import uuid

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


class ChannelEndpoint(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    name = models.CharField(max_length=120, unique=True)
    adapter_type = models.CharField(max_length=40, default="generic_webhook")
    outbound_url = models.URLField(max_length=500, blank=True)
    webhook_secret_encrypted = models.TextField(blank=True)
    outbound_token_encrypted = models.TextField(blank=True)
    enabled = models.BooleanField(default=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="created_channel_endpoints",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["name"]


class ChannelConversation(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    endpoint = models.ForeignKey(
        ChannelEndpoint,
        on_delete=models.PROTECT,
        related_name="conversations",
    )
    external_conversation_id = models.CharField(max_length=200)
    title = models.CharField(max_length=200, blank=True)
    participants = models.JSONField(default=list, blank=True)
    ticket = models.ForeignKey(
        "tickets.Ticket",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="channel_conversations",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-updated_at"]
        constraints = [
            models.UniqueConstraint(
                fields=["endpoint", "external_conversation_id"],
                name="unique_channel_external_conversation",
            )
        ]


class ChannelMessage(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    endpoint = models.ForeignKey(
        ChannelEndpoint,
        on_delete=models.PROTECT,
        related_name="messages",
    )
    conversation = models.ForeignKey(
        ChannelConversation,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="messages",
    )
    ticket = models.ForeignKey(
        "tickets.Ticket",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="channel_messages",
    )
    customer_reply_task = models.ForeignKey(
        "tickets.CustomerReplyTask",
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="channel_messages",
    )
    reply_revision = models.PositiveIntegerField(null=True, blank=True)
    direction = models.CharField(max_length=16)
    external_message_id = models.CharField(max_length=200, blank=True)
    idempotency_key = models.CharField(max_length=200, blank=True)
    sender = models.CharField(max_length=160, blank=True)
    message_type = models.CharField(max_length=24, default="text")
    text = models.TextField(blank=True)
    payload = models.JSONField(default=dict, blank=True)
    status = models.CharField(max_length=24)
    error_message = models.TextField(blank=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="created_channel_messages",
    )
    occurred_at = models.DateTimeField(null=True, blank=True)
    sent_at = models.DateTimeField(null=True, blank=True)
    delivered_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"]
        constraints = [
            models.UniqueConstraint(
                fields=["endpoint", "direction", "external_message_id"],
                condition=Q(external_message_id__gt=""),
                name="unique_channel_external_message",
            ),
            models.UniqueConstraint(
                fields=["endpoint", "direction", "idempotency_key"],
                condition=Q(idempotency_key__gt=""),
                name="unique_channel_message_idempotency",
            ),
            models.UniqueConstraint(
                fields=["customer_reply_task", "reply_revision"],
                condition=Q(
                    direction="outbound",
                    customer_reply_task__isnull=False,
                ),
                name="unique_channel_reply_revision",
            ),
        ]
        indexes = [
            models.Index(fields=["endpoint", "direction", "created_at"]),
            models.Index(fields=["status", "created_at"]),
        ]


class ChannelReceipt(models.Model):
    message = models.ForeignKey(
        ChannelMessage,
        on_delete=models.CASCADE,
        related_name="receipts",
    )
    receipt_type = models.CharField(max_length=24)
    external_receipt_id = models.CharField(max_length=200)
    payload = models.JSONField(default=dict, blank=True)
    received_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["received_at"]
        constraints = [
            models.UniqueConstraint(
                fields=["message", "receipt_type", "external_receipt_id"],
                name="unique_channel_message_receipt",
            )
        ]