, default=""
    )
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.PENDING,
    )
    processed_at = models.DateTimeField(null=True, blank=True)
    gateway_response = models.JSONField(default=dict, blank=True)
    location = models.ForeignKey(
        "core.Location",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="payments",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Payment"
        verbose_name_plural = "Payments"

    def __str__(self):
        return f"Payment {self.id} - {self.amount} {self.currency}"


class Refund(models.Model):
    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        APPROVED = "approved", "Approved"
        PROCESSED = "processed", "Processed"
        REJECTED = "rejected", "Rejected"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    payment = models.ForeignKey(
        Payment,
        on_delete=models.CASCADE,
        related_name="refunds",
    )
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    reason = models.TextField()
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.PENDING,
    )
    processed_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="processed_refunds",
    )
    processed_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Refund"
        verbose_name_plural = "Refunds"

    def __str__(self):
        return f"Refund {self.id} - {self.amount}"


class RecurringBilling(models.Model):
    class BillingCycle(models.TextChoices):
        WEEKLY = "weekly", "Weekly"
        MONTHLY = "monthly", "Monthly"
        QUARTERLY = "quarterly", "Quarterly"
        ANNUALLY = "annually", "Annually"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    member = models.ForeignKey(
        "members.MemberProfile",
        on_delete=models.CASCADE,
        related_name="recurring_billings",
    )
    plan = models.ForeignKey(
        "members.MembershipPlan",
        on_delete=models.CASCADE,
        related_name="recurring_billings",
    )
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    currency = models.CharField(max_length=3, default="KES")
    billing_cycle = models.CharField(
        max_length=20,
        choices=BillingCycle.choices,
    )
    next_billing_date = models.DateField()
    payment_method = models.CharField(max_length=20)
    is_active = models.BooleanField(default=True)
    failed_attempts = models.PositiveIntegerField(default=0)
    last_attempt_at = models.DateTimeField(null=True, blank=True)
    gateway_subscription_id = models.CharField(
        max_length=255, blank=True, default=""
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Recurring Billing"
        verbose_name_plural = "Recurring Billings"

    def __str__(self):
        return f"RecurringBilling {self.id} - {self.member}"


class PaymentReminder(models.Model):
    class ReminderType(models.TextChoices):
        UPCOMING = "upcoming", "Upcoming"
        OVERDUE = "overdue", "Overdue"
        FINAL = "final", "Final"

    class Channel(models.TextChoices):
        EMAIL = "email", "Email"
        SMS = "sms", "SMS"
        PUSH = "push", "Push"

    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        SENT = "sent", "Sent"
        FAILED = "failed", "Failed"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    member = models.ForeignKey(
        "members.MemberProfile",
        on_delete=models.CASCADE,
        related_name="payment_reminders",
    )
    invoice = models.ForeignKey(
        Invoice,
        on_delete=models.CASCADE,
        related_name="reminders",
    )
    reminder_type = models.CharField(
        max_length=20,
        choices=ReminderType.choices,
    )
    sent_at = models.DateTimeField(null=True, blank=True)
    channel = models.CharField(
        max_length=10,
        choices=Channel.choices,
    )
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.PENDING,
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Payment Reminder"
        verbose_name_plural = "Payment Reminders"

    def __str__(self):
        return f"Reminder {self.reminder_type} - {self.member}"


class DiscountCode(models.Model):
    class DiscountType(models.TextChoices):
        PERCENTAGE = "percentage", "Percentage"
        FIXED = "fixed", "Fixed"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    code = models.CharField(max_length=50, unique=True)
    name = models.CharField(max_length=255)
    discount_type = models.CharField(
        max_length=20,
        choices=DiscountType.choices,
    )
    discount_value = models.DecimalField(max_digits=10, decimal_places=2)
    max_uses = models.PositiveIntegerField(null=True, blank=True)
    times_used = models.PositiveIntegerField(default=0)
    valid_from = models.DateTimeField()
    valid_until = models.DateTimeField()
    is_active = models.BooleanField(default=True)
    applicable_plans = models.ManyToManyField(
        "members.MembershipPlan",
        blank=True,
        related_name="discount_codes",
    )
    min_purchase_amount = models.DecimalField(
        max_digits=10, decimal_places=2, null=True, blank=True
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Discount Code"
        verbose_name_plural = "Discount Codes"

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


class Credit(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    member = models.ForeignKey(
        "members.MemberProfile",
        on_delete=models.CASCADE,
        related_name="credits",
    )
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    reason = models.TextField()
    granted_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        related_name="granted_credits",
    )
    used_amount = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    expires_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Credit"
        verbose_name_plural = "Credits"

    def __str__(self):
        return f"Credit {self.id} - {self.amount}"


class TaxRate(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=100)
    rate = models.DecimalField(max_digits=5, decimal_places=2)
    country = models.CharField(max_length=100)
    is_default = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["name"]
        verbose_name = "Tax Rate"
        verbose_name_plural = "Tax Rates"

    def __str__(self):
        return f"{self.name} - {self.rate}%"


class GymPackage(models.Model):
    """Gym membership packages (e.g. Gold, Silver) with multiple duration/price plans."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=150)
    description = models.TextField(blank=True, default="")
    features = models.TextField(blank=True, default="")
    plans = models.JSONField(
        default=list,
        blank=True,
        help_text='List of {duration, price} objects e.g. [{"duration":"1_month","price":5000}]',
    )
    is_active = models.BooleanField(default=True)
    gym = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="gym_packages",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Gym Package"
        verbose_name_plural = "Gym Packages"

    def __str__(self):
        return self.name


class SubscriptionPackage(models.Model):
    class BillingCycle(models.TextChoices):
        MONTHLY = "monthly", "Monthly"
        QUARTERLY = "quarterly", "Quarterly"
        YEARLY = "yearly", "Yearly"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=150)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    currency = models.CharField(max_length=3, default="KES")
    billing_cycle = models.CharField(
        max_length=20,
        choices=BillingCycle.choices,
        default=BillingCycle.MONTHLY,
    )
    member_limit = models.IntegerField(
        help_text="Max members allowed. -1 for unlimited."
    )
    staff_accounts = models.IntegerField(
        help_text="Max staff accounts. -1 for unlimited."
    )
    description = models.TextField(blank=True, default="")
    features = models.JSONField(default=list, blank=True)
    is_popular = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    sort_order = models.PositiveIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["sort_order", "price"]
        verbose_name = "Subscription Package"
        verbose_name_plural = "Subscription Packages"

    def __str__(self):
        return f"{self.name} - {self.currency} {self.price}/{self.billing_cycle}"


class Subscription(models.Model):
    class Status(models.TextChoices):
        ACTIVE = "active", "Active"
        CANCELLED = "cancelled", "Cancelled"
        EXPIRED = "expired", "Expired"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="subscriptions",
    )
    package = models.ForeignKey(
        SubscriptionPackage,
        on_delete=models.SET_NULL,
        null=True,
        related_name="subscriptions",
    )
    package_name = models.CharField(max_length=150)
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    currency = models.CharField(max_length=3, default="KES")
    billing_cycle = models.CharField(max_length=20)
    payment_reference = models.CharField(max_length=255, blank=True, default="")
    payment_method = models.CharField(max_length=50, default="paystack")
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.ACTIVE,
    )
    paid_at = models.DateTimeField()
    expires_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]
        verbose_name = "Subscription"
        verbose_name_plural = "Subscriptions"

    def __str__(self):
        return f"{self.user} - {self.package_name} ({self.status})"


class PaymentGatewayConfig(models.Model):
    class Gateway(models.TextChoices):
        STRIPE = "stripe", "Stripe"
        PAYSTACK = "paystack", "Paystack"
        MPESA = "mpesa", "M-Pesa"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    gateway = models.CharField(
        max_length=20,
        choices=Gateway.choices,
    )
    gym = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="payment_gateway_configs",
    )
    is_active = models.BooleanField(default=False)
    config = models.JSONField(default=dict)
    location = models.ForeignKey(
        "core.Location",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="payment_gateway_configs",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["gateway"]
        unique_together = [("gateway", "gym")]
        verbose_name = "Payment Gateway Config"
        verbose_name_plural = "Payment Gateway Configs"

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