# Pub/Sub topic for image processing tasks
resource "google_pubsub_topic" "image_processing" {
  name = var.pubsub_topic_name
  
  labels = {
    environment = var.environment
    service     = "sereact"
    component   = "image-processing"
  }
}

# Pub/Sub subscription with retry policy
resource "google_pubsub_subscription" "image_processing" {
  name  = "${var.pubsub_topic_name}-subscription"
  topic = google_pubsub_topic.image_processing.name

  # Retry policy configuration
  retry_policy {
    minimum_backoff = "10s"
    maximum_backoff = "600s"
  }

  # Dead letter policy after 3 failed attempts
  dead_letter_policy {
    dead_letter_topic     = google_pubsub_topic.image_processing_dlq.id
    max_delivery_attempts = 3
  }

  # Message retention
  message_retention_duration = "604800s" # 7 days
  retain_acked_messages      = false

  # Acknowledgment deadline
  ack_deadline_seconds = 600 # 10 minutes

  labels = {
    environment = var.environment
    service     = "sereact"
    component   = "image-processing"
  }
}

# Dead letter queue for failed messages
resource "google_pubsub_topic" "image_processing_dlq" {
  name = "${var.pubsub_topic_name}-dlq"
  
  labels = {
    environment = var.environment
    service     = "sereact"
    component   = "image-processing-dlq"
  }
}

# Dead letter subscription for monitoring failed messages
resource "google_pubsub_subscription" "image_processing_dlq" {
  name  = "${var.pubsub_topic_name}-dlq-subscription"
  topic = google_pubsub_topic.image_processing_dlq.name

  # Long retention for failed messages
  message_retention_duration = "2592000s" # 30 days
  retain_acked_messages      = true

  labels = {
    environment = var.environment
    service     = "sereact"
    component   = "image-processing-dlq"
  }
}

# IAM binding for Cloud Function to publish to topic
resource "google_pubsub_topic_iam_binding" "image_processing_publisher" {
  topic = google_pubsub_topic.image_processing.name
  role  = "roles/pubsub.publisher"

  members = [
    "serviceAccount:${var.cloud_run_service_account}",
  ]
}

# IAM binding for Cloud Function to subscribe
resource "google_pubsub_subscription_iam_binding" "image_processing_subscriber" {
  subscription = google_pubsub_subscription.image_processing.name
  role         = "roles/pubsub.subscriber"

  members = [
    "serviceAccount:${var.cloud_function_service_account}",
  ]
}

# Output the topic and subscription names
output "pubsub_topic_name" {
  description = "Name of the Pub/Sub topic for image processing"
  value       = google_pubsub_topic.image_processing.name
}

output "pubsub_subscription_name" {
  description = "Name of the Pub/Sub subscription for image processing"
  value       = google_pubsub_subscription.image_processing.name
}

output "pubsub_dlq_topic_name" {
  description = "Name of the dead letter queue topic"
  value       = google_pubsub_topic.image_processing_dlq.name
}